Ford Transit USA Forum banner

Electrical Diagram Review - Victron Solar, Multiplus, 420AH batteries

4K views 11 replies 7 participants last post by  RVing 
#1 ·
Hi folks. I was hoping to get some feedback on my diagram to see if I've missed anything or should change anything.


I'll be running two Fullriver DC210-12 4D batteries, which will be fed from a Victron 100/30 MTTP solar controller, a Sterling BB1260 B2B charger, and a Victron Multiplus 2000/12 when on shore power. DC loads will be distributed through a Blue Sea ATC fuse block, and and AC loads through an AC distro panel with ELCI main. All of the battery switches, ANL fuse blocks, and DC return busses will be Marinco Pro Installer stuff, since it'll tie together with connector bars and makes for a small footprint (and it looks sweet).


Thanks.
 

Attachments

#2 ·
I think I'm going to add a battery protector to the system to shut off the DC loads if voltage gets too low. Does anyone know if I have to put it right near the battery, as in before the battery switch or can I put one just between the positive buss and the blue sea fuse block? I "think" the Victron Multiplus has a low voltage cutoff built in, which I would think means I wouldn't need to have the battery protector between it and the battery. Thoughts?
 
#7 ·
I'm digging through the Multiplus manual and I see it has "low voltage protection" listed as a feature, but I don't see a spec or setting instructions. I need to look further. The Victron Battery Protect device is programmable so I can set it where needed.


I've read various opinions on circuit breakers/protection for solar. I see you have a STDP in there; any reference for that you can pass along?

I have a SPDT in there because I've seen it like that on a couple of Victron schematics, and for some reason I have a vague sense that the panels should be able to be completely disconnected from the controller. I really have no idea if this is true or not.


Comments:

I would put a low voltage disconnect on the load side, to protect the batteries from over-discharge. Probably a manual disconnect also - to drop all load from the batteries during storage.

I don't see a reason to have a switch between the solar and batteries, nor between the converter and batteries. I have two commercial RV's that are wired with solar and converter direct to batteries (via fuses or breakers, of course).

How will you keep the Sterling from discharging the chassis batteries? Can you put in a battery isolator/combiner of some sort between the chassis batteries and the Sterling?

I'm not an expert though....

The batteries will have a manual switch on them for sure. My thought on also switching the solar controller and Sterling was to allow for manual disconnection of all three power sources from the positive buss for maintenance purposes. I guess I'll actually already have that on the solar with the SPDT between the panels and controller, so the other switch is redundant.



I had thought that the Sterling included a built in isolator/LVD, but I'll check. I know it only charges when the starting battery hits a target voltage (13.2v), implying the alternator is operating, and cuts off when the start batt voltage hits 13v. I do not know if it can drain the battery when not operating.


I'm going to do some more reading and revise my schematic.
 
#5 ·
Comments:

I would put a low voltage disconnect on the load side, to protect the batteries from over-discharge. Probably a manual disconnect also - to drop all load from the batteries during storage.

I don't see a reason to have a switch between the solar and batteries, nor between the converter and batteries. I have two commercial RV's that are wired with solar and converter direct to batteries (via fuses or breakers, of course).

How will you keep the Sterling from discharging the chassis batteries? Can you put in a battery isolator/combiner of some sort between the chassis batteries and the Sterling?


I'm not an expert though.... :)
 
#8 ·
The schematic has been revised with the following changes:


- Inadvertently had shore power ground shown as connected through 30a SPDT breaker, so I fixed that.
- Removed battery selector switch from between solar charge controller and Sterling charger, and the positive buss. This was redundant since I already had breakers between each units "source". It also saves space and makes for a cleaner install.
- Added Victron BP-100 battery protector between positive buss and DC fuse panel. It's programmable and can be set to an appropriate level for the AGM bank.


I cannot figure out if the inverter has an LVD setting built in, and if so what's it set to...



I like the idea of being able to cut off all loads for a storage type situation, but for the time being we'll be living in it and we have solar so I don't see any long term storage in the future.


I'm on the fence on MBRF fuses on the battery terminals or if I should go to a single class T fuse right there at the batteries. Thoughts?
 

Attachments

#9 ·
Do you need the the 300amp breaker for the inverter off the buss when you already have a 300amp breaker at the batteries and the other two power sources to the buss are even smaller than that?

My system is going to be very similar to yours with some of the identical components. I have most of my parts already but not quite at that point of my build yet.
 
#10 ·
Do you need the the 300amp breaker for the inverter off the buss when you already have a 300amp breaker at the batteries and the other two power sources to the buss are even smaller than that?

My system is going to be very similar to yours with some of the identical components. I have most of my parts already but not quite at that point of my build yet.

Ya, those are fuses, and each chunk of wire really should be fused, so the 300a one going to the inverter protects that bit of the system, while the 300a MBRF fuses on the battery posts protect those wires from potential meltdown.


I just realized I have a mistake though. The Multiplus manual recommends 00AWG, which I was mis-reading as 0AWG or something, when it should be read as two aught (2/0). So I need to bump that wire gauge up to 2/0, and the fuse as well, to a 350a.


That makes me wonder if I need to bump the battery cables up too, since they'll have the inverter plus the DC fuse panel coming off of it.


What size battery or batteries and cables are you planning on using?
 
#11 ·
That's one of the few differences in my system. I only got a 1000 watt Magnum inverter/charger so I'm only going with 2 awg which the inverter manual listed. If I was buying new wire I wold probably go bigger but I already have 2 awg on hand. The only big electrical user I'm going to have is a microwave and I just decided to get a low power one that can run on 1000 watt. I'm not going to have a water heater and I'm doing propane for cooking.

That fuse for the inverter isn't to protect the inverter. Its to protect the wire run for the inverter and if your source power is fused the same it seems redundant. If you get a short the fuse at the battery will protect it. Obviously it doesn't hurt to have the second fuse besides cost, voltage drop, extra complication, etc.
 
#12 · (Edited)
All the inverter manuf recommend huge wires. Magnum says 4/0 for the 2800w inverter I just ordered. And they say to use the same size wires to jumper batteries in parallel as are used to run from the battery bank to the inverter.

In my case, I will have 3 (or 4 if testing shows I need it) grp 31 AGMs in my house bank. Each batt is in a different under-vehicle location. Extra work but the batts don't take up space in the van and I can still install/remove the batts w/o removing the batt holder thingy. Batt wires will come together at a bus bar next to the inverter. Longest run (one way) btwn a batt and the bus bar is 10'. Wire will be 1/0 between individual batts and bus bar, 4/0 for the short hop between the bus bar and inverter (breaker and disconn switch between bus bar & inverter too).

Assuming the batts contribute roughly equally, they will source 50-100A during my max house load. Using 1/0 gives a voltage drop of <1.5% between an individual batt & bus bar on the longest run.

And of course I will fuse appropriately. If 2/3 batts pop their fuse and the remaining batt tries to source the pear inverter current (150-300A), it'll pop its terminal fuse in short order.

So I'm saying if your design and fusing dictate a smaller wire can be used than what the manuf recommends (which will be max current the inverter cld ever draw), I think you're fine.

Finally, if your wire runs are very short, I see no harm in using 4/0 everywhere if it makes you feel better. It won't increase cost too much on very short runs. And you get the benefit of bigger terminal contact area.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top