battery question

[Drkrieger]

I have an issue with my boat killing my batteries. I come to shore and they are swelled bad, like pushing on the hull making it look tumored.

So I will start with the full set up.
MG29 V2
Stock metal prop thinned sharpened and balanced
OSE speedmaster strut bushing with a new flex and stub
OSE raider 150 amp ESC
chinese crap Geforce 3674 2200kv motor
dual rudder with dual pick ups, ESC and motor get fresh cool water.
Gens Ace 2S 7000mah 50c constant, 100C burst batteries. 2s2series, 4S total.


Things i have checked.
The ESC timing set to 0° for a D wound motor
checked for binding in shaft system, all free spinning
adjusted strut for least hull resistance in water. (without flipping it)
moved batteries back a bit, bring weight back a bit for less resistance in the water.

The ESC tops out at 120°F, the motor tops out at 114°F. connectors are hitting 135° BUT THE BATTERIES HIT 155-160°

could it just be the batteries are not strong enough? If so, what is a good battery 3S or 2S to pair with this thing?

[photohoward1]

How long are you running? Do you have a low voltage cut-off set?

[Drkrieger]

LVC set to 3.7V's Runs 8 ish minutes. The batteries when i get them back on the charger are never below 3.65 per cell.
I 2Amp discharge/ 1C charge cycle them a couple times if they get out of balance.

[Bp9145]

I believe 50C is plenty adequate and Gens Ace are pretty good batteries. Since it's the batteries that are in question, have you thoroughly checked the batteries for any irregularities. . .wires, connectors, IR? BTW you did not mention what connectors you are using. . .deans, bullets, traxxas. . .etc? Perhaps your connectors are the weak link. How old are your batteries and have you checked the IRs to make sure each cells are good. Troubleshoot the batteries first then we'll go from there.

[Drkrieger]

These cells are about 3 months old
I charge the batteries as a 4S, and they are read an IR per cell: 014 011 012 009

Using 6mm bullets from castle on the motor connectors. 6.5mm castles on the batteries. But these are Race hard packs, So they have the 4mm, long 4 way split solid connectors on the batteries themselves

[martin]

If your showing 3.65v per cell you are over discharging your batteries, you need them @ a minimum of around 3.74v per cell. This is what is probably causing them to puff.

[Bp9145]

These cells are about 3 months old
I charge the batteries as a 4S, and they are read an IR per cell: 014 011 012 009

Your IR readings 014 011 012 009. . .are you saying then on lipo#1 cell 1 is 14 and cell 2 is 11 and lipo#2 cell 1 is 12 and cell 2 is 9? It should read in single digits or double digits if it's in double digits I'm afraid you're cells are not at par as it should be for a 3 month old batteries. . . .again what are connectors are you using? Fe boats are very demanding when it comes to sucking up power and you need good connectors to deliver high amp draws.

[Bp9145]

Well, if you are using 6.5mm bullets then it certainly can handle up to 200A so good there. Then as Martin stated could be true. When lipos reach around 3.7V it drops much quicker below that. Then in that short period of time, last minute of running, the amp draw is fast and causing the batteries to deliver power at a higher rate and that short high rate amp draw is what is heating up your batteries and eventually puff up. Then, if you've done that many times over in the 3 months you've been using them, then your cells have degraded considerably in such a short period of time which is why your IRs are in double digits. . .assuming your statements about IR readings are actually in double digits.

[martin]

@ 3.65v you only have around 5% left in the battery, you need a min of 20% to avoid permanent battery damage which will cause heat & puffing.

[fweasel]

If these packs are questionable, I would be balance charging them individually as 2 x 2S packs.

[Bp9145]

You can still use your batteries but I would advise you to shorten your run time. Further damage could occur if you keep running them down to 3.65V or even lower. I don't know if you're checking the remaining voltage on a simple lipo checker or on your charger because there could be a slight difference in the readings. Depending what lipo checker you are using, most are not very accurate but with the charger you will get better actual readings. However, these batteries are still good for sport running but certainly not for use in a race. I've ran my batteries down below 3.7V before when my kids were running the boats and even though they're only running them at a mere 10mph-20mph they still heat up and a slight swell occurs when voltage has dropped to 3.3V. I can just imagine if you were running them at WOT it would certainly cause swelling and high temps. . .which in your case 155-160°F. . .not good. Shorten run time and monitor your temps and voltage by timing your runs or put a cheap lipo buzzer set at 3.8-3.9V since they are not very accurate but at least you won't go below 3.7V. Also, put your batteries in your charger and balance charge them and after try matching the batteries. Find out how close the cells are at full charge and use the two closest to each other. This way you have matching 2S lipos and hopefully, they will discharge equally. Hopefully, this will help with your battery's heat issues and puffing up.

[Drkrieger]

You can still use your batteries but I would advise you to shorten your run time. Further damage could occur if you keep running them down to 3.65V or even lower. I don't know if you're checking the remaining voltage on a simple lipo checker or on your charger because there could be a slight difference in the readings. Depending what lipo checker you are using, most are not very accurate but with the charger you will get better actual readings. However, these batteries are still good for sport running but certainly not for use in a race. I've ran my batteries down below 3.7V before when my kids were running the boats and even though they're only running them at a mere 10mph-20mph they still heat up and a slight swell occurs when voltage has dropped to 3.3V. I can just imagine if you were running them at WOT it would certainly cause swelling and high temps. . .which in your case 155-160°F. . .not good. Shorten run time and monitor your temps and voltage by timing your runs or put a cheap lipo buzzer set at 3.8-3.9V since they are not very accurate but at least you won't go below 3.7V. Also, put your batteries in your charger and balance charge them and after try matching the batteries. Find out how close the cells are at full charge and use the two closest to each other. This way you have matching 2S lipos and hopefully, they will discharge equally. Hopefully, this will help with your battery's heat issues and puffing up.

The batteries being charged as a 4S has never caused an issue, I do balance them every time. The cells are always within .02 Vs. I actually seem to get closer to all being at 4.2V's if i charge them as a 4S. I built the balance and charge lead harness myself, and works well.

As for the voltage cut. I think this may be where I can get some improvement. If the cells are almost always at 3.7 ish, 3.76 most of the time. by the time I put them on the charger to check them, I am sure they are dropping quite a bit under load.

I will set my LVC to 3.9, and see when (timed) i get the cut off.

One thing i did notice when the first one swelled like crazy, is that they are built as 4 cells. 2 pairs parallel, and those in series. I am sure this is how they achieve the 50C rating. I may take all cells out of the hard casings, and make them 4S in Parallel. Unless i get the 6S bug. Then I can eliminate the high resistance cells, and make 2 3S packs.

Thanks for the input guys

[fweasel]

I will set my LVC to 3.9, and see when (timed) i get the cut off.

It's been my experience, setting the LVC that high, will result in premature activation, very early in your run time because of brief voltage sags. I love my Proboat Dynamite 120A ESC's, but can't get away with anything higher than 3.2V on the LVC for continuous, reliable timed runs. Not sure how sensitive the LVC is on the Raider/Flycolor ESC. I have two of those myself, but nolonger rely on the LVC and routinely set them at 3.2V

[Drkrieger]

Only one way to find out. Eventually I will get a real time logger. But will have to mess with the run times and LVC for now.

[Bp9145]

............

I will set my LVC to 3.9, and see when (timed) i get the cut off.

Thanks for the input guys

As I mentioned if using a lipo buzzer to set at 3.8-3.9V at first then after a few runs find out what the average voltage is. Then if it's between 3.8-3.9V then set it at 3.7-3.8V so you can get a bit more run time.. . etc.I don't know about the sensitivity of your LVC on your Raider ESC . . .as Ryan said he sets his at 3.2V. . .my suggestion was for use with a lipo buzzer. I have two of the Raider 150A myself but as with many of my ESCs, I haven't used them yet so I don't know the sensitivity of the LVC on the OSE raider 150A. So if I'm understanding this correctly you have 4 X 2S 7000mah in your MG29? Isn't that making your MG29 super heavy? So you have 2 X 2S 7000mah in parallel to make 2S 14000mah then same with the other two to make another 2S 14000mah then connecting them in series to make 4S 14000mah? Regardless if you have one 2S 50C or two in parallel or in series the C rating is always 50C .. . .if the C rating is 50C then each cell is 50C. I would run two 2S 7000mah in series to make 4S and your boat would be less heavy and run better then placing 4 X 2S 7000mah in the boat. . .that is if I'm understanding it correctly. . .perhaps i'm just easily confused at my old age, so you'll have to excuse me. .LOL