I have some history building DIY systems based on Victron products - two off-grid house systems and one small electric boat. All these systems where 48 volt based. No major problems. Everything works fine.
Now I want to build a bigger boat, and the motor is 96 volt. There will be battery storage, a lot of solar panels to charge the battery, inverter to get AC 230 volt for house appliances. Here is my problem: I cannot find 96 volt products for this system.
One potential solution I have in mind is to have two systems:
Normal 48 volt Victron based system for solar charging and AC conversion and use. There will be a large 48 volt battery pack.
(Relatively) smaller 96 volt battery for the motor only. This battery should be charged by AC or DC charger from my “normal” system. Unfortunately, 96 volt chargers are not a very popular product too.
Here is my question: is it possible to connect Victron products in series to increase the voltage? For example, connect two Orion Tr 48/48 converters or two Skylla 48/50 chargers in series to get 96 volt output?
Are there any other options to support 96 volt battery pack?
Using unisolated DC-DC converters (which have a direct ground connection between input and output) would short-circuit the bottom half of the 96V battery bank:
Since they have galvanic isolation there should be no potential between lower bank converter output (+) and upper bank converter output (-), even with both being connected to the same 48V battery bank on their inputs.
But I would measure that before connecting them together (either on a 96V-midpoint busbar or on the midpoint of the 96V battery)… just to be sure that their galvanic isolation is intact
To be sure I would also fuse the upper bank converter (-) output (connecting to the 96V battery midpoint), in addition to both converters (+) outputs, before it meets with either the fused lower bank converter (+) output or the 96V battery midpoint.
