Axpert Solar Watt Question

[Mark1981]

I just wanted to ask a question. I have a Axpert 12V 1KW inverter currently grid linked for load shedding backup. I am thinking of expanding for solar backup if load shedding stage escalates and the time between shedding is maybe not sufficient to charge my batteries fully or if I decide I just want a longer backup for weekends.

The manual for the inverter mentions 85W panels and connecting 10 in parallel. It does not mention a max solar wattage. I assume this is simply an example and I can use any size panels as long as I don't exceed the 50A and I make sure I have 12V panels connected in parallel.

For example I would rather be looking at 150W panels. Pmax voltage is 18.1V and pmax current is 8.3A

Am I able to use these panels with the inverter and I assume I would be able to connect up to 6 of them in parallel?

[Chris Louw]

This is the specs for 1K 12v Axpert . Hope this will help . 

[Coulomb]

40 minutes ago, Chris Louw said:

This is the specs for 1K 12v Axpert.

Ick. I'm hoping that the 15 -18 V MPPT voltage range is a typo. In this 2017 manual that I happened to have open, it's 15 - 80 V, which makes a lot more sense. Especially with the upper limit of 102 V; there's a lot of room between 18 V and 102 V. "18" and "80" sound similar, so it does suggest a typographic error of some sort. But then the whole concept of the umpteen nominally 12 V panels in parallel would have to have arisen from that typo.

I'd be very tempted to try two nominally 24 V panels in series; three of even 60-cell panels would exceed the upper limit of 102 V. 24 V panels are presumably much easier to source, and are far better value per peak watt. If the panels are very low power by today's standards, you could try two pairs of nominally 24 V panels in parallel. But no more than 600  W total nominal power. So you'll probably have to shop around for 300 W or below panels, and use a single pair.

If you have some nominally 12 V panels already, you could try those in series, to see if you get the expected behaviour. It looks like your MPPT will generate at most 40 A [ edit: on the battery side ] (which at 12.5 V comes to 500 W).

 

Edited February 26, 2020 by Coulomb

[Chris Louw]

Would also like to know . The manual is for a 2018 unit version 1.7 . I also have a manual for a Meccer 2018 version 1.0 that also states 15 - 18 Vdc ?  . The 102Vdc also while the 1K. 24 v is only 75 v

[Mark1981]

I seem to have a different axpert version. Mine is a 1000W 12v version

 

This is the specs from the side of my inverter as well as from the manual.

 

I assume the 85W panels in the manual is purely as an example to show how to calculate how many panels you can run in parallel to not exceed to 50A max.

I assume I don't actually have to use 85W panels and could instead run up to 6 x 150W panels with pmax current of 8.3A in order to be within the 50A limit?

Edited February 26, 2020 by Mark1981
Mistake

[Chris Louw]

The different specifications is because there is 2 different solar chargers available with these 1000 w inverters , a MPPT charger or a PWM charger . Look like you have the PWM charger . The example with the 85 watt panels seems the best for inverter with the PWM .This will keep voltage best working range 15 v - 18 v . Just make sure witch tipe of solar charger you have .The expert Coulomb will then be able to assist you better .

[Mark1981]

Looking at my manual with the last screenshot it seems the charger is PWM

The 150W panels are also 15-18v which is why I thought they would be better. Fewer panels to install to get more power. Also I already have one of these 150W panels.

So as long as I stay within the 15-18v, does it matter what wattage the panels are? I assume as long as the combined Amps are less than 50A then I'm fine?

Edited February 26, 2020 by Mark1981

[Coulomb]

2 hours ago, Mark1981 said:

Looking at my manual with the last screenshot it seems the charger is PWM

Indeed. I was not thinking PWM; this is why it's so important to quote the exact model number, or just post the photo of the label straight away.

2 hours ago, Mark1981 said:

The 150W panels are also 15-18v which is why I thought they would be better. Fewer panels to install to get more power.

Yes. All the panels will be pulled down to battery voltage most of the time.

2 hours ago, Mark1981 said:

So as long as I stay within the 15-18v, does it matter what wattage the panels are? I assume as long as the combined Amps are less than 50A then I'm fine?

As above, it doesn't matter the panel wattage. You could add panels until the combine Imp came to about 55 A, possibly up to 60 A. The inverter will just use what it needs. The battery voltage may overshoot and undershoot a little more the more you "overclock" the solar charge controller, but this effect will matter less with a PWM charge controller.

[Mark1981]

Thanks very much. That is what I suspected, I just need to be sure.