Low amps on Victron.

[tvanjay]

Hi all,
New member but Murranji mk4 owner for 2 years.
I couldn't find any relevant posts on this, so if there is, I apologise now.

I have 2 105ah Fullriver batteries and programmed as such in the BMS.
My 60 watt roof panel only reads 22 to 26 watts, 1.8a to 2.2a, on my Victron BMS.
Should this be more. was in optimum conditions, 26oC full sun, middle of the day.
I run the freezer in the camper for 24 hours to drain some power. It used 34ah in that time. battery down to 89.5%.

First I cover up the roof panel.
I also have Blue Apple 165w Solar, regulated, with Projecta Watts/Amps meter. When I plug this in to the Anderson plug
at the drawbar, the Projecta meter reads 130 watt and 9.8amp, but only reads 66watt and 4.9amp on the Victron.
Even when I connect it to the shunt load and the battery positive, I get the same reading on the Projecta 130w and 9.8a,
while the Victron still reads 66w and 4.9a.

When I uncover the roof panel I got 88 watt and 6.7amp combined on the Victron.

Problems, suggestions, solutions, theories, help, all would be gratefully received.

Many thanks indeed.

[Slick]

Did you have any "consumers" (e.g. fridge, fan, lights etc) running when you were taking your measurements? If so, the BMV would show the nett result  (Power in minus load).

Vince

[tvanjay]

Hi Vince,

No. Everything turned off and unplugged, including main circuit switch.
No amps being drawn from anything, anywhere.

[Frankrhona]

It is hard to analyse your problem without understanding how it is all interconnected, a wiring diagram!
I did lookup the Blue Apple 165w Solar Panels: they are rated at 150W, 14.1V and 8.8A. Doing the maths VxA/W= 82% rated efficiency. I usually work on about 70% efficiency which would give an output of 7.4A.
However, you appear to be loosing more. I would suggest checking connections and wiring size vs length for losses. By example 4mm wire will have a voltage drop of 2% over just 1.5m of cable run, (3m total wire length).
To analyse losses you could use Clamp Meter, ($49.95, Item number: BM823A from http://www.sidewinder.com.au/page153aa.html), to  measure voltage and current at various points.
Apologies, I can't offer better advice.

Welcome to the forum!
Cheers,
Andrew

[tvanjay]

Thanks Frank,

I got an Email from Graeme at Track Trailer. he told me to re-calibrate my victron.

After doing this, my readings were a little better.
The 60watt on the roof, maximum output is 41w and 3.4amp.
Today I got a reading of 35w max, 2.7a, and a steady 32w and 2.5a.
Although my 165w panel still only produced 75w and 5.9a, at the Victron.
On the Projecta Watt/Amp Meter, I am getting 116w and 8.8a.
Also, my readings are on a day when it is 52oC in the sun.
I know the panels don't like extreme heat, so I think it's not too bad

So if you add the two together, I am getting approx 110w and 8.35a.
I am not really worried how I get there, but this is satisfactory to me.

I would still like to know what other people get.

[tvanjay]

Thanks for the input, everybody.

Auto Elec didn't connect both batteries negatives together, or/either both negatives to top of shunt.
He had A battery negative to top of shunt, and B battery straight to common earth.

I have since joined A+B negatives together, and then to top of shunt.
All works fine now.

Cheers
Jay.

[Slick]

Jay,

Pleased that you found a resolution to your issues. Thanks for sharing to root cause👍

Vince.