Desert Toad

Hi all,

I'm beginning to put together a Sig Mayhem and plan on using Hitech HS-5625s for all control surfaces. I've read that digital servos use a lot more juice so a 6 volt battery would be best. My only question is which one? How many MAs do I need?

thanks,

DT

JohnMac

So what you need is a higher capacity battery for digital servos. There is nothing wrong with a 6v battery; you will get higher performance from your servos, but at the cost of a shorter life from the servo motor. But you will also get a higher current draw with a 6v battery over a 4.8v battery, so go for a bigger battery to compensate.

XJet

My preferred batteries are two-cell A123 packs. These come in 1100mAH or 2300mAH capacities and produce a healthy 6.4V even under heavy load.

If you want to stick with conventional NiMH packs then the 5-cell Intellect 1500mAH 2/3A packs are also very good -- able to handle a constant drain of up to 20A without blinking.

I used two of the 1500mAH 2/3A packs in my 30% Extra (with 9 Hitec digital servos) and they worked perfectly -- although I've since switched to A123 packs.

rcairflr

My Feedback: (44)

New!! 1500 Series Elite '2/3 A' Rx pack, 4 cell

The new Elite HR-1500 is another step ahead in NiMH technology, replacing the earlier GP1100 and Intellect 1400 at the same small size and weight. With it's superb high capacity and low impedance current handling capability it's an excellent pack for sport flyers and 3-D pilots alike as a building block to a safer, better choice then high impedance AA Nicads in applications with digital high drain servos. Sport, Sailplane and Heli pilots love it for its higher capacity without a size or significant weight penalty usually associated with capacity increases. Also very popular in a parallel arrangement driving digital servo's for 25% IMAC/3D pilots looking to get maximum capacity and dependability with minimum weight gain. We're also seeing this pack used in Ignition applications where a little extra run time without the voltage drop under load usually associated with higher impedance NiMH 1650-AA's. This is a small pack, with a better 'punch' than ANY AA sized pack; Nicad OR NiMH can deliver!

Single cell dimension: .67 x 1.1
Finished pack weight, inc connector: 3.4oz $27.95
Internal Impedance: 7.5 mOhms


Above is copied from Hangtime hobbies website. The low impedance Elite 1500 would work fine for your application, or as listed above a 1100mA A123 would also work great, there would be no need for a 2300mA A123. Keep in mind just because you are using digital servos doesn't mean you are going to draw massive amounts of current. The workload on servos with a Sig Mayhem is much less than on a giant scale airplane, which equates to less current draw.

Desert Toad

Looks like quite a battery pack. Would there be any benefit of going with a 6 volt? Only running 4 digital and one standard servo.

thanks.

Zeeb

My Feedback: (41)

I asked myself this question not long after I started with this hobby and looking back now, I wonder why it was even a question.

If you're getting into bigger planes, just do it...

As mentioned, not all battery packs are created equal. The biggest issue you'll face is the magic word you've already seen here; impedence. Generally speaking, the lower the pack cost the higher the impedence but that is by no means a rule. Check the specs on any pack you are thinking about buying and make sure they are low impedence cells.

Crash-RCU

I use JR 2300 5 cell reciever packs and have not had any problems other than I have get my LHS to order them for me as they only carry the 4 cell packs