Overdischarged battery help

[Pensacola_RC_Guy]

Hey I'm trying to find a way to "wake up" one of my sons over discharged nimh batteries without making a trip up to the rc shop. Any advice?

 

[tntpoof]

you can't over discharge a nimh pack...ever if its a zero volts your charger should charge it...whats the exact issue? what is charger saying?

 

[Pensacola_RC_Guy]

you can't over discharge a nimh pack...ever if its a zero volts your charger should charge it...whats the exact issue? what is charger saying?

I plug it into my charger and it gives me an error saying cell voltage too low to charge safely

you can't over discharge a nimh pack...ever if its a zero volts your charger should charge it...whats the exact issue? what is charger saying?

I even contacted traxxas tech support and this is what they said:

Hello,

It sounds like the battery has been discharged to the point that the charger cannot recognize it or charge it. The most common way to do this is to leave the battery plugged into the vehicle when it is not in use. Your local hobby shop where you purchased the vehicle may be able to help put a charge on the battery with their shop charger. Putting some charge on the battery will usually allow the stock charger to recognize the battery and charge it normally.

 

[DavidB1126]

Not the battery, it's the charger. That's why I don't like Traxxas chargers.
Any regular charger that does nimh and is not Traxxas brand should be able to charge it right up.

 

[Pensacola_RC_Guy]

Not the battery, it's the charger. That's why I don't like Traxxas chargers.
Any regular charger that does nimh and is not Traxxas brand should be able to charge it right up.

I can see that being a possibility but I have two identical batteries and three separate traxxas chargers. One of the two batteries will charge on all three chargers. The other battery, the one I'm posting about, won't charge on any of them.

 

[tudordewolf]

Hey I'm trying to find a way to "wake up" one of my sons over discharged nimh batteries without making a trip up to the rc shop. Any advice?

This is where dumb chargers come in handy. The best option, in my opinion, would be to leave the pack on a trickle charge of ~150ma for 24 hours. This will fully charge all the cells. If you have a DC bench supply, piece of cake, but then you could also do the second option-

If you can get it to register a charge even briefly, the smart charger will be able to take over and charge it back up. If you can put the dead pack in parallel with a good battery for just 5-10 seconds, then immediately put it on the charger, it should detect and begin charging.

 

[Ramp addict]

Have you tried the trickle charger your trucks came with originally?

 

[Pensacola_RC_Guy]

This is where dumb chargers come in handy. The best option, in my opinion, would be to leave the pack on a trickle charge of ~150ma for 24 hours. This will fully charge all the cells. If you have a DC bench supply, piece of cake, but then you could also do the second option-

If you can get it to register a charge even briefly, the smart charger will be able to take over and charge it back up. If you can put the dead pack in parallel with a good battery for just 5-10 seconds, then immediately put it on the charger, it should detect and begin charging.

That's exactly what I'm trying to do. How do I parallel them? Wire the good pack directly to the dead one?

Have you tried the trickle charger your trucks came with originally?

This is what I'm working with. And none of them will put a charge on it

 

[Pensacola_RC_Guy]

This is where dumb chargers come in handy. The best option, in my opinion, would be to leave the pack on a trickle charge of ~150ma for 24 hours. This will fully charge all the cells. If you have a DC bench supply, piece of cake, but then you could also do the second option-

If you can get it to register a charge even briefly, the smart charger will be able to take over and charge it back up. If you can put the dead pack in parallel with a good battery for just 5-10 seconds, then immediately put it on the charger, it should detect and begin charging.

I wired the batteries together for a couple seconds and now it's awake and charging.

 

[J’sCrawler]

Ditch that traxxas charger asap

Anything traxxas for that matter….. sorry @DavidB1126 haha

 

[Pensacola_RC_Guy]

Ditch that traxxas charger asap

Anything traxxas for that matter….. sorry @DavidB1126 haha

I know traxxas stuff ain't the best, but it was a gift and for now it'll do what I need. I have no doubt that not long from now I'll have better chargers and better batteries. I'm on my third week of rc ownership and learning as I go.

 

[Lostinthewoods86]

I'm on my third week of rc ownership and learning as I go.

You’re not the only one I’ve been serving time since Christmas with my son

 

[Pensacola_RC_Guy]

You’re not the only one I’ve been serving time since Christmas with my son

Man it's a waterfall effect. First my oldest got a hand me down slash, then my youngest wanted a hobby rc like his brother, then I wanted to join the fun. So here we are

 

[Lostinthewoods86]

then I wanted to join the fun.

It’s all downhill from here my friend

 

[tntpoof]

I dint know you had a junky traxxas charger. you can put 3 D batterie together + to - down the line so you have 4.5 v attach to nimh i will give it enough voltage to have that traxxas charger charge it.buy a different charger that aint so smart.

 

[Pensacola_RC_Guy]

I dint know you had a junky traxxas charger. you can put 3 D batterie together + to - down the line so you have 4.5 v attach to nimh i will give it enough voltage to have that traxxas charger charge it.buy a different charger that aint so smart.

I will eventually. For now I just wired the good battery to the dead one for a couple seconds and then into my crappy traxxas charger. It charged to full after that.

 

[bill_delong]

I am not familiar with this charger, but just want to double check that you are charging in NIMH mode and not LIPO correct? Looks like there's a toggle button to switch between modes on it and picture appears to be showing a green light indicating that it's in LIPO mode:

 

[Hornet49]

I am not familiar with this charger, but just want to double check that you are charging in NIMH mode and not LIPO correct? Looks like there's a toggle button to switch between modes on it and picture appears to be showing a green light indicating that it's in LIPO mode:

View attachment 182959

I saw that too and it made me wonder. I have the dual 4s live charger and know it has to be on nimh to charge correctly. I don’t think it selects nimh by itself.

 

[Pensacola_RC_Guy]

I am not familiar with this charger, but just want to double check that you are charging in NIMH mode and not LIPO correct? Looks like there's a toggle button to switch between modes on it and picture appears to be showing a green light indicating that it's in LIPO mode:

View attachment 182959

No I wasn't charging on lipo. It won't give you the option to pick a mode until it recognizes the battery. Which until I wired it to a good battery and woke it up, it just gave me a voltage too low error.

I saw that too and it made me wonder. I have the dual 4s live charger and know it has to be on nimh to charge correctly. I don’t think it selects nimh by itself.

No no the green lights were all off. The only light on was the error light. It didn't even recognize the battery because the voltage was too low.

 

[bill_delong]

Sounds like you killed the battery then, especially if it was over discharged for an extended period of time.

I have used various chargers with digital readouts that provide information on the battery voltage and that can be useful to understand what the minimum voltage is for the charger to provide current.

If you want to "hack" some charge into a dead pack, you can try wiring it in parallel with a fully charged pack to help level the voltage. Back in the 80's we used to charge our batteries with a mini jumper cable hooked directly up to a 12V automobile with a charge cable that looked like this:

Basically we would touch the NiCd battery every few minutes until the pack was hot to the touch and that was the indicator that it was fully charged. talk about low tech, ha!