First try at solar.. which panels?

[greybeard23]

After studying the difference on isolators and solenoids I found the isolator has some solid state circuitry, which tends to fail. The solenoid is a simple electric magnet, so the cost difference and the fail rate had me go with the solenoid.

Have since taken out most of the carpet in the van, wish I had removed it before I started the build.

This is a page that shows my van about a year and a half ago, has changed some since.

http://davidswanderings.com/van/

 

[riffraff]

Quite a nice setup there! is that just one panel? I got 2 of those renogy 100w panels for my van (they are scheduled to arrive tomorrow). Hoping they will fit. (yeah I should have measured before ordering)

 

[greybeard23]

Quite a nice setup there! is that just one panel? I got 2 of those renogy 100w panels for my van (they are scheduled to arrive tomorrow). Hoping they will fit. (yeah I should have measured before ordering)

That is one 245 watt panel, added another 100 watts this summer, plus another AGM 105 AH battery.

If you notice, they are mounted using door hinges, I can tilt in either direction. Helps out come January and February.

 

[highdesertranger]

I agree with the solenoids being more reliable than the solid state isolators. every time I have trouble shot a dual battery system not working, the isolator has been bad. I have seen a few solenoids bad also but every time the system had one of those solid state ones in there, it's been the culprit. I really have no explanation for this, because solid state usually means more reliable, no moving parts. but that's the way it is. highdesertranger

 

[akrvbob]

Actually, it is fairly easy for panel to go over-voltage so my recommendation is to give yourself plenty of wiggle room for voltage.

I had a friend go over a 12,000 foot pass on a cold, clear day in Colorado. It blew his Blue Sky controller even though it wqs sized for the panel.

He called Blue Sky and talked to a tech and he explained what happened. The tech said, yes, the elevation meant thinner air and the cold meant the panel was working at max efficiency and the combination caused a voltage spike the controller couldn't handle.

He sent him a replacement controller with a little more wiggle room for no extra charge.

That's why I recommend 1) buy a Blue Sky controllers and 2) give yourself some wiggle room with your controllers voltage.
Bob

 

[RogueRV2]

Because of the AGM batteries, I'd have 3 or more 100 watts panels. Use 10 awg wire, or an on-line voltage drop calculator to keep the line loss to less than 2%. Panels laid flat are only about 65% efficient and those AGM bats need more current to charge up correctly. As for myself, I'll always go with the old lead acid battery unless forced.

 

[TucsonAZ]

Here's my best advice, if you're going over 400w or plan to, use 24v panels and a MPPT controller, if over about 800 watts, I would also be sure to go with a 24v system. If you're under 400w go with a good PWM controller or a small (and confirmed not just labeled) MPPT controller. For many situations 400w will be fine and do more than what you need.

As for breakers, fuses and so on. I would breaker each panel or bank in a combiner box, any din rail box will do, I avoided MidNite intentionally, I also got the CBI QY breakers by the case on eBay for far less than what they (MidNite) charge for the same thing (it worked out to like 12 for the price of 3). In a pinch, marine breakers will do fine but won't really save you any money, I would avoid fuses personally.

Give yourself the absolute best wiring you can find, look at thrift shops for old jumper cables or whatever you have to do to keep the voltage drop as low as you can.

Grid tie (or 24v) panels will be less cost per watt, with that said, I would rather have three 100w 12v panels than a single 300w in the event you catch any shade because of where you're parked or whatever. I often hit the breakers on my panels one at a time and will be getting say 250w from one bank, 180 from another and maybe 115 from the third, all depending on something as simple as a branch shading one of the two panels in a particular bank.

 

[riffraff]

So to recap I'm going with: 25Amp MPPT Blue Sky controller, 2x 100w renogy panels, and 2x 125AH batteries. If I can run a laptop and fans for a while each day I'll be happy.

Get lots of sun here in Cali. If I have enough power I might try to add a Playstation 3 in the mix and do some guerrilla live streaming =) (PS3, LDC TV & HDMI switcher would need to be powered)

As for breakers, fuses and so on. I would breaker each panel or bank in a combiner box

I'll go this way if possible.

 

[TucsonAZ]

So to recap I'm going with: 25Amp MPPT Blue Sky controller, 2x 100w renogy panels, and 2x 125AH batteries. If I can run a laptop and fans for a while each day I'll be happy.

Get lots of sun here in Cali. If I have enough power I might try to add a Playstation 3 in the mix and do some guerrilla live streaming =) (PS3, LDC TV & HDMI switcher would need to be powered)

I'll go this way if possible.

If you don't already own the charge controller, I would make a very different choice, either a MidNite Kid or a Rogue, both are local, quality units with a very high level of support. It will allow you to have a lot of future flexibility but that's just my 2 cents. Otherwise I'm sure you will be more than happy with that setup.

It will be a no go on the PS3, well, maybe a little here and there but I tossed mine on the Kill-O-Watt and almost crapped when I saw the power that thing used, like, I could seriously run my 5cuft chest freezer for an entire day with the power the PS3 consumed in an hour.

 

[riffraff]

If you don't already own the charge controller, I would make a very different choice, either a MidNite Kid or a Rogue, both are local, quality units with a very high level of support. It will allow you to have a lot of future flexibility but that's just my 2 cents. Otherwise I'm sure you will be more than happy with that setup.

Yeah the controller is on it's way already. Maybe a tad pricey but I was a little worried about "fake" MPPT controllers and knew that one was good.

It will be a no go on the PS3, well, maybe a little here and there but I tossed mine on the Kill-O-Watt and almost crapped when I saw the power that thing used, like, I could seriously run my 5cuft chest freezer for an entire day with the power the PS3 consumed in an hour.

I figured the PS3 would be a pig. Do you have the old fat one or one of the new slim ones? I'm wondering if the newer models are less energy hungry. There's always the vita =)

 

[akrvbob]

roffraff, that is a great controller and a great system. You will be very happy with it!!
Bob

 

[riffraff]

Excellent! controllers and panels arrived today, spent the day at the home depot parking lot putting up some R-Max insulation. It's getting real! =)

 

[akrvbob]

I think you are in the funniest part, when it all starts to come together and become real for the first time! You're really doing this crazy thing!

Savor it!
Bob