MPPT vs PWM - The Solar Controller Test!

[SquirrellCook]

Yes 5 panels in a mix can be fun. I had thought about 3 in series and the other two in series then paralleled. I guess if you like puzzles, brushing up on Kurchhoffs laws would resolve it.
Sod being clever, simple is often best. Don't buy one extra panel, buy 2 smaller ones?

 

[wildebus]

Yes 5 panels in a mix can be fun. I had thought about 3 in series and the other two in series then paralleled. I guess if you like puzzles, brushing up on Kurchhoffs laws would resolve it.
Sod being clever, simple is often best. Don't buy one extra panel, buy 2 smaller ones?

The problem with mixing panels is you can if you are not careful actually lower the total potential. I have 3 very nice 30W Mono Panels and have thought about - after checking suitability of mixing - fitting 2 of those - so 2 parallel sets of [100W + 100W + 30W in series].

The Rule you never see mentioned when it comes to Solar Panels, but maybe should do ..... Never fit a Prime Number of PV Panels

 

[trevskoda]

After all the reading I've been doing, including this thread, I've decided to replace my solar charge controller. The dead cheap one I'm running may or may not be working well. It's too vague to know. It tells me I'm getting 1.7A from the battery during the day today but it was saying the same thing in the dead of night last night. I'm sure it's making up the figures.
Victron 100/20 now ordered because I downloaded their App and the demo mode convinced me it's worth the money.

Think this model is better as it charges vh battery as well,also you can buy a add on panel.

 

[wildebus]

The testing with the solar panels has not really made much impact due to the combination of bad time of year for testing plus lots of restrictions such as house and trees.
Harvesting has dropped down to well below 1W per panel now so that is it for the day. To eliminate Location and Panel difference, I have swapped over the cables and will leave running for a second day.
Total harvest from 200W of PV Panel today .... 73Wh - That works out to be just 6Ah of energy back into the battery.

Will wait until end of play tomorrow to evaluate the results and do the comparisons.

Oh, and I had a thought and will be adding another Solar Controller into the mix .... I'll wire up an Ablemail B2B/MPPT 30A Combo Unit and test that the same way as the others i.e. using the 27V 2.15A Power Supply to see how that one goes (the extra cost of choosing the B2B/MPPT over the B2B is less than buying the most basic genuine MPPT controller so can be an economical way to add a quality solar controller if getting a B2B anyway)

 

[wildebus]

Think this model is better as it charges vh battery as well,also you can buy a add on panel.View attachment 1779

the Victron 100/20 has a LOAD output that can be configured in many ways, including to charge a second (e.g. Starter) Battery. With the access to a lot more configurability of all the settings then any typical alternatives, plus access using the Victron App to both instant and history data, I reckon the Victron is much better

 

[SquirrellCook]

I have 3 very nice 30W Mono Panels and have thought about - after checking suitability of mixing - fitting 2 of those - so 2 parallel sets of [100W + 100W + 30W in series].

That's my thinking, if you can get each series set in a row so that they are all subjected to the same light conditions.
Some double sided carpet tape for safety and mock it up and see what happens?

 

[SquirrellCook]

Total harvest from 200W of PV Panel today .... 73Wh - That works out to be just 6Ah of energy back into the battery.

These are the type of conditions I'm hoping to improve performance in. I have read stories about PV harvesting from moonlight. I have noticed with Murky at home 1 watt of energy is been absorbed from somewhere. lol

 

[RAW]

After all the reading I've been doing, including this thread, I've decided to replace my solar charge controller. The dead cheap one I'm running may or may not be working well. It's too vague to know. It tells me I'm getting 1.7A from the battery during the day today but it was saying the same thing in the dead of night last night. I'm sure it's making up the figures.
Victron 100/20 now ordered because I downloaded their App and the demo mode convinced me it's worth the money.

Did you get the Smart solar (Bluetooth enabled one) ?

 

[RAW]

Here's an aside, looking at a potential new Van, curved roof and no roof rack I am thinking the best idea for Solar would be to put a roof rack on the Van and fix panels to that rather than have the faff of fixing the panels to Van roof somehow. Do may folk fix their panels on this way ?

 

[RAW]

These are the type of conditions I'm hoping to improve performance in. I have read stories about PV harvesting from moonlight. I have noticed with Murky at home 1 watt of energy is been absorbed from somewhere. lol

This is from mine TODAY 285W Panel - Location HX7 @wildebus

 

[Pugwash69]

Did you get the Smart solar (Bluetooth enabled one) ?

Yes. I do like gadgets.

 

[Pugwash69]

Here's an aside, looking at a potential new Van, curved roof and no roof rack I am thinking the best idea for Solar would be to put a roof rack on the Van and fix panels to that rather than have the faff of fixing the panels to Van roof somehow. Do may folk fix their panels on this way ?

I bolted two unistrut bars lengthways, then two on top across. I found edge clamps on ebay for solar panels on unistrut.

 

[wildebus]

Here's an aside, looking at a potential new Van, curved roof and no roof rack I am thinking the best idea for Solar would be to put a roof rack on the Van and fix panels to that rather than have the faff of fixing the panels to Van roof somehow. Do may folk fix their panels on this way ?

I took this approach. Bought two lengths of seat tracking and fixed it to the van roof

400W in Place by David, on Flickr
The photo above shows 4 panels in place. I used the same tracking to add on a light bar at the front and a roof basket at the rear.
PS. I used the Renogy Z Brackets to fit the panels to the tracking. These brackets raise a height a but and this increased height allowed the panel to just clear the centre of the roof (like most panel vans the roof was convex and the centre was actually quite a bit higher then the sides).

 

[SquirrellCook]

I took this approach. Bought two lengths of seat tracking and fixed it to the van roof

Watch out for that aerial casting a shadow Dave

 

[wildebus]

Watch out for that aerial casting a shadow Dave

It is an interesting observation. You can see what looks like a shadow from the radio aerial - but the van is pointing near enough due North, which makes it a bit odd? (Unless you are meaning the white protrustion? MaxxAir Fan The sun would have to be very low for that cast a shadow and at that point solar harvesting is ineffectual anyway. TBH, this time of year I could drive to the local shop and back and put more energy into the battery then 2 days of solar harvesting from my parking spot)

I sometimes have a tall CB Aerial right in front of the first panel - that could stuff things up a bit if facing the wrong way though?

 

[RAW]

I took this approach. Bought two lengths of seat tracking and fixed it to the van roof

I bolted two unistrut bars lengthways, then two on top across. I found edge clamps on ebay for solar panels on unistrut.

Did you both Bolt through the roof panelling to fix the long bars ? If Bolting through the roof how do you ensure fully sealed holes from water ingress when there is likely going to be some movement and force exerted on panels through driving momentum etc

 

[wildebus]

Did you both Bolt through the roof panelling to fix the long bars ? If Bolting through the roof how do you ensure fully sealed holes from water ingress when there is likely going to be some movement and force exerted on panels through driving momentum etc

Each length (mine are separated so they don't straddle the roof seams) are bolted down fore and aft with hi-tensile bolts through the roof and then spreader plates (used thick penny/repair washers) and nuts to secure. I have runs of 3M VHB tape also underneath the whole length of the bars but I wouldn't rely on that alone. Use of sealent in the hole before pushing bolt to stop water and blobs underneath to stop water ingress. Seemed to work well (I had no ceiling cover for months after fitting the bars so could easily just do occasional checks.

I decided to use the "panels on rails" method after doing the same kind of thing on my previous vehicle - a VW T5 and it working very nicely

Solar Array by David, on Flickr

In the above case however, the Rails mounted onto pre-fitted threaded mounts on the roof. Some vehicles have these, some don't (for example, my VW LT/MB Sprinter Mk1 did not; the later Crafter/Sprinter Mk 2 does)

 

[RAW]

Thanks @wildebus

In the above case however, the Rails mounted onto pre-fitted threaded mounts on the roof.

The Transit has those gutter rails which I have seen Racks fitted too and roof bars BUT they are well below the roof top

If I had to drill through Roof then I would need to take down the internal panelling which is T&G all over (big job)

Other option would be stick down panels, flexible ones, which I have looked at but for good ones they cost quite a lot

Thanks

 

[wildebus]

The downside of using the gutter rails is that it generally preclude the fitting of an awning on the side of the van (plus it looks a bit industrial)

I know some people use rivnuts to provide a a better fixing then say self-tappers as a mechanical fixing, but I personally wonder if that is good enough? (I've had rivnuts pull out under stress and as you say, the life forces on a roof panel when driving can be pretty substantial I would think!)
GOOD Flexible panels can be good - but are always pricey compared to glass panels (you do have a weight saving though with the thin panels - have you/do you know the actual running weight of that van? I am guessing it is no more than 3.5t going by rear wheels - how close to that limit will you be do you think?)

 

[RAW]

The downside of using the gutter rails is that it generally preclude the fitting of an awning on the side of the van (plus it looks a bit industrial)

I know some people use rivnuts to provide a a better fixing then say self-tappers as a mechanical fixing, but I personally wonder if that is good enough? (I've had rivnuts pull out under stress and as you say, the life forces on a roof panel when driving can be pretty substantial I would think!)
GOOD Flexible panels can be good - but are always pricey compared to glass panels (you do have a weight saving though with the thin panels - have you/do you know the actual running weight of that van? I am guessing it is no more than 3.5t going by rear wheels - how close to that limit will you be do you think?)

The Running Weight of the Van, the actual weight as it stands I have no idea, on the Gov website it says 3.5T
Another option may be to weld some brackets on the side and go from there
There is an awning with the Van, a new one, I was thinking that if there was a way to fit a rack with vertical uprights from the Gutter Rails then I could potentially fix the awning to the uprights just above the gutter rail

Cheers
Robert