Solar setup help

[RubyOptics]

Lenny HB I need to pick your brains if I may!!

I'm planning our solar setup for the new van. I've read up on the difference between mono and poly panels, PWM and MPPT and want to run this by you before ordering parts if that would be ok?

plan would be for 2 of these 175W Victron mono rigid panels. These would be wired in parallel into this 100/20 Victron smart-solar controller.

I've used the Victron MPPT calculator for working out which controller I should be using, but would appreciate your expertise here as this is a bit new to me.

Want to stay with the victron controller at least, as I like the way their products seem to work well together and provide a good upgrade path for additional units to be linked in to a common infrastructure.

 

[Googlebot]

Great controllers!

A mate runs his house off one and the data he gets off it is really useful.

 

[Raul]

For the 2x 175w, you will need the 100/30 controller. The 100/20 is good up to 280w only.

 

[RubyOptics]

For the 2x 175w, you will need the 100/30 controler. The 100/20 is good up to 280w only.

Ah-ha, the plot thickens. Thanks for the heads up. Bloody strange that Victron suggest the 100/20 using their own calculator with their own panel inputs. Thanks Raul

 

[Lenny HB]

That is a great price for Victron panels as Raul says you need the larger controller.

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[Raul]

As for poly vs mono, both good; the poly fairs better in hot climates, and the mono better in low light. Same power output in fair like for like irradiation.

 

[RubyOptics]

As for poly vs mono, both good; the poly fairs better in hot climates, and the mono better in low light. Same power output in fair like for like irradiation.

Oh, ok? I hadn't read about this. May I ask for some further advice the please? We live in Poland, so our summers are bloody hot (it's 30 degrees right now) but then our winters are bloody cold (-23 last winter). Would you recommend poly or mono panels?

 

[RubyOptics]

That is a great price for Victron panels as Raul says you need the larger controller.

Yes, I'm slightly suspicious about the price to be honest with you.

 

[Lenny HB]

Oh, ok? I hadn't read about this. May I ask for some further advice the please? We live in Poland, so our summers are bloody hot (it's 30 degrees right now) but then our winters are bloody cold (-23 last winter). Would you recommend poly or mono panels?

I would go for Mono as when there is loads of sun you won't be worried about losing a few percent of the output also in winter you want every bit of power you can harvest. Also for the same power Poly panels are larger.

 

[RubyOptics]

I would go for Mono as when there is loads of sun you won't be worried about losing a few percent of the output also in winter you want every bit of power you can harvest. Also for the same power Poly panels are larger.

Thanks, really appreciate the advice here. Another question, regarding what I said about the common infrastructure of Victron stuff. My longer-term plan is to go to lithium. I'm fairly sure that I would need to change quite a bit of the charging system on the Challenger (being a more budget van) to get it optimised, which I'm fine with. Would the solar controller (100/30) be the right choice with a lithium end-goal in mind?

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[steveh57]

Not that know much at all so I accept I could easily be wrong , but I believe those panels are 24v each, so if connected in series that controller specified by the victron controller should be capable at 48v of 1160W PV power.

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-75-10,-75-15,-100-15,-100-20_48V-EN.pdf

 

[Lenny HB]

Thanks, really appreciate the advice here. Another question, regarding what I said about the common infrastructure of Victron stuff. My longer-term plan is to go to lithium. I'm fairly sure that I would need to change quite a bit of the charging system on the Challenger (being a more budget van) to get it optimised, which I'm fine with. Would the solar controller (100/30) be the right choice with a lithium end-goal in mind?

Although it has a Lithium setting it does not appear to have the facility for a temperature sensor.
Raul can probably advise on the best controller.

 

[steveh57]

Although it has a Lithium setting it does not appear to have the facility for a temperature sensor.
Raul can probably advise on the best controller.

You can integrate the temp sensor, either via smart connect with a battery monitor or smartshunt - Bluetooth or via V.E direct .The later needs additional hardware.

 

[RubyOptics]

You can integrate the temp sensor, either via smart connect with a battery monitor or smartshunt - Bluetooth or via V.E direct .The later needs additional hardware.

So later down the line, when we make the transition to Lithium, I can integrate the victron bluetooth battery monitor into the system which would give me the functionality I need? This is what I was hoping for by buying in to the whole victron "thing" - that I can add modules as and when I require them to expand my system to better suit our needs as we discover more what they will be given that it's a new, much more modern, van than our old one.

 

[steveh57]

Funnily enough this is exactly the same system I started with some 6 weeks ago. So you have me worried about the MPPT capacity but then I went by Vitron's advice for the panels etc. I believe with addition of a battery monitor or smart shunt with additional temp sensor you should be lithium ready .I' ve recently moved from the Bluetooth integration to V.E direct , DIY cables and a Raspberry Pi mimicking the GX controller., Then connected to Vitron's VRM So all data is available anywhere not just within a few metres of the van.

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[Raul]

Oh, ok? I hadn't read about this. May I ask for some further advice the please? We live in Poland, so our summers are bloody hot (it's 30 degrees right now) but then our winters are bloody cold (-23 last winter). Would you recommend poly or mono panels?

The colder it is, the better the production. Cold raises voltage and impedance. This is directly related to the temp coefficient of the panel. Victron lists it’s mono’s at 0,4% per deg C from 25degC test point. That means, for every deg C above 25 will loose 0,4% per degre, in voltage and some amps. So if panel has 20v at 25C Celsius, at 40 will be 20v minus 0,08v times 15 deg. = 18,8v. At negative temps. We gain 0,08v per deg. At negative 20 C the voltage will be 20v plus 3,6v= 23,6v. At over 20 amps this is a considerate amount of power. From 23,6 to 18,8v we have 4,8v advantage times 20 amps= 96w of power. Over 10 hrs we gain 1kwh in extra energy just purely for the cold.
Now the poly don’t drop as much in heat, but gain in cold. If your requirements are more important in days with limited daylight, the mono is the choice. You don’t care the loss in the summer, because you will gain in sun hrs, that makes up for the heat loss. If you need more in summer, the poly are more stable in heat. This you can see a life test on victron, they do a like for like mono poly and update results. It’s been running life in the past year and revealed some surprising data.

 

[RubyOptics]

Funnily enough this is exactly the same system I started with some 6 weeks ago. So you have me worried about the MPPT capacity but then I went by Vitron's advice for the panels etc. I believe with addition of a battery monitor or smart shunt with additional temp sensor you should be lithium ready .I' ve recently moved from the Bluetooth integration to V.E direct , DIY cables and a Raspberry Pi mimicking the GX controller., Then connected to Vitron's VRM So all data is available anywhere not just within a few metres of the van.

That sounds pretty much what I would eventually like. The remote monitoring would be awesome, but I suppose not strictly necessary for my personal needs. I had in mind staying with bluetooth and then installing a tablet and mount somewhere to act as a "power centre" where I can monitor all the electrical systems. More of a gimmick than anything strictly useful!!

 

[Raul]

Thanks, really appreciate the advice here. Another question, regarding what I said about the common infrastructure of Victron stuff. My longer-term plan is to go to lithium. I'm fairly sure that I would need to change quite a bit of the charging system on the Challenger (being a more budget van) to get it optimised, which I'm fine with. Would the solar controller (100/30) be the right choice with a lithium end-goal in mind?

Yes, absolutely compatible with Li. It has temp sensor built in the charger and can charge accordingly. Alternatively, for more accurate temp control, you get a temp sense by the batt. and networked in with the charger, via ve network. All charger temp sense has to be Bluetooth so they can communicate.

 

[autorouter]

Not that know much at all so I accept I could easily be wrong , but I believe those panels are 24v each, so if connected in series that controller specified by the victron controller should be capable at 48v of 1160W PV power.

If you're referring to the Victron 100/20 MPPT controller, be careful because the 100 means up to 100V INPUT, but the 20 means up to 20A OUTPUT. So if it's charging a 12V battery bank, the maximum power is going to be 12 x 20 = 240W. Since a panel usually won't ever give 100% of its power rating, especially in Northern Europe, then a 280W panel limit is about right.

Of course if you had a 48V battery bank, then as you say at 20A the maximum power is 48 x 20 = 960W, and could support 1120W of panels. This is another reason why off-grid house batteries are 48V.

 

[RubyOptics]

The colder it is, the better the production. Cold raises voltage and impedance. This is directly related to the temp coefficient of the panel. Victron lists it’s mono’s at 0,4% per deg C from 25degC test point. That means, for every deg C above 25 will loose 0,4% per degre, in voltage and some amps. So if panel has 20v at 25C Celsius, at 40 will be 20v minus 0,08v times 15 deg. = 18,8v. At negative temps. We gain 0,08v per deg. At negative 20 C the voltage will be 20v plus 3,6v= 23,6v. At over 20 amps this is a considerate amount of power. From 23,6 to 18,8v we have 4,8v advantage times 20 amps= 96w of power. Over 10 hrs we gain 1kwh in extra energy just purely for the cold.
Now the poly don’t drop as much in heat, but gain in cold. If your requirements are more important in days with limited daylight, the mono is the choice. You don’t care the loss in the summer, because you will gain in sun hrs, that makes up for the heat loss. If you need more in summer, the poly are more stable in heat. This you can see a life test on victron, they do a like for like mono poly and update results. It’s been running life in the past year and revealed some surprising data.

That's some great info, thank you. Our primary uses for the solar production will be to power the diesel heating during winter at night and to power 1 (or possibly 2) maxxfan units during the summer. I'm fully aware that the 85ah battery fitted as standard to the van is going to be my limiting factor when we get it, and that has been taken into account for our upgrade path. That path consists of a larger battery bank (hopefully roughly 300Ah if funds allow),

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[RubyOptics]

If you're referring to the Victron 100/20 MPPT controller, be careful because the 100 means up to 100V INPUT, but the 20 means up to 20A OUTPUT. So if it's charging a 12V battery bank, the maximum power is going to be 12 x 20 = 240W. Since a panel usually won't ever give 100% of its power rating, especially in Northern Europe, then a 280W panel limit is about right.

Of course if you had a 48V battery bank, then as you say at 20A the maximum power is 48 x 20 = 960W, and could support 1120W of panels. This is another reason why off-grid house batteries are 48V.

I think, for the small additional expense, upgrading to the 100/30 would be a worthwhile investment to allow myself an amount of overhead for a possible third panel, or higher wattage panels, in the future.

 

[Raul]

If you're referring to the Victron 100/20 MPPT controller, be careful because the 100 means up to 100V INPUT, but the 20 means up to 20A OUTPUT. So if it's charging a 12V battery bank, the maximum power is going to be 12 x 20 = 240W. Since a panel usually won't ever give 100% of its power rating, especially in Northern Europe, then a 280W panel limit is about right.

Of course if you had a 48V battery bank, then as you say at 20A the maximum power is 48 x 20 = 960W, and could support 1120W of panels. This is another reason why off-grid house batteries are 48V.

The 280w for the 100/20 comes from 14,4v absorb as 14,4x 20 gives 288w. This is the max the controller can modulate without wasting panel power. In theory you can have as much solar as long you stay below 100voc open voltage and max 20a per incoming strings. It’s capable of modulating as long you stay below those two parameters. Don’t forget this controller is the same for 24 and 48v. At 48v you can have 2kwp of panels.

 

[RubyOptics]

The 280w for the 100/20 comes from 14,4v absorb as 14,4x 20 gives 288w. This is the max the controller can modulate without wasting panel power. In theory you can have as much solar as long you stay below 100voc open voltage and max 20a per incoming strings. It’s capable of modulating as long you stay below those two parameters. Don’t forget this controller is the same for 24 and 48v. At 48v you can have 2kwp of panels.

Sorry Raul, So should i go for the 100/20 or 100/30 in this case?

 

[Raul]

Sorry Raul, So should i go for the 100/20 or 100/30 in this case?

The 100/30 hands down, otherwise you will be throwing away 70w from the two 175’s. It will work with the 100/20 but always limited to 280w despite you got more panel.
Your van is already limited in panel surface, so make the most of it. On a fixed installation, the over panel ig is not such a issue.

 

[Captain Yoghurtpot]

What a very interesting thread!
I am learning all the time.
Fascinating stuff this Solar power and what you can do with it.
Good luck RubyOptics and hope you enjoy your new van.

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[RubyOptics]

Many thanks Captain Yoghurtpot , we'll do our best! I thought the stressful part was over once we'd paid the deposit, but I fear that was just the beginning. I think we are suffering from a slightly over-enthusiastic salesman, in that I told him exactly the specs of the solar I wanted which he assured me was no problem. We got there today to try to look for a place for the solar controller and whilst there, I asked to see the panels they intended to use to get a weight and spec. The panels were a no-name job, they were poly and not mono as I requested. So I'm not trying to get a list together of the EXACT components I want used so there can be no mistakes made.

 

[Captain Yoghurtpot]

Did you buy the nice van you posted pictures of, or something else?

 

[RubyOptics]

Did you buy the nice van you posted pictures of, or something else?

If it was the Challenger, then yes! If it wasn't, I'm not sure what else I have been posting pictures of!

 

[Captain Yoghurtpot]

If it was the Challenger, then yes! If it wasn't, I'm not sure what else I have been posting pictures of!

Is the Benimar a Challenger?
You posted on a Benimar you were to look at very early one morning in early June, I think.

 

[RubyOptics]

Is the Benimar a Challenger?
You posted on a Benimar you were to look at very early one morning in early June, I think.

Ahhh, that one. No, we decided to pass on that once we had had a chance to actually see the condition and speak with the owner. Too many question marks about certain aspects and the price was incredibly high for the age and condition. We ended up buying new. Went with this one in the end, but with a lower trim level to avoid the black cabinets which made it feel smaller than it actually is inside.