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DRV W/50 amp service, installing 24v Victron II, 2X120?

Greg1968

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Wyoming
I'm going to install my Victron II, 2x120 inverter charger where my sofa bed is (rear of RV) to save putting so much weight up front. I'm putting 4 eg4 v2, 24v batteries, 200 amps each into this system. I'm putting 8 24v, 200 watt solar panels on the roof, for a total of 1600 watts. running them in (2s4p). I think that means 2 strings of 4 panels each, paralleling 4 panels on each string. Each string will be on it's own solar charge controller. This design will NOT be powering the 12v systems, since it gets power from a Intel-power 120v to 12v @ 80amps plus 2x12v batteries. I'm leaving this system alone, and I know it's not the efficient way.... I'll move the Surge Guard from the front bay to the rear and hook it into the shower power that I'll bring up through the floor, out of the power cord real box and power the AC side of the Victron unit. I'll use the existing AC cables to power the RV. I hope I made sense?
I would like to stick with Victron products so the can communicate with each other but I see a design flaw with the Victron Lynx products. If using the Lynx power in with, the Lynx smart shunt, with the Lynx Distributor, you are pulling negative and positive battery power from the #1 battery first. My thoughts are to use the Lynx power in to connect the batteries along with the Lynx Distributor. I can then pull DC power off the opposite side of the Lynx power buss bar and install a inline shunt. The Lynx Distributor gives me the ability to fuse my power leads to the inverter/ charger and fuse my solar in. The Multiplus-II 2x120 manual suggests 2x1/0 cables to power the unit with a 400 amp fuse? Would that be 2x200 amp fuses on each cable?
My next problem is what size of Victron shunt do I use with this configuration? I have the potential of 800 amps at 24v, so do I need a shunt capable of passing 800 amps through? Or since the Inverter is fused at a max of 400 amps will the 500 amp shunt work?
I could keep going on but I think this hits all the key points, any input will be appreciated, thanks.
 
I'm going to install my Victron II, 2x120 inverter charger where my sofa bed is (rear of RV) to save putting so much weight up front. I'm putting 4 eg4 v2, 24v batteries, 200 amps each into this system. I'm putting 8 24v, 200 watt solar panels on the roof, for a total of 1600 watts. running them in (2s4p). I think that means 2 strings of 4 panels each, paralleling 4 panels on each string.

2S4P means 8 panels, 2 in series strings, and 4 strings in parallel.

Each string will be on it's own solar charge controller.

That's 8 charge controllers based on your description.

I would go with 2X 4S2P arrays. Four panels in series strings, two strings in parallel.

800W/24V = 33A per array.

This design will NOT be powering the 12v systems, since it gets power from a Intel-power 120v to 12v @ 80amps plus 2x12v batteries. I'm leaving this system alone, and I know it's not the efficient way....

I'm with you on this. I see it as a backup to the 12V system in case the main system goes down. You're only losing about 10% efficiency vs. direct 24-12V conversion, and the presence of the 12V batteries give you wicked tolerance in the event of 12V motor surge.

I'll move the Surge Guard from the front bay to the rear and hook it into the shower power that I'll bring up through the floor, out of the power cord real box and power the AC side of the Victron unit. I'll use the existing AC cables to power the RV. I hope I made sense?

I assume you're just talking about how you're going to connect shore power to the MP. Assuming you have an existing ATS to select between shore and on-board genny, it may be easier to just connect the output of the ATS to the input of the MP and the output of the MP to the AC panel.

I would like to stick with Victron products so the can communicate with each other but I see a design flaw with the Victron Lynx products.

I would be very surprised if you've discovered something along these lines.

If using the Lynx power in with, the Lynx smart shunt, with the Lynx Distributor, you are pulling negative and positive battery power from the #1 battery first.

This would imply you have not properly connected the bank.

My next problem is what size of Victron shunt do I use with this configuration? I have the potential of 800 amps at 24v, so do I need a shunt capable of passing 800 amps through? Or since the Inverter is fused at a max of 400 amps will the 500 amp shunt work?

So you have a 24V * 800A = 19,200W inverter?
 
2S4P means 8 panels, 2 in series strings, and 4 strings in parallel.



That's 8 charge controllers based on your description.

I would go with 2X 4S2P arrays. Four panels in series strings, two strings in parallel.

800W/24V = 33A per array.



I'm with you on this. I see it as a backup to the 12V system in case the main system goes down. You're only losing about 10% efficiency vs. direct 24-12V conversion, and the presence of the 12V batteries give you wicked tolerance in the event of 12V motor surge.



I assume you're just talking about how you're going to connect shore power to the MP. Assuming you have an existing ATS to select between shore and on-board genny, it may be easier to just connect the output of the ATS to the input of the MP and the output of the MP to the AC panel.



I would be very surprised if you've discovered something along these lines.



This would imply you have not properly connected the bank.



So you have a 24V * 800A = 19,200W inverter?

2S4P means 8 panels, 2 in series strings, and 4 strings in parallel.



That's 8 charge controllers based on your description.

I would go with 2X 4S2P arrays. Four panels in series strings, two strings in parallel.

800W/24V = 33A per array.



I'm with you on this. I see it as a backup to the 12V system in case the main system goes down. You're only losing about 10% efficiency vs. direct 24-12V conversion, and the presence of the 12V batteries give you wicked tolerance in the event of 12V motor surge.



I assume you're just talking about how you're going to connect shore power to the MP. Assuming you have an existing ATS to select between shore and on-board genny, it may be easier to just connect the output of the ATS to the input of the MP and the output of the MP to the AC panel.



I would be very surprised if you've discovered something along these lines.



This would imply you have not properly connected the bank.



So you have a 24V * 800A = 19,200W inverter?
My batteries and solar panels are 24v. My battery bank will be 4 eg4 24 volt batteries each battery is 200 amps. I have 4 of them, so total capacity is 800 amps in parallel. My solar panels are 24 volt panels rated for 200 watts each. My thoughts are 4 panels in parallel x 2. Each string would, or could produce 800 watts of power, for a total of 1600 watts.
Hooking the batteries to a buss bar is strait forward but using the victron lynx products would
 
My batteries and solar panels are 24v. My battery bank will be 4 eg4 24 volt batteries each battery is 200 amps. I have 4 of them, so total capacity is 800 amps in parallel.

Nope. You have 800Ah in parallel. Current is amps. Capacity is Amp-hr.

Inverter max continuous power / 24V = design current.

My solar panels are 24 volt panels rated for 200 watts each. My thoughts are 4 panels in parallel x 2. Each string would, or could produce 800 watts of power, for a total of 1600 watts.

Gotcha. I read them as 100W panels. Sorry.

4P2S is unconventional and not advantageous. If you experience any partial shading on one parallel group in series with a second parallel group, you will also reduce the output of the second group.

4S2P may be more advantageous all around as well. Fewer connectors and no need for fuses.

Hooking the batteries to a buss bar is strait forward but using the victron lynx products would

?
 

sunshine_eggo:​

Thanks for the reply. Thanks for clearing up my 2S4P mistake. I guess I'll keep my post with language I know.

This RV has a surge guard and a ATS, separate units. My thoughts of moving the surge guard is to protect the MP from possible dirty shore power damage. The ATS is a problem because I'm mounting the new 24v system in the rear of the RV for weight issues while utilizing the existing AC line on the MP power out side.
I'll probably remove the ATS and make the GEN a stand alone unit wired to a 50amp plug. If I need to use the Gen I'll simply roll out the power cord and plug in.
The Victron Lynx would work as advertised but would require crossing the negative cables in the reverse order of the positive cables. I hope that makes since?
The MP is the 24v 3kva 2x120 and not 19,200w. The manual indicates a 400amp fuse to protect the MP but I'm confused on the fuse sizing at the shunt with having a battery bank capable of 800 amp hour at 24v? Also the MP manual suggest using two 1/0 cables for power in? How do you fuse these cables when the unit requires a 400amp fuse? Would you put a 200 amp fuse on each of the 1/0 cables?
 
Confused? 8 panels total divided into two lines, 4 panels in each line using 2 charge controllers, one for each line. Panels will be hooked positive to positive on all 8 so voltage stays the same. Is the right way? I thought this is how you eliminate the shading problem? I keep watching those darn videos from Will and I guess I missed the meaning.:unsure:
 
I should have also told everyone that the batteries will go into a homemade rack. the rack will have 2 batteries stacked together with the other 2 batteries stacked right beside them.
battery #4Battery #1
Battery #3Battery #2
 

sunshine_eggo:​

Thanks for the reply. Thanks for clearing up my 2S4P mistake. I guess I'll keep my post with language I know.

This RV has a surge guard and a ATS, separate units. My thoughts of moving the surge guard is to protect the MP from possible dirty shore power damage. The ATS is a problem because I'm mounting the new 24v system in the rear of the RV for weight issues while utilizing the existing AC line on the MP power out side.
I'll probably remove the ATS and make the GEN a stand alone unit wired to a 50amp plug. If I need to use the Gen I'll simply roll out the power cord and plug in.

Since I can't see your config, I was making a recommendation based on simplicity, but it may not work for you.

The Victron Lynx would work as advertised but would require crossing the negative cables in the reverse order of the positive cables. I hope that makes since?

Kinda. You may simply need to run either the (+) or (-) to the opposite end/side of the bus bar.

1678983272557.png

The MP is the 24v 3kva 2x120 and not 19,200w.

So the maximum you can draw from the battery is 3000/24V = 125A.
The manual indicates a 400amp fuse to protect the MP

Fuses don't protect devices. They protect wires.

but I'm confused on the fuse sizing at the shunt with having a battery bank capable of 800 amp hour at 24v?

Again, Amp-hr is capacity, not current. Perhaps the batteries are actually capable of discharging at 800A, but that doesn't matter. You size the wires for the current and fuse the wires for 1.25X to protect the wire.


Also the MP manual suggest using two 1/0 cables for power in? How do you fuse these cables when the unit requires a 400amp fuse? Would you put a 200 amp fuse on each of the 1/0 cables?

Victron makes recommendations based on their certifications, EU conventions and desired performance. It doesn't necessarily correlated to what's typical or meets code.

The manual I see says the 24V unit needs a single 1/0 cable for 0-5m cable lengths with a 300A fuse OR for 5-10m runs, two 1/0 cables with the same 300A fuse. For NEC compliance, each wire needs to be fused.

Confused? 8 panels total divided into two lines, 4 panels in each line using 2 charge controllers, one for each line. Panels will be hooked positive to positive on all 8 so voltage stays the same. Is the right way? I thought this is how you eliminate the shading problem? I keep watching those darn videos from Will and I guess I missed the meaning.:unsure:

Ah, so you actually mean four panels in parallel on a single controller? This would work, but I think it's actually incorrect based on the way panels typically work.
 
Since I can't see your config, I was making a recommendation based on simplicity, but it may not work for you.



Kinda. You may simply need to run either the (+) or (-) to the opposite end/side of the bus bar.

View attachment 139833



So the maximum you can draw from the battery is 3000/24V = 125A.


Fuses don't protect devices. They protect wires.



Again, Amp-hr is capacity, not current. Perhaps the batteries are actually capable of discharging at 800A, but that doesn't matter. You size the wires for the current and fuse the wires for 1.25X to protect the wire.




Victron makes recommendations based on their certifications, EU conventions and desired performance. It doesn't necessarily correlated to what's typical or meets code.

The manual I see says the 24V unit needs a single 1/0 cable for 0-5m cable lengths with a 300A fuse OR for 5-10m runs, two 1/0 cables with the same 300A fuse. For NEC compliance, each wire needs to be fused.



Ah, so you actually mean four panels in parallel on a single controller? This would work, but I think it's actually incorrect based on the way panels typically work.
 
The 12V model was released before the 24V model was. I suspect your printed manual is out of date:


View attachment 139842

Don't understand why you also mentioned "two charge controllers"
Thanks, I literally just bought my MP, not sure why it came with the outdated manual. Probably would have saved a little confusion, probably! I mentioned the two solar charge controllers because I wanted to use two smaller controllers. That would be beneficial with that shading problem. Making them independent of each other.
 
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I finally got the problem with my solar design. To many amps for the mc4 connector.

Yep. Good catch. You can get around that with a combiner box.

I've started this thread, and I hope there's some discussion:

 
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