LeisureTime2012

I am setting up a Bird of Time glider, no engine. The recommended battery is a "square battery with at least 500 mAh capacity."

I'd like to use newer battery technology (as opposed to NiCD) and I'd like to avoid using a BEC or ESC due to the additional cost and weight.

Ihave a Tactic TR624 Rx that says it needs "four AA Alkaline, NiCd or NiMH cells (4-6.0V)".

Many battery packshave a voltage higher than 6.0, so Iassume those would require a BEC or ESC that Iam trying to avoid. One solution would be to use LSDNiMH's in a battery holder like these:

http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER

http://www3.towerhobbies.com/cgi-bin...&I=LXXLP9&P=ML

That should keep the voltage down to 4.8V Ibelieve and should provide 8000 mAh(!?) capacity for less weight than a single Futaba NR4QB 600MA NiCD .

Is that right, that it's 13 times more powerful or am Imissing something?

Will the charge lead charge the batteries when using the battery holder?

Any other thoughts or concerns on this setup?

Any advice would be appreciated.

Goldenduff

Didnt look at your links as my iPhone doesn't like doing it.

LeisureTime2012

Thanks for the response - one link was to "Sanyo NEW 1500 eneloop 4 Pack AA Ni-MH Pre-Charged Rechargeable Batteries" and the other link was to "Tactic 4 Cell AA Battery Holder w/Futaba J Connector" at Tower Hobbies.

Do you see any potential issues with this setup?

Charlie P.

How about a HydriMax HCAM6322? 2,000mAh, square 4.8v packs. I have been using the flats in my glow and gasmodels asRx batteriesand I get over 90 minutes of aerobaticflight time before they drop to 4.8v Spread out over 15 minutes flights with some rest time between.



http://www.gravesrc.com/HYDRIMAX_4_8...p/hcam6322.htm

bgosselin

4 of those LSD cells in series would give you 4.8v nominal at 1500mAh. Not sure where you figured 8000mAh?

Hmm, I would think going to a lipo with a BEC would be a good choice too. I would think the added weight of the BEC would be more than offset by the lighter battery type. A 2s 2000mAh lipo pack and small BEC has got to be lighter than 4 NiXX cells? The [link=http://www.dimensionengineering.com/products/parkbec]Dimension Engineering Park BEC[/link] is very small/light. Yeah, it would cost a bit more, but not sure how much is too much for you.

Goldenduff

A BEC would an unnecessary risk as it is extra connections and components?

bgosselin

I suppose, but the same thing can be said for any other BEC on the market (including ones built into ESCs). And generally, those fail because current draw is high. I have only had one BEC fail on me ever, and that again was from a stalled hi-torque servo.

Anyway, it was just an idea. Not sure if weight was the OP's primary concern or what.

Goldenduff

Yea, weight might be needed to to balance the plane. A battery plugged directly in to Rx requires no bec or esc.

LeisureTime2012

Thanks to all of you for your suggestions.

Someone on another forum told me that 4 x 2000 mAh AA <> 8000 mAh because they are wired in series in that battery holder. I am new to this subject and none of it makes sense at this point, which is why Iam asking for help.

They also suggested Ilook in the manual (doh! I hadn't thought of that!), which suggested this pack:

http://www3.towerhobbies.com/cgi-bin...?&I=LXYAS7&P=0

It has a higher voltage (6.6) than the receiver says it likes (4-6.0V), but if it's in the manual it must be okay.

Now Ijust have to wait and see if it will fit. Had to return the Bird of Time today because it was damaged during shipping. Will be almost 2 weeks before Iget the replacement and can check clearances.

Goldenduff

If wired in series the voltages of each cell are added together and the capacity stays the same.