I agree with Mark. I use Winston LiFePO4 cells and have discovered the same 2 to 1 ratio in usable a-hr. When you understand how the LiFePO4 cells get their a-hr rating, combined with 80% DOD and nil Peukert effect, a 200 a-hr lithium bank will easily do the work of a 400 a-hr lead bank. Case in point, lead derives its a-hr rating on an easy 20 hour discharge all the way to dead, whereas the LiFePO4 cells get their rating in a brutal 1 hour discharge (1.0C vs 0.05C) and only down to 80% DOD, leaving 20% capacity still in the cells.
Bob
From: Mark n Angela <mstafford@natca.net>
To: electricboats@yahoogroups.com
Sent: Tuesday, October 8, 2013 9:12 AM
Subject: [Electric Boats] Re: Hello Everyone
Welcome Sheya & Jason,
You seem to have realistic expectations from electric auxiliary propulsion. The rhythm of the Earth is slow and steady, with occasional punctuations of power. Electric auxiliary propulsion does this well. It's not for the "full speed ahead" folks who want to get there when THEY want to get there, and not have to work with the wind and tides.
One thing I notice in your post, is 300ah AGM vs 400ah LiFePo4. AGM (and other lead-acid types) prefer less than 50% discharge cycles, while lithium chemistry types prefer less than 80% discharge cycles. In other words, a lead battery needs filling as soon as you've used "1/4 tank", while lithium batteries need filling after you've used 3/4 tank. That would make your choice reversed (300ah LiFePo4 vs 400ah AGM). You could even target 200ah LiFePo4. This makes the weight and size penalty of lead more obvious, and the price penalty of LiFePo4 less egregious.
Mark Stafford, Oakland, CA
eGEO, eScooter, eH55 Marco Polo, eCal2-24, eKayak, eHouse (grid-tie & solar water), biodiesel cars and trucks.
--- In electricboats@yahoogroups.com, Sheya <sheyagiggles@...> wrote:
>
> Hello,
> I am new to this group and have been going through the different conversations trying to take in the wealth of information that this group has to offer. My partner and I have a 41' Morgan OI. Its original engine is a Perkins 4107 and is coming to the end of its life. We have been doing research into Electric and I think we will end up repowering our boat this winter.
> Currently we are looking at either a 20.0 QuieTorque through ElectricYacht or a Curtis/HPEVS brushless AC motor 30hp continuous 45hp peak through a local company here in Vancouver BC. We are thinking of going with either 300ah AGM or 400ah LiFePo4 batteries. Pros and cons being mainly weight vs money and expected lifespan.
> We live in Vancouver BC and our sailing plans include a trip north along the coast to Alaska and then probably south and across the Pacific in the future. We plan to take our time and will have solar and wind and won't mind spending time in a bay to charge up. We also plan to get a little 5kw Yanmar diesel generator for emergencies. We have a sailboat because we love to sail and as it is we don't use our engine much, mainly just for getting in and out of dock or anchor and getting through passes.
> We will continue to absorb the information on this page and would appreciate any thoughts or comments you may have on our plans.
> Cheers,
> Sheya and Jason
>
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/electricboats/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/electricboats/join
(Yahoo! ID required)
<*> To change settings via email:
electricboats-digest@yahoogroups.com
electricboats-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
electricboats-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://info.yahoo.com/legal/us/yahoo/utos/terms/
__._,_.___
| Reply via web post | Reply to sender | Reply to group | Start a New Topic | Messages in this topic (11) |
.
__,_._,___
No comments:
Post a Comment