Very nice description and nice system.
I am just starting to dig into the mess which the AC system is on my new vessel and I ran into an interesting problem:
About half of the US marinas
which have plugs which are 120/240 (or 125/250 on the plug
if I remember correctly) are actually two out of three phases from a three phase source.
So, instead of having two phases which are 180 degrees out of phase and the neutral to hot on each phase being 120V you now have two phases which are 120 degrees out of phase.
The result is 208V (yes, I had to get out Matlab for a minute to think about it but it is still a sinusoid) power.
The downside is that split phase inverters (the 120/240V equipment) will refuse to talk to it (for example the Xantrex equipment)
The biggest issue is that while most equipment
designed for 230V will run from about 205V up to 255V it is down near the bottom and equipment
is pulling more amperage and struggling.
In my case the boat started out as a 230V system, single
phase with neutral & hot, single
pole breakers with the exception of the GFCIs for each of the two load panels
So, I am looking at various solutions to create a generic system which can work with the existing equipment and have a path toward the future. I recently ran across the Victron Energy equipment and I have been very impressed. Your post has been a great confirmation that the equipment works as advertised.
In my most "bulletproof" solution (also the most expensive of course
) is to use two or three of the 100Amp @ 24V battery chargers which can absorb power between 90V and 260V and charge the batteries. This would be able to absorb all of the power from the current dock
circuit (which happens to be one of the 208V circuits) and would be able to produce 200 - 300Amps @ 27ish volts.
Then, a pair of the 5KVA Victron 240V inverters to carry the house loads, either in parallel or seperated depending on the current
equipment on board.
For example, the washer/dryer is currently a 50 cycle only unit as is the microwave, the air conditioners don't care about frequency, etc.
So, I can parallel the systems or run one as a 50 cycle unit and one as a 60 cycle unit in the event I have some large equipment which requires 60 cycles and other equipment which requires 50 cycle.
Additionally, the generator
would be run into the battery chargers (it is an older mechanically governed unit which runs 2hz high when unloaded and 2hz low when fully loaded, an 8KW Westerbeake).
For the 110V circuits I would probably use a small (2kw) unit to drive those independently.
The alternative is a step up transformer (noisy) from Charles marine
or there is a high frequency transformer with automatic boost from Mastervolt (I wish Victron produced such a beast).
However, when a combined inverter/charger sees shore power
it is going to match the frequency if it is going to provide charging
or support capabilities.
So, the question is am I completely nuts? The peak load for the boat is about 9kw if everything is on, reasonable normal loads are in the 5kw range (not all the time but two air conditioners running when at the dock
The other big question (I have a request in with Victron but they have not answered my e-mail request) is if I only wire shore power
to the victron battery chargers and they are galvanically isolated (as advertised) does this provide the same isolation as an isolation transformer? If so, this would allow the shore safety
ground to stop at the chargers assuming that the wiring
is conduited from the shore power plug
to the charger
compartment and there is no metal objects in with the chargers?
The nice thing is that I can use any type of power commonly found in the world:
230V 50hz (16A, 32A)
240V 60hz (50A)
240V/120V 60hz (50A)
208V/120V 60hz (50A)
120V 60hz (50A, 30A, 20A, 15A)
All that would be required is to tune back the chargers to limit the power consumed from shore power.
From a reliability
standpoint, loss of a battery charger
is not a huge deal so long as on average there is enough capacity to keep up with the average load. I am concerned that the inverter
side running day in and day out might not hold up.
Yes, this is a somewhat complicated system, luckily I do have the technical background to maintain such a system.
Any thoughts are most appreciated.