Re: [electricboats] Anyone uses a used EV car battery for powering ?

Myles, it's great, that you are so much into this, with experience since 2003 and before !

That's what we need here.

Well Myles, I said "the trend", not MY trend.

If you look at eg. cruisersforum, you will see that it is a trend.

A trend is, when most people follow that path.

I'm asking this group questions of using used car batteries to make a useful bank, so I think that makes me not biased towards LiFePO4's in any way.

Especially not, if they are shipped directly to you from China, without any decent quality control.

If you order for a few thousand $$ as a private, you will definitely not be first in line to be shipped the top grade quality, that the car factories gets.

Remember, in these days, everything you buy, produced in China, is solely controlled by local chinese supervisors !!!

There are virtually NO western inspectors in China to check export goods anymore, due to very hard quarantine restrictions when entering China. No one wants to go to China now, just to sit quarantined alone in an appointed hotel room for 4 weeks.

Carsten

On Friday, 11 June 2021, 02:45:21 GMT+8, Myles Twete <matwete@comcast.net> wrote:

Ø  Most used EV batteries are Li-Ion, except some odd ones, like Think City Zebra, which (as I read it) is a salt battery and needs some kind of heating before use.

Yes, of course.

 

Ø  The trend for boats is to use LiFePO4.  Is that for the safety of operation (no fires !), or for the charging/discharging benefits ?  I guess both can be discharged 90%.

If you're a follower of trends, not sure why you are pursuing an E-boat…

I converted my boat to electric in 2003 and wanted to since 1998 or so.

There was nothing trendy about it.  And at that time, while we had LiFePO4 and even Zinc-Air battery options, affordability dictated lead acid for E-boat conversions.  And so, nearly everyone until maybe 2011 or so was using lead-acid.  Around that time we started to hear of folks using packs made from cheap LiFePO4 from China.  And that has continued to the present.  If there is a trend, it is that since 2012, many folks have found it attractive to adapt used land-EV LiIon battery modules for their boats.  It may not be a majority, but it certainly has gone from zero to some percentage, vs LiFePO4 which surely jumped out of the gate earlier.

 

As for safety, people have different levels of paranoia, perspective, risk tolerance and philosophy.  I do not consider the marine environment I experience as any more risky than the under-car environment of my 2011 THINK in terms of likeliness of a cell to self-immolate.  And so, I have used super-high quality American LiIon since 2012 or so on my boat as I do with my car.  An advantage in safety is that these are in the original metal cases developed for these cells.  Is there risk?  Sure.  Is it mitigated?  Absolutely.  Is there enough scare for folks to be steering away from LiIon to LiFePO4---sure, some exaggerate the risks and others listen---then they order low cost LiFePO4 from China and are happy.

 

As for charge/discharge %capacities and rates, I don't think it's a factor in folks' choices.

 

Not a trend follower…

 

-Myles