Samiguel
Member
I've had the Victron 30a DC-DC for a few years now and it’s been great - it’s partially why I want to go Victron again for the MPPT
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[Guide] Mobile Solar Panels ? . . . - How I Did It -
- Thread starter Dellmassive
- Start date
I bought the Renogy smart shunt to give me an idea of what the Renogy ecosystem is like. I also have a couple of Victron 240v chargers, and well, the Renogy stuff is 'OK' but if (when) I start upgrading my electrics later this year I'm currently sitting very firmly on the Victron side. It just works. And the support is extremely good.
It'll end up costing double the 'equivalent' Renogy set up (£800 vs £400) but it'll still be worth it!
#team_blue
Defo good kit.
Defo good kit.
Samiguel
Member
This turned out to be great advice - thank you. I have everything set up in the garden and on a slightly gloomy day, the Renogy panel is kicking out 130w and, having taken off the PMW controller that came with the panel, the Victron MPPT that I replaced it with is charging my crappy battery at 8a or so.
I paid about £270 in total for the RENOGY 200w panel, the Victron 75|15 charge controller, cable and connectors which feels like a bargain (and money well spent!)
Samiguel
Member
OK - further logic check please. I need an PV extension lead so I can position the panel away from the van and I've been looking at 10m ones on Amazon. I've also pondered making up my own to save a bit of cash (not that much admittedly) so I could do with a bit of clarification on the following:
- At 10m, I'm assuming I would need 6mm PV cable to cope with potential voltage drop? (Renogy 200w panel - 5.45a open circuit current)
- I have a load of Anderson connectors, so could I use these to connect the extension cable to the MPPT instead of MC4? This connection is inside the van so does not necessarily need to be waterproof?
- Do I need a fuse on the positive cable? The Amazon ones don't seem to have them (and they are not shown on @Dellmassive wiring diagrams). If so, would the fuse go nearer the panel, or the controller?
- If so, are the MC4 inline fuses like this one the best/easiest?
- I know they are cheap, but to what extent do you NEED the MC4 spanners?
- fuses are not needed on 12v solar systems IMHO as the short circuit current is so low versus the cable gauge used (next to no chance of burning out cables) - so leave it out. ( if you wanted to fit one, it would go as close as possible to the source of power - so at the panel end of the cable)OK - further logic check please. I need an PV extension lead so I can position the panel away from the van and I've been looking at 10m ones on Amazon. I've also pondered making up my own to save a bit of cash (not that much admittedly) so I could do with a bit of clarification on the following:
- At 10m, I'm assuming I would need 6mm PV cable to cope with potential voltage drop? (Renogy 200w panel - 5.45a open circuit current)
- I have a load of Anderson connectors, so could I use these to connect the extension cable to the MPPT instead of MC4? This connection is inside the van so does not necessarily need to be waterproof?
- Do I need a fuse on the positive cable? The Amazon ones don't seem to have them (and they are not shown on @Dellmassive wiring diagrams). If so, would the fuse go nearer the panel, or the controller?
- If so, are the MC4 inline fuses like this one the best/easiest?
- I know they are cheap, but to what extent do you NEED the MC4 spanners?
- a 10m extension cable is fine, 6mm is better than 4mm for power transfer, but 4mm will also suffice. . . . cable physical size is also larger etc etc .. ( i use 4mm for my 10m extension runs)
- MC4 VS Anderson - you can use whatever you want provide the connector has sufficient ratings. so you you can do that. However, im a firm believer in using the correct connector for the job, and for solar thats MC4.
personally i keep MC4 for all solar panels, extension leads, interconnectors etc etc ,
and use Anderson SB50 connectors to the Power side of things. .
that way its impossible to connect any thing up wrong as everything is keyed correctly, so solar will only connect to a solar input and SB50 will only connect to the Power side.
so all my solar pv side stuff is MC4, that way any controller will connect to any extension cable that will connect to pv panel.
and same on the power side, i make up fused SB50 connection on the battery, then any SB50 extension cable can be used to any solar controller. etc et c
- MC4 tool - yes and no, for the spanner bit, you could prob do the connection tight enough by hand - but once clicked together, some of the MC4 connections are next to impossible to undo without the two prongs bit of the tool . . . especially when its cold out.
there are loads of MC4 plugs that all vary slightly, same with the tools . . they are all slightly different. so id suggest getting a MC4 tool to make like easier.
+++
i make up all my solar controllers so that they are plug and play using MC4 and SB50 with flexible 8AWG silicone cable
you can see here about the making solar cables. . .
[Guide] Solar Cables? . . . - How I Did It -
[Guide] Solar Cables? . . . - How I Did It - its time for another guide . . . This time on solar cables. we use these cables for permanent install and for mobile installs. lets start with the Solar PV MC4-MC4 cable. Solar PV cable is not actually standard cable . . . its more specialised...
and MC4 leads. . .
.
Mc4 tools. .
.
If you only need simple extensions you're not going to save any cash because you'll also need to invest in the tools to assemble the connectors. If you intend to make more than a couple, or need to thread unterminated cable through a grommet or wiring run then that may change things.
Don't be tempted to try and assemble/crimp with normal DIY tools like pliers to save money - a 100w panel still has 8A flowing and that will very happily overheat bad connections.
I'll repeat my general warning about cable from eBay/Amazon unless it's from a known supplier. I'm about to do the same and for the modest increase in price I'll probably get them from 12v Planet.
Due to the ever increasing number of flexible solar panels failing, mostly due to being installed incorrectly.
I've added the install guide to the start of this thread...
its not the panel (mostly) - its the poor fitting.
that causes uneven thermal expansion, where the panel is not evenly bonded. ( and even sagging into the troughs)
these hot/cold daily cycles cause the panels busbars to crack, and eventually fail. - causing a failed panel.
have the panel fitted correctly to ensure a long life,
and also fit vinyl wrap so you don't stick direct to paint work. . . that will save you loads of hassle if and when you decide to remove it.
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so ill link back to it here : [Guide] Mobile Solar Panels ? . . . - How I Did It -
.
I've added the install guide to the start of this thread...
its not the panel (mostly) - its the poor fitting.
that causes uneven thermal expansion, where the panel is not evenly bonded. ( and even sagging into the troughs)
these hot/cold daily cycles cause the panels busbars to crack, and eventually fail. - causing a failed panel.
have the panel fitted correctly to ensure a long life,
and also fit vinyl wrap so you don't stick direct to paint work. . . that will save you loads of hassle if and when you decide to remove it.
++++++++++++++++++
+++++++++++
so ill link back to it here : [Guide] Mobile Solar Panels ? . . . - How I Did It -
.
got a link for some? or some pics etc etc .
Heres mine, twin wall is fixed to the roof using quality double sided tape and the panel to the twin wall using plastic bolts through the eyelets, been on since May last year, no sign of it coming loose. There is another thread on here somewhere where someone says it’s common practice in Australia cause of the heat
Tried out the Bluefusion panel with the Victron in the sun today. Put the panel on the car roof:
For a panel rated at 50w and 2.8A, I'm fairly happy
For a panel rated at 50w and 2.8A, I'm fairly happy
@Dellmassive or anyone. In the pic above why is the panel voltage 2.5A and the battery voltage 3.6A? This happens all the time with mine too.
P=VI
Power in = Power out.
Therefore reduce voltage = increase current
So for Solar 49W = 19.77 x 2.5
Without losses should get 49W out
However there is some energy loss. So for the output we get:
13.08 x 3.6 = 47.088W
ie lost just under 2W due to ineffieiencies.
Aaah I understand now. Thanks Jon. A mystery solved.
Aaah I understand now. Thanks Jon. A mystery solved
yeh what he said. . .
an MPPT controller uses BUCK / BOOST circuits, to either riase or lower the voltage from the PV to charge a battery..
normally it takes a higher voltage 11-75v from the solar panel - at a low current.
and converts that into a lower voltage say 13.8v but at a higher current say 8A which is best to charge a battery.
.........
a good example here from the solar shed this morning shows:
PV = 68v @ 2.9A (197w)
is converter to a battery bank bulk charge of
Battery = 14v @ 13.3A (186w)
...
an MPPT controller uses BUCK / BOOST circuits, to either riase or lower the voltage from the PV to charge a battery..
normally it takes a higher voltage 11-75v from the solar panel - at a low current.
and converts that into a lower voltage say 13.8v but at a higher current say 8A which is best to charge a battery.
.........
a good example here from the solar shed this morning shows:
PV = 68v @ 2.9A (197w)
is converter to a battery bank bulk charge of
Battery = 14v @ 13.3A (186w)
...
thats very good to get that close to the STC ratings.
Strictly speaking it's the DC-DC charger element of the solar charger that's doing the BUCK/BOOST (same as your main DC-DC charger)
What the MPPT side is doing is maximising the power output of the panel. Power (watts) is voltage x current, so what it does is vary the resistance of the PV circuit until it finds the point where voltage x current is at it's highest (Maximum Power Point) and then continuously varies this to keep at that point (Tracking) - the precise MPP will vary according to many variables like temperature, panel angle, shading, strength of sunlight, the MPPT aim is always to squeeze the most it can out and then pass that power on to the DC-DC side which in turn uses it to charge the battery the best way it can.
So there's a lot going on in those little boxes! Modern DC power conversion circuits have really revolutionised devices like this, before Buck/Boost the only way to do this kind of shifting was by turning into AC and using a big heavy transformer and shifting back to DC and the losses were so big it would erase any gain.
How does this look?
50w foldable Bluefusion on the roof sunny for most of the morning, then a few clouds.
Started off with this
Had this much out of the panel
And ended up with this. I don't have a monitor on the leisure battery, but it looks like some power has been pushed through the SCR into that too.
50w foldable Bluefusion on the roof sunny for most of the morning, then a few clouds.
Started off with this
Had this much out of the panel
And ended up with this. I don't have a monitor on the leisure battery, but it looks like some power has been pushed through the SCR into that too.
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