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Small Cabin Forum / Off-Grid Living / Charging from 2 sources?
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Nate R
Member
# Posted: 26 Mar 2016 09:59
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How do others handle charging from 2 sources?

For example: It's 3 PM, and I realize that I won't get enough solar charge for the day to get my battery through the night. So I need to start the generator to get the battery charger going.

How do you handle the solar charge controller AND the AC battery charger connection to the battery? One option I've seen is to just put a breaker on the PV panel wires, giving the ability to manually kill the solar power to the charge controller.

Is this the best route? From what I gather, I don't want 2 charging sources going at once, confusing the solar charge controller, etc.

Coyote Flats
Member
# Posted: 26 Mar 2016 11:07
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Most systems are designed to run both at the same time. Are you running outback system

davestreck
Member
# Posted: 26 Mar 2016 12:04
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In most cases there is no need to disconnect the panels when the genny is charging.

I currently have 2 separate charge controllers connected to my battery bank. One connects my 2 main 150W panels, the other connects my 30W "maintainer" panel. Both run concurrently with no issues. I also plan on adding an inverter/charger to the system this year to allow me to top off the batteries using my genny. When its installed, I will occasionally have three separate sources charging the batteries at the same time. As long as each source is properly regulated this isn't a problem.

MtnDon
Member
# Posted: 26 Mar 2016 14:28
Reply 


FYI,if you suspect the batteries won't reach full charge with solar only early enough in the day you are better off to start the generator early to build bulk charge up quickly and then let theavailable solar finish the charge. Bulk charge is better use of gas than absorb charge.

As the voltage rises each charge source will switch from bulk to absorb according to their set voltages.

offgridjunkie
Member
# Posted: 26 Mar 2016 15:08
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I have a small system and sometimes need to add in a little generator support.

My practice is to start up the generator in the morning when I get up. Run it while having coffee and breakfast, then run the vacuum, etc. Then let the solar do the rest for the day.

Usually run my EU2000 for about 1.5 hours with a 40 AMP charger on my 100 AMP AGM battery bank.

Another guy I know, has a bigger system. Does the same thing, but runs his generator to make coffee every morning. He says, yeah I get my batteries charged and lazy mans coffee at the same time.

offgridjunkie
Member
# Posted: 26 Mar 2016 15:10
Reply 


Quoting: davestreck
In most cases there is no need to disconnect the panels when the genny is charging.


This is why you have a charge controller. It is made (good ones at least) to disconnect at certain voltages etc.

pizzadude
Member
# Posted: 27 Mar 2016 00:17
Reply 


Good Q from the op and sweet feedback peeps..
I've wondered about this and I've always just lifted an end of the 30A fuse connecting my cc to my bank when charging with the Honda,, just to be safe.

creeky
Member
# Posted: 27 Mar 2016 10:17 - Edited by: creeky
Reply 


Ran both solar and a genny together for years. No problem.

I also charge in the early a.m. with the genny when I need to. It's win/win. your batteries haven't received any charging overnight so they are at the lowest point. You bulk charge. Best use of gas. And then let what sun you get that day finish up for you.

Plus you can run heavy draw appliances like kettles or microwaves or vacuums without drawing your batteries down.

I'll add one point: there is some concern that running a charger and using your inverter at the same time will damage the inverter long term. This is a valid point. For that reason I installed an ATS (automatic transfer switch). When my genny is running it is charging the batteries and running my loads. The inverter is out of the loop. When the genny goes off, the inverter takes over.

This is one advantage to the inverter/chargers. ATS is built in.

Note that some of the new top-of-the-line inverter/chargers will actually use inverted power to run loads while charging on a smaller genny.

This is a super sweet feature. It means you can run a smaller (fuel thriftier) genny. Happily have it charging your batteries. Then if you run the microwave and the vacuum at the same time. The inverter will automatically fill in with additional power from the batteries to run the heavy load. No damaging your small genny. Totally cool.

what will they think of next.

Nate R
Member
# Posted: 27 Mar 2016 19:08
Reply 


Thanks for the replies, all! Interesting point about the inverter and charging running at the same time. Maybe I'll include an ATS in my mini-system to prevent that possibility.

Good to know that I can not worry too much about the solar charger and the genny together.

offgridjunkie
Member
# Posted: 29 Mar 2016 13:41
Reply 


Quoting: creeky
This is one advantage to the inverter/chargers. ATS is built in.


Nate R : This is really the sweet spot as it just simplifies things and you don't have to worry about moving switches, etc. I took my design a step further. I have plugs that are fed only by the Generator and plugs only fed by the inverter. When my inverter takes a shit, I will be moving to the more expensive Inverter/Chargers. In reality, my charger and inverter costs the same as the inverter/charger combined - i just put my system together in peaces so did't really do it right.

pizzadude
Member
# Posted: 29 Mar 2016 14:00
Reply 


Quoting: offgridjunkie
takes a shit

Mine did that only after a couple months of use. I'm glad I had a backup

creeky
Member
# Posted: 29 Mar 2016 18:52
Reply 


offgridjunkie. that's the ! idea. be ready to upgrade. don't ask me about my inverter crapping out the week before xmas. serious. the week before eff'in xmas. not its fault. bad ground fault interrupt. still...

many sounds similar to laughter were heard. ha.

pd. ezzactly.

following: that's why to buy the current (cough, what. still?) best. we are lucky here to have so many options. prices slowly dropping. and the quality. pah!!! beloved by this boy. (chest fist thump to engineers)

and still. no harm.good sense in upgrading over time. works $$$ wize. just. once in awhile. see above.

Nate R
Member
# Posted: 29 Mar 2016 18:59
Reply 


I'm leaning more in that direction offgridjunkie and creeky, for my future set up. For now, I'm assembling a system to learn about it and figure out my needs down the road once I build a place. So, since this one is quasi-temporary, I'll keep it cheaper for now.

At this point, I have 2 acres of land and a travel trailer on it. So I need something to get me going for now, but complex/advanced enough to understand my wants/needs/desires for the future. (Eventually will be building a cabin.)

pizzadude
Member
# Posted: 29 Mar 2016 21:57 - Edited by: pizzadude
Reply 


Quoting: creeky
crapping out

Hmmmm.
I wonder if we had the same inverter. Mine had too high voltage output. Nothing worked.

pizzadude
Member
# Posted: 29 Mar 2016 22:12
Reply 


When my inverter took a crap, it didn't stink. No smoke, no burnt smells. If I can remember, I think the voltage was around 132vac. Not terribly high

spoofer
Member
# Posted: 4 Apr 2016 10:11
Reply 


So ... Can I hook my Honda eu2000 up to my solar panel batteries, without disengaging them from the system?

Jebediah
Member
# Posted: 4 Apr 2016 10:57
Reply 


I'm just learning about solar and I came across this.....Some of you my be looking for an ATS, automatic transfer switch for 30amp genny outlet. It will sense the power coming from your genny and by pass your inverter. Turn your genny off and it will revert back to your solar/inverter set up. They are on ebay and amazon.

spoofer
Member
# Posted: 4 Apr 2016 12:57
Reply 


I just want to know if I have to disconnect my 2 battery system from my panel be fore I charge them with my honda that has 12v dc outlet..

MtnDon
Member
# Posted: 4 Apr 2016 13:20
Reply 


No need to disconnect the PV... But the 12 VDC output is not very high amperage so charging will take a long time. Plus a lot of gas as the manual tells you to turn the ECO setting off when using the EU2000 as a battery charger. The feature is really only there to be used on a more or less emergency basis.

spoofer
Member
# Posted: 4 Apr 2016 14:43
Reply 


Well I figured if my batteries were to low to use and I switched to the Genny for power, I could use it to power the cabin and charge the batteries at the same time.

MtnDon
Member
# Posted: 4 Apr 2016 14:49
Reply 


I was simply pointing out the disadvantages of using an EU2000 for battery charging. The DC output is a maximum of 8 amps. And ECO must be off, so that uses more gas. IF you charge batteries a lot with the generator charging will be quicker with a battery charger sized to the size of the battery. You still would not have to disconnect the PV.

spoofer
Member
# Posted: 4 Apr 2016 15:00
Reply 


OK Thanks. I am new to the Genny. I have had a Renogy 100 watt kit for a couple of years. We get lots of gray days here in a row and my 2 six volt batteries wired together run low at times. I forgot how mant amp hrs. they are, but they are quite large. I only use the camp for weekends. I run 4 led lights, a radio and a very small led TV. I'm in the Orwell-Redfield NY area of the Tug Hill. There is so much snow I have to take the batteries home with me in the Fall.

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