Is It a Good Idea to Retrofit a Boat From 12V to 24V?

Such a great question! A boater wrote to us to ask, "Jeff, great channel, much appreciated. I have a @SeawindCatamarans Seawind 1190 with a 1,000W solar array. I would like to install an inverter/charger and I am wondering if I should go 12 volts or 24 volts. I am setting up for extended periods off-grid and was wondering if 24 volts would benefit future solar additions?"

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[izq]

the problem stickin with 12v is the solar charger, 1000w means 80-90A and for that you would need a big solar charger and huge cables to inverter.

A solution I would consider if you already have a 12v boat is to have 2 battery banks, 48v and 12v. Solar charger and inverter running to 48v batteries, then a dc-dc charger for the 12v bank.

[projetsterna]

Merci pour la qualité de l'information fournit! Benoit

[tao]

That certainly is a great question, and 24 volts has many advantages, but to RETROFIT is very different from a new build. The current wiring could mostly be re-used (but you're not saving weight that way), some equipment will run at either voltage, although a lot of the older (and some newer) gear needs a single voltage range, so you'll either adapt for that with buck converters, or you'll end up running both voltages, which adds complexity and extra equipment (done this before, works, expensive, big PITA). Running almost any load at a higher nominal voltage makes sense for many reasons, weight and cash savings are the obvious ones and it would be absurd these days to BUILD a live-on size vessel all in 12 volts, but even I wouldn't retrofit 24 volts, despite my perfectionist mindset. I might be tempted to leave the engine systems at 12 volts and adapt for house bank charging at the higher voltage (boost chargers are a new thing, but long-awaited), because changing out the entire starting/charging and possibly even engine management systems is a horrifying prospect. You could always buck to 12 for your windlasses and so forth, but you run into amperage limitations. The largest commonly available (stock device, easily found) buck converter is something like 100 amps maximum for a few hundred bucks; not bad money, good efficiency, etc. It is a failure point though; that thing overheats, it shuts down and you have to wait 10 minutes for it to cool before you have power to your running gear, meanwhile you wash up on a rock pile and realize 12 volts, contrary to logic, was actually safer. So sure, you can retrofit if you're willing to bear the expense and some unique challenges, but having played with these situations, I agree with Jeff, it would not be worth the tears to do a full retrofit. Just my 20 cents. Happy sailing.

[luisgcasiquet]

Great subject! Thanks for the valuable info

[jshrawder]

Interesting what are the advantages of the 24V as to the 12V system? If there is a video already let me know. Thanks

[sailingsqualo]

Hi, all this electrical stuff is like black magic to me.So here is a question to which answer may seem obvious to most... We have an OLD 39 feet sailing boat, for some reason she is set up for 24 V, but because we are doing a full refit (including rewiring her completely, all new equipment) we are considering going to 12V. However one thing which we are most likely going to keep is the engine which is also 24V. Does changing only the alternator on it to 12V would be enough to make the engine 12V? Or do we actually have to change the entire engine? Or perhaps you would advise against it? Best, Natalia

[martinlacroix]

Hello Jeff, to work around high load device lime inverter on a 12V system, what’s your thought on using parralel cable (ex. 2x 2/0 câble). What’s should we pay attention to in that Kind of scénario ?

[kennyparrish]

I want to do a split system on my boat 120/220 v. . To run my clothes dryer ?

[izaacbanks]

is it possible to have a 24v system on a boat if i cannot get a 24v starter motor for the engine

[bethells]

Wiring wont need to be changed. Alternator and starter would be the only challenges.