Solar query

[Nabsim]

I have a friend who is going to fit solar and I would like some clarification on which Victron controller he needs. Total of 600w solar which is made up of 4 of these https://www.alpha-batteries.co.uk/12v-150w-xplorer-solar-panel-for-caravans-boats-motorhomes/

Using the calculator on the Victron website it comes up with this for Bluetooth with terminals. Is this correct? I am never sure what Victron stuff is with the way they label which is one reason I didn’t use them but he already has Victron mains charger and BMV so it makes sense to stay with the same brand.

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SmartSolar MPPT 150/45 up to 250/100

 

[RAW]

3 x 150 Watt panel = 450 watt Max
P=IV

450/12 = I

I = 37.5 A (MAX)

That's a simple calculation really so I have a 285W Panel and Solar installer I used recommended 100/30 MPPT from Victron which he said was a bit over spec but best be on safe side, sadly I got a dumb one and not a smart one. SO definitely get one with Bluetooth built in!

I would say that one of these would be better:
www.victronenergy.com/solar-charge-controllers/smartsolar-100-50

If you buy one then get it from Onboard energy as there are discounts there for being full member of site.
@wildebus is your man for a definitive answer on this
www.onboardenergydirect.co.uk/shop/Victron-Smart-Solar-Charge-controller-MPPT-100-50.html

 

[wildebus]

I have a friend who is going to fit solar and I would like some clarification on which Victron controller he needs. Total of 600w solar which is made up of 4 of these https://www.alpha-batteries.co.uk/12v-150w-xplorer-solar-panel-for-caravans-boats-motorhomes/

Using the calculator on the Victron website it comes up with this for Bluetooth with terminals. Is this correct? I am never sure what Victron stuff is with the way they label which is one reason I didn’t use them but he already has Victron mains charger and BMV so it makes sense to stay with the same brand.

• 
• 
• 

SmartSolar MPPT 150/45 up to 250/100

First question is - is his Leisure Battery setup 12V or 24V? I would guess 12V, but if it were 24V, then it makes a big difference to what he needs (the power rating of a given Solar Controller is doubled when using a 24V setup, which allows you to go for a smaller one compared to what a 12V system needs).

The labelling is quite straightforward I think TBH.
take the SmartSolar MPPT 150/45
Smart = Bluetooth
Solar = Solar (as opposed to Wind or Water for example (that is a serious observation))
MPPT - as opposed to PWM
150 = Maximum Voltage allowed
45 = Maximum Current allowed (in OR out)
There is a reason why power ratings are not part of the description (read on )


Those Panels from Alpha have the key numbers 21.6V Voc and 9.1A Isc -
So connect them all in series, and you need a Controller that can handle 86.4V
connect them all in parallel and you need a Controller thay can handle 36.4A
connect them in a series/parallel combo and the key numbers are 43.2V and 18.2A

In the Victron range, you would likely be looking at the SmartSolar 100/50 - that can handle all 4 panels in whatever configuration is used (it supports 100V and 50A) and is rated at 700W on a 12V Battery System
The SmartSolar 100/20 is rated at 330W on a 12V Battery System, but will support 660W on a 24V Battery System. IF the chap has 24V, then the 100/20 is the one to go for as he would set up the panels as all series (86.4V, so within the 100V capability) or a Series/Parallel combo (max current is 18.2A - within the 20A capability of the 100/20 unit).
Finally, the SmartSolar 100/30 unit, despite having a limit of 440W, is still an acceptable choice on a 600W Array on a 12V Battery System and will work fine. The only thing that will happen is that any power over 440W will get clipped so he will not get the full use of his panels for around, what? 10% of the time? That is something to maybe consider when the price of the controllers are taken into account - the 100/50 is more expensive than the 100/30 (about £100 more) and the real-world benefits of the 100/50 is fairly small on a 600W array.
For a 600W system I was selling, I would probably opt for the 100/50 for a simple as can be setup.
For myself, I would maybe go for a pair of 100/20 controllers, with two panels on each controller. You have redundancy and separation (Pro) and you are spending around the same amount of money compared to a single 100/50

 

[RAW]

For myself, I would maybe go for a pair of 100/20 controllers, with two panels on each controller. You have redundancy and separation (Pro) and you are spending around the same amount of money compared to a single 100/50

THAT's a clever idea !!

 

[Nabsim]

Yes it is a 12v system. I would say to him to connect all panels in parallel as I did myself, not as much loss with shading is worth the reduced current in my mind. Simplest option is best for him so I take it that’s 4 panels into one controller?

 

[SquirrellCook]

I'm running a pair of https://midsummerenergy.co.uk/buy/flexible-solar-panels/miasole-120W-CIGS-flexible-solar-panel down each side of betty's roof. I too was wondering about two controllers. Any real life pro's or con's?
Two of these would be on the limits, but cheap. https://www.onboardenergydirect.co....r-Charge-controller-MPPT-75V-10A.html#SID=276

 

[wildebus]

Yes it is a 12v system. I would say to him to connect all panels in parallel as I did myself, not as much loss with shading is worth the reduced current in my mind. Simplest option is best for him so I take it that’s 4 panels into one controller?

Yup - 4 into one. He will need something tlike this to make life easy to connect - https://amzn.to/37GP0OO
I think parallel would work nicely and in truth he would see no more power loss than if a cloud or two passed over.
What he MUST do is make sure the cabling is up to the job though. I would expect the panels have cables with MC4s fitted - they will be fine to leave, but the cable from the 4-way combiner to the controller must be able to take 30A with ease. I would go for 6mm Solar (double-insulated cables).
If he wants any ready prepared plug and play for the setup and knows what length, I can setup a pair of cables with MC4s one end, ferrules fitted on the other and a Entry Gland box in white for the cables into the roof.

I'm running a pair of https://midsummerenergy.co.uk/buy/flexible-solar-panels/miasole-120W-CIGS-flexible-solar-panel down each side of betty's roof. I too was wondering about two controllers. Any real life pro's or con's?
Two of these would be on the limits, but cheap. https://www.onboardenergydirect.co....r-Charge-controller-MPPT-75V-10A.html#SID=276

Cons right at this moment is the controllers don't talk to each other to sync and optimize charging, but Victron are promising a firmware update for their MPPT Smart Controllers to do so and I strongly believe that will be delivered by the summer (it is overdue right now). Another con would be two pairs of cables having to come into the roof.
But Pros are redundancy which can be invaluable if the situation arises (I'd suggest the 75/15 rather than 75/10 - extra £10 is giving you 50% extra amperage (extra flexibility) and 30% more power handling. For example, with your 120W panels, you could double up at a later stage if you wanted and use the same controllers and only be slightly over the max power rating (240W max into a 220W controller))

 

[SquirrellCook]

Good to know Dave that the Victron MPPT’ s haven’t formed a relationship yet. I’d have been annoyed if they wouldn’t mate.
For a big vehicle I don’t have much roof space. So two panels each side in series is the most that will fit with ease. Keeping the wiring tidy it will be easier to have two junction boxes. Hence the idea of two MPPT’s btw it’s going to be 24volts.

 

[wildebus]

Good to know Dave that the Victron MPPT’ s haven’t formed a relationship yet. I’d have been annoyed if they wouldn’t mate.
For a big vehicle I don’t have much roof space. So two panels each side in series is the most that will fit with ease. Keeping the wiring tidy it will be easier to have two junction boxes. Hence the idea of two MPPT’s btw it’s going to be 24volts.

ah, of course. 24V system means a good saving on Controllers
on my van I have 400W (100W x 4 panels) and a 100/30 - so 440W maximum rating. I have worked out various options to add more capacity but will use a second controller (either the 100/20 I got it for some testing or if the additional capacity requires it, another 100/30). It also makes it easier to use different panels when adding (maybe get smaller panels to fit into gaps, for example?)

This conversation has reminded me to check where Victron are with their firmware update ....

 

[wildebus]

Good to know Dave that the Victron MPPT’ s haven’t formed a relationship yet. I’d have been annoyed if they wouldn’t mate.
For a big vehicle I don’t have much roof space. So two panels each side in series is the most that will fit with ease. Keeping the wiring tidy it will be easier to have two junction boxes. Hence the idea of two MPPT’s btw it’s going to be 24volts.

Do you want the good news or the bad news first?





Good News
Version 1.47 has added Sync Charging to the SmartSolar MPPT, and possibly BlueSolar controllers with Dongles.


Bad News (possibly?)
There seems to be a limitation to the upgrade for the 75/xx models. Not clear if this is SmartSolar models or just BlueSolar though?

I can't check anything on my setup as have no mobile data network available (local O2 mast has been faulty for around a week now!)

 

[SquirrellCook]

Thanks Dave, I intend it all to be done with new kit. This can be the danger buying stuff to early. Cerbo looks tempting. Also read about SmartShunt, I wonder if that’ll be cheaper than the 712.

 

[wildebus]

Thanks Dave, I intend it all to be done with new kit. This can be the danger buying stuff to early. Cerbo looks tempting. Also read about SmartShunt, I wonder if that’ll be cheaper than the 712.

£150. So saving around £50 or so over the 712. I don't think it has a secondary input though (in your build you would use as battery midpoint I guess). I don't often use the BMV display, but when I do, I'm glad it is there (used it today for example as connections hassles due to O2 issues meant I could not just use the PC to check stuff.

 

[SquirrellCook]

Always good to run ideas past others Dave, You make a good point. I could have a display somewhere handy to the engine start bank and the habitation bank.