Domestic solar panels for a vehicle

[VladTepes]

A mate came around yesterday and showed me his Hilux rig. He has a couple of big domestic solar panels mounted on racks above his tray (he had teh panels which came off his roof when he got a new system)

I can't recall the specifics of his set up, but he says it is cheaper, for more power output than a normal solar 12V system sold for vehicle use. (I'm not convinced. It MAY be the case if you already have the panels perhaps but if having to purchase panels I doubt it's better?)

He runs his two panels through a Victron 75/15 mppt (means nothing to me but might help others when offering opinions on the matter) (manufacturer info link BlueSolar MPPT 75/10, 75/15 & 100/15 (12 / 24 Volt + load output) - Victron Energy (https://www.victronenergy.com.au/solar-charge-controllers/mppt7510) )

One thing I did find impressive is that he has fitted a bluetooth dongle to the Victon and with an app on his phone can see the last 30days of consumption and production, plus the amount of time at each level of charging

Edit: Oh I better add that he claimed one main advantage of this system is that vehicle panels require direct sunlight whereas domestic panels can charge even on cloudy days. Any truth in this?


So I suppose I'm wondering whether its worth pursuing any such system or whether a 'normal' 12 V system with 200W panel would be a better way of going?
How would costs compare?

I assume the usual vehicle panels would be smaller/lighter than domestic panels.... ?

Cheers

[VladTepes]

My mate has [privded more info on hi set up:

Victron BlueSolar 75 15 MPPT Solar Regulator - Springers Solar (http://www.springers.com.au/product/victron-bluesolar-75-15/)
Think handles 250w household. New can get the $300new or gumtree has plenty 2nd pnels for under $100 max.
Allow $120 for some mc4 connects and a pre made lead from them for pv to mppt and 5m of 6mm lead to battery.

Those prices made it cheaper for decent quality set up rather than saupacentre 12v folding panel setup.
Dont have to be sunflower all day chasing the direct sunlight for panels to produce charge.
To prove charge need 4.5v over charging voltage usually14. To 14.6 depending battery type. 19.0 volts basically. A 12v panell needs direct sunlight for voc of 19.0volts to start producing charge current.

My panels is 44.0volt voc. So even in shade the voc is usually 19.0 voc. Watts maybe low but they can still pump charge in.

Victron VE.Direct Bluetooth LE Dongle - Springers (http://www.springers.com.au/product/victron-ve-direct-bluetooth-le-dongle-2/)

Dongle is about $75 atm. Need Bluetooth 4.0 to run the app.
Very handy. 30day history is great feature of use and charging
Will get a screen shot of app where it show mmpt suppling load terminals to frige 3.0amps and charging battery 2.0 amps at same time. Once had decent mppt you know why the cheaper Pwm solar chargers are so cheap. Because they are crap and kill batteries.


4days of rain and storms leading up to xmas last year the Batterylife it cut power to load terminals on 4th day. But that was deliberate not using 2nd deep cycle battery to run fridge and thats at -15c. Battery that Batterylife function cut power was back to float charge on 5th day as was pure sunshine and my 165w panels peak draw was 195watts produced. Yes over rated amount as mppt must have really needed the power to charge up.

[goingbush]

I have two domestic solar panels on the roof of my single axle van , with Viltron blue MPPT , keeps both batteries charged and fridge running even parked up through winter . And one domestic panel on the roof of Truck , ditto keeps house battery and fridge running permanently , then topples into the starter battery to keep that alive if parked up. A LOT cheaper and more efficient than so called Off road solar panels .

[Pedro_The_Swift]

why do you need a history of charge?
surely your undry washing will tell you that yesterday was no good for your batts,,,[bigrolf]
I would think anyone that uses a monthly recording probably is set up so they can safely ignore it,,

[The ho har's]

Interesting Vlad.. Harry is rebuilding a classic caravan and it was suggested by Springers that we use a house solar panel as it will run the 12volt fridge more efficiently.

Mrs hh

[Milton477]

I have a VIctron MPPT 10/30 controller with two 200W, 24V (house?) panels on my van. The Victron Bluetooth interface has been useful in a geeky kind of way to see just how much energy is being harvested & to compare the voltage at the controller with that at the battery. A difference in voltage prompted me to uprate the cables between the controller & the batteries.
When stopped, I use an Anderson plug to between the D4 & the caravan which keeps the Engel running & 2 Optima batteries + the cranking battery charged.

Problem with the house panels is they measure roughly 1600x800mm & weigh 15 kilos each.

[Tombie]

why do you need a history of charge?
surely your undry washing will tell you that yesterday was no good for your batts,,,[bigrolf]
I would think anyone that uses a monthly recording probably is set up so they can safely ignore it,,

Probably the same people who log mileage and fuel consumption [emoji41]

Aside from knowing how far We can get on a tank, does it really help to know the history of $$$ consumed by the engine [emoji56]

[VladTepes]

Problem with the house panels is they measure roughly 1600x800mm & weigh 15 kilos each.

Is that for two panels or one?
When I get the canopy on the ute I should have room for something 1600x800.

[loanrangie]

Panels pop up on gumtree pretty cheap so if you have the space to mount them and a suitable reg then sounds like a good option.

[Milton477]

Is that for two panels or one?
When I get the canopy on the ute I should have room for something 1600x800.

Each.

[incisor]

I picked up one of those 75/15 controllers on special the other week for $85

yet to hook it up but they have a good rap...

going to replace the $15 unit that i put on the van when we bought it.... (which has been working just fine btw)

[biggrin]

[martnH]

is the MC4 better than the Anderson plug? (just the normal Anderson but the power-pole)

Cheers

[DiscoMick]

I have an MC4 connecting the 80 watt panel on the roof rack of the Defender to the starting battery and it works fine. Smaller than an Anderson plug. I wrapped mine in insulation tape for extra sealing.
The cheap regulators seem to limit the panel output to protect the battery from being overcharged, so adding a bigger panel may not automatically increase the charge going to the battery. Does the Victron unit adjust the charging rate to the charging capacity of the battery?
It might also be an idea to check the maximum safe charging rate of the battery to avoid overcharging it.
Domestic panels might have a heavier frame than auto ones.