What Solar Panel/controller Dc-dc Leisure Battery - Have You Got ?
- Thread starter Dellmassive
- Start date
Thanks to everyone for contributing to this thread, it's my first look into solar options and it's been very informative. As I'm still in the planning stage of my T6 conversion, I'm not certain what my power use will be. I am considering a 12V water heater which will be the largest load, but will be for occasional use only and mostly heating when driving. The other draw is the fridge, which is rated at 40W so quite efficient. @Dellmassive reported positively on the 160W PU panel, would the similar 180W be a good bet? 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
Yes... but that's only half the story.
You need the solar controller to be matched to the panel.... ie a Victron 75/15.
That 180 panel specs are...
Solar panel specifications:
- Peak power: 180W
- Maximum power voltage: 20.2V
- Maximum power current: 8.91A
- Open circuit voltage: 23.9V
- Short circuit current: 9.44A
- Power allowance range: +/- 5%
- Solar Panel dimensions: 1470 x 665 x 4 mm
- Junction Box diameter: 30 mm
- Weight: 5.90 kg
- 1 x 3m high quality dual core solar cable attached (4mm cross section
VOC. 23.9V
And
ISC 9.44A
Yes, I see many have the Victron 75/15. I thought I may go for the 100/20 to allow a little current headroom for another panel in the future, only a small price increase over the 75/15. At 665mm wide, I may be able to mount it on the side of the roof rather than centrally to allow another to be added later...I don't have the pop top yet but I believe they are approx 1450mm wide.
The “headroom“ thing is more important than Victron and their retailers seem to be aware of.
On my caravan I had 2 x 175W Victron Bluesolar Poly panels which had a combined max theoretical output of 350W in ideal conditions.
The Victron MPPT calculator stated that the correct MPPT was 100/20.
Before the Xmas 2020, I installed a Smartsolar 100/30 as I had a spare 175W panel and was going to add it to my solar array on my roof. I installed the 100/30 in the winter and then due to lockdowns etc never found time to install the extra panel as the van is in storage. , (I will soon.)
The thing is that the two 175W panels had never given more than a max combined output of around 270-280 watts, even on clear days in June/July where I’d deliberately run down my batteries and also run loads to guarantee that the charger remained in a bulk charging state. (For geeky test purposes)
Check out the below screenshot from the last week where it’s been common to get P Max numbers which far exceed 300W and even the theoretical 350W max of the panels. I stress that it’s not been particularly bright and sunny and the daily yield of 1.39kWh was never achievable prior to upgrading the MPPT well above the recommended spec from Victron.
On my caravan I had 2 x 175W Victron Bluesolar Poly panels which had a combined max theoretical output of 350W in ideal conditions.
The Victron MPPT calculator stated that the correct MPPT was 100/20.
Before the Xmas 2020, I installed a Smartsolar 100/30 as I had a spare 175W panel and was going to add it to my solar array on my roof. I installed the 100/30 in the winter and then due to lockdowns etc never found time to install the extra panel as the van is in storage. , (I will soon.)
The thing is that the two 175W panels had never given more than a max combined output of around 270-280 watts, even on clear days in June/July where I’d deliberately run down my batteries and also run loads to guarantee that the charger remained in a bulk charging state. (For geeky test purposes)
Check out the below screenshot from the last week where it’s been common to get P Max numbers which far exceed 300W and even the theoretical 350W max of the panels. I stress that it’s not been particularly bright and sunny and the daily yield of 1.39kWh was never achievable prior to upgrading the MPPT well above the recommended spec from Victron.
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Very interesting results. Which controller did you have before the Victron 100/30?
Victron SCC110020060R (100/20 as per the Victron MPPT calculator on their website for two Blue Solar 175W Poly panels in series.)
Since making the change, the improvement in solar yield has been really quite spectacular.
On dull days there is no real noticeable difference between the performance with the 100/20 and 100/30, but on any days with actual sun (The yellow thing in the sky), the yield is massively improved.
I first noticed this in early May when it became noticeable that whenever the panels see unobscured sun the MPPT chucks in over 320W. I would estimate that the VRM is showing around 30% more power generation than before the change in controller.
The only downsides are that the 100/30 is physically much bigger and costs more.
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This is a really significant increase. I'd be tempted to present these results to Victron to see if matches their expectation and the relative performance comparison between controllers. Your results point to the 100/30 being a good value investment in terms of W/£.
I doubt it will match Victron's expectations due the gains (that I've observed) far exceeding the info provided here.
I was wondering if I am missing something on how to spec these controllers as the above link seems to specify undersize controllers pretty much for every combination of panels that I require.
The rated charge output for the 100/30 is 30A and 20A for the 100/20. I am yet to install a third identical panel to the array, but it seems that with the third panel installed I will then find the 100/30 too small which contradicts Victron.
It's weird because if you look at @JBR80 's original query about a 100/20 being specified in preference to a 75/15, then I would say that the additional "headroom" isn't required as based on my recent findings I would ignore anything Victron tell me and spec the MPPT's rated charge output based on the panel power/system voltage! I.E.180W/12 = 15A.
(In theory there is already headroom in this because the system volatile will be 12-15V)
I was wondering if I am missing something on how to spec these controllers as the above link seems to specify undersize controllers pretty much for every combination of panels that I require.
The rated charge output for the 100/30 is 30A and 20A for the 100/20. I am yet to install a third identical panel to the array, but it seems that with the third panel installed I will then find the 100/30 too small which contradicts Victron.
It's weird because if you look at @JBR80 's original query about a 100/20 being specified in preference to a 75/15, then I would say that the additional "headroom" isn't required as based on my recent findings I would ignore anything Victron tell me and spec the MPPT's rated charge output based on the panel power/system voltage! I.E.180W/12 = 15A.
(In theory there is already headroom in this because the system volatile will be 12-15V)
I was considering a 100/20 to allow for a second 180W panel, but a 100/30 may be a better bet.
Interesting stuff, on my house system the panel peak power is 3.6kW but the inverter is only 3kW. I was told this will give a higher overall yield due to efficiency and the fact that the panel peak output is only on those sunny days & when the sun is straight onto the panels, it does seem to generate well even on typical days.
On a van they’re flat on the roof... so you’d have to get a fair way south before that were true.
On a van they’re flat on the roof... so you’d have to get a fair way south before that were true.
Photonic Universe have panels manufactured in Germany with better efficiency in low light, and a range of panels that are not. It looks like the regular ones could be Victron monocrystalline panels based on specs. Any idea what brand the German manufactured panels could be? Asking as most of the PU panels are out of stock.
It pays to always go for a bigger sized (current /amps )input on your solar controller than what you calculate you need as this will also allow for future expansion if you want/need to.
In an effort to try and track down an alternative to the 320w photonic universe panel: 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
I found these: 340w Solar Panel (168x100cm) — Craig Solar
Specs and description look good, but it does feel like a roll of the dice. Any thoughts?
I found these: 340w Solar Panel (168x100cm) — Craig Solar
Specs and description look good, but it does feel like a roll of the dice. Any thoughts?
And another similar: JA Solar JAM60S10-340/MR BF Half Cell
I just ordered a JA Solar JAM60S20-380/MR from here: https://greenpowershop.co.uk/products/ja-solar-380w-mono-mbb-percium-half-cell-black-frame-mc4
Most places charge a huge amount for delivery, green power shop charge less than £9.
The Victron MPPT calculator points to the 100/30 controller.
I'll report back when I'm setup.
Most places charge a huge amount for delivery, green power shop charge less than £9.
The Victron MPPT calculator points to the 100/30 controller.
I'll report back when I'm setup.
Isn't this completely expected though? On the 100/20 controller, the 20 bit refers to the maximum amps delivered to the battery? In which case, if we assume a charging voltage of, say, 14v then the maximum wattage is 20a*14v = 280w - which is exactly what you got in practice? In which case, it's nothing to do with headroom/efficiency effects, just the advertised spec of the unit? The equivalent number for the 100/30 unit is 420 which is comfortably in excess of your panel wattage so the panel can deliver its full power.
The only mystery is why the victron calculator gizmo recommended that 100/20 in the first place....
