Peter99

Helo

Justr before maiden of my katana gs40 my battery failed when charging.
Now when i have to buy a new one i want to get the litest posible battery to keep my plane lite
Did any one use 5 cell packs made of SANYO 720 AAA nimh cells (pack weights less than 3 oz.) ??
Will they be powerful enough to power 4 HS-475 servos??

Thanks for any info

Peter99

i can allso get Packs made of 5/4 AAA 850 nimh sanyo cells

buildflycrash

I have had trouble with the small MiNH packs. They DO have the power to push 4 or 5 standard servos. The problem is duribilty when charging- they burn-up!

I use 5 cell 1200Mah packs from Radical RC. Only 4 oz and good for 40 or 60 size profile - No problem. Six or more flights on a charge. The little packs will really only do 3 or 4 flights.

Dave McDonald

My Feedback: (19)

I've been using 5 cell AAA NiMH Energizers and Rayovacs from Walmart for years on 40 size profiles. Several of them are outfitted with Futaba 9252 digital servos. I use a Triton to charge them and haven't had any problems. But one of the keys to using these AAA NiMH battery packs is that you can't charge them any higher than 1.2 amps or it will overheat the battery and/or cause a false peak detection.

Peter99

thanks

I think yhat i will go with the 5/4 AAA 850 cells.
They should last for 3 ten minut flights that i usually do when im at the airfeeld

wessco

My Feedback: (7)

How do you build a pack with these batteries?

Dave McDonald

My Feedback: (19)

The cells need to be wired in series. (+ to -, + to -, + to -, etc.)

The red wire from the connector gets soldered to the "+" end of the first battery.
The black wire from the connector gets soldered to the "-" end of the last battery.

Use sandpaper on the metal ends of each battery to break through the factory gloss finish before soldering.

After building the 5 cell AAA battery pack, I recommend charging for about 24 hours on a standard 4.8 volt wall charger to stabilize the cells. After that, they can be field charged, but at no higher than a 1.2 amp charge rate.

The photo explains the steps.

XJet

I'll put a vote in for the 2/3A 5-cell packs from Radical too.

I tried AAA packs and got badly bitten -- had one go flat after two flights.

It should have had heaps of capcity left but the problem is the internal risistance of those small cells. It means that a cell rated at 800mAH will not deliver anywhere near that amount when you start sucking a couple of amps out of it.

There's a lot of money, time and sweat involved in building a new plane after a crash -- I'd rather just use a good battery to start with and save myself some grief.

danny31292

I would defiantly go 5 cell. Dont get a battery that is too small. You dont want to only fly 3 time and have to charge. I'd say go with a 1000 mah battery. Nihm of course