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krmarine avatar image
krmarine asked

Using a Quattro and DC Battery Isolators.

We are using a 5KVA 230VAC Quattro on a marine vessel. Our vessel has a requirement for DC battery isolator switches to used at each battery bank.


The setup is we have our ‘House’ battery bank routed to a single large capacity isolation switch from 100mmsq cable (we are switching the DC high side only) - the output side of the isolation switch routes to a large capacity busbar.

Connected to the busbar is the Quattro DC cables and also the vessel DC loads.


We are also using an onboard Generator - connected to AC-IN-1 and we have shore AC power when available, routed to AC-IN-2.


There is a behaviour that we are seeing that we would like clarification on if possible please.


With the generator not running, so no AC-IN-1.

Shore power is connected on AC-IN-2.

All appears fine, AC power available - and the house battery bank gets charged correctly, the Quattro works through the bulk / absorb / float modes as is expected.


When it comes to the end of day - if the AC-IN-2 is still present at the point the House isolation switch is opened - the house DC loads continue to be ‘ON’ and the only source for DC in that state is the Quattro DC Power lines.

There is no longer a battery present, the Quattro presumably does not know this and continues to attempt charging something.


Q) Is there a way to stop this occurring or is this to be expected ?

The obvious answer is AC power off first, then the DC....

Q2) We do have a colour GX fitted, where the operator could manually request the Quattro switch OFF (first) - then switch off the house battery.

-If this would work - Would the Quattro need to be manually switched back ‘ON’ on the next power cycle ?


Incase anyone wonders, as is to be expected - if just AC-IN-2 is applied with the battery isolation switch in the OFF position we do not get this same behaviour / nothing happens within the Quattro until the DC Power is switched ON.


Thanks guys

Dave



battery charging
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2 Answers
daniel1957 avatar image
daniel1957 answered ·

To me this sounds like a good way to blow up the Quattro.

Unless the Quattro functions differently, an inverter/charger relies on the DC input for all of its control circuitry. If you are isolating it from DC whilst it is operating then it will be destroyed sooner or later.

Unless the Quattro functions differently.......

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boekel avatar image boekel ♦ commented ·

altough I don't know if it is damaging, I do know I never had a problem with it. When testing setups, had some DC breakers open, DC voltage never spiked too high (I think 33 volts on 24 volt system).

What I do think is a problem: closing the DC isolater switch on a discharged system, this gives a very high current and I would advice using a pre-charge for this if it is really necessary to isolate the Battery.

What regulations require to isolate the battery from the charger?

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ben avatar image ben ♦ commented ·

As discussed in the other question, Quattro operates differently.

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geomz avatar image
geomz answered ·

@KRMarine, a couple of things,

1) a Quattro will run/start/etc from AC1, even without DC. If you take the batteries out of circuit and leave your loads on the bus-bar, the Quattro, in essence, becomes a DC power supply and it will feed the DC loads itself. It's not "charging", per se, just providing DC as requested.

2) a Quattro will also run off of AC2 and continue to do as above (provide DC), as long as it's already on. It will NOT, however, start from an Off state from AC2 alone (just learned this myself :) ).

If I understand your requirements, you don't want the Quattro to provide any DC, when that condition is met. If so, you can create an assistant that's triggered by a switch (I have it connected it to aux1). That assistant (I think it's called "Charge Current Control") can be configured to set the DC output to 0 based on aux1 voltage (and remember to also check the box for turning off the charger when it should be 0).

With the switch "on" the charger will be Off and with the switch "Off" the charger will behave normally -at the rate you set in the assistant. You can probably reverse that logic as you see fit. It's only looking for the status of the contacts and their voltage on aux 1.

2V is the median voltage if you just short aux1's contacts.


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