I'm starting to think about building and setting up a new plane. I've been trying to figure out what engine servos and batteries I want. I have almost everything figured out except for the battery. Up until this point I have bought all of my electronics in a radio combo, but now I have the radio and need to buy the servos, reciever, and batteries separtate. So what battery do I buy? I will have a JR R700 reciever, three 72.oz digital servos, a 107.oz servo, and a standard servo. I want to go with 4.8V but how many mAh? I also don't know if I want to go with a NiCd or NiMH. What does mAh mean anyway? I know that which battery I buy probably isn't a big issue, but any coments or advice would be great.

Thanks,

LT-40

A standard 4.8 volt 600-700 maH should be fine for practical applications

mah is how many milli amps the battery can supply in one hour. if you have a 600 mah battery and your average current draw is 1200 ma your battery will last 1/2 hour. That said those digital servos will eat up their share of the battery and I would not expect much more than 2 maybe 3 flights with a 600 mah battery. I don't know what battery packs JR has out but I use 1500 mah 4.8 volt Futaba packs. (that is a Nicad pack, nimh packs have higher capacity in the same size)

LT40;
I'm assuming with those servos you aren't talking about an LT40. If you want more than one flight a 1400 MAh battery is more appropriate. The JR700 is a good little receiver.

http://bpassociates.homestead.com/bp.html

Give Max a call at BP associates (address above) and tell him you need an 1100mah 4.8V Nicad. Hes a super guy and builds some of the best NiCad and NiMH batteries and starters around.

Thanks guys. This is just what I need. Thats very interesting about what the mah means. I think I will go with a pack that is between 1100 and 1500 mah depending on the cost. I'll also look into those BP associates. Once I get a pack, what do I use to charge it with? Can I use my JR trickle charger that came with my last radio or do I need to get a new one? I can always use my quick field charger, but I like to trickle charge whenever possible.

Thanks again,

LT-40

Hi LT-40,

JR 700 is a good receiver, I have this receiver somehow it stopped working after my P51 Mustang PTS crashed. The Tx/Radio of JR is 5 channel XF421 EX, the battery is pack for the receiver has 4 cells pack and is 4.8volts, and its 600 mah/milliampere per hour. its Nicd=Nickel Cadmium, was first introduced in 70's in sweden, due to weight it was replaced by Nimh=Nickel metal hydride which was introduced in I think 90's anyway, more have been introduced like Li-ion, lithium ion, lithium ion polymer but these are used for cell fones, laptops etc. Ni-mh is more powerful than Ni-cd, and it doesnt store memory, well, all battery cells rechargeable have same 1.2 volts and total make 9.6 volt for Tx, and 4.8 for Rx. In order to increase your flight time, you can use Higher Mah battery pack cells, like 1500 mah or even 2600 mah. As I had the battery problem of my Tx, I got Nicd battery pack of 700mah, honestly speaking, Ni-mh was doubled of its price so I bought Ni-cd, anyway, its working very well, and Im sure my radio would easily give me 7 to 9 flights. Anyway hope for the best for you.

Mody

Well,

A NiMH pack of adequate size will work just fine with your trickle charger, but digitals eat lots of power. I did not catch what plane you are going to be putting them in, but you could go with a 6V pack or even Li-Ion batteries, (not lipos).

I wish I had started out using 6V and regulators, (in larger planes only). I am now switching everything over slowly. With those digitals, get an 1100 MAH pack or larger.

What plane are you building anyway...some of this may be overkill.

Good Luck!!

I would go with a JR Sport 4.8 volt 1500 mAh NIMH. I have two, one in my U-Can-D0 .46 and in my 25% Giles. They last long and work well.

Garret H