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Old Nov 16, 2014, 09:38 PM
Naval gazing
United States, MA, Boston
Joined May 2008
1,232 Posts
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Ignorant lifePO4 queatuons

I'm looking to power my proboat PT something other than the 7cell 4200 mah NICADs I currently have. I'm hoping for somenthing with higher mah. I use a pair of nicads to run the two 560 motors in my proboat PT. I get a run time of at most, 15min with the current setup.

I was talking with folks in the Nerf modification community (yes there is one) about powering flywheel guns and I expressed my concerns about LIPo batteries being tempermental and that I tend to have bad lucky with touchy electronics and these guys told me about lifePO batteries being a little less powerful but still great. In a nerf application there is no speed control. Just on and off. High RPMs are required of the motors and long endurance too.

I did a forum search here and most of the hits for "lifepo4" give me posts about tx or rx power choices or charging questions and options. The only hits for powering for propulsion were from Dock Talk which is encouraging but they were vague.

But the hits did say that this kind of battery was a good choice

Can folks tell me more about them? Also why does it seem that there aren't more people using these for propulsion?

Footnote: I usually like to run my boat at or near top speed whenever possible.

Thanks in advance.
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Old Nov 17, 2014, 02:22 PM
Big Boats Rule!
boater_dave's Avatar
Wisconsin
Joined Jun 2007
2,040 Posts
I can fill in some info. The LiFe packs are just what you heard, slightly less powerful than a Lipo, but a bit safer. If you misuse one, it will just go dead instead of starting on fire. That's not saying you can do anything you want with one. They are still large energy storage units capable of delivering lots of amps and should be handled with care. I think that because they are less powerful, the airplane guys tend to favor Lipo. And there are many more Lipo sizes available.
I use LiFe packs for my rc sailboats because they can power the rx without a voltage regulator. Probably the reason so many are targeting rx and tx packs. No reason why you couldn't power your PT with one. Here is a Hobby King LiFe pack, 3S (9.9 volt), 4200 mah, 30C (delivers over 100 amps) that sounds like a good replacement for a common NiCad stick pack.
http://www.hobbyking.com/hobbyking/s...ePo4_Pack.html
You must use a charger capable of LiFe chemistry. Another great think obout all of the lithium based batteries is that they don't self discharge like NiCad does.

Dave
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Old Nov 17, 2014, 05:10 PM
Naval gazing
United States, MA, Boston
Joined May 2008
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Thanks awfully much. I think my motors are 7volt or something. The 7.2 volt batteries are what was recommended by the manufacturer. Does it matter?

Edit:
Would over-volting my motors harm them
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Last edited by spacephrawg; Nov 17, 2014 at 05:35 PM. Reason: Needed to restate
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