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andrew-taylor asked

Can I use a Quattro to Charge 32v Battery Banks?

We recently purchased an older Hatteras motor yacht and are trying to update some of the electrical systems. The boat currently has a pair of generators, a single 30A battery charger, and two banks of 4x8V 155ah batteries (32v 155ah).

I need to replace the batteries ASAP. The units I'm planning to purchase are 190ah, so I'll have two banks of 4x8V 190ah. We do not currently have any solar but would like to add some in the future.

We do not currently have an inverter; all DC (windlass, bilge pumps, some lights) is provided directly from the house bank + DC switching panel.

I like the features provided by the Quattro but I'm unsure if it's the correct product for our application - specifically, whether it's capable of properly charging the 8v battery banks.

MultiPlus Quattro Inverter Charger
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Mike Dorsett avatar image Mike Dorsett commented ·
32v is an extremely unusual voltage. I would double check the volt ratings on the anchor winch and bilge pumps. Look at standardising the voltage to either 24, 36 or 48v.
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Justin Cook answered ·

32v would not be supported by any Quattro, nor would 36v; if you were able to convert the system to 8*3 for a 24vNom bank, that would be ideal. Otherwise, I know Sterling makes 32v chargers, not sure about any companies that make 32v inverters though.

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andrew-taylor answered ·

Just to clarify, I don’t have any intention of plugging 32v batteries into the input side of the inverter. We will eventually install new solar in either 12, 24, or 48v that will get plugged into the inverter input.

What I need to know is if that inverter charger will charge the existing 32v batteries. Sorry if I did not make that clear in my original post.

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Justin Cook avatar image Justin Cook ♦♦ commented ·
The input side of the inverter is the output side of the charger, it's the same connection. It will not charge a 32v bank.
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andrew-taylor avatar image andrew-taylor Justin Cook ♦♦ commented ·

So if I connect, say, 48v lithium batteries to the inverter, it'll only charge a 48v battery system?

I saw a deal online a while back where a guy with one of these older Hatteras motor yachts installed solar panels and 48v lithium batteries (as a new 'house' bank), plus a solar charge controller/inverter. He connected the inverter to one leg of his AC panel and was able to power the house loads via the inverter from the lithium batteries.

(Because his battery chargers were connected to the switched AC panel, he could actually use the lithium to recharge his starter battery bank, too. Not sure how smart that is, but it's interesting.)

This is sort of what we'd like to accomplish - a new, separate 'house' bank (in the future) through an inverter to the switched AC panel to run house loads...but I need the inverter to also keep the 32v starter banks charged.


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Justin Cook avatar image Justin Cook ♦♦ andrew-taylor commented ·
Yes, if you installed a -for instance- 48vNom separate bank, and connected a 48v Quattro to the 48v bank, it would only charge the 48v bank. Presumably what you could then do is maybe find a 48-32v DC-DC converter to trickle-charge the 32v bank, or like the online thing you reference, you could get a Sterling (or other brand) 32v AC-to-DC charger, plug that into one of the inverted outlets, and charge the 32v bank that way (would be quite inefficient, but better than nothing I suppose).


Any inverter/charger, or inverter and charger separately, is going to be voltage-specific. A 48v inverter/charger only works for 48v nominal batteries, etc. Victron chargers are highly configurable to be able to handle a fairly wide range around their nominal voltages, but a 32vNom bank is going to need higher charge voltages than a 24vNom charger can output, and much lower charge voltages than a 48vNom charger can output - even a 36vNom charger wouldn't be good for a 32vNom battery bank, and while some Victron solar controllers can be manually programmed to a 36vNom profile, those are about all in the Victron ecosphere that can deal with even 36v which still isn't much use for your 32v system.

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