My wire runs will be less than 10 feet total; do you think everything should be 2/0 from the LifePO4 bank and Inverter?
2000W/12V= 167Amps. Furthermore, the Vicrons can handle surge currents up to 3x the normal run rate. That is why they recommend a 300 amp breaker. Even though you do not expect to draw this much, I still recommend the wires between the battery and busbars should be 2/0. The wires between the inverter and the busbars should also be 2/0. You could use 1/0 but you would want to make sure to put a 150A breaker in. The other wires can typically be much smaller. (Charge currents and load currents other than the inverter are rarely that large on a boat)
I was thinking we could keep an eye on it with the BMS shutting current off to keep us between a 10% - 90% SOC?
That works......You become the BMS. Personally I don't trust myself to remember to check. I would end up forgetting it is on and fry my batteries.
Windmills are tricky for a couple of reasons.
1) if you quit drawing the power off of them and the wind is still blowing, the open circuit voltage can get very high.
2) If you quit drawing the power off of them and the wind is still blowing, they will spin very fast... at a minimum, it is not good for the bearings. At worst, the windmill can tare itself apart.
It must be desogned for a 12V system... but do you know the wattage and/or current? do you have any documentation on it?
I have ordered 2 4S 120A from Overkill Solar. Can the negatives be connected in parallel to handle 240A?
Yup, that is the one I have been using on 12V systems. You can definitely set them up in parallel like you show.
If I could find a higher amp 4S BMS that has low-temp charge protect, I would use it and go 2P4S with a single BMS.... but I have not found a BMS like that so I use the one Overkill sells and double it up like you show in the diagram.
Note: Even though they are rated at 120 Amps, the general concensous is that the FET Based China BMS should be derated by quite a bit. Consequently, the two BMS are probably not at all over speced for your system. They are about right. (I would be worried if you were using the 100A version of that BMS)
5) Why do you have a disconnect between the engine and the battery?That is the way it is set up now from the manufacturer. We have a 1-Both-2 Combiner switch which we will want to remove the start battery from, and a disconnect from the Starter Battery to the Engine.
I can see the value in being able to totally disconnect the starter battery. If you want to be sure the system is off and nothing is draining the battery....just flip the switch. On the other hand, starting the engine on a boat is sacrosanct....it must always work. Having a switch there is something that can fail. It comes down to personal choice.... there is no 'right' answer
6) Is the inverter an inverter/charger? Victron MultiPlus Compact 12/2000 Inverter Charger
Nice unit!! I just worked with my Brother-in-law to install one of those on a Nordic Tug 26 up near Seattle.
As far as charging the Starter battery from shore power I believe The MultiPlus has a secondary output for the starter battery? Otherwise, we always have jumper cables on board just in case.
I believe your starter is remaining lead-acid.... Correct? Unfortunately the MultiPlus line of inverter/chargerss can only be programed for one charge profile even if they have multiple battery outputs. (Also, does the MultiPlus Compact have the multiple charger outputs? I don't recall seeing that..... but was not looking for it either).
If there is any chance the boat will sit for extended periods, you definitely want some kind of smart trickle charger on the lead acid starter battery. Lead acid really does not like being discharged.... and they self discharge fairly rapidly. If it will be on shore power while it sits, a small Smart Charger running off of shore power would be a good idea.
I have attached the current electrical plan just in case it helps?
It looks somewhat typical.
I notice there is a battery that appears to be located near the Windlass. If this is the case, it was probably done that way to avoid the voltage drop of a high-amp circuit leading to the Windlass. (A large voltage drop on the wires can damage the windlass). Have you decided how the windlass will tie into the new system? Will you leave it on the starter circuit or put it on the house battery? If you put it on the house battery, you need to make sure you have a very heavy circuit going to it. What is the make/model of the windlass? We can look up the specs and figure out what is needed.
the boat is in SFO Bay and when this project is complete, we are taking her South.
Cool, I live in Los Gatos. PM me if you need some help.
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Thanks again to all for your input, it truly was a community effort.
