Just want to make sure im not missing something

vendeta44

New Member
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.
 

snoobler

Solar Honey Badger
Moderator
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.
 

vendeta44

New Member
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.
 

snoobler

Solar Honey Badger
Moderator
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.
 

vendeta44

New Member
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.
 

snoobler

Solar Honey Badger
Moderator
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.
 

vendeta44

New Member
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.
 

snoobler

Solar Honey Badger
Moderator
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.
 

vendeta44

New Member
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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