Solar conundrum (updated with shopping list)

I've found these discussions to be interesting. I'll just tell you what I installed last year.

Yes, get the Trimetric. You can't really tell what's going on with your batteries without one.

I installed smaller 100 watt panels (Renogy) so I could place them where I wanted to. Get larger ones and you'll have to make compromises about where they go. I've 400 watts total.

Since I only installed 100 watt and 12 volt panels I didn't need MPPT. Put in a Morningstar PWM (45 amp) instead so I could add panels if I wanted - cost $180 with a battery temp. sensor.

I replaced the two 12v 'deep cycle' NAPA batteries with four Trojan T-105s (about $700). Figured I could check the water level once or twice a month instead of spending twice or more much for AGM.

Bought a 4kw inverter (really only wanted ~2kw, but the price was too good!) on eBay for around $700.

Total system cost me $4k installed, with six and eight gauge cable used everywhere.

We went on a 9 week trip to the southwest last year and it worked flawlessly. My wife insisted on bringing a generator along just in case we needed AC, but I never started it. I tried the system out for a few days before we went on the trip while parked in our driveway. Ran the 40" tv, several lights (switched to LEDs) and other stuff during the day and evening. Ran a table top fan 24 hours a day. Even made microwave popcorn a couple of times. Batteries would be down to about 80 - 85% in the mornings and be charged up by evening, even when a little cloudy. I don't even have my converter turned on anymore and may even remove it.

While my goal was to keep total costs as low as possible while still having a really efficient system, there's a million different ways to skin this cat. Guess the bottom line is to pay attention to details. Use the biggest cable you can for any DC runs, and keep them as short as possible. Put in disconnects for your battery bank, your inverter and your solar panels (there's a LOT of DC current just waiting to arc weld something!). Photobucket links:

http://s1354.photobucket.com/user/theonewaltben/slideshow/Solar%20Install%20-%20Part%201

http://s1354.photobucket.com/user/theonewaltben/slideshow/Solar%20Install%20-%20Part%202

http://s1354.photobucket.com/user/theonewaltben/slideshow/Solar%20Install%20-%20Part%203

http://s1354.photobucket.com/user/theonewaltben/slideshow/Solar%20Install%20-%20Part%204

I have the Bogart SC-2030 PWM controller, does a good job but then I only have one fixed 160W panel on a very small trailer. For what I need I can't justify the extra $ for MPPT. The Bogart allows me to adjust the absorption to what the Interstates require for a modest price. I do like the way you program the controller from the monitor.

If I were going with a bigger system with long cable runs I'd go with an MPPT for the reasons okan-star states. Like the SC-2030, there are a few MPPT's that allow you to adjust the absorption stage voltages high enough for the Trojans. The Tristar being one.

I just put 480watts on my Hitchhiker
Bought 4 ,120 watt Kocera panels that where re furbished by the factory for 120.00 each
A Morningstar Tristar MPPT 45 watt controller and remote panel for 530.00
Not a kit
Wire and everything , babybox and breakers including shipping was about 1350.00 at AR WIND and SUN( panels under about 140 watts ship UPS , large panels have to go truck freight)

One thing to consider when choosing controllers is a with an MPPT you can wire the panels in series , that multiplies the voltage of the panels but leaves the amps the same as one panel , allowing you to use 10 ga wire all the way to the controller , saving lots of dollars on wire
If you where to use a PWM and the same panels you need to wire in parallel , which leaves the voltage the same as one panel , but multiplies the amperage by the number of panels , making it necessary to use large wire , like #4 and a combiner box near the panels
Reason is ,PWM only converts voltage that your bat system is , about 14.4 - 14.8 max , the rest is not used , like on a panel that has 18 volts
MPPT can take high voltages , like 4 panels at 18 volts each , in series is 72 volts and convert it all into usable system voltage

If your fifth is pre-wired with smaller wire 12 ga or 10 ga you may be able to still use it with MPPT

smkettner wrote:
If you are in So Cal you can pick these up in person in Norco at Solar Blvd. I think the pair of 140 watt with MC4 Y connectors would serve you well.

Oh man I did not know they were located less than 2 hours from me! That definitely changes things.

Do you guys think I should go with a PWM charger, or spend the money now for a MPPT charger? I am looking for a good 3-stage charger that I can adjust the charge voltage. I like the idea of the bogart controller. I was also looking at the Blue Sky and Mourning Star chargers. I want to spend the money now as opposed upgrading later.

+1 for solarblvd.

Since you are looking at the Bogart I recommend the 2030 over the 2025 and get the Bogart solar controller that integrates with the monitor.

Then you just need some panels, brackets, MC4 wire and a couple fuses etc. If you are in So Cal you can pick these up in person in Norco at Solar Blvd. I think the pair of 140 watt with MC4 Y connectors would serve you well.

https://www.solarblvd.com/ 280w panels $318 Get a 3rd panel later if needed for 420 watts.

http://www.solar-electric.com/bogart-engineering-tm-2030-a-battery-monitor.html

http://www.solar-electric.com/bogart-engineering-sc-2030-solar-charge-controller.html

Hi,

Try solarblvd instead.

280 watts for $518

I have the same batteries as you, and I get fully charged pretty much every day with only 200W of solar. Of course, I'm in Southern Arizona, so the sun is pretty intense.