I have a 12v boat and just installed a 24v, 8Kw bow thruster. No solar at the moment, just two alternators. I’d like to design a 24v system that has 800Ah. I’m hoping that I can make the 24v system support or replace my 12v batteries by conversion and then running my 12v systems. I’d like to do it with the less expensive 3.2v cells (I’m not sure which ones yet because I haven’t read enough to intelligently pick the proper one) instead of the retail 12v battery system drop-in’s for the obvious reason of expense. All the posts and system blueprints here on the site I only see them in smaller Ah configurations. Can these cells not be hooked up on a series to equal 800Ah safely or without difficulties? A 200Ah system is just way too small for my needs. Is there anyone out there that would be willing help me design a system?
800 Amp system possible?
- Thread starter CaptGregR
- Start date
that amount of amperage requires very expensive non off the shelf saftey devices. that is why most limit their systems to 400a or less. and more than 12v. or 24v. what are the specs. for your bow thruster, make and model.you need the batteries very close to the unit.it probrably has a pwm speed control system . since you only use it for short controlled burst while the main engine is running the batteries are getting recharged so your 800ah might be excessive.
Ampster
Renewable Energy Hobbyist
If I understand your correctly you want a 24 volt system to drive some heavy loads like a bow thruster and have more Ahrs of storage but you still want some small 12 v loads. There are very efficient DC to DC converters that can do that efficiently. If I have made a wrong assumption correct me.
The unknown issue is the most efficient way to charge that 24 volt system.
The unknown issue is the most efficient way to charge that 24 volt system.
You made the correct assumption. Yes, I’ve been reading that you’re correct about the charging too. The boat is equipped with a belt driven 200amp alternator that currently charges the 10 lead acid golf cart batteries. Not sure if that alternator will work with a 24v LFP batteries. Do you have any idea?
Ampster
Renewable Energy Hobbyist
Now that I understand the installation more, the issues that @mikeb brought up need to be considered. That alternator will not charge a 24 volt bank and the starter motor will probably not run off 24 volts. You would need expensive high Amperage DC to DC converters or change out the alternator and starter motor if that is even possible. Even if you find a 24 volt alternator there are some things that would have to be coordinated with Lithium to protect the alternator.
I would have to give some more thought to other work arounds but this is approaching the limit of my recent knowledge and others may have some better suggestions.
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