Reviving older NiMh Batteries - R/C Tech Forums (2024)

$$$...

Join Date: Aug 2005

Location: Sydney, Australia

Posts: 627

Hi guys, hoping someone can help me out. I was cleaning out my hobby room/closet and found some of my older NiMh batteries, which turned out well because I've just overhauled my old HPI Pro 2 and was hoping to run these packs in it, just for fun in the street and during free practice at my local track. I can't remember when I used them last, and when I try to charge them they start, and then after a few minutes they cut-off. I know that the most likely answer is going to be bin them, and I'm quite prepared to do so, just wondering if anyone has any old school tips for reviving them... trickle charge for hours then try to cycle them???

Thanks in advance for any help
Daniel

ps - I'm using a Duratrax Ice Charger

Bishop

Join Date: May 2004

Location: Brisbane

Posts: 2,223

I'd forget about it and bin then, I tried just about every trick I could find on some myself, cold/heat, high and low charge, they come up briefly then die again just as fast, not worth the effort when you can buy a few perfectly good LiPo pack from Hobbyking for around $30 a pack these days.

$$$...

Join Date: Aug 2005

Location: Sydney, Australia

Posts: 627

torg

Join Date: Jul 2009

Location: Tustin,CA,USA

Posts: 420

You don't *have* to get a Lipo compatible ESC. Only thing to worry about is the LIPO cutoff. A cheap way to still run on old ESC is to use a Low Voltage Buzzer Alarm Indicator you can by them on ebay for $2US.

I use it in my RC tank

OldSkool

Join Date: Jul 2003

Location: Barnawartha, Victoria

Posts: 798

Mate chin up, hobby king turnigy saddle lipos should fit into you pro2. If your not sure take it to a track and see if you can test fit a pack before you make a purchase.
Lipo chargers like the B6 are cheap and balance, you can get one for about $30. If you need a lipo cutoff for your ESC to stop over discharging the battery when running, either the buzzer, or an inline cutoff is available. Around $15.

A cheap brushless motor combo will only set you back a little over $100.
Longer runtime, let maintenance, and generally faster.

Last edited by OldSkool; 01-02-2013 at 03:18 AM.Reason: Covered most in above post

terry.sc

Join Date: Aug 2008

Location: Stockport, UK

Posts: 1,024

it depends on the nimh, some makes can be brought back to life, some struggled to last a whole seasons racing before having to be binned. I regularly use old nimhs for bashing every year and after being left over winter they usually need a few cycles to come back to life. If they can be brought back a long trickle charge will stabilise the voltage so your charger can then monitor the cells when being charged as the battery voltage is too low for your charger. If they do recover they will need a few cycles before you can see how much power they have.

If the cells are dead, you still don't have to spend on lipos and all the equipment to go with them. Nimhs are still around, still the most popular battery packs amongst non racers. Because racers don't use them any more decent nimhs are available for $20-30 a pack. It can be hard to find saddle pack nimhs, but www.cheapbatterypacks.com will happily build them for you.

Geezatec

Join Date: Oct 2007

Posts: 1,702

NiMh did have memory like NiCd. Completely discharged, charge half the capacity. Let them cool down a couple hours the discharge. Then cycle them to 75% then 100%. remember to let them cool down while cycling. Then discharge them by running the car.

If you charge the cold!! You'll probably see or hear one of the cells burst.

Then you can consider Lipo's, that everyone recommends. Answering the original question.

Skiddins

Join Date: Feb 2006

Location: Windsor, UK

Posts: 4,952

I'm not recommending this, but I used to 'flash' them with a 12V battery.

A very quick flick of some wires connected to a 12V and then to the individual cell, so the 12V source is connected fora fraction of a second. It's not to charge them in any way, but to 'wake them up' Leave alone for an hour or so then try charging them.

But in all honesty, get some cheap lipo's or saddle lipo's as others have mentioned.

Skiddins

Johnny Wishbone

Join Date: Feb 2006

Posts: 3,756

$$$...

Join Date: Aug 2005

Location: Sydney, Australia

Posts: 627

IndyRC_Racer

Join Date: Jul 2006

Location: Indianapolis

Posts: 2,355

Don't forget that the HPI PRO 2 can be configured to use stick pack batteries as well. If you are just bashing, this might be the easiest option. In case you don't have the manual, here is the information directly from HPI (http://www.hpiracing.com/graphics/instr/p2/pro2-17.jpg)

Companies like Orion sell inexpensive "stick pack" lipos that should fit in the car just fine.

Hopefully you will be able to revive your Nihm batteries though...good luck.

InspGadgt

Join Date: Nov 2001

Location: Hawaii, USA

Posts: 7,191

Geezatec

Join Date: Oct 2007

Posts: 1,702

exellant charger for NiMh's for cold mode or any mode. Wont sell it also.

InspGadgt

Join Date: Nov 2001

Location: Hawaii, USA

Posts: 7,191

$$$...

Join Date: Aug 2005

Location: Sydney, Australia

Posts: 627

Nah mate I don't need to buy a new charger yet, even if I go down the Lipo road my Duratrax ICE wil do LiPo charging. Will be taking my car to the LHS with me, if I can get some Lipo saddle packs to fit I might buy some of those, or else I'm sure they'll have some NiMh packs/cells that I will be able to use.

Thanks for all the help guys
Daniel