diy solar

diy solar

What I have and what else do I need for a 24v system for van?

Kayte

New Member
Joined
Mar 22, 2020
Messages
40
I've estimated my needs to be 2000whrs. What I currently have: (will not be using alternator for charging)
2 - 200w panel,,, 1 - 24v 100a LiFePo batt
24v pure sine 3000w inverter DC24v to AC120,,, 50' - 10 gauge pure stranded copper wire
thermal circuit breaker w/manual on/off,,, 12v St blade fuse block 12 circuits 1a to 30a
DC digital multifunction meter & shunt 100a,,, 1 cable gland
24 to 12v converter,,, 6 port USB w/DC plug
50a circuit breaker w/ manual reset,,, 10awg solar panel & controller connector adapter MC4
Battery meter capacity checker LiFePo,,, Voltage power energy multimeter DC 6.5-100v 0-100a
lots of heat shrink connectors,,, 56 piece 8-4awg heavy duty wire lugs,,, batt cable ends,,, 50' 1/2" wire loom

I have what I need to attach panels to roof and it looks like I don't have room for more panels unless a much smaller one is allowed to be hooked up with 200w panels. I have a '22 148wb transit and have installed a fan toward the front. Currently don't have plans for full time living but hopefully 3 or more months at a time.
What don't I have that I need for a complete 24v system? Is one battery sufficient at this time? What will I need to plan on future expansion if needs require? I haven't seen a wiring diagram for a 24v van system that isn't way over the top.

I will not have an electric hot water heater or an electric stove/oven/microwave/toaster. Will not have video equipment or TV. Will have 1 maxair fan, 2 DC personal fans, DC blender, DC water pump, 8 DC puck lights, 2-3 DC reading lights, DC 5cuft fridge, DC exterior and garage lights, phone and computer charging and instant pot.

I appreciate your help very much.
 
Last edited:
24v pure sine 3000w inverter DC24v to AC120,,, 50' - 10 gauge pure stranded copper wire
Bigger wire! 3Kw can draw upwards of 150a and your 10AWG is only rated for 30a. That's a fire hazard!

DC digital multifunction meter & shunt 100a,,, 1 cable gland
Again, upwards of 150a, gonna need a bigger shunt.

Charge controller is going to be needed. At 400w you'll want a 30a at least.
 
I see I do have a 40a MPPT w/over current protection
300amp battery switch on/off blue sea systems 6006 correct switch?
Is a DC to DC charge controller just for alternating charging or something else too?
Anything else?
 
Last edited:
Bigger wire! 3Kw can draw upwards of 150a and your 10AWG is only rated for 30a. That's a fire hazard!
Are you saying bigger wire to run my 12/24 lights etc or bigger wire for wiring the board? And what size wire are you suggesting? Does a 24v system use smaller wire or is that just for powering the electrical runs? ie lights, fans...

Again, upwards of 150a, gonna need a bigger shunt.
So a 150 or 200a shunt?

Charge controller is going to be needed. At 400w you'll want a 30a at least. Gotcha
 
Are you saying bigger wire to run my 12/24 lights etc or bigger wire for wiring the board? And what size wire are you suggesting? Does a 24v system use smaller wire or is that just for powering the electrical runs? ie lights, fans...
You're going to need big wire to the inverter to supply the amperage load it's going to want to pull when maxed out. I have a similar setup and used 4AWG for anything. The wire size is based on your amperage loads so however many amps you're going to be drawing from the battery to the inverter and however many amps you'll be drawing from the battery to the 24v->12v converter will need to be calculated. The wires from the fuse block will be sized according to the load you'll be drawing from the fuse block to the device, usually much smaller than your main battery legs.

So a 150 or 200a shunt?
Everything I've seen comes in 3 sizes, 100a, 250a, and 500a. You'll want a 250a unit.

Charge controller is going to be needed. At 400w you'll want a 30a at least. Gotcha
Find the sweet spot for price/performance. If a 40a SCC is only $5 more than a 30a then it's worth it to give yourself room to grow. If on the other hand it's twice the price then don't bother.
 
I’m intrigued why you’ve gone for a 3000W inverter, what are you planning to run off it?

3000W + 15% in efficiencies / 24V = 144A

Just make sure your battery cable to your busbar and busbar to inverter are correctly sized and fused to cope with the potential power draw

I have a 12V system with 480W of solar, 2000W inverter and a 200Ah Lifepo4 battery so more or less a 12V version of your plan. I don’t have alternator charging either. I use the van for extended periods here in New Zealand. Time will tell whether I need to add a dc to dc charger to cope with low solar in the winter. I’ve left the space.

I hope not because I use the van as a base for activities like sea kayaking and mountain biking where I might not be driving for a few days at a time. With a 2000W inverter I can use an induction cook top but will likely substitute that out for a portable gas cooker in the winter
 
The 3Kw makes sense, it's kinda the top end for realistic 24v systems and even if Kayte only uses a max of 1500w now, she has the option of running 2500w later without having to buy new equipment.
 
With a use of 2000 watt hours, using only 400 watts of panels, you will need ideal solar conditions each and every day. This is not practical.
Consider alternative charging, Battery to battery charger for engine charging, shore power charging, generator or more panels.

Since most of your stuff is 12v DC and the Inverter power needed Is low, opting for a 24 volt system seems odd. However you already have purchaced 24 volt major items so it will be a 24 volt system. Ensure the 24 to 12 converter is a quality part, like Victron, the converters on ebay and Amazon are junk.

Mike
 
I see I do have a 40a MPPT w/over current protection
300amp battery switch on/off blue sea systems 6006 correct switch?
Anything else?

With a use of 2000 watt hours, using only 400 watts of panels, you will need ideal solar conditions each and every day. This is not practical.
Consider alternative charging, Battery to battery charger for engine charging, shore power charging, generator or more panels.

Since most of your stuff is 12v DC and the Inverter power needed Is low, opting for a 24 volt system seems odd. However you already have purchaced 24 volt major items so it will be a 24 volt system. Ensure the 24 to 12 converter is a quality part, like Victron, the converters on ebay and Amazon are junk.

Mike
I will install a shore power option but have no plans for alternator charging. I chose 24v because it's what is recommended these days. I know I won't always have ideal solar everyday, if I have enough to keep the fridge running I'll be happy and grateful for the better days. Maybe get a suitcase/portable panel if I can't fit another panel on top. It is a Victron and am purchasing only quality per Will's recommendations.
 
I’m intrigued why you’ve gone for a 3000W inverter, what are you planning to run off it?

3000W + 15% in efficiencies / 24V = 144A

Just make sure your battery cable to your busbar and busbar to inverter are correctly sized and fused to cope with the potential power draw

I have a 12V system with 480W of solar, 2000W inverter and a 200Ah Lifepo4 battery so more or less a 12V version of your plan. I don’t have alternator charging either. I use the van for extended periods here in New Zealand. Time will tell whether I need to add a dc to dc charger to cope with low solar in the winter. I’ve left the space.

I hope not because I use the van as a base for activities like sea kayaking and mountain biking where I might not be driving for a few days at a time. With a 2000W inverter I can use an induction cook top but will likely substitute that out for a portable gas cooker in the winter
The 24v system is recommended so that's what I went with and the 3000w inverter is also what Will recommends. I may never need it but right now I don't know what I'll need down the road so just want to build it now for more demand just in case. I really appreciate all the comments and help. It helps clarify all the info my brain's been trying to make sense of. Any and all additional info is welcome.
 
You're going to need big wire to the inverter to supply the amperage load it's going to want to pull when maxed out. I have a similar setup and used 4AWG for anything. The wire size is based on your amperage loads so however many amps you're going to be drawing from the battery to the inverter and however many amps you'll be drawing from the battery to the 24v->12v converter will need to be calculated. The wires from the fuse block will be sized according to the load you'll be drawing from the fuse block to the device, usually much smaller than your main battery legs.


Everything I've seen comes in 3 sizes, 100a, 250a, and 500a. You'll want a 250a unit.


Find the sweet spot for price/performance. If a 40a SCC is only $5 more than a 30a then it's worth it to give yourself room to grow. If on the other hand it's twice the price then don't bother.
Because it's going to be a 24v system, don't I only need a 15a charge controller? and 2AWG rather than 4AWG?
 
Because it's going to be a 24v system, don't I only need a 15a charge controller? and 2AWG rather than 4AWG?
You never want to run any kind of equipment at full load all the time, give yourself some head space and go for a 20a as it'll be easier to find than a 15a. That gives you some headroom on the controller.

Wire size is backwards in sizing so 10AWG is smaller than 8AWG which is smaller than 6AWG. The smaller the number the higher the amperage capability. For a 20a SCC you can use 12AWG just fine or grab some 10AWG just to buy you some head room for length and voltage drop.
 
You never want to run any kind of equipment at full load all the time, give yourself some head space and go for a 20a as it'll be easier to find than a 15a. That gives you some headroom on the controller.

Wire size is backwards in sizing so 10AWG is smaller than 8AWG which is smaller than 6AWG. The smaller the number the higher the amperage capability. For a 20a SCC you can use 12AWG just fine or grab some 10AWG just to buy you some head room for length and voltage drop.
Thanks! Does the victron MPPT 100v 20a 12-24-48 SCC make sense then?
 
Last edited:
Back
Top