Need some help choosing/finding batteries for SLS

[yyz]

I recently bought the Florian Schambeck EMAscale 1400 (http://www.klapptriebwerk.de/produkt...ebe/ema-scale/) for my 1:3 scale Ventus C.

To match the 1400, I purchased the YGE 90 HV speed controller (http://www.yge.de/artikel.php?search=yge90hv).

The glider is 6 meters and will likely be in the 20-30 lb range. The usage will be doing several 500 meter climbs with rest periods in between.

Can someone please recommend a known-working battery configuration and where I can purchase them? Len recommended the XPS batteries a while back but they are out of stock.

Thanks!

Mike

[Charlie]

Mike I agree with Len , The XPS batteries are the way to go
I just got in a shipment from them yesterday
Call Scott and He might be able to help
How many cells are You looking for

Charlie

[Len]

Hyperion is another good choice,

Len

[yyz]

I think I'll go w/ the same setup Len recommended: 2 5-cell 4000 mAh packs as his Shark is the same size and probably weight as my Ventus. Again, looking for advice so my reasoning might not be right.

M

[Alex]

XPS packs hold their voltage very well under load. I know because I'm using them on my S2 tug. Good batteries. Not sure your size is in stock. They are now coming out with 70C packs!

Yes, the Hyperion are also good.

[Mac Powell]

Mike:
The 1400 model name indicates that the rated power is about 1400 watts. For your glider at 30 pounds that is about 47 watts/pound or 100watts/kg. That is a typical european metric for scale gliders. On my TD electric gliders I try for 100 watts/pound which typically gives a climb rate of 2000 feet/min. Assuming that the ratios are linear I would expect your sailplane to get to 500m is about 1.6 minutes.

All the new 60C batteries have very little voltage sag so you can expect that a 2 5 cells in series will give you about 38 volts. Taking the 4 ah battery to 20% of capacity will give you 3.2 ah of useable capacity. 1400 watts at 38 volts will draw about 37 amps and a produce a run time of 5 minutes or amount three ups to 500m.

My personal battery choice is Thunder Power which I have been using for many years without a problem. If you don't have the room for 2 5 cell packs you can drop down to 4 cells with a proportional increase in amperage. You could go to an even lower cell count but you are limited by the name plate maximum amperage on the 1400.
I hope this information was of value and more or less what you asked for
Mac

[yyz]

Wow! Thanks Mac and everyone else for your help. Truly appreciated.

Mike

[Mac Powell]

Mike:
After I posted #6 above I realized that your prop diameter can't be any bigger than the height of the post on the EMA, so you can forget what I said about going to lower cell counts.
Hurry up and get this thing installed so that you can tell us all about how well it works. Then I'll go out and buy one and we can formation fly scale gliders!
Mac