T-Pain Is On A Boat: Re: [Electric Boats] LiFePO4 battery experience?

Monday, November 2, 2009

Re: [Electric Boats] LiFePO4 battery experience?

Chris,

It's good to hear from you. I spent the morning reading just about everything on your boat's website, so I've only got a few more technical questions about your storage system. I also own a Farrier F-27, so I understand your focus on weight. Interestingly, my Cheoy Lee Bermuda 30 has serious space constraints that is leading me to an LiFePO4 solution, the initial plan is for 16 LFP160AHA for a total of 7.6Kwh. If all goes well, I could always add a second bank of the same to double the capacity/range. I have understood many of the additional benefits that you described in your post, but it's nice to hear that these bonuses are more than just theoretical.

I see that you're running the BMS cell modules from EV Works on each cell, I was already planning on doing same thing. Are you also running their MCU-TS90? I can really see the advantage to having a low voltage shut-off. I read about your experiences with charge balancing, have those issues become less prevalent now that your bank is more balanced? What kind of A/C charger are you using? Since my boat lives in a berth in a marina, I plan to utilize shore power for almost all of my charging.

For my project, there's really no good space for solar panels on Serenity; narrow beam, low booms and a sail plan that extends a couple of feet past the stern. With a full keel and a prop in an aperture, effective regen seems unlikely. The top of the mizzen mast may be optimal for a wind generator, but that will have to be release 2.0 of my project. My backup will be a Honda generator to run the shore charger, but I want to keep that to a minimum.

Fair winds,
Eric
SoCal

--- In electricboats@yahoogroups.com, Chris Baker <chris@...> wrote:
>
> Hi Eric,
>
> I've got a pack of 16 x 200 ah ThunderSky LFP cells - the initial
> impetus for their purchase was the weight factor. I have a light
> trimaran and its very sensitive to weight so I wanted to keep that
> down as much as possible. Using the Thunderskys and a Torqeedo 4kw
> outboard I was able to limit the weight to the same as the 25hp yamaha
> outboard and fuel tanks that were removed....
>
>
> The only downside with LFPs for me is that because it is new
> technology I have had learn as I go about the unexpected properties of
> LFPs. Such as the need to cycle them a few times when new to achieve
> full amphour capacity. And putting together charging/management
> system needed some cobbling together of various parts and building an
> understanding as I go....
>
>
> Right now Current Sunshine is on the hard and my actual use of these
> batteries has been limited and there is still some fine tuning to do
> related to the charging system. But I hope to be back in the water
> soon and I'll post again when I have more news about this.
>
> Cheers
>
> Chris
> 1986 Crowther 43 ft Trimaran
> http://currentsunshine.com
>