Hi Toph
Re Lithium batteries
There are lots of guys with opinions on Youtube.
One guy that I take seriously is Kevin Bothby.
He is a full time live aboard with a circumnavigation in the engineless Ruth Avery. under his belt.
5 years ago he switched to Lithium batteries. and he has had no problems since then.


Re your question "Has Lithium just come down to brand name or is there still a bog difference in the cells?"
My answer, We used to say you get what you pay for.
Now with rebranding that is not so set in stone.
Distributors buy in bulk and then rebrand, so it has become really difficult to discern between expensive = the best and expensive = a rebrand.
Made in China or assembled in the U.S?
Assembled in the U. S. (or any other country) could just mean slipped into the shipping cardboard box.
Check Kevin's take. I might help you decide.

gary

IMHO even LiFePO4 barreries can burn but are enormously safer than other chemistries. Thermal run away much less likely. Since we cant see inside a big battery we have to assume its unknown BMS and cell quality unless certified. So take precautions. Put them in a metal vented box so if they fail the fire is less likely to sink the boat. Like on aircraft that use them. And monitor their temperature. I dont have mine in a box but both batteries have temperature sensors glued on top to trigger an alarm if they get hot and isolation relays to disconnect them if that happens.Maybe Im paranoid but fires on boats are scary.

There actually is a USA standard for installation of lithium batteries on boats ABYC E-13. The American Boat and Yacht Council’s industry-standard for the safe installation, operation, and maintenance of lithium-ion battery systems on recreational boats. It requires marine-certified batteries that meet IEC62619 (ie. they should come with a certificate of safety), proper ventilation, robust Battery Management Systems (BMS that actually work and are bullet proof), and secure restraints. This is an excellent guide. In Australia there is AS/NZS 3004.2:2014 which are government mandated standards for installation of lithium batteries on recreational vessels.

I actually contacted my insurance carrier and was told that they had no problem with lithium provided that it was lifePo4, met the relevant standard and the installation was inspected for compliance with the relevant installation standards.