No problem Alessandro,
I had a look back in this thread to see if Duncan had posted something simmilar to me, I found it quite amusing at the time.
I will alter my post otherwise it will be confusing to anyone reading in the future.
Don't hold your breath for test resalts, I have probably had the cells for close to 6 months.
Cheers,
Stephen.
Sorry, Stephen, I messed up the copy/paste process.
I've fixed it, sorry again. When you've finished the tests, as I said, I'd love to hear the results and see some images. There's always more to learn.
Sorry, Stephen, I messed up the copy/paste process.
I've fixed it, sorry again. When you've finished the tests, as I said, I'd love to hear the results and see some images. There's always more to learn.
Hi Alessandro,
When I get around to making a couple of battrie packs I will wire in ballance leads in the same manor as the Hobby King packs I have, then it will be easy to read individual cell voltages and connect them to my 4 button charger that has a ballance port.
The battries you are looking at, as you have stated have the electronic wizardy to balance the cells.
Cheers,
Stephen.
When I get around to making a couple of battrie packs I will wire in ballance leads in the same manor as the Hobby King packs I have, then it will be easy to read individual cell voltages and connect them to my 4 button charger that has a ballance port.
The battries you are looking at, as you have stated have the electronic wizardy to balance the cells.
Hi Stephen
Thank you so much for sharing your experience; it's very helpful.
You wrote:
"I recently bought some single LiFePO4 cells to make up my own pack. I plan on testing these cells to determine if they have similar capacity to each other and if it reflects the claimed capacity; this hasn't happened yet."
I admire these attempts and tests, and I'm very interested and curious to see the results. With multiple LiFePO4 cells in series, manufacturers include a control board.
Thank you so much for sharing your experience; it's very helpful.
You wrote:
"I recently bought some single LiFePO4 cells to make up my own pack. I plan on testing these cells to determine if they have similar capacity to each other and if it reflects the claimed capacity; this hasn't happened yet."
I admire these attempts and tests, and I'm very interested and curious to see the results. With multiple LiFePO4 cells in series, manufacturers include a control board.
Hi Alessandro,
For my 2 cents worth, I have been using LiFePO4 batteries in my boats for a long time, lets say more than 10 years.
I have no experiance with the battries you are talking about.
My battries were bought from Hobby King quite a long time ago, Hobby King didn't have a big range of LiFePO4 battries.
I agree this chemistry is much safer than LiPo's although if abused they would present risks in my opinon.
Personaly I have never had any problems with either LiFePO4 or LiPo battries.
The recomended minium cell voltage is 2.5 volts lower than this voltage will cause perminant damage.
I have never discharged my battries lower than 2.8 volts, there are ways of knowing what the voltage is for your battries, one is what I do and that is using telematry on my Taranas 9X programable radio with telemerty, this is now an old radio this gives me the actual voltage at any point in time while operating, I also have a voltage alarm set on the transmitter to warn me the voltage is getting low. Another way of knowing if the voltage is low is a "chirper" that is pluged into the balance lead and chirps when the set voltage is reached, the only down side to this is you need to be within hearing distance.
As for charging I use a 4 button charger, I have only ever charged my battries at 1C.
I have recently bought some single LiFePO4 cells to make up my own pack, I do plan on testing these cells to determine if they have simmilar capacity to each other and if it reflects the clamed capacity, this hasn't happened yet.
Cheers,
stephen.
For my 2 cents worth, I have been using LiFePO4 batteries in my boats for a long time, lets say more than 10 years.
I have no experiance with the battries you are talking about.
My battries were bought from Hobby King quite a long time ago, Hobby King didn't have a big range of LiFePO4 battries.
I agree this chemistry is much safer than LiPo's although if abused they would present risks in my opinon.
Personaly I have never had any problems with either LiFePO4 or LiPo battries.
The recomended minium cell voltage is 2.5 volts lower than this voltage will cause perminant damage.
I have never discharged my battries lower than 2.8 volts, there are ways of knowing what the voltage is for your battries, one is what I do and that is using telematry on my Taranas 9X programable radio with telemerty, this is now an old radio this gives me the actual voltage at any point in time while operating, I also have a voltage alarm set on the transmitter to warn me the voltage is getting low. Another way of knowing if the voltage is low is a "chirper" that is pluged into the balance lead and chirps when the set voltage is reached, the only down side to this is you need to be within hearing distance.
As for charging I use a 4 button charger, I have only ever charged my battries at 1C.
I have recently bought some single LiFePO4 cells to make up my own pack, I do plan on testing these cells to determine if they have simmilar capacity to each other and if it reflects the clamed capacity, this hasn't happened yet.
I have a fast electric with two LiPos in parallel and likewise separate them for charging. I think that is the only way to safely charge them and use the balance function of the charger. I may be mistaken but I think I read that it is unwise to connect LiPos in series or maybe that is for charging?
Most of my batteries are LiPos which I've used since getting into the hobby around 9 years ago but ideally would like to replace them with LifePO4 but unfortunately at the moment are only available in limited sizes/capacities which from my limited research so far aren't really suitable for my Fairey sports cruisers.
I have a fast electric with two LiPos in parallel and likewise separate them for charging. I think that is the only way to safely charge them and use the balance function of the charger. I may be mistaken but I think I read that it is unwise to connect LiPos in series or maybe that is for charging?
Most of my batteries are LiPos which I've used since getting into the hobby around 9 years ago but ideally would like to replace them with LifePO4 but unfortunately at the moment are only available in limited sizes/capacities which from my limited research so far aren't really suitable for my Fairey sports cruisers.
Hi Yabbie, it's exactly as you said.
I've already written this in other posts, but you did a good job of doing so, as it's not something everyone knows.
You've explained the difference between the ideal and the real generator well.
It's easy to verify experimentally: If we measure a battery in an open circuit (without a load), it will give us a certain value in volts; if we immediately afterwards measure the same battery under load (in a closed circuit), it will give a lower value in volts than the first.
For example, my 12-volt, 7-ah AGM lead-acid battery, measured at the terminals in an open circuit, gave 12.60 volts. Immediately afterwards, under load with a current of 1.82 amperes, it measured 12.09 volts (I took the data from previous test measurements).
In the first measurement, no current flows, so the internal resistance (Ri) will not create any voltage drop.
In the second measurement, the current flow will create a voltage drop across the internal resistance. The voltage drop across the internal resistance must be subtracted from the EMF (voltage at the terminals without load).
The voltage drop across the internal resistance is not a fixed value, but will be higher the higher the current drawn (according to Ohm's law V = R x I).
In short, in the first case (battery in an open circuit, without load), the EMF corresponds to the voltage at the terminals; in the second case, it does not.
Hi Yabbie, it's exactly as you said.
I've already written this in other posts, but you did a good job of doing so, as it's not something everyone knows.
You've explained the difference between the ideal and the real generator well.
It's easy to verify experimentally: If we measure a battery in an open circuit (without a load), it will give us a certain value in volts; if we immediately afterwards measure the same battery under load (in a closed circuit), it will give a lower value in volts than the first.
For example, my 12-volt, 7-ah AGM lead-acid battery, measured at the terminals in an open circuit, gave 12.60 volts. Immediately afterwards, under load with a current of 1.82 amperes, it measured 12.09 volts (I took the data from previous test measurements).
In the first measurement, no current flows, so the internal resistance (Ri) will not create any voltage drop.
In the second measurement, the current flow will create a voltage drop across the internal resistance. The voltage drop across the internal resistance must be subtracted from the EMF (voltage at the terminals without load).
The voltage drop across the internal resistance is not a fixed value, but will be higher the higher the current drawn (according to Ohm's law V = R x I).
In short, in the first case (battery in an open circuit, without load), the EMF corresponds to the voltage at the terminals; in the second case, it does not.
I think the reduction in capacity of a battery with increasing load can be explained if we consider the battery to consist of an 'ideal' voltage source in series with an internal resistance.
Lead-acid batteries have a high internal resistance. Therefore, as the discharge current is increased, there is a greater voltage drop across the internal resistance. More of the battery's energy is being dissipated as heat inside the battery and less is available for the load. Hence the available ampere-hour capacity reduces.
Other battery types have a much lower internal resistance, so the effect is much less to the point where the battery, within large discharge limits, can be considered to have a known fixed capacity.
I think the reduction in capacity of a battery with increasing load can be explained if we consider the battery to consist of an 'ideal' voltage source in series with an internal resistance.
Lead-acid batteries have a high internal resistance. Therefore, as the discharge current is increased, there is a greater voltage drop across the internal resistance. More of the battery's energy is being dissipated as heat inside the battery and less is available for the load. Hence the available ampere-hour capacity reduces.
Other battery types have a much lower internal resistance, so the effect is much less to the point where the battery, within large discharge limits, can be considered to have a known fixed capacity.
Allesandro,
I am not the person to ask your question of. I do not know. I have head that connecting LiPo's can be tricky, be it in series or parallel. I would suggest doing some web research on that. I know that my friends at the flying field often parrallel LiPo packs, but I believe that separate them for charging.
I would look to manufacturer's web sites for the answer.
Sorry.
Allesandro,
I am not the person to ask your question of. I do not know. I have head that connecting LiPo's can be tricky, be it in series or parallel. I would suggest doing some web research on that. I know that my friends at the flying field often parrallel LiPo packs, but I believe that separate them for charging.
I would look to manufacturer's web sites for the answer.
Sorry.
Thanks so much, ToraDog, that was exactly what I was looking for, so I can ask you another question.
I'm considering the 6-Volt 6-Ah battery, which has the same casing as the AGM lead-acid ones and the faston connectors, but actually contains two cylindrical LiFePO4 cells.
Do you think I can connect two batteries of this type in parallel by connecting the fastons (as if I were connecting two lead-acid batteries in parallel) or are there any contraindications?
Logically, I would use batteries of the same brand, with as equal charges as possible, and with connections between the fastons of the same cross-section and length.
Possibly a diode in the parallel connection.
Thanks so much, ToraDog, that was exactly what I was looking for, so I can ask you another question.
I'm considering the 6-Volt 6-Ah battery, which has the same casing as the AGM lead-acid ones and the faston connectors, but actually contains two cylindrical LiFePO4 cells.
Do you think I can connect two batteries of this type in parallel by connecting the fastons (as if I were connecting two lead-acid batteries in parallel) or are there any contraindications?
Logically, I would use batteries of the same brand, with as equal charges as possible, and with connections between the fastons of the same cross-section and length.
Possibly a diode in the parallel connection.
Allesandro,
The batteries I mentioned have the following dimensions, all mm, 149.225 long, 90.4875 high, 65.0875 wide 1089 gm for weight. As I mentioned, they have the same case as a SLA 12v 7 amp battery.
cheers
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Allesandro,
The batteries I mentioned have the following dimensions, all mm, 149.225 long, 90.4875 high, 65.0875 wide 1089 gm for weight. As I mentioned, they have the same case as a SLA 12v 7 amp battery.
cheers
Sorry Roy, I can't follow your reasoning, but it's definitely a language limitation of mine.
And, most likely, the discussion I made about discharge curves in the two previous messages was not understood (certainly because I am the one who doesn't explain myself well).
Sorry Roy, I can't follow your reasoning, but it's definitely a language limitation of mine.
And, most likely, the discussion I made about discharge curves in the two previous messages was not understood (certainly because I am the one who doesn't explain myself well).
I was sceptical at first but now only us Pb gel batteries when I need the weight for ballast. I use an Overlander LiPo charger which has given me successful battery life of 3 plus years. To prevent fires etc I only use batteries from a reputable firm like Overlander not cheapo Chinese ones.
I was sceptical at first but now only us Pb gel batteries when I need the weight for ballast. I use an Overlander LiPo charger which has given me successful battery life of 3 plus years. To prevent fires etc I only use batteries from a reputable firm like Overlander not cheapo Chinese ones.
Hi Alessandro nearly all our modellers on the web site have used SLA batteries and you put down the experience I have had to an effect I have never heard of wheras it is a straight forward piece of arithmetic.
I have not seen the lead acid batteries you refer to at the size suitable for model use.
I compared NiMh as they were known batteries to me and the arithmetic was about Amp hour capacity calculations rather than battery types.
Roy
Hi Alessandro nearly all our modellers on the web site have used SLA batteries and you put down the experience I have had to an effect I have never heard of wheras it is a straight forward piece of arithmetic.
I have not seen the lead acid batteries you refer to at the size suitable for model use.
I compared NiMh as they were known batteries to me and the arithmetic was about Amp hour capacity calculations rather than battery types.
Sorry, Roy, but I've never mentioned NiMH batteries in this thread.
I actually talked about LiFePO4 and compared LiFePO4 with AGM lead-acid and LiPo batteries.
Apparently, theoretically, LiFePO4 batteries are considered among the safest in the world, despite belonging to the lithium battery family.
This was precisely one of the topics I wanted to explore further and a question that needed answers based on firsthand experience.
Sorry, Roy, but I've never mentioned NiMH batteries in this thread.
I actually talked about LiFePO4 and compared LiFePO4 with AGM lead-acid and LiPo batteries.
Apparently, theoretically, LiFePO4 batteries are considered among the safest in the world, despite belonging to the lithium battery family.
This was precisely one of the topics I wanted to explore further and a question that needed answers based on firsthand experience.
Hi Allesandro I do not agree.
Just to compare SLA and NiMh at say 5Ah each stated capacity.
SLA to give the full capacity has to discharge for 20 hours which is 250 mamps multiplying 20 x 0.25 = 5 (Ahrs).
NiMh which will deliver full capacity over 5 hours and gives a discharge rate of 1 amp for 5 hours. As I said witness the price difference.
I have run both of the above and stopped using SLA batteries years ago.
To answer the other question I do not use for my models any Lithium batteries purely from a safety angle.
The last part of your post supports the arithmetic I have put forward.
Regards
Roy
Hi Roy, I think the difference you noticed could be explained by the Peukert effect. Lead-acid batteries (including AGMs) are very susceptible to this phenomenon: the faster you discharge them, the less total energy they can deliver. This is why manufacturers publish tables for up to 20, 100, or even 120 hours (C20, C100) to show the maximum capacity achievable with very slow discharges. Lithium is almost immune to the Peukert effect. Whether you discharge the battery in 1 hour or 10, the capacity restored is practically the same (close to 100%). There's no point in "extending" the times in the tables because the data wouldn't change significantly. Lead-acid batteries have a high internal resistance; discharging them quickly (e.g., 1-2 hours) causes the voltage to drop very quickly. LiFePO4 batteries maintain a flat and constant voltage even under heavy loads, making very long-term analyses unnecessary. AGMs are often used for very long and weak backup loads. LiFePO4 batteries are designed for deep cycling and high performance, so tests focus on their ability to handle high currents in short periods of time (1C, 0.5C, or 0.2C, corresponding to 1, 2, or 5 hours).
In short: AGM ratings serve to "save face" for the battery by demonstrating capacity that would otherwise be unavailable in rapid tests; lithium ratings serve to confirm that power is readily available.
This is a plausible hypothesis.
Have you ever used or tested LiFePO4 batteries?
Hi Roy, I think the difference you noticed could be explained by the Peukert effect. Lead-acid batteries (including AGMs) are very susceptible to this phenomenon: the faster you discharge them, the less total energy they can deliver. This is why manufacturers publish tables for up to 20, 100, or even 120 hours (C20, C100) to show the maximum capacity achievable with very slow discharges. Lithium is almost immune to the Peukert effect. Whether you discharge the battery in 1 hour or 10, the capacity restored is practically the same (close to 100%). There's no point in "extending" the times in the tables because the data wouldn't change significantly. Lead-acid batteries have a high internal resistance; discharging them quickly (e.g., 1-2 hours) causes the voltage to drop very quickly. LiFePO4 batteries maintain a flat and constant voltage even under heavy loads, making very long-term analyses unnecessary. AGMs are often used for very long and weak backup loads. LiFePO4 batteries are designed for deep cycling and high performance, so tests focus on their ability to handle high currents in short periods of time (1C, 0.5C, or 0.2C, corresponding to 1, 2, or 5 hours).
In short: AGM ratings serve to "save face" for the battery by demonstrating capacity that would otherwise be unavailable in rapid tests; lithium ratings serve to confirm that power is readily available.
This is a plausible hypothesis.
Great question, Yabbie1, you hit the nail on the head.
Indeed, at least in theory, AGM lead-acid batteries have a higher starting current than LiFePO4, making them suitable for starting electric motors.
Great question, Yabbie1, you hit the nail on the head.
Indeed, at least in theory, AGM lead-acid batteries have a higher starting current than LiFePO4, making them suitable for starting electric motors.
Good discussion. I agree with AlessandroSPQR that Lithium Ion or Polymer batteries are overkill for most model boats, I see so many scale tugs and submarines powered by them and they just need more ballast as a result. I am disappointed by the poor characteristics of lead-acid batteries though and have been very happy to use NiMHs whilst keeping a watchful eye on the progress of LiFePO4 batteries.
The DREAMDASH types illustrated in Alessandro's posting appear to be suitable candidates for scale boats. Much safer than standard lithium types, much better electrical characteristics than SLA, and cheaper in the long run because you won't be replacing them as often. But one thing bothers me - the maximum continuous discharge current is only 1C - 6 amps in the case of the 6v SLA equivalent. This would rule them out for some applications.
I wonder it any modellers have had experience with them, and whether or not they live up to their claimed specifications.
https://www.aliexpress.com/item/1005008380732622.html?spm=a2g0o.productlist.main.27.65cc4680JqFSPc&algo_pvid=e8a70812-379b-4f11-8300-9c612054b40c&pdp_ext_f=%7B%22order%22%3A%22304%22%2C%22spu_best_type%22%3A%22price%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005008380732622%7C_p_origin_prod%3A
Good discussion. I agree with AlessandroSPQR that Lithium Ion or Polymer batteries are overkill for most model boats, I see so many scale tugs and submarines powered by them and they just need more ballast as a result. I am disappointed by the poor characteristics of lead-acid batteries though and have been very happy to use NiMHs whilst keeping a watchful eye on the progress of LiFePO4 batteries.
The DREAMDASH types illustrated in Alessandro's posting appear to be suitable candidates for scale boats. Much safer than standard lithium types, much better electrical characteristics than SLA, and cheaper in the long run because you won't be replacing them as often. But one thing bothers me - the maximum continuous discharge current is only 1C - 6 amps in the case of the 6v SLA equivalent. This would rule them out for some applications.
I wonder it any modellers have had experience with them, and whether or not they live up to their claimed specifications.
Thank you so much, ToraDog, for your reply.
Sorry for the question (just to be sure): are the batteries you mentioned [made by CTC Battery, Inc. They are 12.8v, 7.5A/H 96Wh] LiFePO4? The nominal voltage 12.8 = 3.2 x 4 makes me think so.
If so, do you have a photo? I'm asking because your report is very important and useful to me, but I'd like to ask you some more questions.
Thank you so much, ToraDog, for your reply.
Sorry for the question (just to be sure): are the batteries you mentioned [made by CTC Battery, Inc. They are 12.8v, 7.5A/H 96Wh] LiFePO4? The nominal voltage 12.8 = 3.2 x 4 makes me think so.
If so, do you have a photo? I'm asking because your report is very important and useful to me, but I'd like to ask you some more questions.
Hhager2, your account of lithium batteries is very important. I've heard many cases of lithium batteries exploding or catching fire.
Today, this is less common and they've improved a lot.
In any case, as I've already said, I'm still wary of Li-Po batteries and only use them when I need lightness and charge density.
In practice, for the naval models I've used so far, I have no need for them. I'm not considering Li-Ion batteries.
But since the focus is on LiFePO4, and my mention of LiPo was only to highlight some differences between the two technologies, I wanted to ask you if the batteries you mentioned, A123 (before they were acquired by Sony), are actually LiFePO4 or belong to another technology in the lithium battery family.
Sorry for the question, but I haven't been able to fully understand this fundamental point.
Hhager2, your account of lithium batteries is very important. I've heard many cases of lithium batteries exploding or catching fire.
Today, this is less common and they've improved a lot.
In any case, as I've already said, I'm still wary of Li-Po batteries and only use them when I need lightness and charge density.
In practice, for the naval models I've used so far, I have no need for them. I'm not considering Li-Ion batteries.
But since the focus is on LiFePO4, and my mention of LiPo was only to highlight some differences between the two technologies, I wanted to ask you if the batteries you mentioned, A123 (before they were acquired by Sony), are actually LiFePO4 or belong to another technology in the lithium battery family.
Sorry for the question, but I haven't been able to fully understand this fundamental point.
Hi all Have you considered how the amp/hour capacity is measured?
Lead acid batteries are measured against a discharge time of 20 hours.
However the lead acid cylindrical cell batteries are measured against a 5 hour discharge rate.
NiMh batteries and NiCad batteries are measured against a 5 hour discharge rate.
From what I have read LiPo and Life Po4 batteries are measured against a 1 hour discharge rate, happy to be corrected on this.
So we are not comparing like with like as the capacity discharge rates are different. If you discharge a SLA battery in 1 hour it will get hot and give a much lower value of capacity, (volts x amps x time).
That is why there is a difference in price between SLA and NiMh batteries of the same 'indicated' capacity.
There are now several types of lead acid battery AGM etc. This should also be noted by car owners. Modern cars with a stop/start option need different (AGM etc.) and dearer batteries to the older and cheaper ones.
A more inclusive measurement would be the Watt hour capacity of a battery and this can become more clear if you use a capacity measuring electronic unit with i/p and o/p connections.
They can be connected to measure charging or discharging values.
Also if there is heat involved in the battery or the discharge component (motor) then this is part of the power available.
Interesting discussion point.
Roy
Hi all Have you considered how the amp/hour capacity is measured?
Lead acid batteries are measured against a discharge time of 20 hours.
However the lead acid cylindrical cell batteries are measured against a 5 hour discharge rate.
NiMh batteries and NiCad batteries are measured against a 5 hour discharge rate.
From what I have read LiPo and Life Po4 batteries are measured against a 1 hour discharge rate, happy to be corrected on this.
So we are not comparing like with like as the capacity discharge rates are different. If you discharge a SLA battery in 1 hour it will get hot and give a much lower value of capacity, (volts x amps x time).
That is why there is a difference in price between SLA and NiMh batteries of the same 'indicated' capacity.
There are now several types of lead acid battery AGM etc. This should also be noted by car owners. Modern cars with a stop/start option need different (AGM etc.) and dearer batteries to the older and cheaper ones.
A more inclusive measurement would be the Watt hour capacity of a battery and this can become more clear if you use a capacity measuring electronic unit with i/p and o/p connections.
They can be connected to measure charging or discharging values.
Also if there is heat involved in the battery or the discharge component (motor) then this is part of the power available.
Alessandro,
I am using batteries made by CTC Battery,Inc. They are 12.8v, 7.5A/H 96Wh batteries. The charger I am using is a ExpertPower, 12V, 1amp charger. It comes with a stereo style jack as well as an alligator clip adapter. The batteries are plastic cased and a direct fit replacement for 12 V 7 A/h SLA batteries. It has flat spade connectors for battery connections.
I have had these for around 6 years and have had good results from them. They are used to power AstroFlite 25 and 40, Super Ferrite brushed marine motors that have a 35 amp max draw. I run three motors in my ELCO pt boat and the batteries have done well. I can usually run for around 10-15 minutes as long as I stay away from full throttle.
Charging, I treat these as any other lithium battery, with lot's of respect.
Cheers😀😀
Alessandro,
I am using batteries made by CTC Battery,Inc. They are 12.8v, 7.5A/H 96Wh batteries. The charger I am using is a ExpertPower, 12V, 1amp charger. It comes with a stereo style jack as well as an alligator clip adapter. The batteries are plastic cased and a direct fit replacement for 12 V 7 A/h SLA batteries. It has flat spade connectors for battery connections.
I have had these for around 6 years and have had good results from them. They are used to power AstroFlite 25 and 40, Super Ferrite brushed marine motors that have a 35 amp max draw. I run three motors in my ELCO pt boat and the batteries have done well. I can usually run for around 10-15 minutes as long as I stay away from full throttle.
Charging, I treat these as any other lithium battery, with lot's of respect.
Cheers😀😀
Also there comes can safely be disposed in your garbage or buried in ground. Lipos are a hand grande n need to be handled in same way carefully. Btw the insurance fixed the house better than before fire but we did loose collectibles, ships n planes.
Also there comes can safely be disposed in your garbage or buried in ground. Lipos are a hand grande n need to be handled in same way carefully. Btw the insurance fixed the house better than before fire but we did loose collectibles, ships n planes.
Before Sony bought them A123 was an early manufacturer. They had the r&d lab in next town. I got friendly with the engineers. I tested the early ones for RC aircraft. Then later in life I got to work with BYD of China. They made the elect car before Tesla and electric busses. They were doing the busses in CA where they had a large plant. I have been using those type batteries in hobby use. A123 provided many electric screwdriver companies with batteries. We got hold of the packs n separated the cells. They are safer than lithium poly in that they don’t have volatile liquids. I still have some n they still charge just fine. One word of warning: I did use lithium poly in very large packs for a large scale plane. I had 2 packs ( this was before vendors forced to have safety circuits). I charged on n then thought I was charging another. It was same pack. With no over voltage circuitry in chargers then it exploded. House went on fire. $500k in damages. I was visited by federal n state fire marshal n investigators. New rules on chargers came out soon after. So I only use smaller Lipos. Moral of story watch what your doing when charging n do it outside of house basement!
Before Sony bought them A123 was an early manufacturer. They had the r&d lab in next town. I got friendly with the engineers. I tested the early ones for RC aircraft. Then later in life I got to work with BYD of China. They made the elect car before Tesla and electric busses. They were doing the busses in CA where they had a large plant. I have been using those type batteries in hobby use. A123 provided many electric screwdriver companies with batteries. We got hold of the packs n separated the cells. They are safer than lithium poly in that they don’t have volatile liquids. I still have some n they still charge just fine. One word of warning: I did use lithium poly in very large packs for a large scale plane. I had 2 packs ( this was before vendors forced to have safety circuits). I charged on n then thought I was charging another. It was same pack. With no over voltage circuitry in chargers then it exploded. House went on fire. $500k in damages. I was visited by federal n state fire marshal n investigators. New rules on chargers came out soon after. So I only use smaller Lipos. Moral of story watch what your doing when charging n do it outside of house basement!
LiFePO4 BATTERIES (Lithium-Iron-Phosphate batteries)
Good morning everyone.
Has anyone ever used or tested this type of battery?
I wanted to know your opinion on this type of technology.
However, I was interested in hearing an opinion based on your personal experience, not on theoretical knowledge.
I also wanted to know what type of charger you use and if you've encountered any problems.
I'm asking for a personal opinion based on direct experience because, theoretically, I've already done a lot of research on this type of battery, which I'm very interested in.
While looking for an alternative to the AGM lead-acid batteries I use, I came across various options and have also started investigating LiFePO4.
In particular, I discovered that a product is being marketed (by several brands) that has identical dimensions to the 6-volt AGM lead-acid batteries (4 or 4.5 Ah) I'm using.
The AGM battery I use has the following dimensions (70 x 47 x 100 mm) and has faston connectors, as you can see in the attached images.
The 6-volt, 6 Ah LiFePO4 battery has the same dimensions and the same connectors, as you can see in the attached images.
I discovered that this shape for LiFePO4 batteries is merely an adaptation, as they are designed (unlike AGM batteries) as cylindrical cells.
In this specific case, the parallelepiped-shaped case contains two cylindrical LiFEPO4 batteries and a BMS (Battery Management System) electronic board, which is required to manage the cells (as you can see in the images).
The advantage is very clear because the housing is identical and I don't have to make any adaptations in the event of a replacement.
Weight savings; Approximately 370 grams per battery and a full 740 grams for two batteries (720-350/380 grams); this isn't essential for me in this specific case, but it is in general.
Gain on two batteries from 3000 Ah to 4000 Ah (12 Ah – 8 or 9 Ah).
In reality, beyond a simple mathematical calculation to quantify the advantage of the greater electrical charge of LiFePO4 compared to AGM lead batteries, a much more important aspect must be considered.
AGM lead-acid batteries have a linear discharge, meaning the voltage drops progressively from the very first moments. This undoubtedly negative characteristic, in addition to having learned from the information provided by various manufacturers (tables showing voltages after fixed time intervals) and available online, I have verified it experimentally.
Plotting the voltage on the y-axis and the time on the x-axis in a graph, you can see that the collected data draws a decreasing curve, whose slope increases downwards the higher the current draw.
Some graphs provided by the manufacturers do not show time on the x-axis, but rather the charge. In my practical experiment, to gain further confirmation, I measured the voltage at regular intervals as the AGM battery discharged.
In practice, with AGM batteries, the voltage drops after just a short time of use. So, considering that AGM batteries should never drop below 50%, we can easily understand that 4.5 Ah is actually much less, meaning it's not fully usable.
LiFePO4 batteries, on the other hand, after a brief initial phase of rapid drop, maintain a constant voltage between 90% and 10% of their state of charge; then, when the battery charge drops between 10% and 5%, the voltage plummets to very low values.
Since during the flat phase (which lasts a very long time), the voltage drops very little (0.1–0.2 volts), it's clear that we can utilize almost all of the 6 Ah declared by the manufacturer.
This is a significant difference between AGM lead-acid batteries and LiFePO4 batteries, and it's entirely in favor of LiFePO4.
Essentially, when it comes to Depth of Discharge (DoD), a LiFePO4 battery can be used up to 90-100% of its capacity without harm, while AGM batteries, as mentioned, should never drop below 50%. Not to mention that many devices (such as receivers or servos, for example) simply don't work at all under certain voltages.
Another advantage of LiFePO4 batteries is their cycle life: a LiFePO4 lasts between 3,000 and 5,000 cycles, compared to 300-600 for an AGM.
They also seem to recharge much faster and don't suffer from sulfation if left partially discharged.
The problem is that LiFePO4 batteries cost much more, so I'll have to figure out if they're worth it.
I prefer not to use LiPos for marine applications, but comparing LiPos with LiFePO4s, the latter are heavier and bulkier for the same charge capacity and have a lower energy density than Lipos, but they have a longer lifespan and are considered among the safest batteries in the world. Their chemistry is intrinsically stable and not subject to spontaneous combustion or explosion, even if punctured or overloaded. LiPos, on the other hand, are much more volatile. If physically damaged, overloaded, or overheated, they can swell and catch fire violently.
The voltage per cell is different for each technology (LiPo 3.7 volts; LiFePO4 3.2 volts; and Lead-acid AGM 2 volts), but I consider this a characteristic; there are neither advantages nor disadvantages.
One of the disadvantages of using LiFePO4s is charging at low temperatures. They cannot be recharged below 0 C (under penalty of permanent damage), unless they are equipped with integrated heating systems.
This is absolutely not a problem for me.
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Has anyone ever used or tested this type of battery?
I wanted to know your opinion on this type of technology.
However, I was interested in hearing an opinion based on your personal experience, not on theoretical knowledge.
I also wanted to know what type of charger you use and if you've encountered any problems.
I'm asking for a personal opinion based on direct experience because, theoretically, I've already done a lot of research on this type of battery, which I'm very interested in.
While looking for an alternative to the AGM lead-acid batteries I use, I came across various options and have also started investigating LiFePO4.
In particular, I discovered that a product is being marketed (by several brands) that has identical dimensions to the 6-volt AGM lead-acid batteries (4 or 4.5 Ah) I'm using.
The AGM battery I use has the following dimensions (70 x 47 x 100 mm) and has faston connectors, as you can see in the attached images.
The 6-volt, 6 Ah LiFePO4 battery has the same dimensions and the same connectors, as you can see in the attached images.
I discovered that this shape for LiFePO4 batteries is merely an adaptation, as they are designed (unlike AGM batteries) as cylindrical cells.
In this specific case, the parallelepiped-shaped case contains two cylindrical LiFEPO4 batteries and a BMS (Battery Management System) electronic board, which is required to manage the cells (as you can see in the images).
The advantage is very clear because the housing is identical and I don't have to make any adaptations in the event of a replacement.
Weight savings; Approximately 370 grams per battery and a full 740 grams for two batteries (720-350/380 grams); this isn't essential for me in this specific case, but it is in general.
Gain on two batteries from 3000 Ah to 4000 Ah (12 Ah – 8 or 9 Ah).
In reality, beyond a simple mathematical calculation to quantify the advantage of the greater electrical charge of LiFePO4 compared to AGM lead batteries, a much more important aspect must be considered.
AGM lead-acid batteries have a linear discharge, meaning the voltage drops progressively from the very first moments. This undoubtedly negative characteristic, in addition to having learned from the information provided by various manufacturers (tables showing voltages after fixed time intervals) and available online, I have verified it experimentally.
Plotting the voltage on the y-axis and the time on the x-axis in a graph, you can see that the collected data draws a decreasing curve, whose slope increases downwards the higher the current draw.
Some graphs provided by the manufacturers do not show time on the x-axis, but rather the charge. In my practical experiment, to gain further confirmation, I measured the voltage at regular intervals as the AGM battery discharged.
In practice, with AGM batteries, the voltage drops after just a short time of use. So, considering that AGM batteries should never drop below 50%, we can easily understand that 4.5 Ah is actually much less, meaning it's not fully usable.
LiFePO4 batteries, on the other hand, after a brief initial phase of rapid drop, maintain a constant voltage between 90% and 10% of their state of charge; then, when the battery charge drops between 10% and 5%, the voltage plummets to very low values.
Since during the flat phase (which lasts a very long time), the voltage drops very little (0.1–0.2 volts), it's clear that we can utilize almost all of the 6 Ah declared by the manufacturer.
This is a significant difference between AGM lead-acid batteries and LiFePO4 batteries, and it's entirely in favor of LiFePO4.
Essentially, when it comes to Depth of Discharge (DoD), a LiFePO4 battery can be used up to 90-100% of its capacity without harm, while AGM batteries, as mentioned, should never drop below 50%. Not to mention that many devices (such as receivers or servos, for example) simply don't work at all under certain voltages.
Another advantage of LiFePO4 batteries is their cycle life: a LiFePO4 lasts between 3,000 and 5,000 cycles, compared to 300-600 for an AGM.
They also seem to recharge much faster and don't suffer from sulfation if left partially discharged.
The problem is that LiFePO4 batteries cost much more, so I'll have to figure out if they're worth it.
I prefer not to use LiPos for marine applications, but comparing LiPos with LiFePO4s, the latter are heavier and bulkier for the same charge capacity and have a lower energy density than Lipos, but they have a longer lifespan and are considered among the safest batteries in the world. Their chemistry is intrinsically stable and not subject to spontaneous combustion or explosion, even if punctured or overloaded. LiPos, on the other hand, are much more volatile. If physically damaged, overloaded, or overheated, they can swell and catch fire violently.
The voltage per cell is different for each technology (LiPo 3.7 volts; LiFePO4 3.2 volts; and Lead-acid AGM 2 volts), but I consider this a characteristic; there are neither advantages nor disadvantages.
One of the disadvantages of using LiFePO4s is charging at low temperatures. They cannot be recharged below 0 C (under penalty of permanent damage), unless they are equipped with integrated heating systems.
This is absolutely not a problem for me.
