Okay, but what I mean is: as a principle, why is it generally better to have multiple smaller groups of batteries than one bigger group? You say 'in sync'. Do you mean that it will be easier for the system to keep the SoC over all the batteries at an equal level?
Ah, right. I think there’s a misconception here. To reiterate: I have 14 BMS units, so one per 4 cells, i.e. per individual battery, not one for the entire bank/group. This means I should theoretically be able to pull 14 X 150A = 2100 amps, even if I build one bank, right?
Ah yes, course. That was a fairly stupid question of mine, sorry ?
Ok we are thinking of very different ways to wire the cells.
At the risk of offending someone - and I really do not intend to - I think I need to try and provide some "translation" here.
I'll see if that's still doable. Potential bottleneck here is that the windlass is on the front of the boat, and the batteries in the stern. That's mucho metros of high power 12VDC wiring that needs to be added / fed thru the boat, which is not an attractive idea.
Lol makes sense.
So far so good on similar boats with similar setups, but it is indeed something to keep into consideration.
Yes and no. Most catamaran owners don't actually run both engines together if it's not really necessary. The fuel consumption is way higher than the speed you gain. So, for instance, if we have to motor for 3 hours, we'll do 1,5 on one engine and 1,5 on the other, which unfortunately makes your suggestion less practical. With that being said, I do intend to integrate alternator charing to both the starter batteries and house bank. I just don't know if my 115~130A stock alternators can handle that as-is (as mentioned before, I can't access my engine bays until the weekend). If they can, no problem. If they can't, modifications will be needed, which I don't want to invest time and effort (or money) into right now. We've had our boat for 1,5 years and it's been in refit since day one. We're splashing on March 15th and wanna get outta here ASAP.
Yes, that's it. There are a few 12VDC loads on a sailboat that are bigger than what you will likely see anywhere else. The bow thruster on the boat I was helping to upgrade draws just under 500A. I'm not sure why everything has stayed at 12V for all these years, but it seems like that is what people stick with.
I'd have to check, but I believe it's now setup to be connected to the LFP bank. Either that or to the starter battery. Definitely no separate battery though (there is none).
Makes sense indeed, although if I understand correctly, this will eliminate the option of monitoring every individual cell, right? How much of a disadvantage should that be considered?
Just to clarify - I don't have Overkill batteries, I have Fortune cells. Only the BMS is JBD (aka Overkill).
Right, this answers / confirms my first question. I'll have to think about what route I'll be taking. Tradeoff vs Tradeoff ¯\_(ツ)_/¯
I think what @Rocketman is referring to is a battery monitored by an Overkill BMS.
I'm pretty confused by this. You are talking about charging the LFP bank from the alternator, but you are talking about hooking the alternators to the starter battery. So is the alternator going to charge the starter battery, or the house battery? Also, you don't want your starter batteries connected to the Multiplus, unless you are doing something completely different than I can picture.
If you want to charge the LFP from AGM start batteries, add a good Victron DC-to-DC charger to your list, rather than just hooking the two together.
Yes I forgot to mention that rather important little detail, lol.
Yeah it's a bit vague, but I'm reading nothing but good feedback from users on it. From what I understand, it's initially designed for alternators with built-in regulators, which our alternators do have (although they only regulate down to 14V). Anyway, will contact them for further clarification. Thanks!
