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carien asked

Victron Blue system - Multiplus 48V/5000VA/70Amp and Blue solar chargerMPPT150volt/70 AMp- no more power after sunset

I have been off the grid 6 years and now my system does not want to provide power at night (when source disappears). Batteries (4x 200A12V deep gel cell) do charge and during day all seems fine but problem seems that the moment power use to switch to batteries the system goes down. Could this be the result of a fuse. If so which one most likely. Who can I contact to assist (lockdown considered) or any assistance on what to do appreciated?

battery charging
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Hi @Carien

What is the V on your battery pack when this happens?

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Morning John.

Reading prior to sunset:

battery icon: 48V actual 54.3V (very little sun yesterday but usually was not a problem)

An hour after sunset no power and readings on charge controller as follows:

First reading -charge controller - battery icon: 48V actual 52.7V (usually worki ng at this reading through the night)

- measured cross across battery pack = 115,2 A reading

- measured at cable points from battery to charge controller = 112.1A

- measured at cable points from battery to invertor = 112.1A

At this stage the took following readings from charge controller :

Second reading 5 minutes later -charge controller :

- battery icon: 48V actual 51.2V (Usually working at this reading through night )

- battery icon: 0.0 W

- - 0.0 A

- - 37.2V

- battery icon: 48V 0.0A

Third reading a minute later

- battery icon: 48V actual 44.9V (Should still be on and usually only goes from under 40 and even as low as 37 sometimes)

- measured cross across battery pack now dropped to 97A reading

This happened and got very suddenly worse over last 3 weeks and now not feasible anymore

I had somebody testing batteries and they are all still fine according to readings etc? charge to 13.4V

In the mornings the power does not switch back on automatically (invertor needs to be manually switched off and on) and this morning almost immediately when switched on reflected again at battery icon: 48V actual 56.7V

I can get some batteries (very limited stock currently) but do not want to do especially now if it will not fix the problem?

It seems as if the batteries charge but that it either cannot push through power for use or maybe loose very quickly?

Appreciate any help please

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@JohnC left all readings appreciate if any insights

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1 Answer
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JohnC answered ·

Evening here @Carien And I hope your day is better than my dreary lockdown one. :)

A Multi doesn't shutdown for no reason. One though is low Vbat. And that 37.2V you've quoted stands off the page. My own identical Multi came with exactly that as default and I left it there. If that's what it's seeing then it will shut down at 37.2. Let's roll for starters with that 'coincidence'.

Now that's not to say that your batts are faulty, but if that's what the Multi is seeing on it's terminals then you need to find out why. If the batt V is ok, it's likely somewhere in the wiring/cable crimps/isolator/fuse between the batts and the Multi. On either + or - sides. If you're handy with a multimeter it shouldn't be too hard to find a point along the wire-trail where the V is lost.

Try this first and come back.

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