diy solar

diy solar

Just want to make sure im not missing something

vendeta44

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Mar 29, 2021
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After a few weeks of researching I think I have a game plan for the solar setup on my bus conversion. But Id like some confirmation before I start putting orders in. I plan to start with this load out and then when I have the money add a minimum of two more batteries(upping to 48v system), double the solar panels and replace the inverter with a 48v one.

4-6x QCELL-315-60BLK Hanwha 315 Watt Solar Panels

2x 300Ah 12v Ampere Time batteries in series

Victron Bluesolar MPPT 150/70-TR with battery temp sensor for low temperature cutoff.

Giandel 4000w Pure Sine Wave 24v Inverter

*missing* 24/48v mains charger - I found the 12/24v charger suggested in the DIY solar blueprints but as I'll be upping to a 48v system eventually what's the best way to accomplish this? Or can I just go through the victron mppt for mains charging with a isolator switch(probably a stupid question)?

*Almost certainly a small diesel generator to pick up any slack since I know the solar setup is under powered for what I want, but its all i have the budget for atm.

I'll have a licensed electrician helping me with the install and setup, and I'll be going through his sources for all the wiring other bits to connect it all. I just need to supply the crucial solar specific items that he doesn't deal with on the regular.
 
Saw in your other thread that you only need 1.1kWh/day.




After a few weeks of researching I think I have a game plan for the solar setup on my bus conversion. But Id like some confirmation before I start putting orders in. I plan to start with this load out and then when I have the money add a minimum of two more batteries(upping to 48v system), double the solar panels and replace the inverter with a 48v one.

What's the logic behind going 48V?

With such limited energy needs (unless you need like 11000W over 6 minutes), 24V should be more than adequate.

4-6x QCELL-315-60BLK Hanwha 315 Watt Solar Panels

1260W of solar is more than adequate to get 1.1kWh/day in most cases, so unless you're dealing with horrible weather and a sun you never see, I don't know why you're calling it inadequate. It's likely good for 3-4X on good solar days.


2x 300Ah 12v Ampere Time batteries in series

Victron Bluesolar MPPT 150/70-TR with battery temp sensor for low temperature cutoff.

Giandel 4000w Pure Sine Wave 24v Inverter

*missing* 24/48v mains charger - I found the 12/24v charger suggested in the DIY solar blueprints but as I'll be upping to a 48v system eventually what's the best way to accomplish this? Or can I just go through the victron mppt for mains charging with a isolator switch(probably a stupid question)?

MPPT needs high voltage DC input. Mains power is AC.

*Almost certainly a small diesel generator to pick up any slack since I know the solar setup is under powered for what I want, but its all i have the budget for atm.

Another backup option is never a bad idea, but again, not underpowered unless you're not telling us something.
 
Saw in your other thread that you only need 1.1kWh/day.

What's the logic behind going 48V?

With such limited energy needs (unless you need like 11000W over 6 minutes), 24V should be more than adequate.

1260W of solar is more than adequate to get 1.1kWh/day in most cases, so unless you're dealing with horrible weather and a sun you never see, I don't know why you're calling it inadequate. It's likely good for 3-4X on good solar days.

That might explain why no one commented... My numbers made no sense at all. My original power audit had me at 11.1kWh/day not 1.1kWh/day and the battery setup I was looking at when I wrote that post was 27kWh not 2.7kWh. Ya no excuse, I just forgot where decimals go I guess... Since I've figured some ways I can lower my usage quite a bit hence thinking I might be able to get away with this setup at least during the summer sunshine. Eventually Ill want to get 9+ panels on the roof which would exceed the Victron's output rating and possibly a few ground mount panels for when I'm camped out so upping to 48v is just for future proofing.
 
Okay. That makes a lot more sense. FWIW, my neighbor uses about 6kWh in his 3200sqft home. Propane hot water, stove, oven, and dryer. Wood burning stove for heat. I imagine there may be ways for you to cut back.

I guess in that case 48V makes sense if you're really going to 2835W and you want to keep it at one SCC.

I'd weigh getting a second charge controller vs. swapping out a 24V for 48V inverter.
 
Okay. That makes a lot more sense. FWIW, my neighbor uses about 6kWh in his 3200sqft home. Propane hot water, stove, oven, and dryer. Wood burning stove for heat. I imagine there may be ways for you to cut back.

I guess in that case 48V makes sense if you're really going to 2835W and you want to keep it at one SCC.

I'd weigh getting a second charge controller vs. swapping out a 24V for 48V inverter.

Do inverters lose resale value much? I just naively assumed I would be able to sell the old 24v inverter after 6-12months for 60-75% what I paid for it and take a small loss assuming that would be less than going with a bigger controller from the start or two smaller controllers.
 
Would you pay 60-75% for a 6-12 month old inverter?

Personally, I wouldn't. Likely no possibility of warranty coverage if there's a problem.
 
Would you pay 60-75% for a 6-12 month old inverter?

Personally, I wouldn't. Likely no possibility of warranty coverage if there's a problem.

Fair enough. Ill have to look into the price difference when I get to that point. Either switching out the inverter or adding another SCC either way is going to be better for my budget, otherwise I'd have to pony up for a full 48v pack or a massive SCC right from the start, and both would blow my budget. But otherwise the setup looks okay?

Appreciate the help btw thank you.
 
For alternator charging, there's the 12/24 Orion chargers.

70*28.8 = 2016W for the current Victron.

Another 30A SCC will get you all 9 panels.

Victrons are also very tolerant of over-paneling if you want to go that route. Unlikely your panels flat on your roof will output peak power.
 
For alternator charging, there's the 12/24 Orion chargers.

70*28.8 = 2016W for the current Victron.

Another 30A SCC will get you all 9 panels.

Victrons are also very tolerant of over-paneling if you want to go that route. Unlikely your panels flat on your roof will output peak power.

Good point. I suppose the intermediate time with the smaller setup will let me figure out how efficient they are in my application, I used this https://www.explorist.life/solar-charge-controller-calculator/ for the SCC to panel specifications. With 9 panels it's 94.57A output for 9 panels so only 20A over at optimal conditions.

I'm gonna have to look more into the Orion. I don't like the idea of getting into a habit of letting the engine run for a few extra watts if I was low so its only real use for me would be for the extra while driving.
 
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