LSP972

My Feedback: (13)

Just finished the H9 Extra/OS 1.60, and the battery must be next to (as in alongside) the engine for the plane to balance.

Its no big trick to fabricate a wood platform to bolt to the side of the motor box and get the battery where its needed. BTW, we're talking a 2850mAh NiMH pack comprised of four sub-C cells, so I'm as big and heavy as I can get there.

What concerns me is, how is the battery going to like being right next to that engine/muffler, with all the heat and vibration?

I've seen photos here that guys have done this on EF Yaks, etc. So my question to those guys is, how did the battery hold up?

Spaceclam

isolate the batteries from vibration and you will be fine. you should not be drawing enough current for those cells to heat up
you could probaly get away without the isolation, but it is always a good idea since those batteries are not too cheap..

2slow2matter

My Feedback: (1)

Replacing the batteries isn't the concern here, it's replacing the airplane if the batteries fail. Also, I believe he was referring to heat generated by the engine being transferred to the batteries, not heat generated by current.

Anyway, I have lots of ideas on this subject, but take them for what they are worth--just ideas. Never tested.
But, you could isolate the battery box by a thin strip of rubber between the box and the mount. THen, use some high density foam surrounding the battery inside of the box. This should definitely take care of most of the vibration problem. The foam should also insulate from some of that heat, but definitely put the battery opposite of the muffler. THis would help counter-balance the muffler anyway.

Just ideas....

MinnFlyer

My Feedback: (4)

I have made platforms for placing battery packs over, or along side engines before with no adverse results.

Spaceclam

i know he is talking about the heat of the engine, but the batteries should not get hot enough that they require cooling from the kin of current they would draw. just isolate the batteries from vibration and you should be good

LSP972

My Feedback: (13)

Yup. I was beginning to wonder if my writing was THAT imprecise?

The battery won't be in a box; it will be strapped to a piece of 3/16" birch five-ply directly "under" the engine, just "above the muffler. The OS 1.60 is side-mounted; attaching a ply plate on the left side of the motor box puts the battery next to the underside of the crankcase.

I'm more concerned about heat than vibration. Batteries, especially NiMH batteries, do NOT like high temperatures. I was thinking of wrapping the battery in aluminum foil; then visions of major RF glitching danced into view. Okay, scratch that; I'll put the foil on the bottom of the ply plate, next to the engine.

OTOH, the foil trick may be a waste of time. I think I'll just wrap the battery in plastic, use LOTS of foam padding, strap that puppy down, and go fly; keeping, of course, a close eye on the battery state. The size of this airplane is already causing me grief; just getting it out of my room to the truck without banging the wheels or tail feathers on something is a feat. Having to pay more attention to battery condition is a small thing.

Mike, thanks for the info.