batterys

Anoptimistprime · Post by **Anoptimistprime** » Mon May 02, 2011 1:55 pm

Hi I'm kinda new to all this I've orderd some servos and a rx/tx system and I know how to modify the servos as I tested it on a spare from an old boat
I was just curious as to whats the smallest kind of battery i can get away with and where can i get a charger for them?
I have a holder for 4 aa batteries would this run it successfully on 3 servos?
Thanks
Danny

joey_picus · Post by **joey_picus** » Mon May 02, 2011 2:47 pm

Welcome to the forums

It depends largely on what sort of battery chemistry you intend to go for - realistically, in an antweight, you can get away with 100mah or thereabouts provided you're not doing a spinner and with lithium polymer packs that would be a bit less than 10g. However, if you're using servos, they (and the reciever) might need a voltage regulator to lower the battery voltage to a level that they can handle without detonating, so you might be better off going for some NiCad or NiMh packs which are about 10-15g for the same capacity (about 120mah at 6v?)

NiCads and NiMh can usually be charged from a transmitter/reciever charger, Lithium polymer on the other hand require specialist chargers such as the ProPeak Quattro if you can find one of those (Technobots have stopped selling them it seems?)

I don't know where you'd get the small NiCad/Mh packs from though, I've only ever used LiPos, usually with speed controllers and geared motors rather than servos, so it's not my field of expertise I'm afraid.

Hope that helps

4 AAs would run it with no trouble but they'd weigh a hell of a lot...

haz · Post by **haz** » Mon May 02, 2011 3:45 pm

4 aas would be about 100g

Anoptimistprime · Post by **Anoptimistprime** » Mon May 02, 2011 3:57 pm

Thanks or your help
I have a charger with a tamiya connector
And I can get hold of an adapter to a jr thingy for a receiver battery, how long would it need to be charged for to fill a 6.0v battery?
Here's the specs for the charger if it's any help

input : AC110-240V

output : DC 1.2-12V
100-220mA

Chemistry: Ni-Mh Mi-Cd?

As for the battery there's a 6.0v nimh hump battery and it's only 29g

for only ?5 with postage woopwoop

haz · Post by **haz** » Mon May 02, 2011 4:01 pm

29g is quite a lot for a battery still

earthwormjim · Post by **earthwormjim** » Mon May 02, 2011 4:01 pm

http://component-shop.co.uk/

Batteries,
Remote Control,
Small,
9th entry...

6.0V 120mAh 1/4 AAA NiMH Battery Pack.

When weight is absolutely critical - weighs just 18.5g (0.65oz)

* ?4.00 each.
( I used the first entry,4.8v annd 15g for my featherweight,it was fine for running three small servos.)

Post by **BeligerAnt** » Mon May 02, 2011 4:08 pm

For NiMH or NiCd batteries, charge at a constant current generally not exceeding the capacity of the cells. Charge for 140% of the capacity.

So, for a 110mAh battery, charging at <110mA will be OK.

Total charge = 110 * 1.4 = 154mAh.
Charging at 100mA, charge time = 154/100 = 1.54 hours

Anoptimistprime · Post by **Anoptimistprime** » Mon May 02, 2011 4:21 pm

just found this
http://component-shop.co.uk/html/body_mw2168vd.html
near the bottom the tables really helpful
so im probably going to buy one of those and a few batteries
how long would these batteries genreally last for?
im initially going to stick with a flipper arm or similiar
if i was to modify it and attach a spinner for example would th
is battery still last a reasonable time?

haz · Post by **haz** » Mon May 02, 2011 4:25 pm

for a spinner you need to go lipo, im afraid

Anoptimistprime · Post by **Anoptimistprime** » Mon May 02, 2011 4:34 pm

okay for just 3 servos how long would the battery last?
the servos are 2x micro 9g towerpro 1x hitec standard 3s11(maybe a micro i am undecided atm)