Batteries & Chargers Nicads, Nickel Metal Hydride, Lithium, LiPoly, Chargers, Cyclers, etc...

battery capacity

Old 05-09-2007, 01:00 AM
Senior Member
Thread Starter
Join Date: Jun 2002
Location: Dallas, TX
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
Default battery capacity

I charge my 700 mah receiver battery with the Futaba charger that comes with the radio. I have read that after charging, the battery losses about 1% capacity per day. I don't know how to transfer this loss with voltage. What percent of capacity is it still safe to fly, and can these percentage of capacity be related to voltage. Also, let's say I charge the plane and then don't fly for 5 or 10 days (this has happened a lot lately due to the weather). To be safe, I usually just give it another full charge. If we way five days, how lone should I charge to bring the battery to full capacity. Thanks for the help and information.
Old 05-09-2007, 01:17 AM
Senior Member
Join Date: Jan 2007
Location: Sometown, Northern Utah
Posts: 4,432
Likes: 0
Received 0 Likes on 0 Posts
Default RE: battery capacity

4.8v is the absolute lowest you want to be, but most guys stop between that and 5.1v or so. You didn't mention how fast your charger was, but going off of mine which is 55mA

If the 1% rule is true, then you are going to loose 35mA in 5 days and 70mA in 10 days. Probably something like an hour top off should get you right up to peak capacity after a week of the pack laying around.
Old 05-09-2007, 06:23 AM
Senior Member
Join Date: Apr 2007
Location: Dunedin, FL
Posts: 155
Likes: 0
Received 0 Likes on 0 Posts
Default RE: battery capacity

Ive heard its more like 10% per day for Nicads and 20% per day for Nimh.
Old 05-09-2007, 07:46 AM
Senior Member
Join Date: Jul 2005
Location: Waterford, PA
Posts: 984
Likes: 0
Received 0 Likes on 0 Posts
Default RE: battery capacity

NiMH are rated at 20% self dischareg after 30 days. then slows down to 70% 60 days etc. This was duracell spec. all batteries are differant. Sanyo new enevole "sp?" are rated the best talking months..Also as batteries get old they self discharge faster if dead in two weeks it's time to replace. Thats why a good charger that can repeak is the best, I can top off my pack in 5 to 10 minutes hit all the packs Iam takeing to field as I load the car. Then do'nt have to say did I charge that plane
Old 05-09-2007, 09:03 AM
Senior Member
Deadeye's Avatar
Join Date: Jul 2002
Location: Dutton, MT
Posts: 4,516
Likes: 0
Received 1 Like on 1 Post
Default RE: battery capacity

Buy a $5 appliance timer, and set it to charge for an hour or so twice a day. No chance of over charging, and the plane is always topped off.
Old 05-09-2007, 09:19 AM
Senior Member
My Feedback: (16)
Join Date: Apr 2002
Location: Locust Grove, GA
Posts: 12,942
Likes: 0
Received 0 Likes on 0 Posts
Default RE: battery capacity

Your question is really open ended.
I have charged a pack and let it sit for a week then get 3 flights out of the plane with no problem.
So it really depends. get a loaded volt meter and just check your pack before the first flight and AFTER each additional flight.
When packs sit without a load, the voltage will recover a little. This is why you want to check it after the flight.
Old 05-09-2007, 03:32 PM
Senior Member
Join Date: Dec 2001
Location: FL
Posts: 7,769
Likes: 0
Received 5 Likes on 5 Posts
Default RE: battery capacity

The discharge rate is not a fixed value as it varies with the age and to some degree on how it was manufactured. The remaining capacity as it discharges is not a linear decrease as the discharge (typically 1 to 3 % per day) is like a capacitor discharge, it discharges less mah hours each day as the next days discharge is a percentage of the remaining charge i.e. 3% the first day, then 3% of the remaining 97% the next day then 3% of the remaining 95.09% etc. so never get completely discharged.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.