Change over to Lithium

[bill424]

I'm about to buy a Pearson 424 that has an old school battery bank consisting of two 8d lead acid Sportsman units wired via a 1-2-Both-Off switch. When shore power is connected, it will charge batteries, heat water and power outlets. There are a few more AC breakers that I haven't figured out yet.

These batteries are old and have been unattended on the hard for over two years in scorching heat and cold winters. Unsurprisingly, they wouldn't start the boat by themselves, so their state is somewhat questionable and I don't want to start a 250 mile passage to her new home port without being reassured that I can start the diesel whenever I feel like it.

If I have to buy batteries, I would prefer to take the road to start/house banks and I'd like as much of that as feasible to be Lithium.

I would prefer, if possible to go all lithium, but then the twin problems of melting the alternator or blowing its regulator crop up. Obviously I can make the starter battery AGM and do DC to DC charging of the lithiums, but I'm not clear what Alternator protection and bank wiring I need if the starter is lithium too.

For now, shore or alternator charging will do, but eventually of course there will be some solar.

Thoughts?

[Mal Reynolds]

The existing batteries are toast. Forget about them & have the P.O. recycle them to save you the hassle of getting them off the boat.

Go to Costco or Walmart and buy two FLA 6 volt GC2's & install them. This will get her home and you can use the boat while you figure out the lithium system design.

You can take your time figuring out what the priorities are for your new boat.

[ltd]

Agree with Mal. Switching to lithium properly usually involves additional work on peripheral equipment. It's best to plan out carefully so you're not setting yourself up for heartache and a bunch of wasted money.