Battery Problems

[porky 1]

can any one help i got some new batts off ebay 7.2 volt 3800mah when i charge them they don't seem to last very long 5 mins,i use a pro-peak varipulse charger i charge my 2200 mah on quick charge they last 30 mins + i charge at 4 amps so can anyone tell me if i'm charging at wrong amps as lost instuctions at moment PLEASE HELP many thanks

[deejay1711 0]

i might be wrong but i don't think pro peak chargers charge nimh batterys properly without damaging the cells. they only do nicd. Don't take this as a definite cos i'm not sure. someone will be along in a bit and give you better info and detail.

[porky 1]

JUST CHECKED THE BOX, IT DOES SAY NICAD/NI-MH CAN BE CHARGED THANKS ANYWAY

[owsey15 0]

on the charger does it say what mah it will charge up to? cos sometimes they will only charge upto a certain amount

cheers john

[grizy 12]

The manual is on the Ripmax website

Pro Peak Varipulse Charger

Max charge setting on AC 3A. Are you using an external 12v supply?

Have you tried charging at 3A?

Hope this helps

Grizy

[dimblum 1]

can any one help i got some new batts off ebay 7.2 volt 3800mah when i charge them they don't seem to last very long 5 mins,i use a pro-peak varipulse charger i charge my 2200 mah on quick charge they last 30 mins + i charge at 4 amps so can anyone tell me if i'm charging at wrong amps as lost instuctions at moment PLEASE HELP many thanks

Most NiMH batteries I have bought -Venom Racing- never recommend charging higher than 2 amps. 4 amps might be killing the life of the battery (not sure). If it gets hot during charging, then it could be destroying the cells.

Is there any special brand/name on the battery? There might be info online for charging recommendations.

[94eg! 834]

NiMH cells are notorious for false peaking. The best way to check for a false peak is by checking the temp of the battery as soon as the charger shuts off. The cells are still room temp, then you know it's not done charging. If the charger shuts off and the cells are warm, then you know the battery is ready to run...

I know babysitting the charger sounds like a total pain in the butt, but it's the only thing you can do without buying a more advanced charger (if that even helps). I own two separate chargers, and get false peaks on my non-race packs all the time. I have one charger (MRC Super Brain 959) that false peaks at least 5 times during a GP3300 charge no matter what I do different.

PS: As soon as the battery starts getting warm, it's done. You don't want it to get really hot...

At a 3amp charge rate, it should take over an hour to charge a 3800mah battery if it was empty...

[type54 0]

just to throw a spanner in the works i got some cheap batterys of evil bay surposed to be 33oomah but had no markings on them which diidnt last long when i cut the cover of the cells inside were only 1600 hope its not the case for you but it might be worth checkin.

[Lemming 48]

can any one help i got some new batts off ebay 7.2 volt 3800mah when i charge them they don't seem to last very long 5 mins,i use a pro-peak varipulse charger i charge my 2200 mah on quick charge they last 30 mins + i charge at 4 amps so can anyone tell me if i'm charging at wrong amps as lost instuctions at moment PLEASE HELP many thanks

JUST CHECKED THE BOX, IT DOES SAY NICAD/NI-MH CAN BE CHARGED THANKS ANYWAY

From experience...

Pro Peak chargers (both the fixed rate 3.5amp one, and the varipulse chargers) seem make a real mess of charging nimh cells. One of my packs (1900mah nimh) worked for maybe 10 mins off a charge, whilst the other worked for 45 mins (both on a TLT with a Lathe motor, hence the long run-times).

Same problem with 3300mah Vapextech packs. Kept getting less punch and run-time than my 1700mah nicd packs charged off the same charger. False peaks continuously on anything bigger then 2500mah, and nimh batteries just get messed with as well as false peaking.

I bought a BMI Digipeak 14 AC/DC charger (replaced for free with a BMI 4 in 1 by Mtroniks when it went wonky) and within 2 cycles the 1900mah battery was back up to 40 mins run-time, and the 3300mah batteries charged properly each time (taking 3100mah to 3500mah each - charger has a digital display). Also works fine on my 4400mah 8.4v nimh packs.

I have since bought my dad one (as he is into the hobby as well and used Pro Peak chargers) and sent it down to him. He now has got 7 out of 9 "dead" batteries working at 75% capacity or better (batteries that died after 2 - 5 minutes on a standard silver can motor).

Moral of the story is that I won't ever use these particular Pro Peak chargers again on anything bigger than 2000mah in nicd, and never again on any of my nimh packs!

Steve

[dimblum 1]

NiMH cells are notorious for false peaking. The best way to check for a false peak is by checking the temp of the battery as soon as the charger shuts off. The cells are still room temp, then you know it's not done charging. If the charger shuts off and the cells are warm, then you know the battery is ready to run...

I know babysitting the charger sounds like a total pain in the butt, but it's the only thing you can do without buying a more advanced charger (if that even helps). I own two separate chargers, and get false peaks on my non-race packs all the time. I have one charger (MRC Super Brain 959) that false peaks at least 5 times during a GP3300 charge no matter what I do different.

PS: As soon as the battery starts getting warm, it's done. You don't want it to get really hot...

At a 3amp charge rate, it should take over an hour to charge a 3800mah battery if it was empty...

This message just made my day. I have lost a few batteries to false peaks and always thought I was setting something wrong. I used the MRC Super Brain 820 in the past and figured that the "Auto Detect" feature killed my batteries by over amping the charge rate. I switched to the MRC Super Brain 960 which has worked much better since I can set the amps in the control panel.

On occasion, the 960 would still attempt to overcharge my batteries and I would have to disconnect them. I thought I had bad luck, now I know that it is just the nature of NiMH

Dan

[HunterZero 76]

just to throw a spanner in the works i got some cheap batterys of evil bay surposed to be 33oomah but had no markings on them which diidnt last long when i cut the cover of the cells inside were only 1600 hope its not the case for you but it might be worth checkin.

Oooh, that is sly.

- James

[porky 1]

thanks to all who replied going on hols in couple of weeks so will look for a nother charger when get home thanks again

[DCLXVI 3]

I'm using a Imex B5 and I'm really happy with the NiMH performance on it...it does require a 12v supply though (and it doesn't have a discharge function)...