Li – Poly batteries

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27 August 2008 at 17:28 #15438
Mike Davidson
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@mikedavidson22772
Many of you will have heard about the DIY bomb kits called Lithium Poly batteries. I was fascinated by an article I read about setting a new record of 200 miles an hour for a fast electric model boat, and I don’t know enough about Li-Poly batteries or brushless motors, so I would appreciate any advice more experienced modellers can offer.
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28 August 2008 at 19:51 #15457
ashley needham
Participant
@ashleyneedham69188
I think the aircraft boys are probly the ones to ask aboiut LiPo batteries, as they have been in use for a while with them, same for brushless motors. The only use on a model boat I would have thought is on a racer type..are there any websites devoted to model powerboats ?? Must be. Ashley
28 August 2008 at 22:06 #15460
Penny Lee
Participant
@pennylee76979
I too am trying to find out about Li-Poly batteries and brushless motors.Any help,in plain English would be appreciated by me too.I have been fruitlessly browsing a U.S. forum,occasionally, for a week now.I have listed the limit of what I could find.

What I found out that made any sense whatever was that :-
- it was mainly negligent use that causes Li-poly batteries to explode.
- There is a safer LiPo alternative but it is expensive and more bulky.
- The flyboys are drawing up to 80 amps per battery (one I saw on youtube had 6 Lipo’s in series meaning the battery output was 1.6 kilowatts)
- Brushless motors are like "3 phase AC motors with rotor magnets"?
- Efficiency is up to 80% which permits space and weight saving.
- The motors are simple and flight types have exposed windings that are force cooled by the prop.
Is the above correct? Any more info? Does anyone have any non technical weblinks?

Penny Lee
28 August 2008 at 22:32 #15461
Kevin Bellman
Participant
@kevinbellman86047
Hi Mike,

Couple of sites for you that will help improve your knowledge

http://www.batteryuniversity.com/index.htm

This is a very good site for info on all battery types.

http://www.modelpower.co.uk/acatalog/Lithium_Polymer_Safety_Information.html

This takes you direct to safety info on LiPo & LiIon cells

Model Power sell batteries and I’m sure would be happy to advise if you had a project in mind

Regards
29 August 2008 at 00:25 #15463
Penny Lee
Participant
@pennylee76979
Thanks for the links,Kevin.

More on the same subject,please!

"Safety Information" is completely free of jargon but it still took me three attempts to decipher or decomma.

Penny Lee
29 August 2008 at 19:12 #15474
Mike Davidson
Participant
@mikedavidson22772
Thanks Kevin, I printed out pages from those two links you gave, they weremost useful Penny, you could benefit too from the two links given by Kevin, Those Lipo batteries are something else, and coupled to a motor that will return 43 thousand RPM must be wicked. some of the brushless motors have torque figures quoted in pounds/feet WOW !, I can see the thrust bearings on my propshafts melting if I get that lot together. Change my preferred option to fast electrics
25 November 2008 at 22:11 #17271
Tony Bell 2
Participant
@tonybell2
Li-Po safety leaflet can be found on http://store.modelpower.co.uk/lipo-safety-4-w.asp
9 January 2009 at 19:20 #6490
Mike Davidson
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@mikedavidson22772
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