Battery Question

[Need4speed423]

Hey,

I was just wondering if its bad to let batterys sit without use for like 2 months without charging them. Because my batterys have been sitting by my car since september without being used or even charged.

P.S They are NIMH

Thanks!

[SS Pede]

Depends on how much voltage was in the batteries when you left them. NiMH cells are more likely to be damaged by over-discharging than NiCd's. In addition, stick packs can be vulnerable to cell reversal because the cells could have uneven voltage to begin with (and you have no access to them to even the voltage out).

What are your exact batteries? Were they charged or discharged when you left them? They are probably OK, but what exact packs are they (for example, GP3300 unmatched stick pack).

[Need4speed423]

they are venom 3000s and there just a normal stick pack.

[losiguy1090]

How much charge did you leave in them?

[Need4speed423]

i would say they were about 1/4 way full

[SS Pede]

If they were 1/4 full you're probably just fine. :) If you aren't going to be using the packs soon, you could put a bit more charge in them. Next time you charge them up fully to run your car, pay attention to how warm the pack is. If one area of the pack (in other words, one cell) is much hotter than the rest, then that cell is likely reversed. You will also notice when using the pack that your car is much slower than normal.

[highroller]

I've left NiMH from the Panansonics to GP3300 stored discharged with only a .90 volt per cell level for over 8 months.
The only problems I encountered when charging them after those long periods where more problems with false peaks, peak voltage, MAH wasn't as constant, in use there wasn't the punch or crispness. Once the pack was used a couple of times it then exhibited normal performance.
Make sure the cells are discharged or any residual voltage, charge the pack - if charger displays voltage, MAH rate note that. Run the pack in vehicle, then put pack(s) away. Wait a day or two, completely discharge the pack (allow it to cool at room temperature) then charge noting the peak voltage, MAH rate -they should be back within what you saw before and should be better that what you saw. Depending on what type of 3000 there may be some decline in the MAH rate at peak, Panasonics normally had more of a decline that other types of NIMH no matter what you did.
In any case a sign of cells going bad is the MAH rate when pack has peaked charged - pack should exceed the rate MA capacity of cell - 3000 while normally peak at 3100 to 3280 + depending on cell grade matched/zapped or unmatched.