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Victron multiplus 12/3000/120 how do I use power assist?


meerlaan

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Victrons take on it:

 

Dynamic current limiter

This setting is an expansion of the AC input current limit mechanism. If disabled, the AC input current limit is specified by the AC input current limit setting. When this setting is enabled the effective AC input current limit depends on the load history. When the load is lower than the AC input current limit the effective AC input current limit is also lower but slightly above the load. If the load increases the effective limit also increases with a delay. The thought behind this is that when a generator is running at a low load it cannot switch to full load immediately and it needs some time to increase the power.

 

An example:

We have a 2kVA generator. We adjust the AC input current limit setting to 8A and we enable PowerAssist. We have no load connected and the batteries are fully charged so therefore no current from generator is drawn. At this moment we connect a load of 7A to the Multi.

Normally the Multi would not react because the load is below the AC input current limit setting. The result is that the full load is connected to the generator which will drop in voltage because it cannot deliver that current instantly. If the output of the generator drops to below the AC low disconnect limit, the Multi will switch to inverter function and the back feed relay will open, disconnecting the generator from the load. If however we had this "Dynamic current limiter" setting enabled the effective AC input current limit would be far lower than 8A because the load was zero. So connecting a load of 7A will result in the Multi starting to Assist and no voltage drop is seen on the output. The generator will start to supply the load and the effective AC input current limit will slowly increase to 8A. At that moment the Multi will stop assisting and the full load is on the generator.

 

This is a powerful option in combination with PowerAssist but even with PowerControl it can prevent unnecessary switching to inverter because the charge current will reduce when AC input current becomes higher than the effective AC input current limit.

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Thanks for your responses ! Will have to have a good read through so I can understand, I have sent back my 202a to get a 203, thanks for that, what an idiot ! smile.png

 

I have included a few photos, of my BMV readings and some photos of my setup. I was wondering what my outback should be reading but cant seem to find much about this, for 905w of solar it seems to read about 100v in, in good sunshine, does this seem like a good reading ?


sorry cannot seem to get the photos the right way around :/

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Thanks for your responses ! Will have to have a good read through so I can understand, I have sent back my 202a to get a 203, thanks for that, what an idiot ! :)

 

I have included a few photos, of my BMV readings and some photos of my setup. I was wondering what my outback should be reading but cant seem to find much about this, for 905w of solar it seems to read about 100v in, in good sunshine, does this seem like a good reading ?

sorry cannot seem to get the photos the right way around :/

Generally the indications look fine to me. The Outback will typically show much the same panel voltage regardless, what is relevant is the current. In the first photo of it, the battery voltage is quite high and the current is not that high, but probably this is just due to the batteries approaching fully charged. I note that with the second outback photo it has gone to float, and yet there is still a fair bit of current. This could be due to some loads on the boat (ie the current is going to service the loads, rather than going into the battery) or it could be because the Outback is going to float prematurely. Not enough info to say which.

 

But in general this all looks fine what is not covered is the voltage at the Combi and batteries when the washer is on, which was the original problem IIRC.

 

Generally the Ouback shows how much current is being produced. The BMV shows what current is going into the batteries. So Outback current - BMV current = load going to the boat's services (you need to bear in mind the sign of the BMV current as it could be negative if the boat's load is greater than outback output, and obviously the alternator is another source of current that is not directly being monitored - when the engine is running)

Edited by nicknorman
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  • 3 weeks later...

Hi Nick and all,

 

So finally managed to do some test today to try and begin to understand whats going on, with your advice.

 

This is what I found... Hope it makes some sense....

 

BATTERIES WITH WASHING MACHINE RUNNING 30min 40Deg wash.

- At start all batts measure 6.4v (I made a not to not let them get below 5.9v30%)

- Inverter battery cables measure 12.71v measured with front of, putting wires onto terminals.

- Then I plugged generator in and measured 15v when on bulk charge and then it dropped down to 14.8v

- Then measured the batteries and the measured 6.3v then dropped to 5.8v, both times I measured two batteries to be sure. I then cancelled the wash as I worried the batteries were too low. This was after about 5-6mins. I left the the generator and charger running and measured the battery volatage to be 7.1 ?

 

I then tried to read off the battery monitor to see what this said regarding battery condition, Is it correct that my monitor says 12v even tho they are 6v batteries, it read 13.63v at this time.

All the time the multiplus was set to 'on' When I switched multiplus to charger only, it first went to bulk but only for a few moments and then onto absorbtion, but when it was on 'ON' which is suposably inverter and charger it was on float charge so I thought perhaps the batteries were good.

How long does charger stay in float mode ? I waited about 30mins for it in absorbiton and it went to float mode and was drawing less amps. When I stopped the genny the monitor read 13.24v All batteries measure 6.53v with volmeter at end.

After 1 hour the battery monitor reads 12.66v

 

I took some video along the way which probably help explain whats going on here is a link to them https://www.dropbox.com/sh/dvkc83peowxtkiy/AACOqtR0kkmE2WrT18FNaE5za?dl=0if anyone could help me put them in here that would be apreciated also, when I try to attach files it says they are too big.

 

Thanks all for any help or advice

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