Victron Charger and Equalizing?

[SoonerSailor]

Looking at the datasheet for the Victron chargers, and I don't see an option to equalize the battery. Am I missing something, or do Victrons not provide this capability? If they don't do it, how do users of these units equalize?

[btrayfors]

You're right...they sure hide it. Had a Victron MultiPlus inverter/charger for two years before I discovered it's hidden equalization cycle.

Should have read the manual more closely, I guess!

And, on mine, it's a bit of a pain to get started. You have to flip a toggle switch on the remote at precisely the right rhythm to get it going. But, it works, and works well. I believe they've made it easier on the new "shortie" models of the MultiPlus.

Don't know about the chargers, but I'd bet there's something similar. Why not shoot an email to a Victron dealer? Pete Kennedy in Annapolis is one dealer; there's another in Maine.

Bill

[SoonerSailor]

Thanks, Bill. Actually it was the Multiplus charger/inverter I was looking at. I'm surprised there is no mention of equalization voltages on the datasheet, but I'll obviously need to look at the manual.

Our Freedom20 is going in for repair, and I want to have a backup plan in case they want too much to fix it.

[botanybay]

Well, hard to find is better than the current charger I have, brush by the push button and the equalization cycle is off to the races. Turns out I ended up with a nearly new battery bank because someone bumped it a few months before I bought the boat!

[OceanPlanet]

Originally Posted by botanybay

Well, hard to find is better than the current charger I have, brush by the push button and the equalization cycle is off to the races. Turns out I ended up with a nearly new battery bank because someone bumped it a few months before I bought the boat!

Yikes! Better put a cover over that!!

[botanybay]

Exactly!

Still waiting for a definitive answer from either Mastervolt or Victron about if the galvanic isolation of the charger allows the charger to act as an isolation transformer if only the chargers are connected to shore power.

Something to push on harder in the new year.

[goboatingnow]

Still waiting for a definitive answer from either Mastervolt or Victron about if the galvanic isolation of the charger allows the charger to act as an isolation transformer if only the chargers are connected to shore power.

You will never get an answer to that or the stock answer is No , it will not. As itdepends on the internal design, even if it was a fully isolated output stage it will never be rated to act as an isolating transformer, even less so as a marine certified one.

This is not the way to go if you want the benefits of a proper isolating transformer( which you want becuase its primarily a SAFETY device, right).

[botanybay]

Originally Posted by goboatingnow

You will never get an answer to that or the stock answer is No , it will not. As itdepends on the internal design, even if it was a fully isolated output stage it will never be rated to act as an isolating transformer, even less so as a marine certified one.

This is not the way to go if you want the benefits of a proper isolating transformer( which you want becuase its primarily a SAFETY device, right).

Actually, it turns out that A/Sea systems makes a device which is exactly that, a AC -> DC converter and then a DC -> AC inverter to convert from any type of power to any other type of power. They specifically note that due the the "galvanic isolation" of the device that it performs the same function as the isolation transformer by design and is intended to be wired that way.

I did get a "we think so" but want to check with the engineers from the Victron folks so it is possible I might just get an answer in the end

The safety is the primary feature but an extra 200 lbs of transformer if not needed is not my idea of fun.

The isolation transformer installation requries bringing power (either neutral + hot in europe or L1 + L2 for 240 or 208V US) and the safety ground aboard to the transformer. The guts of the transformer are connected to shore safety ground, the shield is connected to ships ground, thus breaking the galvanic connection to shore power while providing a proper safety ground by either connecting Neutral (230/240 single phase) or the center tap of split phase from the transformer to ships ground providing the return path to a short circuit.

Now, in the case of the A/Sea systems equipment (which is essentially a charger followed by an inverter) the wiring is the same with no connection between shore safety ground and ships ground.

So, the hope is that Victron's or Mastervolt's battery chargers provide isolation in much the same way. (the inverter does not matter as it would be the same when disconnected from shore power). Neutral + Hot or L1 & L2 are brought aboard, with safety ground (three wires), come through a dedicated shore power circuit breaker (three pole or should it be 4 pole, i.e. should you trip ground also, perhaps not...) and then a dedicated GFCI then to the battery chargers.

Just like an isolation transformer, it would be prudent to conduit the power from the shore power inlet to prevent chafe in the power feed and then a short to ships ground (but an isolation transformer has the same problem), then place the battery chargers in a dedicated locker which has no metal components. The battery chargers safety ground is connected to shore power safety ground. The battery chargers output is connected to the 24V DC bus for the boat at the batteries with dedicated fuses.

Now, the potential issues I see...

1) When out of the water it is necessary to provide a jumper to connect ships ground to shore ground or else the metal of the boat may float at some random voltage.

2) If the DC negative output cable chafes through to the battery charger safety ground (for example the case) then the isolation is compromised. No safety issue here just the galvanic protection is no longer provided and corrosion can occur.

3) Safety ground from shore power is applied only to the battery charger and thus most likely the metal case. If the shore ground is mis-wired this would result in a hot case which would not trip the circuit breaker (this can happen with a "normal" safety ground to ships ground connection in fresh water as the return current through the water is often low enough to not trip the breaker, not sure if it could happen in salt water). Reverse polarity is not an issue in this case as the charger can use a neutral and a hot or two hot leads (for the "normal" safety ground connection reverse polarity can be a huge issue as most of the circuit breakers are often single pole leaving equipment energized even when there is not a completed circuit).

So, if the battery charger case isolated from DC Negative AND from shore power safety ground (My Freedom 20 inverter on the last boat was this way) then you simply hook case ground to ship ground and there is not an issue.

If the case is connected internally to DC negative (unlikely, this is basically not a "galvanically isolated charger" as I understand it) and shore safety ground is used internally then we are good to go.

If the case is connected to the shore safety ground connection internal to the charger then there is the potential for an issue.

I think it will depend on the choices they made for the internal circuitry, i.e. when and how in the circuit do they step down the voltage.

Of course I could use "galvanic isolators" and connect shore ground to ships ground and then everything is fine (provided the shore safety ground is within the blocking voltage of the isolator) or else we get corrosion.

If it were not the weight, space, and hum of the isolation transformer the belt and suspenders approach is appealing, however, if the battery charger is already doing the job then I will avoid it.

Thanks again for your thoughts, I appreciate everyones thoughts to help me avoid some corner condition I did not think of

[jallum]

Originally Posted by botanybay

I did get a "we think so" but want to check with the engineers from the Victron folks so it is possible I might just get an answer in the end

Bump... Did you ever get an answer on this?

[botanybay]

I did in fact get an answer back..

Unfortunately not the one I was hoping for (as some have suggested would almost definitely be the case). The charger does not provide sufficient isolation to be used as the primary isolation source from shore power.

So, an isolation transformer is the only solution...

There are three primary sources of these I have found for the marine market for 7KVA devices (32A @ 230V) which is about the smallest unit which would be useful. I would prefer a 10KVA device to handle the 50A @ 208V power which is on my dock.

1) Charles Marine - Very heavy, very noisy, very robust, traditional transformer design, capable of providing fine control (multitap) to boost or buck the dock voltage to a more or less constant voltage on the boat. (about 230 lbs!) very large

2) Victron Energy - Toroidal design, lighter weight, very quiet, no multi-tap capability so whatever the dock voltage is the boat voltage is. (Weight 22kg or about 50lbs). Medium size

3) Mastervolt - Toroidal design, very light weight (10kg or about 25lbs), multitap capability which will take any dock voltage from 90V - 140V or 185V - 265V becomes 230V +/- 5% (219V - 241V). Built in monitoring circuits to provide KWH consumed, voltages, currents, ect. Size is almost identical to the Victron Energy Device.

So, from that perspective the Mastervolt device looks nice, both the Victron and Mastervolt devices can be paralleled with identical copies (i.e. 2 Victron or 2 Mastervolt) to get twice the capability.

I have heard that the Mastervolt equipment in general is a bit less robust than the Victron and I much prefer the Victron inverter/charger setup. So I am considering a mixed system (not my preference) but since the Victron Energy isolation transformer is not "smart" there is no "interfacing" issues with the Mastervolt equipment.

The downside is that if I set a maximum current draw on the inverter/charger and the dock voltage drops 10% due to a brownout the Mastervolt isolation transformer will boost the voltage but the dock current will go up by 10%. Now if I wanted to go crazy, I could have a computer onboard monitor the isolation transformer digital data link and then based upon the dock voltage set the maximum current the Victron inverter/charger can pull off the dock to deal with the difference. Or I just leave enough margin to not be tripping breakers, if it is a problem I can just put in two of the devices in parallel and have reserve capacity.

So, at this point I am looking at the following system:

Any power coming from the dock goes through the isolation transformer and voltage is adjusted to within 5% of 230V

The first 5KVA Victron Energy inverter/charger running 230V @ 60hz providing 230V power to the boat and charging batteries.

A second 5KVA Victron Energy inverter/charger running 230V @ 50hz providing 50 hz power to those devices which can only run on 50hz. This unit is connected to the 6KVA Genset to charge batteries away from the dock.

A third 3KVA Victron Energy inverter/charger running 110V @ 60 hz which is generally making power from the DC bus.

Now an interesting option is to take the output of the 50hz inverter which is only energized when outside AC power is available (in this case the generator) and feed that into the generator input of the first inverter charger. This would allow as much as 25A to flow through, however, the 230V 60hz bus would then move to 50hz when on generator power.

Currently I don't have any 230V/240V 60hz only equipment aboard so that would avoid having to carry those loads via the inverters and it would provide the maximum battery charging capability. The only reason to run through the first inverter is to allow the first inverter to correctly compute the "power assist" features.

All of the 110V electronics would be powered from an inverter all of the time which will at least keep the clocks from blinking!

I will continue to look at the differences between the Mastervolt and Victron Energy inverters to see if there is a clean solution on the Mastervolt side which has enough margin to allow a totally Mastervolt system but I think I really like the Victron Energy inverter/chargers better. (Anyone have any thoughts here).