There's so many different ways one can make LiFePO4 cells so it is hard to say what goes with each cell we get.
In general and from experiences accumulated so far it is very rarely the case where LFP would die on your hands suddenly. Anything might seem sudden if you're not monitoring the behavior of the cells. All the signs are there even months before failure. For starting application keep it out of high SOC and keep cycles shallow. You should probably even disconnect it after minute or two of charging when you've put in what you got out. Oversize the pack for power and keep it out of too cool or hot temperatures. If you're taking 10C out of any cell you're creating heat on the current collectors and tabs. Mechanics have also quite important role there. But I dare to doubt you're taking 550A to start. More likely it's 1ms of that and then 150-250A for few seconds. If you can charge the battery just before cranking it up you can use the supercap effect of li-ion cells to cut that 550A. If done right you can expect 15-20 year usable life from LFP. All LFP cells I have murdered without clear and planned mayhem (crush, burn, pierce, etc.), have died gradually. -Jukka ti 14. elok. 2018 klo 7.19 Mark Hanson via EV (ev@lists.evdl.org) kirjoitti: > Sounds lik > > Sent from my iPhone > > > On Aug 12, 2018, at 7:31 PM, Bobby Keeland <keela...@gmail.com> wrote: > > > > Mark Hanson asked "curious if LiFePO4 dies suddenly or gradually like > lead." > > > > My experience with lead acid batteries in both a Dodge RAM pickup and in > a Subaru SUV is that they were working great when I stopped at the > dealership (Dodge) and pharmacy (Subaru), but when I got back in the > vehicles the battery was dead. No obvious gradual decline. > > > >> On Sat, Aug 11, 2018, 10:04 AM mark hanson via EV <ev@lists.evdl.org> > wrote: > >> Thanks Cor, > >> > >> > >> > >> Yes, it has a standard 14V alternator regulated. I start and stop > frequently as skiers are getting in/out of the boat, so curious if LiFePO4 > dies suddenly or gradually like lead. I assume a small battery like this > would start fine one second and then not, so I keep a spare battery in the > boat (unless someone has any real data on this battery, couldn’t find on > the great god google) . What is the projective life, 1,5,10 years? > >> > >> > >> > >> I had an electric boat www.evalbnum.com/2749 > >> > >> but couldn’t H20 ski behind it so bought a lean burn Honda BFP60, same > engine that was in my 2000 (real) Insight 65mpg. In the alum 1200lb 6x16 > boat, gets 6.5MPG which is considered “good” most fiberglass 3400lbs are > 2.3MPG. > >> > >> > >> > >> > >> > >> Have a renewable energy day, > >> > >> > >> > >> Mark > >> > >> > >> > >> Mark E. Hanson > >> > >> 184 Vista Lane > >> > >> Fincastle, VA 24090 > >> > >> 540-473-1248 phone & FAX, 540-816-0812 cell > >> > >> REEVA: community service RE & EV project club > >> > >> Website: www.REEVAdiy.org (See Project Gallery) > >> > >> UL Certified PV Installer > >> > >> My RE&EV Circuits: www.EVDL.org/lib/mh > >> > >> FREE Solar EV Charging! ; > http://www.WeatherLink.com/user/MarkHansonREEVA > >> > >> > >> > >> > >> > >> > >> > >> From: Cor van de Water [mailto:cor.vandewa...@gmail.com] > >> Sent: Saturday, August 11, 2018 12:19 AM > >> To: Electric Vehicle Discussion List > >> Cc: mark hanson > >> Subject: Re: [EVDL] Shorai LiFePO4 LFX36L3-BS12 Longevity Reviews > >> > >> > >> > >> Mark, > >> > >> I presume that your boat engine has an alternator and is generating 14v > as long as it keeps running, so not too likely that your boat suddenly dies > in the middle of the lake, but good to have backup. > >> > >> > >> > >> That said, your 4lbs battery probably has between 200 to 300 Wh of > capacity at best, using normal density numbers. > >> > >> At 12.8v this means probably 15 to 20 Ah so the usual Chinese twice (or > more) overspec. > >> > >> Cor. > >> > >> > >> > >> On Fri, Aug 10, 2018, 8:29 PM mark hanson via EV <ev@lists.evdl.org> > wrote: > >> > >> Hi Folks, > >> > >> > >> > >> I was curious if anyone has used/evaluated the Shorai LiFePO4, Lithium > Iron > >> Phosphate LXF35L3-BS12 I bought from Amazon $250 with charger/balancer > $67 > >> for my HondaBFP60 boat (1000cc similar to large motorcycle) claims 550 > >> cranking amps, 36ah but only weighs 4 lbs so probably Chinese inflated > >> specs. Looks more like 7-14ah MC battery. It does start the engine > with > >> little voltage sag, 11V whereas the lead battery sags to 8V when > starting. > >> > >> > >> > >> I'm concerned that it may suddenly die out in the middle of the 80 mile > lake > >> here Smith Mountain Lake near Roanoke, VA so keep a spare tractor > battery on > >> the boat just incase. I replaced a 40lb lead marine battery to save > some > >> weight but curious about the longevity and how LiFePO4 dies, if it's > sudden > >> or gives some warning like lead (that gets gradually saggy when > starting). > >> > >> > >> > >> Have a renewable energy day, > >> > >> > >> > >> Mark > >> > >> > >> > >> Mark E. Hanson > >> > >> 184 Vista Lane > >> > >> Fincastle, VA 24090 > >> > >> 540-473-1248 phone & FAX, 540-816-0812 cell > >> > >> REEVA: community service RE & EV project club > >> > >> Website: www.REEVAdiy.org (See Project Gallery) > >> > >> UL Certified PV Installer > >> > >> My RE&EV Circuits: www.EVDL.org/lib/mh > >> > >> FREE Solar EV Charging! ; > http://www.WeatherLink.com/user/MarkHansonREEVA > >> > >> > >> > >> -------------- next part -------------- > >> An HTML attachment was scrubbed... > >> URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180810/8f64c602/attachment.html > > > >> _______________________________________________ > >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org > >> Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > >> > >> -------------- next part -------------- > >> An HTML attachment was scrubbed... > >> URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180811/d878193c/attachment.html > > > >> _______________________________________________ > >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org > >> Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180813/965628e7/attachment.html > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... 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