Though for the most part I agree with your recommendations for LiFePo, and Lead. I highly disagree with this point. If more could go wrong with LiFePo then there would be more failed packs, the truth is vastly more can and does go wrong with Lead.
Outside of a few stores of old salts that claim to have 10 year old Lead batteries still going strong, few people with typical maintenance using any kind of Lead batteries get more then 4 years out of there Lead batteries. If a Lead battery sees any kind of actual use most people kill them in two years. And it is not that uncommon for a wet cell Lead acid batteries to get an internal short and explode that acid all over engine rooms and people. Lead Acid House banks batteries are probably the most replaced thing on a boat, right after bilge float switches.
LiFePo batteries on the other hand tend to last many years, outside of death by some early cheap mini per cell circuit board BMS that had a habit of internally shorting I have heard of very few LiFePo batteries failing. And a defective BMS is hardly a chemistry issue. And even in these cases the battery stop working and nothing else.
Now it could be said that the lack of pack failures could simply come down to the LiFePo batteries were simply more expensive so there owners took better care of them, but I think the electric car conversion crowd shows that is not the case. When there was only Lead battery packs, most in not all daily drivers where killing those lead packs within 18 month of installing them, no matter the chemistry, once Lithium cells became available most drivers that switched stop needing to replace there packs. Most still work even a decade on. And theses batteries like most home brew boat batteries have minimum safety equipment. Though like you I think any battery should be fused at every connection and be well covered to protect against shock and shorts, especially at the voltages used for car applications. Most boat fires are from wire related fires caused by improperly sized wires and lack of fusing.
Now I do not think everyone should install Lithium batteries, if you only go boating ten times a year, no battery lead or lithium is ever going to pay for itself, you should sell your boat and rent a boat the few times a year you use one. But for those who live aboard or used there boat weekly your traction and house banks will last vastly longer with LiFePo then Lead acid. Even one Lead Acid battery replacement probable makes the Lithium battery cost competitive and the third replacement will bring the lithium battery ahead in value. Not to mention not having to lift, and replace your house bank batteries every three years is just priceless.
Now these new Lead battery chemistries may fix the long standing reliability issues with Lead batteries, who knows they may last decades. But quite frankly we will have to wait ten years to see, if I start seeing live aboard cruisers regularly getting 10 years from there Lead house banks then I may start to trust Lead batteries again, but I already know for a fact, that LiFePo packs do regularly last 10 year, and are still going strong. Even then I will still harbor some pretty strong fears related to Lead reliability. I have to many years dealing with them professionally inside large data centers, and I was an very early EV adopter from way way back. Both in data centers and in EV's, lithium transformed both UPS's and EV's from nearly useless toys to everyday useful trustworthy reliable devices.
Just my opinion, based on my experience, yours may very.
> On Sep 16, 2018, at 12:38 PM, James Lambden james@electroprop.com [electricboats] <electricboats@yahoogroups.com> wrote:
>
> My point is simple. More can go wrong with a LiPo battery, so if you don't need them, don't use them. Besides which, everyone is on a budget, and the extra expense is enormous when you consider the installation too - and professional installation either by a knowledgeable boat owner, or by a marine electrician is highly recommended if you are getting into any kind of Lithium chemistry.
Posted by: "james@deny.org" <james@deny.org>
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