The NiCad batteries in my radio and the gel cell battery in my starter will be unused for 6+ months while I am away. What is the best way to leave them? Charge them up and leave them hoping they will be OK when I get back? Leave the power on an let them discharge faster? (I don't have a charger/discharger unit)
Since NiCads self discharge about 10% the first 24 hours after charge and then about 10% per month after that, I would say that if you charge them up right before you leave, you should still have around 40% capacity left when you get back. Just charge them up again when you get back you should be fine. I am pretty sure you don't want to leave them in a discharged state but I could be wrong.
-- Chris W
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania
| The NiCad batteries in my radio and the gel cell battery in my starter will | be unused for 6+ months while I am away. | What is the best way to leave them? Charge them up and leave them hoping | they will be OK when I get back? Leave the power on an let them discharge | faster? (I don't have a charger/discharger unit)
As others have mentioned, the NiCds are best left discharged. In the fridge (not the freezer), if you really want them to last. If discharged and stored in the fridge, they will barely age at all.
Not having a discharger, you could discharge them in the transmitter and plane, but you'll need to stop discharging when you reach 0.9 volts/cell (7.2v or 3.6v most likely for transmitter and plane) -- if you let them discharge all the way, it will damage the pack (by reverse-charging the weakest cell) and will do more damage than just leaving them alone.
Do you have a ESV? You could use it to discharge them -- you'll just need to check the remaining voltage every few minutes, and stop when it's done.
Nobody seems to have mentioned it, but the gel cell battery *must* be left charged -- these batteries will destory themselves if left discharged for any length of time. Fortunately, they self-discharge very slowly, so 6 months of no use after a full charge will be just fine. No idea if putting it in the fridge would help or not. :) (probably not a safe idea ... they can emit hydrogen.)
Chris,
Actually, nicads don't lose that much the first day. They lose about
1% of their remaining capacity per day. I wouldn't worry about topping off the nicad packs they will be alright for 6 months or a year as is. But the gell cell certainly needs to be topped off. The gell cell can suffer permanent damage if let in an uncharge state. The nicads, on the other hand, are better off if left uncharged.Doug
Store NiCads discharged. The gel cell should be left on a C/50 charge while you are away, they don't tolerate full discharge very well.
Kev
there are two, published, schools of thought on this. As you might suspect, they are exactly opposite. I charge mine.
my ol electronics book says nicads prefer to be stored discharged, will lead acid types (like your gell) are happier stored in a fully charged state
It really matters little as to the state of charge for sealed Ni-Cds when you store them. How you bring them back into use is the important part. ALWAYS give them a slow (C/10) charge, cycle once, recharge at C/10 and you are in business. Lead Acid should always be stored in the charged condition, and recharged every 6 months. Cool storage conditions are recommended, your refrigerator if you have room (not the freezer).
-- Red S. Red's R/C Battery Cl> >
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