Outside opinions on cats. What would you choose?

[Morndenkainen]

Fxykty. This is a bit off topic for the thread, but...

Why 24v? Because there's a LOT of ways to do the same thing, but doubling the voltage, cuts the amperage draw, or the load in half. I can use a 24v step down charger and keep a 12v battery to take care of things that can't be easily converted like nav, autopilot, usb charging ports, etc which eliminates a lot of complexity. The lighting, bilge pumps, windlass motors, and refrigeration can easily be converted to 24v, I can put in a stronger windlass without having to re-wire it, run a 24v watermaker, and enjoy less amperage draw. Also, many manufacturers make 24v solar panels and charge controllers, and the step up charging controller for the 12v alternators to the 24v bank makes swapping to externally regulated alternators unnecessary.

I've priced out the entire system, and added a 20% cost overrun in it and it came out just over $12K, including a BMS, new lighting, bilges, charge controllers, 24v breakers, etc. And that's using about 14.5Kwh of batteries. Basically the equivalent of 1200AH @ 12v.

Also, the 24v 40gph SeaWater Pro water maker is about $5K.

You said you had to re-wire the boat for a LFP conversion? I don't know who told you that, but they were wrong. None of your loads, (refrigerators, pumps, nav, lights, washer/dryer, water heater, etc.) suddenly started drawing more current because of your batteries. Your wiring is rated to handle a certain amount of amperage. The only reason you would ever need to change the wiring is if you INCREASED the load passing through it, like if you went from a 2kw inverter to a 5kw inverter...

But, as Abraham Lincoln once said.
"Everything you read on the internet is true."

[fillintheblank]

I am pretty well versed in electrical. ( master electrician plus many years of working on boat wiring )

I can see doing a 24 volt battery bank and using a 12 volt converter for existing 12 volt loads like lights, nav equipment, water pumps etc. Then changing large loads like water maker, inverter and windlass to 24 volts along with charging. But only if you need to replace those now, not to change them just because.

[Morndenkainen]

fillintheblank:

Normally I'd agree with that thought process, however I'm looking at it from this perspective. Preventative maintenance. The boat's been sitting a while. I'd hate to get out there and have things like bilge pumps, shower pumps, the sink pump, electric head, especially the electric heads, etc all get stuck or break and have to deal with it or interrupt my trip. For the cost, I might as well have new when I do the conversion. But you're right. Given my timeframe, I'll probably hold off on some things just to go sailing and fix whatever breaks next june. Stepdowns are cheap and work quite well.

[fillintheblank]

Originally Posted by Morndenkainen

fillintheblank:

Stepdowns are cheap and work quite well.

I would bring a spare, plus the obvious spare bilge pump or two.

If I was going off shore I would have a spare 2k or higher pump with a hose and wires with alligator clamps long enough to go any where on the boat. That way it could be a complete electric shut down and you can still get a pump running fast.