Solar 300 watt upgrade DIY

[gmillerok1]

Originally Posted by Alex AVI

MIKE - I have not confirmed physically or in schema since I dont plan on adding my 4th panel until it is much cooler outside - so would you know if the units that came from factory with 300w comes with the 12 awg also? It seems a bit skinny for 300w/25A so maybe my unit came with beefier feed? If I have to fish new wiring, I may forego the 4th panel.

I took a look at the 2018 electrical and the single panel is described exactly the same as on my 2011, with the exception that the negative goes to the common ground.

But the schematic didn't show the gauge or the 3 panel option, so you'll probably need to dig further. My money is that it's 12awg, though, and they just wired them up to the same feed to the controller.

Should be easy to determine. Just look at the charge controller yellow wire.

[Alex AVI]

Originally Posted by gmillerok1

I took a look at the 2018 electrical and the single panel is described exactly the same as on my 2011, with the exception that the negative goes to the common ground.

But the schematic didn't show the gauge or the 3 panel option, so you'll probably need to dig further. My money is that it's 12awg, though, and they just wired them up to the same feed to the controller.

Should be easy to determine. Just look at the charge controller yellow wire.

GMILLEROK1 - out of town a few days, so could not confirm my AI physically. Re-checked 2018 schema and you are right, the 12v Diagram at 9-17 does not say. I stumbled into the last diagram at 9-32 (solar wiring). That one does show 10 gauge for yellow and green. But it keeps 12 gauge from controller to bus bar. Why would AS put 10 gauge from panels to controller but not the same from controller to bus bar ? Any ideas why ? Will update you when I get home in few.

[gmillerok1]

Originally Posted by Alex AVI

GMILLEROK1 - out of town a few days, so could not confirm my AI physically. Re-checked 2018 schema and you are right, the 12v Diagram at 9-17 does not say. I stumbled into the last diagram at 9-32 (solar wiring). That one does show 10 gauge for yellow and green. But it keeps 12 gauge from controller to bus bar. Why would AS put 10 gauge from panels to controller but not the same from controller to bus bar ? Any ideas why ? Will update you when I get home in few.

Why? Because they don't care about efficiency or voltage lost because most customers never will know. I certainly don't like how they wired the panels if that schematic is accurate. Guessing that the 10 awg run is about 20 feet (and it could be more) that would cause about a 6 percent loss to the controller if the panels are run in parallel. Probably another 1 percent with the 3 foot 12 awg.and 6awg. So you are looking at losing about 7-8 percent from the panels to the batteries that could instead be used to charge the batteries.

What's even stranger in that schematic is that two of the panels don't show any connection from the negative side of the panels at all! Are they even connected? Did the simply daisy-chain them? That may or may not actually be the case. All of them should be connected and combined as one to the negative and all three positives to the controller. In my setup, I used a combination box from AMSolar with a positive and negative bus bar, and then 6awg from there to the controller. You can count on Airstream to do it the easiest and cheapest way, though.

10awg is fine for the panels until the positive and negatives are tied together, then I'd want 6awg to the controller and 6awg to the batteries (although 4awg may be enough with more voltage drop). I want as much as I can get out of the panels, so that's why I went with 6awg.

And, if you haven't done so, you should toss the OEM controller, which is junk, and get a Victron MPPT 100/30 controller (or if you plan on adding a panel the 100/50) and run 6 or 4awg directly to the positive battery post and avoid the positive bus bar altogether.

It also looks like they use 10 amps fuses on each panel, and 10 amps from the controller to the battery. Although 10amp fuses are safe because they will protect the wire which can handle 30 amps, a 20 amp fuse would be a better fit. Using 6awg, I'd put a 30 amp breaker between the panel and the controller (although this may be overkill) and a 30 or 40 amp breaker between the controller to the battery.

Let us know what you find out about exactly how they wired it up.

[Boxster1971]

Originally Posted by Alex AVI

MIKE - I have not confirmed physically or in schema since I dont plan on adding my 4th panel until it is much cooler outside - so would you know if the units that came from factory with 300w comes with the 12 awg also? It seems a bit skinny for 300w/25A so maybe my unit came with beefier feed? If I have to fish new wiring, I may forego the 4th panel.

ALEX - check the wiring diagrams in back of owners manual - they should show the wire size. That is where I would look, but I’m still driving home at the moment.

[gmillerok1]

I've been working on the second part of my upgrade-batteries.

It's not so simple.

I'd like to go with lithium and convinced myself that a pair of Lifeblue's 125amp models would be the best choice for space for 250 amps but I've found there's a few issues to consider. Alternatively, if I go AGM's I can put a couple of 150amp 12vdc for 300amps, or a pair of 6vdc 300 for the same. The downside is that's almost 200 lbs of batteries sitting just behind the curbside wheel.

If I go lithium, the battery combiner has to go (and would likely go even if I use AGM's). So, a Victron-ct-li combiner has been recommended. But, Airstream stingily only used a 4awg wire from the chassis to the combiner. And lithium's in theory can draw more than 125 amps if fully discharged and I fear the fuse would blow under that extreme circumstance and so, I'm trying to figure out how hard it would be to run 1/0 or 2/0 in its place (for the record, Airstream now uses 1/0) and use a heavier fuse.

The rest is fairly straightforward. Remove the Group 24 batteries and the drop through the floor battery box. Remount the grounding bus bar to the floor. Add a new ground bolt through the floor to ground the house batteries. Although not required, upgrade the 4awg from the inverter to the house battery with 150amp class t fuse.

Then there's the issue of inverter drawing .64 amps from the house batteries. To kill that when the van is not being used and since it is outside, when it's below freezing, I plan on adding a battery disconnect switch both to the positive side of the inverter (and never plug in to shore power when disconnected to avoid damaging the inverter), and another one to kill the alternator charging when it's not needed, which I figure, with the upgraded solar, will be most of the time. I'll have to figure out where to mount them.

Has anyone else dealt with lithium's and the 4awg OEM wire? It just doesn't seem to me to be a good idea to use it with lithiums. I have yet determined how difficult it will be run a larger cable.

[Alex AVI]

Originally Posted by Boxster1971

ALEX - check the wiring diagrams in back of owners manual - they should show the wire size. That is where I would look, but I’m still driving home at the moment.

MIKE, GMILLEROK1 - Sorry, an "Oops moment" - I intended to post the wiring diagram from the manual that shows wiring gauge but playing with grandson has been distracting me. Here it is. Still not home, so a few days before I can physically check for accuracy of diagram. Yes, in few weeks, installing Victron SmartSolar 100/50, BMV712, Blue Sea ACR 7622 in a few weeks. It's probably overkill for my use/needs, not being a boondocker like a lot of folks here. But from all I have read here, I am sold on it's benefits, so it is going in.

I do like your the idea of running the 6 awg straight to batts , bypassing the buss bar altogether. Any downside to doing this? I can't think of any.

[gmillerok1]

Originally Posted by Alex AVI

MIKE, GMILLEROK1 - Sorry, an "Oops moment" - I intended to post the wiring diagram from the manual that shows wiring gauge but playing with grandson has been distracting me. Here it is. Still not home, so a few days before I can physically check for accuracy of diagram. Yes, in few weeks, installing Victron SmartSolar 100/50, BMV712, Blue Sea ACR 7622 in a few weeks. It's probably overkill for my use/needs, not being a boondocker like a lot of folks here. But from all I have read here, I am sold on it's benefits, so it is going in.

If you ever upgrade to lithium, note that the Blue Sea ACR 7622 is not compatible.

I also installed the Victron MPPT controller, although it's not needed because you can access the charge controller via bluetooth, it's nice to have it on the panel as well. Something to consider.

[Alex AVI]

Originally Posted by gmillerok1

If you ever upgrade to lithium, note that the Blue Sea ACR 7622 is not compatible.

I also installed the Victron MPPT controller, although it's not needed because you can access the charge controller via bluetooth, it's nice to have it on the panel as well. Something to consider.

GMILLEROK1 - Thank you for added info. Lithium probably is not in near future for me, due to combination of high cost & our usage pattern still in full hookup mode. Of course, if we start getting comfy boondocking(i.e. grandkids older to appreciate the off beaten path places, then it will rise in priority, prob. 3-4 yrs.

[Boxster1971]

ALEX - bypass the buss bar and run wire from solar controller direct to batteries. That is what I did - works great. I also installed a 30A circuit breaker between solar controller and batteries as recommended by AM Solar.

[Alex AVI]

Originally Posted by Boxster1971

ALEX - bypass the buss bar and run wire from solar controller direct to batteries. That is what I did - works great. I also installed a 30A circuit breaker between solar controller and batteries as recommended by AM Solar.

MIKE - Yes I will. Thanks again . Can't believe I am saying this - can't wait for colder weather so I can do the inside electrical work and be completely disconnected not needing A/C . Also the breaker suggestion, good one there.

[Troutboy]

One of the biggest reasons solar doesn’t satisfy customers needs is inadequate wire size. If you are taking the time to do all the work, install a lathe enough wire.

It’s like changing the oil in your car/truck but not changing the oil filter.

You spend a lot for the batteries, panels, and controllers. Don’t skimp in the wire.

I’m no expert, but have been told this and this summer helping trouble shoot other peoples systems in camp grounds, 90% of the time the panels generate the power and it’s all lost on the way to the controller (or from the controller).

Use adequate wiring, put controller as close to battery as possible. Works every time like a Charm.

[gmillerok1]

Continuing my planning for the battery upgrade, as I previously mention, Airstream used 4awg wire and a 125amp fuse from the chassis battery to the battery combiner. So the question was, would that be adequate to charge the 250amps of lithium's, and the bottom line was no, at least in theory.

So I have two options. Option 1. Replace with 1/0. Airstream routes the wire straight back with a cover plate, through the bottom of the seat, and under the floor a bit, then up and back to the rear. It's doable. Not fun, though.

Option 2. Use a DC-DC charger. I know Sterling makes one, but I don't care for the design and insanely complicated instructions. I found this charger, made by an Australian company. Pricey, but what I like about it is that it only requires a single connections to the chassis positive, and the common chassis ground to the frame. It has a small form factor, and can be programmed for lithium. The best thing is that it's a smart charger, unlike using the Victron ct-li, which simply combines the two.

Option 2, so far, looks like the best option. Has anyone gone this route?

[waninae39]

look at the victron product line
https://www.victronenergy.com

we use many of their products in our as 22Fb for solar, lion battery and inverter/converter

we use a dc-dc between the TV and the As to ensure 1 way power flow

[gmillerok1]

Originally Posted by waninae39

look at the victron product line
https://www.victronenergy.com

we use many of their products in our as 22Fb for solar, lion battery and inverter/converter

we use a dc-dc between the TV and the As to ensure 1 way power flow

I already installed the Victron 100/30 charge controller and the BM712 battery monitor. But my issue is having the run new 1/0 wire for lithium's, something I can avoid if using the Redarc DC-DC charger. It also has a built in isolator, so no Victron ct-li would be necessary. Victron does not make anything I can find that would do the same thing (they do sell converters and other devices, but no DC-DC smart chargers.