This has probably been beat to death already but this is the beginners forum - so... here's a battery question:
If fully charged batteries in both the transmitter and plane (nitro) are used for a few flights, (say a total of twenty minutes) is it a good idea to put them back on the charger for the next day or should they be allowed to discharge further before recharging. I do understand the risk of having low batteries but my current radio system manual estimates about 90 mins of life, and, there is a battery life indicator on the radio as well. The batteries are NICad. Will they tolerate repeated peaking. What about LiPoly's and NiMh? This getting confusing with all the various batteries this hobby entails. My garage wall looks like a charger museum. At least I'm having a good time with the discharging part.

If you charge the batteries with the supplied charger (C/10 rate) they will not overcharge. It's always best to recharge after use unless you really (and I mean really) know your setup. That applies to NiCd and NiMH batteries.

LiPo batteries should be charged fully before use, but they must be charged with a special charger that is peak detecting at a rate no more than 1C. You *should* also balance LiPo's with a balancer if your charger doesn't have that capability.

I agree. Charge them every time. Repeated charges at the low rate do not diminish the service life. This is especially true with Li-xx packs. They last longer if they are never allowed to deep-discharge.

At the field, my instructor checks the receiver batteries about every 2-3 flights, only takes a second if you leave your wire hang out the right side of the fuse or if you have a charger jack installed with your switch and the voltmeters that pull a load are only about $10 at TH. If the receiver battery gets under 5v he will use a field quick charger to bring them back up but only 1 time. After that the night is done and it's back to the radio charger for the slow charge. As a side note (don't ask how I found out) my batteries were fully charged when I left for work yesterday. When I started flying I was only reading 5.1v.....I was told not to leave them in a hot car all day as the heat will pull the charge down (learned something new!). Two short flights and a quick charge and I was good to go for the rest of the night.

At 5.1 volts the battery still has almost all of its capacity. I stop flying when I get below 4.8 volts.

Hell, the battery rated voltage is 1.2 V per cell (nicad). They work fine all the way down to 1.07 Volts per cell. So I have ran packs for years using them down to 4.6 Volts without worry. Packs and airplanes that I know really well and have graphed out to even lower voltage. But I use a very good digital multimeter (Fluke) and a power resistor to load the airborne pack to about 300 mA while testing.

Also you want to recharge the NiMh preferably the night before you plain to fly again. They will loose charge over time so if you charge them up when you get back from flying then dont fly again for 2 weeks you might have some bad results.

High Plains - what kind of resistance are you putting across the battery to make your voltage check? Is this a good enough way to check battery performance? Do commercial battery testers test more than voltage levels? I wouldn't mind springing a few bucks for a tester but I do already own a digital fluke meter and if I can get away for the cost of resistor, why not?
It seems clear from all of you that I'm okay to charge frequently as long as I'm using the charger that was supplied with the batteries. Thanks for all the input.

You'll want to use approximately a 16 ohm resistor. I use a power resistor and meter to check my flight batteries as well.

Any surplus power resistor in the range of 15 to 20 Ohms will work fine for a 4.8 Volt pack of nomenal capacity. If you are into more servos and higher current applications you may want a lower value resistor. Generally I like testing at a current of around 40% of battery capacity. Graphing the discharge curve for new batteries and comparing to the original graph as the pack ages will keep you out of trouble. Pay attention at the end, if it drops suddenly when the voltage is at 4.4 or higher you have a weak lower capacity cell. A good pack will get below 4.3 before hitting the discharge knee.

Last year I started charging my systems with a method proposed by Red Scholefield. I plug everything into a timer set for one hour per day to keep all the batteries fully charged. If I come back from flying, I charge normally overnight, then go to the one hour per day at full wart current. Works really great, costs less than $10 for the timer.

I highly recommend you spend some time reading this web site:

http://www.rcbatteryclinic.com/

I'm pretty sure he has forgot more about NiCad's than the rest of us will ever know. And he didn't forget very much.

If I haven't flown in more than a week, I'll charge everything the night before I plan to go fly. That said, I still check battery voltage before EVERY flight, with a loaded meter, especially when I've brought several planes out. Case in point, at our last fly-in, one of our most experienced pilots flew his 1/4 D-VII after a full charge. Landed, flew another plane, walked around, visited, etc, flew the second plane again, then flew the D-VII about three hours after the first flight. Made it around the pattern once, lost everything, crashed. Cause? He didn't check his battery voltage before the second flight, and had left his Rx on after the 1st flight, and had a semi-bad servo that drained the battery between flights.

I also cycled my NiCd's once a month if I'm using them regularly, or after about 15 recharges, regardless of how little they were used each charge. The newer batteries are less prone to developing a "memory", but I believe it helps make them last longer and hold a fuller charge to occasionally discharge them and then recharge fully. I've pretty much moved to all NiMH, and am exploring Lithium batteries, but can't justify the cost for the advantages yet.

Lots of good input here guys - much appreciated.
Snobelt

Absolutely slow charge them the night before you fly. And check them prior to EVERY flight using an Expanded Scale Voltmeter (ESV). It's like getting into your car and looking at the gas gauge every day rather than simply once a week.

Yes, and EVERY flight includes the first. Setting the battery on the charger does not guarantee a full battery.

>> es, and EVERY flight includes the first. Setting the battery on the charger does not guarantee a full battery. <<

I always check mine at the house before leaving for the field.