Battery Question
 

Hello,

I have a question concerning a replacement battery for a radio that I just replaced. I replaced a battery for a futaba conquest radio, and the old batteries charge rate was for 15 hours. The new battery is almost Identical, my question is for a new battery, what is the best way to charge it? Should i charge it for the 15 hours, then let it run out, and recharge again to set memory? Would it harm the batery if I unplugged it before work, and only let it charge for 13 hours? Or, can I let it charge thoughout the day and unplug it after work tomorrow..which would be almost 24 hours of charge time? I did turn on the transmitter after installing the new battery, and it had a slight charge on it and ran out almost after 10 minutes. It is a ni-cad 600mah i believe.
Thanks for your help!

Len

RE: Battery Question
 

Charge the new battery at about 1/10 of its capacity for 15 hours. So if it is a 600 mAh battery, charge it at 60 mA for 15 hours. This is not that critical. If you have a 50 mA charger (this is very common), this works OK. And the 15 hours is a minimum. You can charge it for 20 hours or 30 hours and it will still be OK. 15 hours is ideal, but at a low charge rate, you really cannot hurt it. I have left batteries on the charger for several weeks and they still work OK. This is not recommended, but it happens. This is with NiCd batteries which are the most bulletproof as far as charging. You need to be a little more careful with NiMh and very careful with LiPo.

RE: Battery Question
 

DM gave good advice. I'll add one or two things.

Always charge your packs overnight before you go to the field, 12 hours minimum, 15 or a bit more is better.

Never fly more than about 3 flights (max) before checking the remaining capacity in your receiver pack with an Expanded Scale Voltmeter (ESV). Then check it every flight after that. You can buy an ESV through Tower Hobbies for about $15, and it's the best investment you can make in this hobby.
Dennis-

RE: Battery Question
 

Thanks for your help guys....I'll just unplug it after work tomorrow. do I need to worry about a memory on these batteries, or was that a problem with the old Nicad batteries. I seem to remember that when I purchased my first camcorder years ago,I had to charge then drain completely, and charge again to "set" a memory. Thanks for the advice on the voltometer....I have built 2 other planes, and all of them have them on board, their the lightweight ones that plug into your reciever, and give a constant lcd readout..I agree, great insurance considering the consequense.

Thanks again,

Len

RE: Battery Question
 

You don't charge to "set memory", you slow charge (c/10) to insure that all the cells have been fully charged as some will charge slightly faster than the others so if you were using a peak charger, you could get false peaks when some cells peak before all are charged fully. Don't worry about memory on either NiCads or NiMh, that is pretty much a myth caused by inadequate data analysis way back in the 60's. There is a function more properly called voltage depression which can occur in NiCads due to the size of the crystal structure within the cells themselvs (this varies with rate of charge, age of cells and purity of the chemicals used) but is no way a memory problem. Cell fabrication has improved greatly over the years so even this is seldom a problem.