NimH 7.2v fully charge size

[leyla1989]

Hi all I have a 1200 mah. 7.2v nimh 6 cell

My charger is currently at 8.52v

I don’t know if it will auto stop I just put the charge rate to 1.2 amp

Should I stop it at a certain voltage ?

Thank you

Hi all I have a 1200 mah. 7.2v nimh 6 cell

My charger is currently at 8.52v

I don’t know if it will auto stop I just put the charge rate to 1.2 amp

Should I stop it at a certain voltage ?

Thank you

It’s now at 8.703v

 

[Bogda89]

Hi all I have a 1200 mah. 7.2v nimh 6 cell

My charger is currently at 8.52v

I don’t know if it will auto stop I just put the charge rate to 1.2 amp

Should I stop it at a certain voltage ?

Thank you

It’s now at 8.703v

I'm am not an expert on nimh batteries but they usually don't charge to a certain voltage like lipo, I believe chargers use internal resistance or some measurement like that to determine state of charge. Usually when they get close to full charge they start to heat up.

I don't know what kind of charger you use but if set to nimh settings it should stop charging automatically. If you charge nimh to full they like trickle charge, as low as 1/10c, if charge to maybe 50% you can blast them 2c, 3c or even higher if they stay cold, obviously slower charge is always better for longevity

 

[bill_delong]

NiMh chargers use peak detection before they shut off, more info here:
https://batteryuniversity.com/article/bu-408-charging-nickel-metal-hydride

Let the charger perform its function, if you disconnect before saturation charge is complete you will not get a full charge... if you charge at higher than 1C then you will likely get a false peak which means you won't get a full charge. The battery should be hot to the touch indicating that it is near a full charge.

 

[tntpoof]

when I raced a sub c pack in the nimh peaks days b4 lipo .
by adjusting the delta peak higher you could push the packs near 1.50 volts a cell but they would only last for like 3 to 4 race days so 12 charges.
at that higher delta peak would give you a higher voltage to start but kill pack in the end.seen guys really abuse nimh packs like charging at 20 amp .


stop charger if you ever have a concern

 

[tudordewolf]

Hi all I have a 1200 mah. 7.2v nimh 6 cell

My charger is currently at 8.52v

I don’t know if it will auto stop I just put the charge rate to 1.2 amp

Should I stop it at a certain voltage ?

Thank you

It’s now at 8.703v

I wouldn't worry about the voltage as much as the current. I would charge that battery at 0.6A, max. C/2 is a good rule of thumb for Nimh


Understanding *why* nimh cells get hot at the end of a charge helps. Unlike other chemistries, Nimh batteries have the ability to "bleed off" a certain amount of overcharge, meaning that the surest way to charge one is to slightly overcharge them and let the extra bleed off. There's a limit to how quickly they can discard that extra energy though, and they do so as heat. Charging them too aggressively will overwhelm that process, causing them to overheat and some of the capacity to be lost with every charge cycle at too-high a rate.

Charging them with high current before they're full is perfectly fine, the problem is you need to know when to lower that current, so a lower charge rate throughout can accomplish the same thing with less risk to the cells.

 

[Greywolf74]

I would also only charge a NiMH pack at .5 ot .6A unless I'm using a temperature sensor while I'm charging. Charging much more than that without a temp sensor will shorten the lifespan of the battery

 

[leyla1989]

I feel like I’m understanding a bit more about the electrics side of the rc world

Thank you all your information is greatly appreciated

God help us all when I finally get to start stripping the the Kraton down if it brakes .!

 

[Greywolf74]

I feel like I’m understanding a bit more about the electrics side of the rc world

Thank you all your information is greatly appreciated

God help us all when I finally get to start stripping the the Kraton down if it brakes .!

Its a lot to take in at first but keep pluggin' away at it and you'll be in here helping other people before you know it