e-revo problem with nimh bronto batteries?

[gordonheyho]

Hi there! I just bought an e-revo and I'm loving it. I have 2 battery packs. The original that came with the package and I bought (after the vendor confirmed it was compatible with my system) 2 Bronto batteries. Nimh 5000 Mah at 8.4 volt. I use a smart charger sky rc e6680 (see pics).
I'm running my truck since 4 days now... the other times I was running in training mode to get used to it. Today I ran in sport mode for the first time and really had a go with it. The original pack run smoothly. I waited 10 mins and I started using the bronto packs. I run it hard for 15 minutes I would say until the batteries started to give in. I swithched it offm, disconnected the batteries and when I took them out they were really hot. Actually one was so hot that melted the battery cover... See pics....

What happened? I'm running everything original out of the box and this was the first time i run at 100% power.....

ARe my Bronto packs dead? If I killed them, why? I even asked the vendor if everything was compatible before buying and they confirmed.... also isn't the esc supposed to cut the power in case of overheating?

Help please,
Thanks a bunch.
Gordon.

Pics:

[67Mustang]

Hi Gordon and welcome to the forum.

The esc protect's itself from over heating, not the batteries. The batteries could be 500 degrees and the esc wouldn't shut off.

Regarding your batteries melting, I think they were just cheaply manufactured. It is normal for the nimh's to get hot, and usually before they die completely (as in end of their life permanently, not per charge) they melt the casing.

How long did you let the bronto packs sit in between being charged and plugging into the truck? If say the bronto packs JUST finished charging, and you put them in the truck as soon as they were done, that could be your problem.

[steelersfan1972]

I had the same problem happen one too many times. Thats when i decided to go lipo. Best decision i ever made! Time to jump on the bandwagon gordon...nimhs are not worth it.

[gordonheyho]

Hey there! I'm a newbie but I read something before starting to play with the revo. I actually charge my batteries (after they have cooled down) the day before I use them. Does it mean that the burned out battery is dead? It didn't come cheap I can tell you that.

Lipo eh? I just got into the brushed version and I should already update? what a hobby!!

Thanks for now. keep them coming!
Gordon.

[ksb51rl]

Hi Gordon and welcome to the forum.

The esc protect's itself from over heating, not the batteries. The batteries could be 500 degrees and the esc wouldn't shut off.

Regarding your batteries melting, I think they were just cheaply manufactured. It is normal for the nimh's to get hot, and usually before they die completely (as in end of their life permanently, not per charge) they melt the casing.

How long did you let the bronto packs sit in between being charged and plugging into the truck? If say the bronto packs JUST finished charging, and you put them in the truck as soon as they were done, that could be your problem.

I totally disagree with this assertion. You will get your best power off a fresh charge. Cells overheat when they are stressed - run down too far or discharged too fast. Since it seems by your description that the first is not the case, I would guess that the packs are simply not up to the task. I am very interested in your current gearing and tires. If you were geared to high, that would cause a significant increase in amp-draw. NiMH packs (except the best ones) don't take too kindly to that.

Never heard of bronto batteries. Only place that came up in Google was a Norsk forum. Makes sense - the above looks like a European setup.

[67Mustang]

I totally disagree with this assertion. You will get your best power off a fresh charge. Cells overheat when they are stressed - run down too far or discharged too fast. Since it seems by your description that the first is not the case, I would guess that the packs are simply not up to the task. I am very interested in your current gearing and tires. If you were geared to high, that would cause a significant increase in amp-draw. NiMH packs (except the best ones) don't take too kindly to that.

Never heard of bronto batteries. Only place that came up in Google was a Norsk forum. Makes sense - the above looks like a European setup.

Hmmh. Interesting. Well the one time I ever had pro-match packs (only nimh's I use) burn up on me, it was because I used them right after they were charged. other then that they are great. I guess it could have been a coincidence.

[ksb51rl]

Hmmh. Interesting. Well the one time I ever had pro-match packs (only nimh's I use) burn up on me, it was because I used them right after they were charged. other then that they are great. I guess it could have been a coincidence.

Yes, those are the "best ones" I was referencing. My battery company owner/builder/tester friend assured me that this is the case and my own experience has corroborated this. Racers normally re-peaked before a race (back when they used NiMH) and did not have a problem with cells going supernova. This is probably because they used the best cells and they knew how to take care of them. Even so, anybody can make a bad pack once in a while.

[gordonheyho]

Actually I didn't change a thing on the e-revo. I bought it and I used it as it was out of the box. Original tyres and original gearing (whatever it is i don't know, I still haven't approached that part). And yes, google is right, I am in Norway and my "local" dealer advised me to buy them with the E-revo. By the way they cost 398 kr (68 $)a pack, I would be very upset it they are dead already. Now I'm sending an email to the vendor and see what they have to say....

What do you people say? Can I still try and recharge them or should I give up on them?

Thanks,
Gordon.

[ksb51rl]

I'd say that it's iffy. If you decide to charge the packs again, watch them carefully.

[steelersfan1972]

this is a brushless erevo thread...so thats where my recommendations came in to go lipo, but i dont think you can run lipos on a brushed motor without a low voltage cutoff. also check your battery with a voltage meter and see what you come up with...my assumption is the battery is toast.

[gordonheyho]

well... it turns out the dealer advised me wrongly.... bronto batteries 5000 nimh are not suitable for my model.... i'm getting the traxxas 4200 nimh for free as a result of the misunderstanding.... it will keep me going for a while I guess... and I'm not really tempted to charge the other ones anymore...If they are going to overheat again there is no point risking burning my erevo... and this is the erevo (brushed) thread.... even as a newbie I was careful enough to choose the right one the brushless thread is just one click above this one...at least I think so... well, i hope the new batteries are not going to fry as quickly as the other ones did....
thanks a bunch.
Gordon