Solar Power

[CJBROWN]

Thank you Jack. That's pretty much what I've been able to glean from all the banter. Everyone touts what they did without a clear basis for comparison of other system configurations.

MPPT seems to be newer technology, it's expensive, so it has to perform or it's just, well, extra expense. From what I can gather it puts out a little more with low voltage PV's at highest output (noon?) but seems to be most valuable when the panels are putting out much higher voltage that the charge rate. So like you say, series wired PV's and grid-tie type high voltage panels.

Again, thank you for lending your industry expertise.

BTW, can you comment on mainstream established controller brands, like MorningStar, Midnight solar, BlueSky, compared to the chinese imports, like Tracer (Reonogy) Eco-Worthy, and others? Are the latter all junk? Or worth experimenting with? I would hate to ruin hundreds of dollars worth of batteries with failed experimentation. LOL.

[01zeosix]

Just for grins, I just looked at my MPPT500 controller to see what my four Kiocera 140 watt panels are putting out here on the right coast (17:50 DST light cloud cover). It's putting out 84.1 battery amps. I'm happy. 50% SOC at 8:00 am. Float charging by Noon. Jack's advice is spot on BTW. Although you should never expect any roi on your solar install, it is a real Genny saver if you boondock.

[JFNM]

In regards to running the cable down the refrigerator vent. Is any protection for the cable necessary or does it need to run behind the insulation or anything?? I do understand that avoiding the propane burner/hot section is necessary.

Thanks!

[CJBROWN]

Originally Posted by 01zeosix

Just for grins, I just looked at my MPPT500 controller to see what my four Kiocera 140 watt panels are putting out here on the right coast (17:50 DST light cloud cover). It's putting out 84.1 battery amps. I'm happy. 50% SOC at 8:00 am. Float charging by Noon. Jack's advice is spot on BTW. Although you should never expect any roi on your solar install, it is a real Genny saver if you boondock.

Who makes that controller or where do you get them? I could only find old references to it and that it was out of stock or sold out.

[Tony Lee]

One poster was asking about a solar system to run a motorhome fitted with a residential fridge. Given that most boondockers probably run a propane fridge, propane heater and HWS and propane stove, any variation that requires a large inverter to be run 24/7 to run a mains fridge is going to require significantly larger area of solar panels and battery storage capacity if you want to avoid running the generator for long periods,

four Kiocera 140 watt panels are putting out here on the right coast (17:50 DST light cloud cover). It's putting out 84.1 battery amps.

That's amazing.

[John Hilley]

How are you measuring the current. The panels aren't capable of half that.

[01zeosix]

Originally Posted by John Hilley

How are you measuring the current. The panels aren't capable of half that.

Solar array wired high voltage in series and a MPPT 500 Charge Controller. MPPT 500 and MPPT 500 HV Maximum Power Point Tracking (MPPT) PV Charge Controllers increase charge current by up to 30%.

Information can be found here.

[John Hilley]

To get the 140 watts

Vmp 17.7v x Imp 7.91 amp = 140 watts

Imp 7.91 x 4 = 31.64 amps

If you got 30% more current with MPPT
31.64 x 1.3 = 41.32

How can you possibly get 84.1 amps going into the batteries?

[caissiel]

Same thinking here.
The calculations are correct.
But most of the time the batteries will only take half the load. Unless there is already a daytime load up to 42 amps.

[01zeosix]

I meant battery VOLTS not amps. Mea Culpa already!!!!! Without starting an unintentional flame war, like I stated before I'm happy with my system.

Remember one size doesn't fit all. Available clear space to avoid peripheral shading, correct wiring, good mppt controller, high quality batteries, properly sized inverter(s), knowledgeable and experienced installer/mentor, and deep pockets enter into the equation, too.

There really is no one-for-one ROI. Having the ability to be "off the grid" boondocking and not running my generator unless I need to "recharge" my bank is all the ROI I need.

Again, I apologize for my error in inserting amps instead of volts. My intent was not to confuse anyone, especially those are searching for information on solar installations for themselves. I'll crawl back into my cave now, still happy with what works for me.

[JFNM]

Originally Posted by CJBROWN

MPPT seems to be newer technology, it's expensive, so it has to perform or it's just, well, extra expense. From what I can gather it puts out a little more with low voltage PV's at highest output (noon?) but seems to be most valuable when the panels are putting out much higher voltage that the charge rate. So like you say, series wired PV's and grid-tie type high voltage panels.

Hi Chris,

I am certainly no expert. However; I do have a brand new, DIY system running in my MH (though I did not sleep at Holiday Inn Express last night). My understanding of MPPT is that it is more efficient, if not necessary(??), with the higher voltage "house" PV panels and larger systems (high total watts, like >400-ish, me thinks). I have limited space (don't we all) and wanted to use it as efficiently as possible. The clear winner for this (from my research) is the newer, higher voltage panels. So, MPPT was "better" for me. Yes, costs a little more but you may save in other places. For example, I purchased two 325 watt panels for $600 (measure about 41" x 61") and the MPPT for $400 (MorningStar TS-MPPT-45). I haven't ran the numbers but kind of suspect that getting 650 watts out of 12 volt panels and a lesser charge controller may end up costing a similar amount.

I ran out of mounting hardware for my second panel (ordered) so only have one currently operating. Here in the southwest sun, it is pumping out about 55 volts and a little over 5 amps which translates into about 22-23 amps at 13 volts. I am happy. However; I can see the trend... Now I really want a good monitor and am starting to think some more batteries would be cool. I suspect it never ends...

[Reed Cundiff]

Always enjoy reading through the exchange of ideas on these fora.

We have six x 235 W panels, approximately 9.5 kW-h of LFP, 4.0 PSW Magnum inverter etc and run the refrigerator on inverter 10 hours a day. The panels are in two series of three so the voltage comes off roof at 90 V, this is dropped to to go into the battery suite (float is 56.7V). We have had over 1200 W going into controller (summertime around solar noon). Have left the refrigerator on AC overnight several times and we wind up about -3000 W-h by morning. We are fully charged by noon.

Have corresponded with Bob several times and have enjoyed the exchange of information. He does think we went way over the edge on solar.

Reed Cundiff

[pocketchange]

Bob's preferred hardware list (which IMO is excellent btw), I believe his suggestions for running with as large a gauge wire as possible in an effort to avoid voltage drop, is dead on along with his other suggestions. I have a Tri-Metric and it's great.
If you can afford the MPPT Solar Controller, go for it but if you are only putting 30-35 amps out, my calculator insists you would be better off spending you funds elsewhere IMO. pc

[Menob55]

I got 6 140 watt solar panels installed and 6 (6 volt) batteries. 3 panels and a controller in BC Canada and then in US I got Solar Mike in Slab City, California. I have 2 (40 amp controllers) three panel on each controller. Way cheaper in Slab the in canada.
I can see which side of the power is coming from. Left or right side. My panels lay flat so I don't get full sun power from them. I am thinking of adding a wind generator for the days the sun is hiding and at night for extra power. When it's cold I run both furnaces at night but when I have to run the furnaces all day two the wind generator will help the batteries out. So far so good.


Bob and my dog Anchor (Shitzu) 1996 American Dream 36 with a Jimmy in tow and a Vespa on back of Jimmy.