MPPT or PWM

[GMLS]

I have a basic PWM connecting my 100w panel to 2x 90amp batteries and wondered whether it was worth upgrading to an MPPT

May have already been posted but in doing a bit of market research, I found this which others might find of interest

https://www.victronenergy.com/upload/documents/White-paper-Which-solar-charge-controller-PWM-or-MPPT.pdf

 

[Figaro]

I swopped to a votronic 250 mppt after recommendations on here when I added another solar panel.
I was amazed at the improvement in performance

 

[Stealaway]

I would suspect the increase in performance would be mostly down to extra panel not the different type of charge controller. They are fractionaly better but not significantly enough to warrant the extra cost--- IMHO
Buy another panel with your money.

 

[funflair]

Well I like a bit of reading but that was too much for me, luckily I did my own back to back test a few years ago and I am sold on MPPT and indeed fitted Votronic on our last van.

Martin

 

[funflair]

I would suspect the increase in performance would be mostly down to extra panel not the different type of charge controller. They are fractionaly better but not significantly enough to warrant the extra cost--- IMHO
Buy another panel with your money.

My test said 25-30% OK still not the same as another panel but if you have as much panel as you can fit the MPPT made sense to me.

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[Lenny HB]

Well worth it a decent MPPT regulator will give 25-30% more output at low sun angles & cloudy days.
Notice I did say a decent MPPT regulator, there are a lot of cheap ones claiming to be MPPT but they are not.
Can't go far wrong with a Votronic or Victron, I have a Votronic MPP 350.

 

[68c]

I have a basic PWM connecting my 100w panel to 2x 90amp batteries and wondered whether it was worth upgrading to an MPPT

May have already been posted but in doing a bit of market research, I found this which others might find of interest

https://www.victronenergy.com/upload/documents/White-paper-Which-solar-charge-controller-PWM-or-MPPT.pdf

Very interesting, well worth a read although I did fall at the first graph, how can we get 6A at 0V?
In particular the paper suggests serial connection of two 12V panels or a single 24V panel is recommended, the MPPT controller being better able to harvest energy at the higher voltage and cable losses are less. It also says problems of shading are not a great concern.

I will confess I have often thought the serial connection is better due to the lower current. Why do folk only seem interested in shading when discussing multiple panels? Does one panel of a parallel setup miraculously move to avoid the shade, similarly do we assume a single panel will never be shaded?

 

[Driventemple]

I think panel voltage is the critical factor when considering MPPT. I was offered a 110W at 18V or a 150W at 28V. I fitted the latter and, looking at the figures on my phone, I note that the current flow into the leisure batteries is often 40 - 50% higher than the current produced by the panel.

 

[funflair]

I think panel voltage is the critical factor when considering MPPT. I was offered a 110W at 18V or a 150W at 28V. I fitted the latter and, looking at the figures on my phone, I note that the current flow into the leisure batteries is often 40 - 50% higher than the current produced by the panel.

It should be higher as it pushes it to your batteries at about 14v and harvests off the panel at 28v so the amps should be significantly higher.

Martin

 

[GMLS]

No room on the roof for another panel so will probably go with their small unit at some point. We camp all year round so the improvement in performance in non perfect conditions does seem worth having

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[68c]

Get a portable panel, a 100Watt panel which can be pointed at the sun will make more than a 100Watt roof mounted panel. I have seen folk put one on the roof for a bit of security if away for the day, or chained to the MH. If facing south will work propped up inside the windscreen. They are not too heavy, the weight will be carried low down when stored for travel.

 

[Minxy]

An alternative MPPT controller is one of these:



When we bought our Carthago this is what they fitted along with the solar panels and its kept our batteries topped up without a problem. The only point I can see in going for the Victron or Votronic ones is if you want to add a specific display to go with them.

Anyone heard of this solar controller?

Due to space/supply issues GoEuropean (GMC) are only able to put a single 150w panel on our new Carthago (instead of 2 x 100w) which AFAIK is being installed with the below controller but I've not come across one of these before so I'd appreciate comments from solar 'aficionados' about it and if...

www.motorhomefun.co.uk

 

[Off da Grid]

MPPT Votronic 350 duo for me.
They can harvest more power on cloudy days than PWM.
The higher the voltage the easier the cables can transmit the power so you can get away with smaller cabling and save on the cost.
That’s why it can be better to connect in series, however if one panel is shaded even slightly it will reduce the power output of the whole array.

 

[68c]

A single panel will also have less output if shaded. And a parallel set up if both shaded.