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>> Home > Tags > battery

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HMS Erebus by Dave M Fleet Admiral!   Posted: 9 hours ago
Hi Gdaynorm That should be OK. The speed controller in the picture is marked made in China and their rating of 128 amps seems very optimistic. That said we have looked at all the components and the only remaining possible cause, assuming the motors and ESC are not faulty, is the prop sizes and pitch. If they are causing a too heavy load on the motor then the current will be excessive and your new battery is certainly capable of providing lots of power. I do believe the ESC was cutting out due the overheating. As others have said you cannot always rely on Chinese ESC quoted ratings, and in my experience they seem to have missed out a decimal point. You have several options: 1. make a reduction unit between each motor and prop so the load on the motor is reduced. 2. fit smaller props 3. measure the stall current of each motor using a watt-meter and buy two speed controllers with double this current capacity. Initially I would experiment with option 2 to prove the props are the cause of the problem. You can then decide if you wan't to try another option. Option 3 will result in shorter sailing times. Davwe

And now it is ESC time by sonar Commander   Posted: 12 hours ago
I will soon be looking for ESC,s I had thought dual esc,s and now thinking two singles. 25 Amp Brushed for a 12 volt sealed lead acid battery. I have seen an awful lot of 320 amp dual on ebay but seems the low price is a little unreal for what they are.and 320 amp again doubtful .. Unless of course someone has one and tried it. So what can the members recommend for a reasonable price and from where ?

HMS Erebus by Dave M Fleet Admiral!   Posted: 1 day ago
Hi Gdaynorm You were using one of the blue ESCs before and it worked OK, for a while anyway which is common in my experience. This was capable of working up to 12volts whereas your Duratrax sprint is limited to 8.4 volts (4-7 cells NiMh) as is common with model car ESCs. The current capability is quoted at 128 amps so should be OK with most standard motor types May I ask for details of the type of battery you are using? Dave

HMS Erebus by RNinMunich Lieutenant   Posted: 2 days ago
Hi Gdaynorm (Why does that name make me think 'strine'?) 😉 Yes you are absolutely right Duratrax seem to specialise in cars & buggies. The Sprint always seems to appear in the context of the Evader buggy series, also it is listed as discontinued on the Duratrax site! http://www.duratrax.com/downlo ads/discontinued.html Nothing lasts for ever!! Maybe it is not happy driving two motors? What is the total current drawn? Since it seems almost certainly to be an overheating problem is there sufficient cooling air flow through the boat? Recycled 5V DC PC processor fans can be useful to help here. Since you can test motors by feeding directly I assume they must be brushed. Are your batteries, LiPo or NiMH? In both cases the Sprint has a low voltage cut-out. 3.3V for LiPo, 5.0 V for NiMH. Maybe the cut-out circuit has a hysteresis effect. This means that if the battery recovers slightly when taken off load, and cools?, the boat runs again - until the cut-out point (thermal or volts) is reached again! I would expect the interval between cut outs to reduce slightly with each cycle until the battery is totally depleted. This effect is also noticeable with sealed lead acid accumulators. I would be tempted to bite the bullet and buy 2 ESCs designed for marine use (e.g Graupner Navy VR series or Viper Marine or US/Canada equivalents) and a 'Y' cable to run both in parallel from one RX port. Then each ESC only has to handle half the load. And ensure sufficient cooling air flow, or even water cooling!? How big and heavy is the boat, what type are the motors and what size & type are the props? Cheers from Munich, Doug 😎

HMS Erebus by Gdaynorm Sub-Lieutenant   Posted: 2 days ago
I am not an electric sort of bloke. What surprises me with the problem is that everything worked well for a long time. She has basically the same set up as my other ships, basically simple. Battery, speed control, two motors turning two shafts, with shafts lubricated. The battery fully charged, the radio and receiver set up okay, motors run with no problem when fed current directly, and no problems with prop shafts. Maybe my best bet is to simply obtain another control same as original. I get the impression the Duratrax is meant for cars?

HMS Erebus by RNinMunich Lieutenant   Posted: 2 days ago
Good clue! - extract from manual re set-up "1. Set throttle trim to neutral and turn on the transmitter. 2. Press the ESC on/off button. The LEDs will light, one green, one red. 3. Wait 3 seconds, the LEDs will change to blue. Your ESC is now set. 4. The ESC has an automatic LiPo cut-off. One flashing red LED means your battery is low and the cut-off has activated." Note point 4 !! Are you using LiPo or NiMH? Also- "Problem: Model runs properly, then motor goes dead. ➤ The built-in thermal protection may be automatically shutting down the ESC due to overheating conditions. Check for binding drivetrain, bad motor or incorrect gear ratio. Adjust gear mesh, replace motor or change gear ratio. Allow the ESC to cool and try again." ESC seems to be mostly used in buggies - above is extract from the Duratrax Evader EXT2.4 manual. Thus, assuming direct drive, 'changing gear ratio' for us means change the prop! May also have been the cause of the blue ESC problems? Which version of the Sprint? There are Sprint DTXM1200, Sprint 2 DTXM1205, and Sprint Waterproof DTXM1220. All with slightly different specs and motor requirements; brushed / brushless. So what is your setup, End to End; battery to prop?

Pro Boat USS Arleigh Burke by rossiter Seaman   Posted: 2 days ago
I have a rather nice Pro Boat 44" USS Arleigh Burke destroyer.It has the accessories that could be bought separately and comes complete with a new 50amp ESC. A 7.2 NIMH battery will be included, so all you will need is a receiver and away you go. These are becoming quite rare now as they are no longer produced. Its had little use, and sails superbly. I'm open to offers as it has to go due to space required. Collection only from Stroud in Gloucestershire, 4 miles from Jnc 13 of the M5. May be able to meet within 50 miles. Feel free to call me on 01453752333

Battery problems by pmdevlin Fleet Admiral!   Posted: 2 days ago
My knowledge of "elecy" stuff is pretty limited, but I see that the model boat world (excluding racing types) is in the dark ages compared to planes, helis, cars etc when it comes to motors, batteries etc We have to reply a lot on testing, fiddling etc when it comes to gettingn a fast electric set up, in a scale heavy old wood boat😁 as there isnt much info out there. I tried testing over a long time, with one boat inparticular, and was lucky enough to have te use of eagle tree data logging, so could measure watts, amps, gps speed, voltage drop and so on, and analyse the resultsd on graphs etc back home on the pc. Its amazing to see that sometime s the fastest set up isnt always the best when you compare run time, amp draw, heat, voltage draw etc, and what "looks fast" sometimes isnt as fast as you thought😊 This boat for example, 6kg, ply construction will do 25mph, after that torque roll is kicking in, and it want to roll over. I tested props over a long time, using cheap plastic "X" props, and with the results was then able to get a more efficient and visually pleasing brass cleaver 3 blade one. Ranging from 50mm to 55mm the amp draw went from 45a to 90a using same batteries!, and teh highest amp draw prop didnt produce the fastest speed, all interesting stuff. The boat is similar to the OP perkassa. I also went from direct drive, to a geared drive, and can change the characteristics of the boat using different cheap gears, eg., small lake, dont need top speed, so change to acceleration, big lake, lets give up acceleration and have top speed, and so on👍

Battery problems by RNinMunich Lieutenant   Posted: 2 days ago
This triggered my curiosity! So have just ordered the Busing in-line 150A Power Analyser, €12 😊 Anyone looking for such a device can find several review videos here https://www.youtube.com/watch? v=Lxv9Rozs774 Happy hunting 😎

Battery problems by RNinMunich Lieutenant   Posted: 2 days ago
Thanks for the watt-meter tip 👍 Will check around my German / Austrian sources, might be worth a trip to Salzburg 😉 I sometimes forget that others outside the industry may not have access to the sophisticated test gear that I do. Time to eat humble pie 🤔 Cheers from Munich 😎

Help Me Please by RNinMunich Lieutenant   Posted: 2 days ago
Wow! Super project 👍 Here the complete history of the ship (Thanks Wiki 😉) https://en.wikipedia.org/wiki/ HMS_Lion_(1910) What's the state of play? How far have you got? Please post some more photos, inside and out, and a list of components; motors, props, ESC, battery, RX and TX. Then maybe we can see what the next step might be. Cheers Doug 😎

Battery problems by pmdevlin Fleet Admiral!   Posted: 3 days ago
something is fundamentally wrong here, there is no way that motor/esc/battery combo should have fried the esc in your perkassa. I have a number of large scale boats with a fast brushless set up, I pull almost 90 amps with one of them, on the initial acceleration, using 6 cells, 120a esc and (here is the difference) a 900kv brushless motor. The racing guys use high kv motors, they need the high revs, with a heavier boat like yours, you need the revs, but also the torque, which is a lower kv motor Before you do anything else, buy something like this http://www.4-max.co.uk/wattmet er-budget.htm really cheap, but saves you a fortune. As many of previous posts have said, you need to measure what is going on, for example, the specs of you motor say max current is 100amps, you need to measure your amp draw. You know the esc was 160a with a burst of 200a, so should have been well within the capabilities of your set up, but we cant see the prop. If its too big, and too coarse, particularly holding the boat, the amp burst would have had to exceed 160a to pop the esc, which is also well over the motor specs. I doubt the hobby shop will do anything, as the fault could have been a multitude of things, Personally, I think that motor is way too high KV, and I'm saying this from experience of large, heavy scale boats, with fast brushless set ups. I would have expected it to rev very high, but not deliver a really fast top speed, but I could be wrong. Shame really as its quite an expensive set up there. Are you sure about the facts, holding that boat, and max throttle must have been pulling your arm off, I cant hold any of mine😱

more work on the solent by Mataroa Captain   Posted: 4 days ago
Hi i did sum modification to the front of the superstructure it was out of line and all so i work on fitting the propeller shaft in.The 2 motor needit to be fitted in and the 2 15A speed controllers . I made up the battery tray and fitted it in the hull . cliff

Battery problems by Dave M Fleet Admiral!   Posted: 4 days ago
Hi Allan If you had water cooling and it was provided by your pump then it would seem the prop was far to coarse a pitch for you fast motor and very powerful battery which was quite capable of delivering well over 200 amps through the 160 amp ESC. Your comment re the power delivered rather confirms this, and holding a model at full speed to test is only possible for about 5-10 secs max. You need to get a much smaller and less coarse pitch 3 blade prop plus a wattmeter to measure the current to make sure you are no where near the max ESC current. Personal experience suggests this should be less than half the rated Max so say 70 amps for your ESC. Testing should be brief and stopped immediately if the current being taken is above 20-30 amps. Smaller props will reduce the current to an acceptable level and your model will go faster and for longer. As a guide 14 volts at 70 amps will be using 980 watts so you will perhaps appreciate why cooling is necessary. Also at such high currents the wiring from battery to ESC then motor will need to be capable of carrying such high currents. As there are three wires to the motor and the power is pulsed at high frequency they are usually not as heavy as the battery to ESC. Your battery to ESC connectors also need to be capable of high current such as Deans, Euro or bullet type. Having looked on U-tube it does appear that others have had similar experiences with this ESC. The specs say it is capable of running at 14.4 volts so when you buy a replacement I would ask your local store to run your motor with the ESC and your battery to ensure it works OK. If they have a wattmeter ask them to test the open current then also buy the wattmeter and a smaller 3 blade prop of slightly less diameter than that of the motor without the water jacket. Do a final brief test at home holding the model and see briefly what the wattmeter reads, this will be near the max current draw. If it's too high you need a smaller prop. There are several Perkassa builds on the site and some use brushless with success. If you search you will find details of their power train which may help you choose the best set up. I do hope you will soon have your model speeding round your lake. Dave

Battery problems by RNinMunich Lieutenant   Posted: 5 days ago
PPS Allan pondering the 'spec' of your LiPo "5300mha -50c-14.8v-4s1p-78wh" The wh rating = Watt Hours. i.e how many watts of power it can deliver in 1 hour. Since Power (P)= Volts(V) x Amps(I) (simple DC calc!) I=P/V i.e. 78/14.8 = 5.27, which is where the nominal capacity of 5.3AH (5300mAH) comes from. I don't think the battery is your only problem, i.e. a) the ESC was fundamentally defective, b) your setup is drawing too much current for more than a few minutes running on a 5 to 7 AH battery with no reserves. Good luck. I run a 1.3 metre destroyer on 2x540 brushed and 2x6V 4AH (4000mAH) SLA and it trundles around for 2 or 3 hours, and can still outrun several wannabee 'boy racers'! 😉