Dumb question: How do you know when your batteries have had it for the day? - RC Groups
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Sep 03, 2005, 02:33 PM
Old Tyme Electric
steve crewdog's Avatar

Dumb question: How do you know when your batteries have had it for the day?

"Back when" we didn't have field chargers, etc. we just flew until we thought it was time to stop or the green light on our tx turned yellow. Now with digital volt readouts, etc, I'm a bit nervous (too much information?) about knowing when to say when.

So nowadays, how do you determine when your rx and/or tx batteries have enough, and how do you field charge them?

Thanks for the answers to dumb questions,

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Sep 03, 2005, 05:23 PM
Registered User
GlowFly's Avatar
My personal no fly volts for 4 cell Rx packs is 4.8v. Less than that & I field charge with a small charger fed from my flight box gel cell.

For a computer Tx I check how long I have from the low volt alarm until the Tx shuts down. If it's less than 15mins or so I buy a larger Tx battery, unless I can change the alarm trigger voltage. For 8 cell Txs without a low voltage alarm I wouldn't fly below 9.5v.
All my Txs currently have battery capacities that will last for a full day's flying without charging.

I guess other folk may use different settings.
Sep 03, 2005, 06:00 PM
Registered User
I stop using the Tx when the needle goes into the red. No different to "back when". We don't all have computer sets these days. I then fast charge it from the lead acid battery I break my arms carrying to the pits for fast charging the electric flight packs.
For electric flight I use an ESC with BEC but usually land before the BEC cuts the power to the motor.
For glo-powered flight I use a battery monitor connected to the Rx pack. Same as with the Tx, I can fast charge when it goes into the red.
I use a Pro-Peak Prodigy which copes with NiCad, NiMH, LiPo and Lead Acid.
Sep 03, 2005, 08:12 PM
Registered User
ebill3's Avatar
I stop at 4.8 and 9.6 under load.

Sep 04, 2005, 06:55 AM
Registered User
SRush99's Avatar
If you are using NiCads make sure you cycle the batteries multiple times to insure you get the most out of your packs. It gives you an idea of how much capacity your batteries actually have. Your flight pack discharge will vary based on your servo current drain and how much you use your servos during flight ( 3D vs Pattern type flying). I also carry one of the Hobbico battery testers in my flight box to check voltage after several flights. I picked my tester up at a swap meet for $5.00! Cheap insurance.

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