Solar panel

Started by Paul, January 04, 2016, 10:51:39 AM

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Powder Hounds

Great setup!

Perfect example of a small very efficient system. You can't knock the harvesting power of your MPPT controller. I was considering changing my basic PWM to a MPPT for the increased efficiency and benefits, but I have other projects that warrant the additional funds. Plus with our Honda eu2000i I use the DC port to top up on cloudy days, this option is only really required in winter. Ah, another great advantage of your MPPT controller.


DavidM

Let me offer some suggestions and advice re the previous posts:

MPPT controllers let you get maybe 10-15% more power out of a solar panel and are absolutely required when hooking up a larger, 24V nominal panel. But they are expensive. Merlin's Morningstar 15A MPPT controller is listed on Amazon for about $250. That is two and a half times the cost of the 100 watt panel it is hooked up to. A Morningstar non water proof PWM controller costs about $70 and a water proof one, about $10 more. Is it worth paying double the cost of a 100 watt system to get maybe 10-15% more power? Particularly when Merlin's system probably can potentially supply twice the amp hours he consumes daily.

Switching to your Honda generator. If you use its DC charging port which is what I think you are saying, you get something like 10 amps and it is not three step regulated. If you hook up the generator's AC output to your camper then you can get the full 45A (typical) output of your converter and it is three step regulated.

David

Powder Hounds

Great advice!

My thoughts of not using the 3 stage converter and sometimes using the DC generator port is due the efficiency of that PD4000 control centre.

While connected to a solar system won't that converter start at the 45 A setting and then drop down into a float or trickle charge? IMO, as soon as it senses the solar current it scales back the output. I would be wasting fuel to charge my batteries in this manner. Having the benefit of a three stage regulated output is muted. Just my opinion.




DavidM

How he solar controller and the PD converter act together depends on the capacity of the batteries and their state of charge plus the charging characteristics of the two devices. If the batteries are relatively big, like two GC batteries and are well discharged, then both may put out at their rated maximums (assuming lots of sun). As they get more fully charged one will start cutting back output. You don't know which one cuts back without doing some testing which requires a clamp on ammeter and an accurate voltmeter.

Yes the DC output of the generator might produce more charging since it has a fixed, relatively high voltage. But it would have to be 14.5 V or more to keep up with the PD converter or the solar controller as the batteries get full. But why not use both the DC output as well as hook up the genset to the shore power connector? You will get the best of both.

David

Merlin

Quote from: DavidM on September 12, 2018, 01:49:29 PM
Let me offer some suggestions and advice re the previous posts:

MPPT controllers let you get maybe 10-15% more power out of a solar panel and are absolutely required when hooking up a larger, 24V nominal panel. But they are expensive. Merlin's Morningstar 15A MPPT controller is listed on Amazon for about $250. That is two and a half times the cost of the 100 watt panel it is hooked up to. A Morningstar non water proof PWM controller costs about $70 and a water proof one, about $10 more. Is it worth paying double the cost of a 100 watt system to get maybe 10-15% more power? Particularly when Merlin's system probably can potentially supply twice the amp hours he consumes daily.

Switching to your Honda generator. If you use its DC charging port which is what I think you are saying, you get something like 10 amps and it is not three step regulated. If you hook up the generator's AC output to your camper then you can get the full 45A (typical) output of your converter and it is three step regulated.

David

You're absolutely right about the economics of an MPPT controller in a very small system like mine. I should have mentioned that the Morningstar I used was an older controller I had sitting on the workbench, removed from another project. If I had purchased all the equipment new, a PWM controller would have been fine! As it was, the only new components were the panel and the Minnkota plug/receptacle.
Michigan