My friend Adam has some experience with LiPo battery’s and uses them to store power collected from his solar panels.

They are much bigger than the ones that we use but they are built and put together in the same way.

Adam thought that the slight amount of “soft pucker” that my batteries displayed suggested something a little different to the way LiPos usually swell up when they are “blown”.

The heat shrink was removed from one of my LiPo batteries (by Adam) and revealed that there was no gas, and is why the slightly blown heat shrink felt softer than a blown LiPo that had “gassed-up” would feel like.

His suggestion was that at some stage both of these LiPo batteries could have suffered from a very temporary “short” that caused a minor “puff” that then dissipated.

This would explain why both these cells still performed well and charged well without getting hot ( or even warm to the touch).

It was interesting to hear this theory and left me to wonder how these two cells could have suffered from a temporary “short circuit”, but they were both safely disposed of in any case.

There is the possibility that these two cells could have both continued to work well for much longer without any problems.

……..but better safe than sorry ………

Bob.

This thread is interesting seeing everyone’s perceptions

This is an internet response to the question and this has always been my actions related to a bloated LiPo

Stop using a swollen LiPo battery immediately. Place it outside in a fireproof container or a bucket of sand away from your home. Never puncture, charge, or try to fix a puffed battery. Discharge it completely to zero volts, then take it to a local hazardous waste or battery recycling facility.

Safe Handling and Storage
Put on safety gear like gloves and eye protection if you must move it.
Move the battery outdoors immediately.
Place it inside a metal ammo can, a ceramic pot, or a deep bucket filled with sand or dirt.
Keep it far away from wood, paper, cars, and any other things that can burn.
Never charge, discharge, or use a puffy battery in your models or devices.

Discharging the Battery
Fully discharge the battery to 0V to make it safe from catching fire.
Connect a small low-draw item like a 12V automotive light bulb or an LED resistor to the leads and leave it outside until the light goes out completely.
Wait at least one full day after the light dies to be sure the voltage stays at zero.
Do not cut both wires at the same time with metal wire cutters, as a short circuit can cause instant sparks or fire.

Disposal
Never throw a swollen or active LiPo battery into your regular household trash or recycling bin.
Look up n
Search through local council hazardous waste disposal

I don't really know if he was just a "car boot salesman" but I got the impression that he had done this type of table top selling many times before at the model shows. I think he knew when he pointed out that the batteries were all new. He certainly wasn't a Model Shop.
I should've said something about them, but I didn't need the hassle and abuse that I might have got - sorry !! 😞😞
PS The seller's were charged- I believe, £10 per table.

@ChrisF That’s why I asked if it was just a “chancer” with a “car boot sale” type operation, or if it was a model shop.

Reporting a “chancer” to the organisers may at least cause them to check out this person more thoroughly before allowing him to trade again at a future event…

…….and possibly educate this seller to the potential dangers that he could be exposing a buyer to - a buyer who may have no knowledge about the risks and dangers that LiPo batteries can have.

In the event of a serious problem, the organisers who gave permission (and maybe even accepted a payment for allowing him to sell at their event) would have some responsibility that they would probably prefer to avoid if it were made clear to them?

A model shop would definitely have known about the potential dangers of selling swollen LiPo batteries and this would suggest a lack of care about their customers safely and they should be named and shamed……..and the organisers who gave permission for this shop to sell at their event need to be made aware of this reckless disregard for their customers safety.

Bob.

Wow, unbelievable! That guy should be reported on safety grounds. To the organisers at the very least.

@Steves-s

Hi Steve,

A trader selling swollen LiPo batteries does sound very dodgy.

Was it a model shop or just a “chancer” with a “car boot sale” type operation?

If I remember correctly, Volts was a brand name used by CML Distribution and I have a couple of their 7.2 NmH batteries that I have used and they have been OK.

Bob.

Hi, I have just come back from the Large Model Aircraft Flying Association's show, or whatever they call themselves?🤔🤔 at Elvington. There was a trader with several tables set up, selling rechargeable batteries and all sorts of modelling things . I got a couple of nimh batteries which I have just charged (name of Voltz ??).They seem ok but I'll have to try them.🙄
He said that all the batteries were brand new-but all the Lipos were really swollen and I had a therapeutic five minutes squishing them 😁😁 and telling a potential customer to stay well clear of them !!
I couldn't believe that the trader had sold lots the previous day unless they weren't swollen?
I only paid £7 for the two nimh's so if they don't hold their charge, I haven't lost much- they were in their boxes and seemed to be new 🤔😐.

New (shorter length) LiPo Collection.

My original Remora 1 and Remora 2 LiPo batteries that Bloated-up have now been safely destroyed and replaced with a new pair of a different make that also have a slightly higher capacity.

Although marked for use in my Remora, they will be used in other projects where their slightly shorter length may come in handy.

The two remaining Turnigy batteries that are marked Remora 3 and Remora 4 were bought at the same time as the two LiPos that have failed, but one has only been charged once and the other has been charged twice and they still look like new.

I will drop my usual (fairly slow) charge rate down from 2.5 amps to 2.0 with these last two Turnigy LiPo batteries in the hope that this could possibly help to prevent them swelling-up like the others, but I am not really convinced that it will make any difference.

These LiPos are fitted with XT60 sockets - my “normal” size LiPo batteries are all fitted with the larger XT90 sockets.

Bob.

@Steves-s

Hi Steve. I race 1/12 scale Mini cars (when I get a chance) and the traditional power for these is a standard brushed 540 motor and a 4 cell (4.8 volt) NiMh battery.

More recently, most drivers have switched to using a single cell LiPo battery, but I have found that using my original 4.8 volt NiMh pack is just as fast - but heavier.

A newer class of 1/12 Mini racers allow the use of brushless motors and two cell LiPo batteries. Although these have more power, I have found better traction (more weight can help) with my old brushed 540/NiMh combination and don’t have too much trouble keeping up with them, but I do use both types of battery myself.

The older NiCad batteries and the NiMh batteries do not generally have as long a life span as the LiPo batteries do ( I have a lot of failed 7.2 volt “Tamiya” type batteries to dispose of), but they cost less, are safer to use and store, and I do understand anyone that prefers to use them instead of LiPo batteries if they work as well in any particular situation.

The extra weight of a NiMh battery pack can also be an advantage if some extra ballast is needed in large displacement hull too !

Bob.

@ColRay

Hi Col,

I have not heard of “Roaring Top” batteries before, but I was away in my static when my two Turnigy LiPo’s “boated” and I saw these “replacements” advertised on Amazon. The label says that they are “powered by” Fullymax Battery Co.,Ltd - and I have never heard of them either !

When I was searching for LiPo batteries of the shame physical dimensions as those that had just failed, these came up on the search pattern.

They have a larger capacity (5200mAh) and a higher discharge rate (50C) and they were a good price too, so I took advantage of the free “next day” delivery to our site and they arrived safely the next morning.

The overall size of these LiPo batteries was about the same as the failed Turnigy ones that I have now disposed of (slightly deeper), and they fit into the LiPo holding frame that I made for the Remora so that was a good start.

I do not have a soldering iron on my van, but Adam had one with him and fitted a pair of XT60 plugs on them to replace the Deans type that they came with so I can plug them into my SeaKing 90A ESC that I use in the Remora.

With a higher capacity I should get slightly longer run times - and the higher C value may even add a little extra “punch” to the performance, so I will give them both a run this weekend to see how they go.

Bob.

zooma New type of battery? I must look into LiPo and get all the info Col

Tempting fate?

I am hoping that this does not tempt fate, but I have printed the identification labels for the two LiPos that I have bought to replace the original (failed) Remora 1 and 2 LiPo batteries..............

Bob.

Just to continue this strange LiPo story.

The other two LiPos ( number 3 and 4) that were bought at the same time (identical and same type) were run in my Remora on Sunday, they worked well, run cool and recharged OK without getting warm and they have not puffed their heat shrink covers!

I did charge them at 2amps rather than my usual 2.5amps, but I doubt that made any difference?

The other two failed LIPo's (number 1 and 2) were only ever run in this same Remora boat from when I bought them new ........

There is a possibility that I just had two duff battery packs, but I will keep a close eye on these other two batteries from the same purchase to see how it goes.....

Bob.

Solution Found.

I am away in our static caravan at the moment and I became aware that one of our fellow neighbours is a retired veteran (ex-army)who occasionally drives public service vehicles a couple of days a week.

The yard that he drives from has a recycling centre including a specialist battery area and he has kindly taken my two bloated LiPos to deposit there this week.

End of problem, and knowing that these LiPo batteries will be safely disposed of is a great relief.

Bob.

Ok, I try to keep away from Lipo batteries if I can !!🙄
I bought a 2 metre powered glider 5 or 6 years ago which came with two 11.1v Lipos fully changed. At the time I wasn't aware of the importance of the storage voltages. I never used them and when I did look at them, both had swollen up. When I checked the individual cells one of the three were showing unchangeable on both packs.
So I have also to dispose of these.🤔🤔.
I use just nimh batteries- 7.2v sets and have replaced individual cells that have gone faulty a number of times without any problems- only with replacing the shrink wrap. Nothing to worry about with these types and they also make good ballast without needing much lead☺ in the "bilge" ☺.

Hi. Regarding the Lipo batteries. It is best to slowly discharge them completely. My first attempt before I knew better was to drive a nail through a battery which was at storage voltage (3.8 ish) There was a lot of smoke and flames for a while but it worked. Not the safest way and don't do it in the kitchen. The next which also worked was to discharge using an old 12 Volt car headlamp bulb. This also worked in a much safer way. Finally I had to buy a new battery charger and I purchased an ISDT D2 MKII twin charger. This is a great bit of kit (very noisy) which has a destroy option on it. Not used it yet but it discharges the battery to a safe limit in a balanced way. Out of all the batteries I have, I have only had 3 puff up on me. Two of those are over 12 years old. Since having the D2 charger and following advice from someone on YouTube who knows what they are talking about (Painless360) I no longer charge batteries to full capacity. The max volts per cell I use is 4.15 and the min discharge is set on the ESC to 3.6. It is also worth noting that the C rating is important if you are running high (Amp) power motors.

@Steves-s

That sounds very frightening and further concerns me that I find the best way to dispose of these two LiPo batteries safely.

Bob.

What to do Next?

Knowing where and how to dispose of these two PiPo batteries safely is the next thing I need to work out.

Previous advice was to dump them in a bucket of salt water for a few days, and that would safely drain them completely allowing them to be given to the appropriate recycling collection point.

When I suggested this to Adam, he advised that it could take much longer than that to drain them enough to make them inert, so any advice would be appreciated as I think they are probably less safe now than they were when they were in their original condition with the wires still attached.

Bob.

I watched the news on tv the other night where a rubbish collection waggon went up in flames.💥💥 😑.
They were blaming it on discarded Lipo batteries 🤔💥💥......

@zooma IMHO you made the right decision.

Scrapped.

The two bloated LiPos that were the subject of this very useful subject were scrapped today after I decided to cut off the wires and dispose of them.

Both had been run in my Remora last week and performed perfectly without getting any warmer than any other LiPo I had used, and they also both re-charged without incident or getting warmer afterwards, but I still felt a little uncomfortable with them due to the usual cause of any LiPo boating,

Once all the wires had been removed from both LiPo batteries, one of the LiPos had the heat shrink cover removed (by Adam) along with the under wrapping to expose the three separate cells.

It was also noted that although the cover was “puffed” (the reason for these cells being scrapped) there was NO GAS to be found under the cover !

This has led Adam to suggest that all three of the cells had a temporary “short” causing them all to “blow” slightly, but the cells had returned to being FLAT under the puffed-up covers with no gas being found under the cover.

Probably these two LiPo battery’s would have been safe to continue using, BUT as they had “bloated” slightly, I decided that rather than take any risks with either of them, I would rather play safe and scrap them both.

Bob.

Hi Bob

When looking at a Lipo battery you should understand how the cells work firstly. The cell is a wrap of basically two films separated by a gel allowing the voltage to be generated and stored. This is called the dyelectric and is the main cause of bloating the cell if it begins to breakdown. When you look at the internal resistance of the batter is show the health of the cell below 10 is OK. If the gel is damaged between the two films or one of the film coatings is damaged you will see the internal resistance climb.

Once the cell is bloated it is no longer considered normal and can become unstable causing gas to be released its very rare to explode (its called thermal runaway and can reach 500 plus degrees and is normally cause by internal issues or a dead short of the battery) . I would suggest being very careful with storage and charging ie not to 100 percent.

So what causes this :-

1 temperature operating outside spec which I cannot see you would have done this.

2 over voltage never take it over 4.2v on a charge or discharge below 3.2v. There is a rule for storage between 75 and 80 percent.

3 over rating current draw. Your battery is 25 to 30c which means

25 x 5000(ah capacity). = 125000 which is 125 amps which is continuous discharge. Which is higher rated than the speed controller.

4 manufacturers issues weakness. Its possible but as you have another 2 batteries with same batch number I would. Monitor them.

5 charging at low temperatures below 0 degrees which most chargers block.

I know no definitive cause is clear which is a problem. I would just monitor the bloating is does look slightly but any boating is not good. Keep them in isolation bag and only charge to 80 or 90 percent.

I terms of fixing the bloating there is nothing you can do. There are no ways to fix the battery.

Hope this may help

Adam

Carry On (for now).

The two bloated 3C LiPo packs that I have been using in my Remora were checked and charged again this evening.

LiPo 1. Before charging the cells resistance was 3 4 2. After charging to 98% the resistance was measured again at 4 2 1.

LiPo 2. Before charging the cells resistance was 3 5 2. After charging to 98% the resistance was measured again at 4 2 2.

Both LiPo packs remained cool during a Balance Charge at 2.5 amps.

Before charging the voltage on both packs measured the same as each other (3.9 3.9 3.9 volts per cell) and were also the same as each other after charging (4.16 4.16 4.16 volts per cell) so both packs still have perfectly balanced cells.

The above readings continue to confuse, I will keep these two packs in a fireproof LiPo sack and continue to use them with caution but monitor them during use in the boat and during charging.

Bob.

Still Working Well.

Both of the “Bloated” LiPo batteries were run in the Remora again this morning and both worked OK.

Both were checked to see if they were running at all hot, but both were only very mildly warm after a full session of driving the Remora “briskly” around the lake.

I will check them again this evening as they are both being balance charged and take a resistance reading both before and after charging as well.

At the moment these cells are the cause of some concern as they are definitely swollen, but both run and charge perfectly without getting hot and both have very low resistance readings.

I am more than happy to dump them both if they show any signs (other than the swollen heat shrink covering) of getting hot when being run or during charging - or showing any high resistance readings, but it would be a shame to throw away two perfectly good working LiPos when both of them display no fault other than a bloated heat shrink covering.

Bob.

Double Bloated.

The picture I showed on here yesterday of the LiPo in the Remora hull identified it as NOT being the same LiPo as the one I noticed as being “bloated” - as it was marked Remora 2.

The “blown” LiPo that I had concerns about was marked Remora 1.

I remember when HobbyKing had an offer on these LiPo’s that their postage costs made buying one a “non-starter” (their LiPo delivery costs to the UK are very high) - so I bought 4 of them to make the cost per battery more affordable.

I marked them as Remora 1, 2, 3, and 4 although they were not all necessarily going to be used exclusively in the Remora hull, it was a way of identifying them.

I took a look inside the “fireproof” LiPo sacks that I store them inside and took all 4 of them out to be checked.

The LiPos marked Remora 3 and 4 had only been charged once - probably after delivery to check they were OK and to see if the cells were balanced. These two LiPos coverings are completely FLAT with no bloating of the heat shrink coverings.

The LiPo marked Remora 2 had only been charged 5 times, and it was found to be almost as bloated as the one marked Remora 1 that first caused me some concern after it had only been balance charged 8 times.

This does prove that all 4 of these LiPos had FLAT heat shrink coverings when they were new (I would have noticed if two out of the four had puffy coverings) and that only the two that had been used now have “blown” heat shrink covers!

The answer to keeping these particular Turnigy 5000mAh LiPos safe is seemingly NOT TO USE THEM !

This may be a bit severe and I will check the resistance of all 4 packs, but the two that have bloated have only been used in the same Remora hull so I would not think they had been put under any great strain in use whatsoever.

This does cause me some concern as I have no reason to suspect that the two unused cells will not also puff-up their coverings when they are actually used.

All of these LiPo’s have only ever been “balance charged” from new at 2.5 amps, which I don’t think is an excessive charge rate for them.

The two that have been used have powered the small Surpass C3548 1100KV out-runner drive motor via a 90amp SeaKing “forwards only” ESC and have not been allowed to run down low enough to cause the ESC to cut-in and stop the power delivery before it could drop below the terminal voltage.

After each run the Remora was always driven back to shore when still able to deliver its full performance, and when re-charged the LiPos still had around 40 - 50 % Fuel in them, so they have never been allowed to run too low.

At the moment I am thinking that I may have bought 4 “duff” Turnigy LiPo batteries, but until number 3 and 4 have been run I wont know this for sure.

Bob.

All of the batteries I use in my larger models are 35C which I think I arrived at when researching when I first got into the hobby.

Problem is that most manufacturers overstate the capacity of their batteries, though the better brands do it less so. But even for them the reality is probably that the capacity in use is less than that stated due to what I mentioned earlier, the internal resistance. Whilst your figures were very good some of the power is still being used to provide heat (all batteries heat up to some extent when being worked). One of the links I posted earlier, the detailed one, says that the actual capacity can be a lot less than the manufactures stated and so like with an ESC it is better to err on the higher side I think.

It's interesting that they quote a range of 20-30C rather than a fixed value like other manufacturers, wonder why that is?

I think the bottom line though Bob is that you now have replacement batteries and the existing one is always going to have a question mark over it in your mind so the best course of action is to dispose of it.

At least with the new ones being stated as 50C you have some leeway. That's what I was going to get for my Swordsman as it needs a 4S and being a bigger heavier boat than my others and requiring a higher rated ESC then components are going to be worked a bit harder.

Chris

Edit: Did a search and this was the AI response. And this from Overlander Batteries. https://overlander.co.uk/understanding-c-rating-how-much-power-does-your-rc-need/?srsltid=AfmBOorrB2PDzzkfQNsfYcLrhkV4nKw2HfLwjSE3VOEc3llT26Hpl0Gf

@zooma at 20c you are assuming a greater disscharge than 100 amps, thats quite unlikely, have you measured how many amps you're using? Sounds like a duff battery to me

Wrong LiPo Choice?

I have only ever used this battery in my Vic Smeed Remora, and I am wondering if the spec of the battery is not good enough for the boat?

The 5000 mah bit is impressive, but the 20-30C Discharge bit may be where the problem lies?

Maybe I am grasping at straws here to try to find a reason why this LiPo has swollen after so little use?

The Remora is quite a nippy little boat, but it is also quite a lightweight little boat that is only 30” long, so maybe it is just a “duff” battery?

Bob.

In one of the high performance laptops the first indication that you have battery issues is random keyboard problems but I have seen some bad cases where the whole case has distorted as the battery bloats

Hard Case.

I share Chris’s observation that a hard cased battery could make it harder to detect if the cells inside the case are swelling?

All of my Overlander LiPo’s that I have been running in my Rapier 1 and my Kopy Kommander are also hard cased.

I am guessing that if the LiPo cells do start to deteriorate and swell they will easily be capable of pushing the two halves of the plastic case apart?

I have been running LiPo batteries of one sort and size or another since they first became available initially for use in r/c helicopters where for the first time they provided a “power to weight ratio” that was good enough to allow a battery powered model helicopter to be able to fly!

This was rapidly followed by their use in competition r/c racing cars and r/c model aircraft where they are now almost universally the only choice of battery chosen to power them with.

I still have some of these early(hard cased) LiPo battery’s that must be 30 plus years old - and I still use them to power my 1/10 racing cars - and they are still able to power the cars competitively against those drivers that have the latest (and most expensive) types of LiPo available.

Interestingly, I also have some of the latest type of racing LiPo battery packs, and they are no better in power output or duration than these originals - and for many years these original LiPo batteries never had the benefit of being charged with the sophisticated types of charger that we have today!

Different balance plugs were used on these early LiPos to those that we use today, but fortunately I still have some of the matching period balance boards that I can plug into my current chargers - so I can still charge them!

These early LiPo helicopter batteries were made in Malaysia. I have no idea if any are still made there any more, but their production quality must have been superb.

I wonder how many of our current LiPo manufactures are capable of making LiPo batteries that will still be as strong in 30 plus years as these are?

My current Turnigy LiPos that have been mentioned here never got as far as having 10 charges from new before swelling!

………quite some comparison…………

Bob.

Bob, if that was my battery it would be condemed

The two LiPo batteries that I bought from Amazon do look like they are good value for money (for the specification), but time will tell if they can perform and last without any problems.

I put them on my charger just to see what condition they were delivered in. I only have one charge lead with a Deans plug on it so both were connected to the B output (the lower scale on the charger) .

The first battery came with 48% Fuel and the three cells were closely matched.

The second battery came with 47% Fuel and again the three cells were also quite well balanced, but no doubt both battery’s cell balance can be improved after some balance charging to align them even closer to each other?

Overall a good pleasing start.

Bob.

As regards the bulging it's difficult isn't it. I've come to the conclusion with mine that it isn't puffing and that it's the heat wrap - I hadn't looked at the battery for awhile and as I said it's probably always looked like that?

But with yours it has obviously changed for you to notice the difference, not much but enough. But the readings say it's OK. A quandary!

Those new batteries look like hard cased? At least you won't be able to see any puffing with those! 🤔 They are a good price though as one battery can be getting on for that two-pack price and good spec. for the price.

Roaring Top LiPos from Amazon.

I saw these battery’s on the Amazon UK site at a fair price and so I thought I would give them a try, they came with a free next day delivery - and here they are!

The size will fit into the Remora’s LiPo retaining frame that I built into the hull so I can use them without having to alter the mounting in any way.

Although “taller” than the original Turnigy battery, the length and width are the same so they fit well and the extra height still fits easily under the rear deck cover.

……I am still not sure about the swollen Turnigy LiPo….

Bob.

Trying to show the bulged heat shrink covering in a photo is proving to be much more difficult than I thought it would be.

When squeezing the LiPo the covering can be pushed in and out in what feels like quite a lot of movement.

The pictures don’t really show the bulging anything like as much - but here is a picture of each side anyway to show the front and the back as both are swollen
.
Bob.

@ChrisF I appreciate your research & subsequent comments regarding resistance testing. That said I appreciate even more your saying you dispose of a suspect pack immediately. The cost of the battery V the cost of the risk is overwhelming. That’s my two cents worth.

@ChrisF I appreciate your research & subsequent resistance testing. That said I appreciate even more your saying you dispose of a suspect pack immediately. The cost of the battery V the cost of the risk is overwhelming. That’s my two cents worth.

And this is worth a read. Same sort of info. but goes into more detail.

https://www.rchelicopterfun.com/lipo-internal-resistance.html

I tripped into the internal resistance thing when I was searching for other info. on Lipos a year or so back. As the guy says rarely mentioned but very useful.

Like you Bob, I'm very wary of Lipos and the slightest hint of anything being up with them then the defective battery will be gone. I take all my spent "normal" batteries to our local tip/recycling centre as they have an area specifically for batteries. Not sure they would welcome a dodgy Lipo though! I've read about that salt water method as well.

Chris

@ChrisF That is very interesting.

Hi Chris,

I did see your post number 12 thanks, but I also found the original charger handbook under the foam packaging at the bottom of the box. It had plain white paper covers over the printed handbook covers so it was very well disguised under the white foam !

The handbook also gave the search sequence to call it up onto the screen which was helpful as this charger has a LOT of functions available.

This has proven to be a helpful blog as it suggests that there is nothing wrong with my battery…….but I admit to buying a replacement from Amazon last night that will be here today !……so now I have a useful spare (of the right size to fit the Remora battery box) as well!

I have tried to picture the bulge for you in the previous pictures I put on here, but the bulge is not big enough to make a significant difference to the profile of the battery but is is very easy to see and feel the bulge on the top and the bottom of the battery.

If it should get any worse (and bad enough to make a good picture), I will not be keeping the battery, no-matter what the resistance figures tell me - because I am naturally nervous of swollen LiPo batteries - but for now, I am happy enough to give this one another outing in my Remora - but I will be monitoring it carefully for heat and swelling both when in use and during charging.

Thanks for your help.

Bob.

Just done a search based on internal resistance of Turnigy Lipo batteries and the AI response pretty much validates what I've said.

Hi Bob, did you miss my post #12!

The symbol is for Ohms and so the measurement is milli-Ohms. Anyway, those results are very good, as I said earlier, the lower the better. Mine were higher than those and varied by a greater amount. So on that basis and the fact that the cells charge to a good and equal voltage I'd say the battery is fine.

To be on the safe side I'd still charge outside though and check how hot it gets after use, getting warm is normal. The risky times for LiPos are when charging and when being worked hard which is more applicable to race boats being driven fast for lap after lap. Your white water but relatively short run times shouldn't cause any problems.

Still be interested to see the puffy part of the battery.

A check of my 2S batteries also gave higher readings than yours at 6 and 7 for one and 8 and 5 for the other, which from what I've read are fine. My 2S and 3S batteries are 3300mAh which I think are lower than yours - I mentioned that resistance tends to be lower the higher capacity you go, which probably explains the lower readings you are getting compared with mine. Out of interest I checked one of my small capacity LiPos yesterday, 7.4v/1500mAh and the results were in the 20s which seems to bear this out as did a 7.4v/2200mAh with results of 16 and 15.

Battery Resistance.

I have found the Battery Resistance Meter on my charger and recorded the results.

The charger shows the numbers followed by a small “m” and what looks like the outline of a tree. I have recorded this second figure here as an “A” as I have no pictures that look like a tree on this keyboard !

The battery with the “puffed” heat shrink cover that I have been using on my Remora is a 3 cell LiPo and has given the following readings:-

Total:- 5 mA.

Individual Cells:- 1 2 2 mA.

I have no idea what this means except that all the readings are very low and that one cell is lower than the other two.

My way of comparison (only), I took one of the two cell LiPo batteries out of my Kopy Kommander and put it on the same program and got the following readings:-

Total:- 4 mA.

Individual Cells:- 2 + 2 mA.

Any help with identifying exactly what the reading for the 3 cell LiPo that has the puffy heat shrink covering tells me about its safety would be greatly appreciated as I have no idea what it means, other than identifying that one cell has a lower reading than the other two cells.

The comparison with the 2 cell battery from my Kopy Kommander has not helped much other than to note that both cells also have low readings of 2 mA that are the same as each other.

Bob.

Just as you suggested Chris, my charger does have a Lithium Battery Resistance Meter.

Page 21 of the Overlander RC-D100 charger shows this function and how to read the display.

It can display the highest resistance, the lowest resistance and each cells resistance.

I am not sure what to do with this information, but I will gather it now and see if I can find out if this LiPo is safe or should be disposed of .

Bob.

The Turnigy battery that I have is no longer in stock from HobbyKing , and has no delivery date.

Maybe after blowing following only 8 balanced charges at 2.5 amp I should try a different type anyway?

WhenI looked this afternoon they had fewer LiPo batteries in stock than I can remember seeing there before.

Maybe they are about to re-stock?

Bob.

Turnigy batteries are good but what is available at any one time tends to vary. I use Giant Power (which Dave Milbourn recommended to me) from Component Shop and Overlander Batteries.

Hi Chris,

We have just walked back from Ainsdale Village and it is really hot, but later I will get the charger out and run through the menu options.

To be honest, I have only ever used the charger to charge and balance my batteries and have never used it for anything else, but knowing about the resistance of each cell is not something I had thought of previously, but if it can be used as a “heath guide “ for each individual cell, it would make sense to check it now and again - if especially on a LiPo pack that has a puffed sleeve covering like this one has.

I chose this particular battery to fit in my Remora and made a close fitting battery holder to keep it safely located during use. I think I will check to see if they are still available or if I can find any other 3 cell LiPo packs of this overall size and shape as I think a replacement may well be needed in the near future……and it would be good to have one here ready !

Bob.

Hi Bob

That's my servo and battery checker. My charger is a Turnigy. If I was buying now I'd get an Overlander as I buy a lot of their stuff and the Turnigy has been discontinued, good charger though.

If you haven't got the instructions they are available to download from the Overlander web-site. This is the relevant page.

Hi Chris

Thanks for your contribution.

You also use an Overlander LiPo charger (these are FlySky re-labeled as far as I know) and I have found them to be very accurate and reliable - but I was unaware of their ability to check the resistance, so I need to scroll through into “unknown areas” until I find it.

I always check the temperature of my motor, ESC and LiPo after every run (nothing clever - just by touch) and I have never had a “hot” LiPo yet, but they do usually feel slightly warm.

This LiPo does have a slightly “puffed” cover that can be pushed in and out a little - like it has some air trapped between the heat shrink and the battery itself.

I will see if I can find the function to check the resistance of each cell, but the LiPo charged normally up to 95% (when I stopped it) last night and each cell had the same voltage reading, so the pack is still balanced nicely.

The heat shrink covering is very tight at each each, so any gas (or air when the pack was made and covered) may be unable to seep away, but I would have thought that any gas (including air) that was under pressure would be able to leak its way out ?

Anyway, the battery has now had 9 balance charges from new, has good balanced voltage readings on each cell…….but it still worries me (a little) so I will search for that internal resistance measurement function on my charger and see if I can find it.

Bob.

Hi Bob

Your charger may be able to check the internal resistance, mine does and yours looks like a good one. As for values, when I checked my 3S I got 7, 5 and 6 milli-ohms for each cell. For info. search for "internal resistance of Lipo battery". But note that any checks will only give you a comparative result as they vary on battery temperature and charge. Hence my comment to check when new to give a baseline. The lower the better but the results will vary on the capacity of the battery.

With my battery, looking at it more, I think it is due to the heat wrap being tighter at the ends as the curvature is only slight from end to end - see photo. What does yours look like side on? I need another one anyway and so will get the exact same battery and compare it.

Lipos can start to puff if worked too hard, did you notice if yours was hot? Some guys carry on using them if they puff but in less power hungry uses like torches - no bloomin' way!!!

For the number of charges you have carried out there shouldn't be a problem with your battery so maybe it had an issue from the start? That's why the internal resistance check is useful as comparatively it will show if a cell is much different from the others.

Jumpugly - I've got a couple of those little units. But bought mainly to use for servo checking as I prefer to use my battery charger for battery functions as it cost somewhat more and I trust it more!

Chris

Edit: Just checked again and internal resistance is 8, 5 and 5 with each cell being at 3.82v. I've had that battery for a few years now but those values are fine.