202QBWE Solar/Inverter/LiPo Build

[Cheesehead4Life]

@MrKABC, I was at the same decision point as you a few months ago. I have 800w up on the roof and at 38ft long, I do have room to double it. My wattage production has been a max of about 66% in summer and only about 50% as we approach winter.

As has been discussed, angling panels provides a huge bang for the buck. After a lot of overthinking, the route I am going for now is a portable/ground approach for additional wattage. I bought some thin/light/flexible panels (350w worth), a cheap PWM charger (for now). That way I get around the issue of a fully shaded site, I can angle directly at the sun and move them from shade if needed. Being a thin and flexible model, they are easy to store as well.

Yes, that is more work to setup/store but if at one site for a week I can live with that. Even at 50% 'efficiency' of the existing roof panels, it obviously maintains batteries in storage, and during travel they can fully power the rig (barely thanks to the 320 watts of the fridge) so I don't NEED more on the roof during those times. Then when living in it the portable panels add to the system and can cover the added demand.

I wrote a post a month or so ago about how I modified the Furrion solar input port to accommodate more amperage and use it for 'loads' as well.

I just thought I'd throw my approach out there as an additional option to consider.

[MrKABC]

Fourth Battle Born GC2 is in!

After testing my setup with three batteries, I learned that running the Victron Multiplus 3000 inverter while running my microwave resulted in undervolt warnings (red light flashing on the control panel). I decided to add more battery reserve power by adding a fourth GC2 LiPo to the mix.

Will test by microwaving something under inverter power to see if I still get undervolt warnings now that I have 400AH.

Of interest - when looking at my negative bus bar, the connection from the bus bar to the Victron BMV712 shunt appeared to show slight "bluing" and a bit of plastic deformation around the metal part of the bus bar. (photo, red arrow point of interest) I'm wondering if my bus bars are not strong enough for the amount of current I am dealing with?

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

The bus bars are rated for 250 amps. I didn't see any other damage and what I did see is slight, but it is making me think that I didn't get bus bars with larger capacity? What do you technically oriented folks think?

Maybe I should ditch these bus bars and get a Victron Lynx Power In?
https://www.amazon.com/dp/B00NT9X5AG...v_ov_lig_dp_it

Says these are rated for 1000 amps. Any thoughts?

[jxnbbl]

What size is that cable between the batteries and the inverter? (and interconnecting the batteries)

[Cheesehead4Life]

@MrKABC - Awesome to be able to add more battery! I'm in the process of adding more too and will take me over the 1,000Ah threshold as well.

The microwave would only draw about 100amps continuously (plus anything else running at the time). I'd be more inclined to suspect an issue at that lug. A loose nut so make sure it's tight? Then how certain are you in the quality of the crimp on that lug? Take it off and see if you can tell if there is any looseness or play. Or crimp it tighter. I personally would just put a new lug on.

I struggled with the decision of using the 250a busbar there too, wondering if I should spend the money on higher capacity busbars. Knowing I'd likely keep building and adding, I did go the route of the Victron Power-in. With that I was able to attach the shunt directly to the Power-in busbar so I eliminated a cable and two lugs. I also did the hack on the Power-in to add fuses for each battery. That mod is easily googleable.

[MrKABC]

Originally Posted by jxnbbl

What size is that cable between the batteries and the inverter? (and interconnecting the batteries)

4 awg wire, all copper (not the aluminum stuff). Seemed sufficient with 2 batteries when I started, but now wondering if I should replace with 0 awg.

@Cheesehead4life Power In might be the way to go! I'm troubled by that temperature/scorch markings and think I will take that bus bar out to learn more.

[jxnbbl]

Originally Posted by MrKABC

4 awg wire, all copper (not the aluminum stuff). Seemed sufficient with 2 batteries when I started, but now wondering if I should replace with 0 awg.

@Cheesehead4life Power In might be the way to go! I'm troubled by that temperature/scorch markings and think I will take that bus bar out to learn more.

I would go back to manual and look this up as this can not be correct. I installed a 2000W inverter in my trailer and the recommended cable is 2/0 for < 5ft of length. I just looked at the manual and for the 3000W model it jumps to 4/0. This certainly has to be the source of the warning light even if the connections were good. Below is the cart and I would expect this recommendation to transfer almost seamlessly to other vendors.


freedom cable size.pdf

[jxnbbl]

I sent back and you posted a pic of you inverter. Their manual has the recommendations but does not use cable gauge but mm sizing. So 50mm cables but doubled up so 2 cables per connection for the 3000W unit. This basically is the same gauging if you went with a single cable. Additionally the fusing increased to a 400V DC fuse for your unit.

[seanrmz]

nice add on my friend, I did the same, had 400ah, and added 200ah more. There is one thing to keep in mind with solar. We underestimate the power 12v carries and flows in our Rv's. I love Amazon too but when it comes to bus bars, fuse panels, lugs, and wiring, go with well known quality brands. I went with Victron ( personal) choice and Blue sea for all connection.
sean

[Stircrazy]

Originally Posted by MrKABC

Fourth Battle Born GC2 is in!

After testing my setup with three batteries, I learned that running the Victron Multiplus 3000 inverter while running my microwave resulted in undervolt warnings (red light flashing on the control panel). I decided to add more battery reserve power by adding a fourth GC2 LiPo to the mix.

Will test by microwaving something under inverter power to see if I still get undervolt warnings now that I have 400AH.

With three LiFePo4 batteries there is no way you should be getting undervoltage on the inverter, unless your wires between the batteries and the inverter are too small and dropping the current.

As for the solar, it's hard to say as I am not familiar with the solar footprint down there at this time of year. as a comparison I am up in the frigid north and in the summer, I get 299watts from my 325-watt panel, in late September I get about 250-270 watts.

If I was only getting 200 watts from a 600-watt system I would be looking for a problem, and since your inverter to battery wires are too small, I would start with the wire size of all your runs. Did you wire the panels in series or parallel?

also make sure the Victron components are programed properly I have seen lots of low output issues from new Victron installs that just had to be setup properly as they weren't preprogramed from Victron (or reseller) like it is when you buy them all as a kit.

[jxnbbl]

Originally Posted by Stircrazy

With three LiFePo4 batteries there is no way you should be getting undervoltage on the inverter, unless your wires between the batteries and the inverter are too small and dropping the current.

.....

I think he basically confirmed this with the 4awg cable post. I did a bit of research at lunch to double check the reasoning. That cable (4awg) can only run about 720W max (60A max current). For a 3000W inverter that is running over that (a microwave) it will get low voltage readings. In looking at the gauge wire charts that is why a 3000W inverter recommends 4/0 cabling as the max amps is 302 or 3624W.



The doubling of 50mm cable (the specific inverter he used) translates to doubling 1/0 AWG which has a max current of 150 per so it works out to be about the same mathematically.


This also probably solves the bluing problem seen when testing with the microwave.

[Cheesehead4Life]

Here a couple of resources on selecting the proper wire size from Blue Sea Systems. The picture is chart with 'base' suggestions.

But the link to their circuit design wizard http://circuitwizard.bluesea.com/# allows for adjustment based on other factors like temperature rating of insulation, number of cables in harness, roundtrip distance, etc.

[Cheesehead4Life]

@MrKABC, a couple of questions/comments:

1) if your schematic is up to date, with 4g wire from battery to the negative busbar, you show a 200a fuse. That's too big of a fuse. Even Blue Sea will say you CAN go up to 30% over based on the situtation, I wouldn't and that is even more than 30%

2) You have a 400a fuse between the inverter (3000VA which is about 2400w I believe I saw in the manual), so what size wire are you running there?

3)In your schematic, it there is a "connection" from the inverter to the converter/charger. Are you still using the converter/charger? It should not be connected while inverting because, in your example, you'd be drawing approx 100a for the microwave, and the converter/charger would be drawing 55a because it is trying to charge the batteries to replace the 100a the microwave is using. (you'd actually be drawing 155a and charging your battery with your battery. Not sure I explained that well enough, and maybe I'm interpreting the schematic wrong, but wanted to throw that out there.

[jxnbbl]

RE: my previous comments/posts. These are based on the recommendations on page 8 of the manual for this model inverter:


LINK


and knowing that 50mm cable translates to 1/0 AWG

[Stircrazy]

Originally Posted by jxnbbl

RE: my previous comments/posts. These are based on the recommendations on page 8 of the manual for this model inverter:


LINK


and knowing that 50mm cable translates to 1/0 AWG

so Im confused, what size wire did you use between the batteries and the inverter? if you know 50mm 1/0 you should have two 1/0 cables on positive and two on negitive or move to a larger size.

if you didnt use that size cable then you are going to be dropping voltage and your inverter will kick out and not run your microwave, you can add 10 more batteries if your cables are to small it won't work.

[jxnbbl]

Yes, that is what I'm assuming. The poster/owner stated that he used 4AGW which is much too light. Personally I would use a single 4/0 welding wire instead of the double 1/0. The hardest part is crimping on the ends. I borrowed an electricians crimper that would handle components that size.

[Stircrazy]

Originally Posted by jxnbbl

Yes, that is what I'm assuming. The poster/owner stated that he used 4AGW which is much too light. Personally I would use a single 4/0 welding wire instead of the double 1/0. The hardest part is crimping on the ends. I borrowed an electricians crimper that would handle components that size.

I don't know if I would go up to 4/0 myself, the two 1/0 will give you more capacity which you won't use but it will also give you a lower voltage drop. Most places you buy wire from will crimp ends on for you for pretty cheep, I used to do that until I bought a hydraulic crimper.

[MrKABC]

Originally Posted by Cheesehead4Life

@MrKABC, a couple of questions/comments:

1) if your schematic is up to date, with 4g wire from battery to the negative busbar, you show a 200a fuse. That's too big of a fuse. Even Blue Sea will say you CAN go up to 30% over based on the situtation, I wouldn't and that is even more than 30%

2) You have a 400a fuse between the inverter (3000VA which is about 2400w I believe I saw in the manual), so what size wire are you running there?

3)In your schematic, it there is a "connection" from the inverter to the converter/charger. Are you still using the converter/charger? It should not be connected while inverting because, in your example, you'd be drawing approx 100a for the microwave, and the converter/charger would be drawing 55a because it is trying to charge the batteries to replace the 100a the microwave is using. (you'd actually be drawing 155a and charging your battery with your battery. Not sure I explained that well enough, and maybe I'm interpreting the schematic wrong, but wanted to throw that out there.

Whoa, thanks for the helpful feedback folks! I really appreciate it!

• All DC wire is 4G to/from battery and inverter, and 6g from bus bar to WFCO.
• There is no charger in the WFCO, I took it out. The 6g wire is connected from the bus bar directly to the circuit panel that runs the 12vdc circuits.

FUSE: The schematic is up to date and it is a 200a fuse. That's too high for a 4-5 battery setup? I was thinking for a final total of five batteries.

INVERTER: Looks to me that I undersized the battery/inverter wire! Shall I get the Lynx busbar and replace with 0 or 00 AWG wire at the batteries/inverter to fix the problem?

https://www.amazon.com/Automotive-Ba...hlbWF0aWM&th=1

SOLAR: I have four 200w panels. Two panels each in series, both sets in parallel hooked to a single Victron MPPT 100/50. I'm not happy about this part of the install since I added on to the OEM 200i solar install, and the MPPT is located in the basement in the front of the trailer, with a 6awg wire run from the giggy box in front to the WFCO panel in the back. Lots of resistance in a wire that long. Unfortunately, to add a second "gland" to the roof and run larger AWG wire directly to my bus bars I'd need to drop a wall and a ceiling panel, steps I didn't quite want to take yet, although it looks like I will have to at some point. That way I can add a second MPPT and route them both directly to the bus bars with bigger AWG wiring.

I do have my own hydraulic crimper and just need to source the wire and crimp ends.

[Cheesehead4Life]

@MrKABC - fusing is sized to the cabling to protect that. It is not based on battery bank size.

The Multiplus 2 3000VA is 2400w (200a) so the manual calls for 2x 1/0 which is equivalent to a single 4/0. I used a 3/0 cable from Overkill Solar which is marine grade (tinned) with 200 degree insulation (which stretches the rating to about a 4/0), and has a silicon jacket which makes it as flexible as a wet noodle. Oh, and it is very very nicely priced. They will do lugs too, but I see you have a crimper.

My setup is the 3/0 from MP2 inverter to the busbar, 3/0 from busbar to 400a T-Fuse. The T-Fuse is connected directly to the Victron Power-In. As I said in previous post, I modified the Power-In to fuse each battery. Then 2g cable from Power -In to each battery (each of the 4 BMS can handle 120 amp continuous current).

That would be my suggestion on how to wire it since you talked about going with a Power -In as well.

[firestation12]

Before this thread fizzles, I just wanted to add that a generator, even a small one would compliment all the equipment that’s been installed. Not incorporating a generator into the Victron Multiplus’ ability to combine different sources of power, would be an oversight at the very least. Should the propane regulator fail or the camper run out of propane, the fridge’s heating element consuming 300 watts at 120 volts or the water heater’s 10 amps, would quickly overwhelm everything that’s currently in place. Merry Christmas to all of you!!!

[jxnbbl]

Originally Posted by Stircrazy

I don't know if I would go up to 4/0 myself, the two 1/0 will give you more capacity which you won't use but it will also give you a lower voltage drop. Most places you buy wire from will crimp ends on for you for pretty cheep, I used to do that until I bought a hydraulic crimper.

I believe that 4/0 and 1/0 are about the same except you are dealing with one cable. Here is a calculator to figure out. I believe all cabling is <5 ft in this case. Additionally one item most forget is that each of the cables including the battery interconnections have to be sized correctly it is not just between the battery and the inverter. IMO the one cable makes that a bit more manageable than 2x even though they are smaller diameters.


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