DIY Lithium Guide

[CatNewBee]

LiFeYPO4 are safe, they have very little Lithium and if they blow up, they create only some very nasty un-healthy smoke - no fire or explosions.

On youtube you can find a lot of videos of the yellow cells and how to blow them up propperly.

BUT: they store a huge amount of energy and if you do not have proper circuit breakers installed you can burn down your boat because the wiring gets overheated and ignites something. But this risk is the same as with large lead acid banks. LiFeYPO4 with the same nominal capacity can produce up to 10 times higher currents than lead acid. That is great for large inverter and chargers but you have to use the right size of the wires.

[zboss]

Originally Posted by arsenelupiga

you make it sound really easy. Do you think risk of fire is acceptable these days for boats, knowing that fire on boat will be catastrophic ?

I've been researching this... These are not your fathers lithium batteries. A couple of things:

1) guidance is that battery size should be physically limited to batts under 200 Ah because of the physical stresses. Many of the old batteries gave up the ghost because they were big massive batteries whose form factor was not suitable to the marine environment.

2) the new chemistries and battery designs, while still not perfect, are no longer susceptible to fires caused by submersion (you can actually buy ones that meet new stringent transportation standards or not) or punctures. Yes lithium ignites in water. In water. Let me repeat that. In water. So while a fire may happen, it's happening.... in water.

Probably the most common cause of battery fires is actually due to poor installation, lose or corroded contacts and so forth, and that can happen with any kind of battery.

The truth is that there are 100's of thousands of lithium powered systems being driven, flown, and sailed all over the world and we are not experiencing a sudden outbreak of vehicle explosions.

[john61ct]

That last may be an overestimate 8-)

But main point, little fire danger from LFP chemistry specifically, is 100% true.

Originally Posted by zboss

lithium powered systems

Too general a term. Use LiFePO4 or LFP specifically to avoid propagating more confusion.

And House bank usage is very different from other use cases, vehicle propulsion or pocket electronics for example.

[zboss]

Originally Posted by john61ct

That last may be an overestimate 8-)

But main point, little fire danger from LFP chemistry specifically, is 100% true.


Too general a term. Use LiFePO4 or LFP specifically to avoid propagating more confusion.

And House bank usage is very different from other use cases, vehicle propulsion or pocket electronics for example.

It's not really an exaggeration. There are over two million high current electric cars in operation now. It's not like hundreds of thousands are exploding in flames.

Then you have the planes, home installations, and so forth.

I would argue that electrical powered vehicles are safer overall then their gas powered counterparts. Back in 2013, when there were three Tesla fires, it was reported by the EPA that 17 gasoline powered cars were exploding or catching on fire due to gas every HOUR in the USA.

And this is for high current draw applications. House battery banks are a lot smaller in watt hours than typical boat battery banks and boat banks are generally low amp draw, making them safer I would assume.

[john61ct]

I was agreeing with you on the safety issue, specifically wrt LiFePO4, the topic at hand in this thread, also about the House bank use case.

My point is that there are many other "lithium ion" chemistries out there, many of which **do** have thermal runaway issues.

EV mfg have been using a wide variety of chemistries, many are not even part of the LI family, much less LiFePO4 specifically.

And their proprietary BMSs play a large role in handling safety concerns.

While the safety of LFP as used in a House bank is **inherent in the chemistry**.

[DeepFrz]

Check out altE.

[john61ct]

A good recent post about the different chemistries and fire risk

http://www.diyelectriccar.com/forums...d.php?p=903450

[zboss]

I found this site today:

Electrical Design For a Marine Lithium Battery Bank | | Nordkyn Design

[Typhoon]

Originally Posted by john61ct

Canadian. Looks to have 300AH anyway

Canadian Electric Vehicles Ltd. - Batteries

Special orders take a long time

This is were I bought mine. Its been almost 3 years and the system is still working within designed perimeters.

Once you have gone with a LifePo4 bank you will never have lead again.

Regards John.

[john61ct]

Originally Posted by ColdEh Marine

Once you have gone with a LifePo4 bank you will never have lead again.

For older folk, you may well never need to replace the bank at all, pass it on to the kids. 8-)

[GTom]

Originally Posted by CatNewBee

LiFeYPO4 are safe, they have very little Lithium and if they blow up, they create only some very nasty un-healthy smoke - no fire or explosions.

Some reference here, indeed not too bad! drilling into a LiFePO4 (probably no Yttrium):

https://www.youtube.com/watch?v=XZf2pKzBErk

- still burns but doesn't explode like LiPo (there are some worse cases and there was a Tesla battery fire too = I wouldn't pile up hundreds of Ah worth of LiFeYPO4 in a boat just yet).

I used to have two concerns: fire hazard and price, price is really coming down, on this side of the pond a 12V/90Ah Winston costs 700€ which is a bit less than 2x the price of the same nominal capacity AGM. Meanwhile Li has faaar better discharge charateristics:
Li-Ion:

Lead:


An idea: a large+cheap lead bank (200Ah?) should provide for all the continuous small loads (fridge, lights, nav instruments) and a separate (90Ah?) Li bank for big, peak loads (SSB, etc).

[daletournier]

Originally Posted by john61ct

For older folk, you may well never need to replace the bank at all, pass it on to the kids. 8-)

Not claiming to no much about Lithium batteries. The claims that you get thousands of cycles out of them may be true....can someone explain to me why phone and tablet batteries dont seem to last for more than several years, arent these lithium?

[GTom]

Originally Posted by daletournier

Not claiming to no much about Lithium batteries. The claims that you get thousands of cycles out of them may be true....can someone explain to me why phone and tablet batteries dont seem to last for more than several years, arent these lithium?

These devices are usually deep cycled to <5% of their capacities, still, I'd be happy to get 2000 real 100%<->50% cycles over 10-15 years from a 5000cycle rated battery. I am afraid they also degrade by time without any cycling - just imagine a daily temp variation of 30°C - thus I wouldn't advise jumping in all-lithium at still heavy $$$.

[john61ct]

The term "Lithium" is a general category.

Each specific chemistry has its own wildly varying specs, including cycle lifetime vs DoD.

And yes pocket gadgets get grossly abused compared to the coddling a House bank (should) get.

[zboss]

I'm still looking for a reliable source of lithium cells by CALB or Sinopoly inside the USA so I don't have to deal with duties or anything. The Sinopoly 200Ah batteries are exactly the footprint we need to replace our trojan t-145s.

Also, I liked the writeup that included information on using "normally open" cutoffs controlled by the BMS between the charging sources and the charge bus to prevent overvoltage situations. That was not something I had considered and is certainly something we would have to use for our solar panels and to turn off our alternator before the BMS switches off the charge.

Who makes the best programmable BMS? I wish Mastervolt made a BMS since that is what we have on the boat.