New Batteries?

27th December 2003, 15:07

Hi

I found something which might be of intrest to people. I have found a 6000mah (6amp) 12v Rechargable battery which weighs only 400g and can do 30amps. they are called Lithium Polymar batteries (li-po)

They have been around a long time now and I have used them in antweights but I was looking into them for my no money limit feather vapour bot. They are possibly affordable and usable in a featherweight but are possibly beyond most Normal peoples reach.

For this 6amp 12v Pack it would be 144pounds including delivery to anywhere in england.

You would also need a charger but they can be simply made by most people. (if your intrested please contact me for a circuit diagram)

What do people thing? I know the price is high but the weight is very low.

Regards
Ian Mc Donald

**blazerbotics** · 27th December 2003, 16:10

cant supply enough current for alot of robots, alpha can pull over 50amps, the Nicads get very warm after a fight so i wouldnt like to run Li-Pos.

**ewan** · 27th December 2003, 16:30

These batteries were going to be my first choice from my battery sponsor, but then I found the general stats-
They are pathetic at giving any high currents, and when they do, they get VERY hot... The actual fluids etc are some of the most dangerous in any battery. The price is VERY HIGH. They take around 14 hours to charge a pack!
Cheers, Ewan

**storm** · 27th December 2003, 16:50

Already been and looked at these - for now I think theyre going to have to stay as Antweight technology as they just cant supply enough current for even a wiper-motor powered feather.

Ed
http://www.stormrobot.com http://www.stormrobot.com

27th December 2003, 17:16

I think your slightly wrong there ed and ewan.

Ewan.
It takes 1hour to chare li-pos from dead. The do not get very hot at high currents once you keep them under the rated currents youll be fine. The 1500mah batts are rated at 5c with a peek of 7C so if you try and draw 100amps out of them they will get hot. But if you try and draw anything up to 7.5amps youll be fine.

Ed.
They can supply enough current for my pusher. It runs drills on 150mm diameter wheels and it does not even draw 30amps. So they could be used.

In general i dont think they are really suitable for featherweights at the moment. But considering 6months ago you could not get a Li-po that could do more than 1c discharge they are advancing rapidly.

By this time next year we might see cells as good as some ni-mhs who knows

regards
Ian Mc Donald

**storm** · 27th December 2003, 23:12

Ian, if youre using drill motors on 150mm wheels and you think each motor is only drawing 15amps PEAK then youre living in cloud cookoo land mate !

Ed
http://www.stormrobot.com http://www.stormrobot.com

**craig_anto** · 28th December 2003, 12:34

Ive been saying that for ages Ed :P

29th December 2003, 18:01

Well ed my total bot when stalled does not draw more than 30 amps on 150mm diameter wheels. This is not theory its fact!

Regards
Ian Mc Donald

**storm** · 29th December 2003, 19:13

How do you know this fact ? I presume you have monitored the current using a clamp meter, or you have calculated your motor constants and evaluated your motor performance for the given circumstances at stall ?

Explain how you know this as a fact.

Sounds highly unlikley to me Ian !

Ed
http://www.stormrobot.com http://www.stormrobot.com

29th December 2003, 19:27

Well i stalled both motors by driving them straight into a wall at top speed. The 20amp fuse blew but then I fitted a 30 and it did not blow when i did the same thing on fully charged batts.

If you dont wanna believe me then thats fine but its true.

regards
Ian Mc Donald

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