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Which battery type

Posted: May 27th, 2019, 11:11 am
by Tony Collins 1073
I am building a nice little foamy biplane. I have used lipo's before but not Li-Ion and I am not sure what to use.
I have read so many conflicting reports as to the safety and performance of these batteries that I have decided to
ask at the most reliable place that I know. LMA forum. Thanks in advance.
Tony.

Re: Which battery type

Posted: May 28th, 2019, 12:33 am
by Steve Perry
Lion does not have the current capability that Lipo's do, I suggest watching https://www.youtube.com/watch?v=UB8fas6zBSE for a comparison between them.

Re: Which battery type

Posted: May 28th, 2019, 7:40 am
by Bob Thompson1894
Safety of lipos is simple, Mike. Charge them (balance every time) outside on a BBQ or similar so nothing can hurt if it decided to go up, and keep them in a tin box in the garage or shed. I only have 3s for foamies but have never had a problem in five years of using them.

Re: Which battery type

Posted: May 28th, 2019, 3:41 pm
by Tony Collins 1073
Thanks for that lads. I once saw a model sitting all by itself suddenly go up in flames. This was at Baldock North London club and some on here may remember it.
My model is the Ultrafly Outrage which is from way back although the kit is untouched.
It is a 3D model , not that I am going to be able to do that It is a high performing bipe which is supposed to come out at about
11 ounces. My big consideration is to use as light a power supply as possible I am well into electronics but am a dumbo where electric flight is concerned so any advice on what battery and type to use would be gratefully received. Don't know whether to use two or 3 cell.
I have a 30A BEC, and the motor is a GOOLRC 2212 1000kv. Is that OTT?
thanks in advance.

Re: Which battery type

Posted: May 28th, 2019, 3:44 pm
by Tony Collins 1073
Thanks for that lads. I once saw a model sitting all by itself suddenly go up in flames. This was at Baldock North London club and some on here may remember it.
My model is the Ultrafly Outrage which is from way back although the kit is untouched.
It is a 3D model , not that I am going to be able to do that It is a high performing bipe which is supposed to come out at
about 11 ounces. My big consideration is to use as light a power supply as possible I am well into electronics but am a dumbo where electric flight is concerned so any advice on what battery and type to use would be gratefully received. Don't know whether to use two or 3 cell.
I have a 30A BEC, and the motor is a GOOLRC 2212 1000kv. Is that OTT?
Thanks in advance.

Re: Which battery type

Posted: May 28th, 2019, 3:45 pm
by Bob Thompson1894
I watched a nmh battery go up in Germany. It was fully charged, and the heat from the sun (it was bloomin hot) set it off. We saved the model with some singed fingers. So it can happen to any battery!

Re: Which battery type

Posted: May 28th, 2019, 5:29 pm
by Nigel Cox
Have a look at https://www.4-max.co.uk/recommended-setups.htm there might be something similar to your kit to give you an idea of what motor to use

Re: Which battery type

Posted: May 28th, 2019, 5:45 pm
by Steve Perry
As for 2 or 3 cells, that depends on the prop size you want to use, 2 cells for bigger props, 3 cells for smaller ones. That might seem backwards as you may be thinking that you would use a bigger battery to swing a bigger prop, the reason for small battery - big prop is the current involved and to reduce it.
One of the important bits of info about brushless motors is the number of turns that they are wound with, more turns = bigger prop, less current and lower rpm, less turns = smaller prop, more current and higher rpm.
I am guessing that your motor is 13 turns, so 8 x 4 or 9 x 5 on 3 cells or 10 x 5 on 2 cells.

For battery / prop size http://www.flybrushless.com ( no login required) Find a Prop & Find a Motor from the menu bar.

Re: Which battery type

Posted: May 28th, 2019, 5:57 pm
by Steve Perry
On the subject of batterys catching fire https://www.youtube.com/watch?v=tBg4ximDrsk

Re: Which battery type

Posted: May 28th, 2019, 7:36 pm
by Tony Collins 1073
Thanks to you all. Very interesting. Looks like I'm going to have to get the old grey cells working. [painful at my age] :lol:
Tony.