24V solar system - 12V DC question

[jbartee7]

Hello all,

I am working on a new solar system to replace the furion system that came with my rv. I am having trouble figuring out the best way to power the DC side of the system since I am going to run a 24v battery bank. I have run through multiple options including using a 24vto12v dc2dc converter, just using the existing ac2dc converter and using a victron orion-tr smart charger. I have been given advice from the diysolarforum that none of these are efficient and I am at a loss at this point on how to power my 12v dc side of the electrical system.

Current solar package:
Furion 165W solar panel
Furion solar charge controller
12v FLA battery

New solar system main components:
4* 250W santan solar panels = 1000W solar (theoritical)
victron smartsolar 100|50 scc
lynx distributor
2* 12v 200ah ampere time plus batteries wired in series = 24v battery bank
victron 24|3000|70 multiplus
Victron smartshunt

What have other people who have installed 24v solar systems/battery banks done to power their dc side?
Should I power everything from the 24v battery bank or keep the existing 12v battery for dc side?

Any opinions/critiques on the components I am using are welcome.
I would just like to figure everything out so I can proceed with the install.

Thanks!

[Soundsailor]

Hello all,

I am working on a new solar system to replace the furion system that came with my rv. I am having trouble figuring out the best way to power the DC side of the system since I am going to run a 24v battery bank. I have run through multiple options including using a 24vto12v dc2dc converter, just using the existing ac2dc converter and using a victron orion-tr smart charger. I have been given advice from the diysolarforum that none of these are efficient and I am at a loss at this point on how to power my 12v dc side of the electrical system.

Current solar package:
Furion 165W solar panel
Furion solar charge controller
12v FLA battery

New solar system main components:
4* 250W santan solar panels = 1000W solar (theoritical)
victron smartsolar 100|50 scc
lynx distributor
2* 12v 200ah ampere time plus batteries wired in series = 24v battery bank
victron 24|3000|70 multiplus
Victron smartshunt

What have other people who have installed 24v solar systems/battery banks done to power their dc side?
Should I power everything from the 24v battery bank or keep the existing 12v battery for dc side?

Any opinions/critiques on the components I am using are welcome.
I would just like to figure everything out so I can proceed with the install.

Thanks!

First off, it looks like you're new here, welcome to the forum.

While I don't run a 24-volt system myself, my understanding is that you would be fine with a simple 24 to 12-volt converter to run the DC side of things. I'm not aware of any better way (there may be others who are) of servicing your 12-volt components from a 24-volt power system.

[MoonShadow_1911]

Hello all,

I am working on a new solar system to replace the furion system that came with my rv. I am having trouble figuring out the best way to power the DC side of the system since I am going to run a 24v battery bank. I have run through multiple options including using a 24vto12v dc2dc converter, just using the existing ac2dc converter and using a victron orion-tr smart charger. I have been given advice from the diysolarforum that none of these are efficient and I am at a loss at this point on how to power my 12v dc side of the electrical system.

Current solar package:
Furion 165W solar panel
Furion solar charge controller
12v FLA battery

New solar system main components:
4* 250W santan solar panels = 1000W solar (theoritical)
victron smartsolar 100|50 scc
lynx distributor
2* 12v 200ah ampere time plus batteries wired in series = 24v battery bank
victron 24|3000|70 multiplus
Victron smartshunt

What have other people who have installed 24v solar systems/battery banks done to power their dc side?
Should I power everything from the 24v battery bank or keep the existing 12v battery for dc side?

Any opinions/critiques on the components I am using are welcome.
I would just like to figure everything out so I can proceed with the install.

Thanks!

Speaking strictly DC voltage and current, a 24vdc to 12vdc stepdown transformer or converter will be your most electrically efficient option. A transformer is the cheapest, and most "complicated" to install, a DC-to-DC converter is pretty much plug and play.

[Tom Traveler]

Technically, "transformers" don't work with DC, only AC. You'll need a DC to DC converter. They are widely available in various sizes. The "Victron Energy Orion IP20 24/12-Volt 70 amp DC-DC Converter Non-Isolated, High Power" available on Amazon for $135, would do the job and provide 70a of 12v DC power. I don't know how much you need. Also, there may be less expensive options.

[Tom Traveler]

Forget to mention, the efficiencies are in the 90+% range. The 70a referenced above is 92%.

[tonygoncalves]

You will never get 100% efficiency, there will always be losses in the form of heat whenever moving or converting electricity. The key is to minimize them. Keeping the highest power consumers and producers at a higher voltage/lower amperage is more efficient than at a lower voltage/higher amperage. With the system you've designed, with batteries, solar charging, and inverter/charger at 24V, and using a 24V-12V DC to DC converter at 90+% efficiency to run the lower power items in your trailer is the best of both worlds.
If I could start over, that would be the system I would design for myself.

[MoonShadow_1911]

Technically, "transformers" don't work with DC, only AC. You'll need a DC to DC converter. They are widely available in various sizes. The "Victron Energy Orion IP20 24/12-Volt 70 amp DC-DC Converter Non-Isolated, High Power" available on Amazon for $135, would do the job and provide 70a of 12v DC power. I don't know how much you need. Also, there may be less expensive options.

I did mention that it was "complicated". [emoji16]

[Ynot4me2]

I think the victron 24|3000|70 multiplus will already do this for you. It takes 24v in but the 3000 inverter output is 12v. I could be mistaken though.

Sent from my SM-P610 using Tapatalk

[tonygoncalves]

I think the victron 24|3000|70 multiplus will already do this for you. It takes 24v in but the 3000 inverter output is 12v. I could be mistaken though.

Sent from my SM-P610 using Tapatalk

Nope, it will only output what it takes in. The inverter output is 120V in north america at 70A (240V elsewhere) and the inverter input/charger output is 24v.

[SolarPoweredRV]

Hello all,

I am working on a new solar system to replace the furion system that came with my rv. I am having trouble figuring out the best way to power the DC side of the system since I am going to run a 24v battery bank. I have run through multiple options including using a 24vto12v dc2dc converter, just using the existing ac2dc converter and using a victron orion-tr smart charger. I have been given advice from the diysolarforum that none of these are efficient and I am at a loss at this point on how to power my 12v dc side of the electrical system.

Current solar package:
Furion 165W solar panel
Furion solar charge controller
12v FLA battery

New solar system main components:
4* 250W santan solar panels = 1000W solar (theoritical)
victron smartsolar 100|50 scc
lynx distributor
2* 12v 200ah ampere time plus batteries wired in series = 24v battery bank
victron 24|3000|70 multiplus
Victron smartshunt

What have other people who have installed 24v solar systems/battery banks done to power their dc side?
Should I power everything from the 24v battery bank or keep the existing 12v battery for dc side?

Any opinions/critiques on the components I am using are welcome.
I would just like to figure everything out so I can proceed with the install.

Thanks!

Technically, "transformers" don't work with DC, only AC. You'll need a DC to DC converter. They are widely available in various sizes. The "Victron Energy Orion IP20 24/12-Volt 70 amp DC-DC Converter Non-Isolated, High Power" available on Amazon for $135, would do the job and provide 70a of 12v DC power. I don't know how much you need. Also, there may be less expensive options.

Having installed a 24 volt Battery Bank I can tell you exactly how I am powering my 12 volt devices in the coach.

I installed the Victron Orion 70a DC to DC Converter mentioned above. I wired the DC to DC converter from the 24v batteries and wired the 12v side directly into the wires that were previously connected to the OEM Converter. That's it, nothing special. However, I did need to consider the load I was going to place on that 70 amp DC to DC Converter.

In my coach I have two 12v High Amp loads, the hydraulic pump for the Landing gear/Stabilizers/Main Slides and the Schwintek bedroom slide. According to the Owners manual each of these loads can draw up to 95 amps, I was going to be short of power with just the 70 amp DC to DC Converter. Consequently, I installed two (small) 10ah Lithium batteries (LiFePo4) in the front hold using the wires that were connected to the original Lead Acid batteries (these batteries act as a buffer when starting the hydraulic pump or Schwintek Slidem motors). Electrically, I can draw 12 volts at 90 amps continuously, additionally, I have 15 amps burst capabilities from the DC to DC Converter and the LiFePo4 batteries are rated for a 20 amp draw (each), giving me a total 12v amp capacity of 125 amps. Enough for me to be comfortable that I am never going to strain the 12v side of my system.

If your coach does not have a hydraulic system, or your Schwintek slide(s) draw less than the 70 amps produced by your DC to DC converter you would not need to add any battery capacity to the 12 volt side of your system. Another way to increase your available amperage is to install a second DC to DC Converter (total amps 140 [plus 30 burst capacity]). However, installing two DC to DC Converters will increase your passive losses and electrical overhead.

EDIT: I just read that you have a Transcend Coach, consequently, your 12v, high amp, draw items won't be the same as mine. If you have an electric slide system, and not the Schwintek slide system, your high power draw will be a lot less than what I described above. You may only need a 40 amp Orion DC to DC Converter with or with out a small Lithium battery to provide "boost/buffer" for your slide motor.