Need help wiring up a small solar set-up.

[marco]

I need some help folks. Here's what I got and what I want.

Two 150 watt solar panels rated at ~20v
Two 75 watt panels rated at ~20v
not sure about the listed amps but will post asap (if needed)

Four 12 volt deep cycle batteries and two 6 volt Trojan T-105's ( I am unsure of the amperage but I'll look and re-post asap)

Outback flexmax 80 MPPT

Xantrax 1800 powerhub inverter (I am thinking of replacing this juice sucking POS)

I want to be able to run a small laptop computer, one or two LED lights, but my biggest hurdle is to be able to run my Enviro III pellet stove which lists the amp draw at 3 amps ( 120v x 3 = 360 watts) I disconnected the ignitor and will light it manually as the surge and current draw would be too much IMO.

So ! What is the best way to hook up my solar array to hit the sweet spot? I know I can hook them in series to run higher voltages safely into my flexmax ( no higher than 144 is listed in my manual )

I have tons of available sun here in Colorado. Will 450 watts of solar panels be enough to fully charge my batteries and most importantly will there be enough storage to run my pellet stove at night?

I would think running my batteries for 24v's would be best? And if so could a simple schematic be laid out for me..same goes for my panels.

Any help would be appreciated..also love the website and forum !

[marco]

As I stated above if anyone needs more info to help dial this in just let me know. Thank you !

[rreidnauer]

The MPPT will handle mixed panels well. I'd hook the 150w ones in series, the 75w ones in series, then parallel the two. Will give you approx 12.8 amps @ 35 volts peak performance. (Ideally, all in series would be best, but on mixed wattages, not a good idea)

Batteries are a little trickier. A 24v system would be best utilizing what you got. I'd probably try paralleling all the 12v, and series the the 6v to the 12v to get 24v. Trying to series the two 6v together then paralleling to the 12v will lead to incomplete charging of either the 12v or 6v depending on capacities.

Really tough getting an efficient system with a mixed bag of components. I'm still looking for more of the panel's I have (long since discontinued) to add to my array, as I don't want mixed components.

[rreidnauer]

Test the pellet stoves actual power usage. Good chance it's lower than rated. Then, I need to know the amp-hr of the deep cycles (at 20hr discharge rate) to calculate how long the pellet stove can run. But it does sound like you might have enough battery to get you through the night.

[marco]

I didnlt read your posts yet Rod..just wanted to lay this on...here's some more info:

my 4 large 12v batteries are NAPA part # 7271 1400 CCA 1750 CCC@ 32 F ( I am going to google that part number...maybe they are not deep cycle..hmm)

two panels are 150 w with 8.7 amps and the other two panels are 75 w pushing 4.3 amps.

i am going to buy one of those watt reader plug in testers..they look slick. I'll be back in two shakes of a rattlers ass-end.

[marco]

googled the batteries...hmmm...dont think they are deep cycle. grrr.
https://www.napaonline.com/napa/en/p/NBR7271_0508118836

[marco]

Thanks Rod, any possibility you could draw me a pic of the connections for the batts and panels. i know parallel is + to + and series - to + but I get lost when stringing them all together.

[marco]

no edit feature? bummer

heres the skinny on the trojans (not the condom variety btw)

Trojan T 105 : 185 (5 Hr Rate AH), 225 (20 Hr Rate AH)
Capacity Minutes: 447 min @25 Amps, 115 min @75Amps

Maybe scrap those NAPA batts and go with 2 more trojan 105's ?

[rreidnauer]

You could use the other batts, they just won't hold up as long as deep cycles in the long run, mainly due to thinner plates.

All the same batteries makes life much easier.

Working up a basic drawing now.

[rreidnauer]

Done!

wiring.png

[marco]

Sweet.....thank you Mr Rod. I will let you know how she goes. And of course I will have breakers in between panels to CC and one to batts.

i am thinking about ditching the Xantrax (aka Xanax, lol) inverter. and just getting a small 1000w 200-300 dollar one. But I'll see how she goes first. My concern is that the Xan may suck up to much of my power.

[marco]

Question for Rod :

Once I wire my batteries for 24v will my Xantrex 1800 Powerhub be able to handle the 24 volts coming into it. The way it is wired up now is that my battery cables plug directly into the side of the Powerhub. I know my FM 80 can handle 12 24,48 and 72v but I'm not sure if the incoming 24v coming directly from those batt cables bypasses the voltage to the CC first ( which then adjusts it adjusts it) and then sends it back to the inverter. I've read the manual and found nothing helpful in those regards. My inverter is also wired into my AC fuse panel. I'm guessing the inverter is most likely fused and if it's too much juice the fuse will blow but I' just want to make sure. Thoughts ?

[rreidnauer]

I'm not familiar with the Power hub, but looking at the manual, I found this:

As long as the battery voltage is between 11.0 Vdc to 15.0 Vdc, the inverter will continue to deliver AC power to the loads connected to it. When the battery voltage falls below 11.0 Vdc or rises above 15.0 Vdc, the PowerHub 1800 High or Low Battery Protection will engage and shut the inverter off, stopping all output voltage to the loads.

[marco]

so it will work as long as my cc keeps things bewtween 11 and 15v ?

[rreidnauer]

That's what the manual says it needs. I don't see how you are going to do that with a 24v battery bank though.

[marco]

Can you recommend me a good reliable brand of inverter in the 300 dollar range or will I have to spend more to keep my 24v battery set up?

[rreidnauer]

I have no idea. I've not done any research on small inverters. The only stuff I've been looking into, is the big multi-thousand dollar stuff.

If you have that 12v power hub inverter, why do you want to have a 24v battery bank?

[marco]

From what I've read, it appears 24v is much better than 12v ........but I didn't know if the inverter could work with 24. Sorry, I'm just trying to DIY and learning the ropes. Thanks for your help.

[rreidnauer]

No big. I'm just asking questions and trying to help out too. Personally, if you have that inverter, I would build you battery bank 12v. You can still use the same number of batteries, just configured differently. Nice thing is, if you later upgraded to a 24 or 48v inverter, you can always rearrange the battery connections to accommodate it. (You said you CC is selectable, so you are golden there)

The down side to lower voltage battery banks is, higher amperage, which means limits on CC capacity, and larger current carrying conductors (> $) are required. But if you system remains small enough that it doesn't exceed your CC's amp limit, by all means go 12v and save yourself the expense. Tons and tons of 12v devices and lighting out there too, to take advantage of.

[Little Eagle]

OK so i have a random question for you Rod, first are inverter's pretty much the same? Second, would a inverter from a truck stop work? You can get up to a 2000 watt inverter at some truck stops and i use a 1500 watt on my truck to run my tv, crock pot and tv with xbox.

[rreidnauer]

Well, the biggest difference between inverters is whether they are modified sinewave or full sinewave. Certain electronics handle full sinewave much better than modified, but full sinewave inverters tend to use more wattage to operate than modified sign wave inverters. (especially at or near idle use current) Good chance any of the sub- $1000 inverters your looking at are modified sinewave. Nothing wrong using them, as long as the equipment you plug into them is happy being fed MSW.

Use care on larger inverters powered by 12v. A 2000w 12v inverter will be drawing over 160 amps at full load. BIG cables are required. This is why larger inverters use higher input voltages. Doubling of voltage divides amperage by half. (a 24v 2000w inverter would be drawing a little over 80 amps, and a 48v inverter would be drawing a little over 40 amps)

Multiple, lower cost inverters might be better than a single big one, as if the big one fails, you lose all 120v power. But setting up a bunch of little ones can be a pain.

Some larger ones have the ability to interlink, increasing their power as a whole. Further, some of those bigger ones can even be set up to provide 120/240v split phase (common neutral) like a typical on grid home. This is the way I plan to set up my system in my home. 100% of production being utilized by a split phase inverter setup directly powering a standard circuit breaker panel. I have no intentions of using low voltage lighting/appliances.