Another solar question....

good morning, quick question has any one fitted a breaker or fuse between your panel and mppt unit if you did what did you use.

 

I have a 20A fuse between the MPPT and the battery but there probably should also be fuses between the panels and the MPPT.

Check those panels before you stick them down.

 

Good morning all. I was wondering about the relative advantages of portable solar panels instead of fixed ones. I've seen this one https://www.sunstore.co.uk/product/12v-lightweight-solar-battery-charger-200w-briefcase/ and there is one for £200 (100w).
Being able to move the panel about seems really useful and it could be left on the dashboard when out, but it will not charge on the move and theft could be be an issue.
What are people's thoughts on these?

 

I dont have solar but looked at these portable ones a while ago.

Pros & cons with both set ups.

Theft could be an issue, but you could park in the shade with the panels in the sun.

Check out the ones at photonic universe.

https://www.photonicuniverse.com/en/catalog/list/category/folding-solar-kits

 

I used to have a portable folding panel until some knob reversed over it
I’ll be putting a rigid panel on the pop top in the future

 

Look at the size of a portable panel, that 200w in your link is 800mm x 685mm (folded), you’re not going to have that on top of the dash and if you want to do more than just keep a battery topped up with a trickle charge the panel needs to be big, IMO less than 200w isn’t worth bothering with.

For me the biggest disadvantage of a portable panel is there is nowhere to put it when it’s not in use, there’s also cables all over the place and you have to connect and disconnect them. I want my solar to be out of sight and take up no useable space. I also just want it to work without messing about setting it up.

 

I had not thought of that disadvantage!

My pie in the sky thinking has dreamt about a demountable panel on the front exterior parcel shelf thingy over the cab. Charges on the move but can be removed and placed in sun if needed. Could even by rotated insitu if I wanted to get really clever/stupid (delete as you see fit!)

Edit, just seen @77 Westy post...size does matter..good point.

 

I keep revisiting the portable option as the idea of parking in the shade and putting the panel in the sun is attractive.

However, and I can't remember the exact figures, but iirc you can go about 20ft with 4mm cable before voltdrop becomes a significant issue.
So that's 20ft of both plus and negative cable to stow.
To alleviate the voltdrop you can go to 6mm cable, but then lugging around a total of 15plus m of cable just on the off chance you can even find a shady spot seemed like too much bother!
I'd be interested in anyone's practical experience of this though...

 

what size inline fuse did you use,

 

What size fuses depends on what system you’re installing.

Fuses protect the wiring and you should be using cables with a far higher current rating than the panels produce. If you’re using 100w panels a 10 or 15amp inline fuse in each panel will be fine. And if you have two 100w panels a 20amp fuse between the MPPT and the battery.

 

@marigold13
Off the top of my head I think I've done the same. 20amp mini blade fuses.
We've got 180w output, 4mm cable is rated to 50amps iirc and the output of the panels rarely exceeds 12 amps so that falls under midway of the cable rating Vs current best practice.
To small a fuse and it'll blow. Too big and it won't protect the cable
It's been a while since I've had to check mind. Next weekend we get Chip out of hibernation...can't wait

 

Ok interesting topic mono crystalline or poly crystalline solar panels that you are all fitting flat on the roof of your vans will only give you a limited output for some of the day ! The optimum angle for out put is between 30 & 45 degrees and south to South west facing in the UK
Look at the roofs of houses with panels on! Any temperature above 24 degrees and the output of the panels will decline massively
Panels are usually assembled on a alluminium frame with an air gap behind them to keep them cool !
Also the panels don't need sun to generate just light a bright clear cloudless day is ideal
Hope this clears up some myths

 

I like the permanent nature of my panel on the roof. Not sure I could be bothered with all the faffing about with a portable one.

I need to install a solar panel on the boat to keep the battery 'topped up/charged' when not being used.

 

Yeah that is too much cable.
@paradox has given the best down side to foldable panels, you might reverse over them.

Ill wait until they invent see through solar panels, then i can replace my perspex roof with them.

 

Yep, we always have fun aligning the bus so the westy roof evelates to the desired angle
However, ours are CIGS thin film and do cope with being fixed to the fibreglass with only the ridges in the roof to allow for airflow. So no framework required.
Best output related to atmospheric conditions was at altitude in Austria on a fairly cool day.
Best continuous output was one summer around the Peloponnese for 6 weeks or so.
So many variables, but the one variable we can do something about is to specify the best kit you can afford and take advice from the pros..

 

Hi All i have a VSR and a 100w portable panel and a 75ah AGM leisure battery,i run a compressor fridge couple of lights and a bit of music and have never come close to running out of power i don't know if we get better results from solar here in Australia though, I find a lot of people seem to have overly complicated systems when they don't need to
Rob

 

Is that one 180w panel, or two 90’s @scrooge95 ?