Receiver batteries

[coogy]

Hi guys, a little question...

I'm currently trying to rebuild my RC trainer aircraft after a few years of neglect. I've got a new engine for it, plus all the old (working) RC gear. However, before returning it to the flying field, I want to invest in some new batteries for the receiver and transmitter. What I'm a little confused about is the different specs. Currently it has 4 x AA Sanyo's NiCad's which I want to swap for some fresh NiMH's. However, I'm not sure whether I want 1300mAh or 2100mAh etc. Does the higher the number, generally indicate a longer charge? Its been so long since i've been into my RC stuff I've completely forgotten!! Any help, greatly appreciated! Cheers

[Quick silver]

Yup - the higher the amp/hour number, the longer it will take to charge & the longer it will last before discharge.

[Roop]

Yes, exactly as has been said above. I'd recommend buying a 5-cell pack as this makes up for the 0.3v per cell dropped between alkaline and NiCd/NiMH:

4xAA alkaline = 4x 1.5v = 6v

5xAA NiCd/NiMH = 5x 1.2v = 6v

Small weight penalty of course, but 25% more capacity and a bit more voltage vs. a 4 cell 4.8v pack allows your servos to deliver their rated speed and torque.

[tr7v8]

Roop said:

Yes, exactly as has been said above. I'd recommend buying a 5-cell pack as this makes up for the 0.3v per cell dropped between alkaline and NiCd/NiMH:

4xAA alkaline = 4x 1.5v = 6v

5xAA NiCd/NiMH = 5x 1.2v = 6v

Small weight penalty of course, but 25% more capacity and a bit more voltage vs. a 4 cell 4.8v pack allows your servos to deliver their rated speed and torque.

Do not run JR on 6V, MacGregor & JR specifically say not to do it. They are designed for 4.8V.

[Roop]

tr7v8 said:

Roop said:

Yes, exactly as has been said above. I'd recommend buying a 5-cell pack as this makes up for the 0.3v per cell dropped between alkaline and NiCd/NiMH:

4xAA alkaline = 4x 1.5v = 6v

5xAA NiCd/NiMH = 5x 1.2v = 6v

Small weight penalty of course, but 25% more capacity and a bit more voltage vs. a 4 cell 4.8v pack allows your servos to deliver their rated speed and torque.

Do not run JR on 6V, MacGregor & JR specifically say not to do it. They are designed for 4.8V.

Are you sure...? No wonder I never see their kit at the field these days if that's so. What a limitation...! I don't know a single flight ESC that outputs 4.8v for BEC. They are all 6.0v, meaning JR kit is all but useless for electric flight. Amazing...!

[hman]

You dont get 6v out of a fully charged 5 x 1.2v pack, you can get considerably more you will only get a solid 6v if you use a regulator, thats the problem with JR kit.

Better safe than sorry, use a regulator or use 4.8v packs.

If its a trainer then 4.8v will be fine, 6v gives you a quicker response with more torque but you really dont need it yet.

However, flying (geddit) in the face of this advice I use 6v packs unregulated on all my gear (futaba and JR) with no problems.