Batteries & solar

Peter your spot on in your assesment of the problem I have a Cpap and it will burn up battery supply. Barnray

I use a 'Remstar pro m series' Cpap on an inverter with no 12v power hassles, so it must be the model that he has that uses more power, or the battery bank is inefficient??

Maîneÿ . . .

Thanks for your help so far, I have 2x 100ah gel batteries and 120watt solar panel.

On the base of the cpap m/c it says "AC:100-240V 50/60 Hz 110v 400Hz. 2.5A DC: 12v 2.5A

The TV manual says power consumption on, <45w off <2w.

As for charging my laptop, forget it I just don't bother, apart from the water pump, I only use 4 of the 16 lights in the MH and those are the 4 that I've changed to LEDs

Rob

You have to remember that all calcs are done on the basis that your panel is directly facing the sun at all times if you panel is fixed then the input power will reduce as the sun moves overhead. B

Hello Robert,

so you've got a more energy efficient cpap using only 2.5A on 12V.
That's 20Ah per night.
Your telly gobbles 12Ah while running, and up to 3Ah in standby.
And the LEDs about 3Ah.
Total: 38Ah

Your 120W panel's only good for an average of 35Ah per day.

But on sunny days, this energy requirement should be easily met, if the panel faces due north at ~30-40 degree up from horizontal. And even better, if you make it fully face the sun every couple of hours or so.

Looking at your voltage figures your batteries don't get to see a lot of charge from the panel, if any at all.

Disconnect the panel and measure the voltage across its terminals while the sun shines. You want to see around 20V.
Then, connect the panel and measure again, this time across the PV+/- terminals on the solar regulator. You want to see a voltage equal to the battery voltage (or slightly higher by 50~100mV).
If this voltage is high (~20V), then there could be a blown fuse on/inside the regulator.
Are there some indicator lights on your regulator, showing something out of the ordinary?
Check this, and report back.

Best regards, Peter

"if the panel faces due north at ~30-40 degree up from horizontal."

- and if the panel is TOTALLY in the sun i.e . not a trace of shade on it.

I'm amazed how often I see panels leaning against the side of the van - i.e. totally or partially in the shade.