# Off-grid shop- solar, battery and generator together



## ToddT58 (Dec 22, 2014)

For the past six years I've run my small business workshop off the grid using a diesel generator running on biodiesel/wvo blends. Most of the time, I only need some lights, my laptop and maybe a radio. Using LED's, I only need 60 watts. The laptop has a good battery so that's 65w I don't need to use all the time. 

I'd like to add some solar panels, from 80w to 140w, feeding two to four golf cart batteries, or something similar. 

How do I bring the generator into a system like this? I know many charger/controllers can accept AC input but not usually many amps. I definitely want a stepped charger. 

If possible, I'd like to do this in stages such as batteries first, then charger/controller and then panels. In time, maybe add more panels. With that in mind, I only want to spend a few hundred at a time. 

Suggestions? Help me wrap around how to incorporate charging the batteries with AC power.


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## stanb999 (Jan 30, 2005)

ToddT58 said:


> For the past six years I've run my small business workshop off the grid using a diesel generator running on biodiesel/wvo blends. Most of the time, I only need some lights, my laptop and maybe a radio. Using LED's, I only need 60 watts. The laptop has a good battery so that's 65w I don't need to use all the time.
> 
> I'd like to add some solar panels, from 80w to 140w, feeding two to four golf cart batteries, or something similar.
> 
> ...



A place to start. Your "small" 60 watt load is actually pretty big. I'm sure you want to have those bulbs on like 8 Hours a day. right? that's like 480 watt hours a day. here is a simple breakdown of what you will need.

First you will need about 500 watts of panels so during winter you can still get enough power all year round. It will vary with location but mostly you want to be able to charge 3 days worth of power on a single good day so you can have 2 "bad" days in a row. What's actually more likely is several days at 50% and you will need the extra panels to keep up.

Next you will need batteries. Once again your load is 480 a day times the 3 days for storage space your at approx 1500 watt hrs. This is 125 amp hrs. You will not want to use more than 1/2 your battery capacity So you will need at least 250 amp hrs of energy. 

The cost for the above depending on components is around 1200-1500 dollars.


Did you think about adding sky lights to your shop? They would be much cheaper and function almost as well most of the time.


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## ToddT58 (Dec 22, 2014)

Thanks for the reply. I rent so skylights are out. Besides, there's a floor above my shop. Along those lines though, I'm going to add either white or foil backed styrofoam to the joists above the lights for reflecting. I'm using some 4' LED bulbs retrofitted into florescent fixtures (ballasts removed, of course). I checked and they have the same lumens.

I know I'll need to run the generator at times. My question is more about what type hardware to use that will allow 115v AC input to charge those batteries.


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## Gary in ohio (May 11, 2002)

Why would you need to merge them. Run two separate systems, a laptop, radio and led lights can run off 12v. So have a 12v system on solar and your generator for your 110v/220v needs.


I do think you need to review power needs. A typical laptop takes 60+ watts all by itself to charge.

Now a couple 100 watt panels feeding several batteries should be more than enough for the radio and laptop and will power a number of LED lights.


I have a similar system, 2x100w panels, 2 deep cycle batteries all feeding my computer/ham radio shack. I have a laptop on 24x7 and my ham gear on 2-3 hours day along with chargers for a number of phones and tablets and task lights. 

Right now I have 3 days of power storage so 3 days of clouds before i run out of power. Working to double my battery bank.


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## wy_white_wolf (Oct 14, 2004)

ToddT58 said:


> T... My question is more about what type hardware to use that will allow 115v AC input to charge those batteries.


That requires an inverter/charger. The inverter puts out 120VAC from the batteries and then charges the batteries when the generator is running. Some have an autostart feature so you don't have to monitor the battery voltage.

WWW


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## ToddT58 (Dec 22, 2014)

As it is now, I'm running a 6kw diesel generator the whole time I'm at the shop (not every day and only a few hours each day) just to power some lights and my laptop. I'm wanting to reduce my generator run time, not to mention make it quieter. The laptop gets charged at home. I have a separate small standalone computer battery that would probably keep that running on its own (saving 65 watts, six hours average). 

Suggestions on a small inverter/charger with AC input so I can charge the batteries when I'm running the generator?


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## wy_white_wolf (Oct 14, 2004)

http://www.amazon.com/Xantrex-Freed...=1420302677&sr=1-19&keywords=inverter+charger

WWW


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## ToddT58 (Dec 22, 2014)

That looks like just the right thing! Thanks! I respect the Xantrex name as good stuff. I like that it has a stepped charger, MSW and can accept AC input. And, it's in my price range. Thank you so much!


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## gundog10 (Dec 9, 2014)

Our set up is 2 185w DM solar panels, 2 Costco gulf cart batteries, 1 morningstar 65 charge controller set for 12v and 14.8 amps, and a zentrax 2000w pure sine wave inverter. We supplement the solar power to the batteries with a 35 amp battery charger plugged into a honda 2000 inverter generator when the sun is hidden for several days. This system runs 2 laptops, tv, dvr and charges other small rechargeable batteries. While the charge controller and inverter are larger then currently needed, we will be expanding our system latter. The battery charger is attached to one batteries positive and the negative to the other batteries negative.


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## TnAndy (Sep 15, 2005)

Iota smart charger if you don't want to go higher price on an inverter/charger. 

$203 for the 45amp model: http://www.batterystuff.com/battery-chargers/brands/iota/IOTA-DLS1245.html

Outback inverter/charger if you want a GREAT inverter/charger:

$1633 for 2,000w model: http://www.wholesalesolar.com/Outback-Power-Inverters.html

Set up enough battery bank to get 24v at least, you'll save with fusing, wiring, etc.


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## kycrawler (Sep 18, 2011)

For an occasional use shop 3-4 hrs per day you could probably get by with a 1000 watt 12 v inverter to run some lights and laptop for about $50 on eBay. And get a 12 volt schumaker battery charger at Walmart for $50 to charge a pair of gc-2golf cart batteries add a solar panel and charge controller of your choice to decrease gen time even more . This isn't a high use residential system just don't forget proper fusing and grounding don't want to start a fire or fry yourself. You may also look at getting one of the cheap 900 watt 2 stroke generators from harbor freight mine will run 9 hours on a gallon of gas running an iota charger for our home battery bank


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## 12vman (Feb 17, 2004)

I have one of these setting around if you're interested..

http://www.tripplite.com/inverter-charger-2000w-automatic-transfer-switching-hardwire~APS2012/


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## ToddT58 (Dec 22, 2014)

Thanks to this discussion plus lots of online research, I decided to go ahead and at least dive off into the shallow end of solar energy. One thing I didn't mention is that I also have an RV that I want to in remote areas without hook ups. My plan is to mount the batteries and hardware in the RV and run a power cord to my small shop for lights and small things like a fan and a radio. When the voltage indicates the batteries are down to 50%, I'll crank up the generator. For using high amperage equipment like a compressor, I'll have the generator running.

I have a feeling most days I'll have enough battery capacity. 

I ordered the following hardware yesterday:
Renogy 100w Suitcase panel system with controllers
Progressive Dynamics PD9260CV 60 Amp Converter with Charge Wizard
2 6v Trojan T-105 batteries, will add two more in a few months

I'm also planning to add pull cords to the lights so that I'll only use them when I need them. I also have an external laptop battery that I'll charge at home so the computer won't be on this system.

This represents about $650, a low enough investment for me to learn more about operating on a mix of solar and biofuel generator power.


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## Ky-Jeeper (Sep 5, 2010)

gundog10 said:


> Our set up is 2 185w DM solar panels, 2 Costco gulf cart batteries, 1 morningstar 65 charge controller set for 12v and 14.8 amps, and a zentrax 2000w pure sine wave inverter. We supplement the solar power to the batteries with a 35 amp battery charger plugged into a honda 2000 inverter generator when the sun is hidden for several days. This system runs 2 laptops, tv, dvr and charges other small rechargeable batteries. While the charge controller and inverter are larger then currently needed, we will be expanding our system latter. The battery charger is attached to one batteries positive and the negative to the other batteries negative.


Gundag10 How do you like your Honda generator?


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## gundog10 (Dec 9, 2014)

Ky-jeeper, You know, I had a champion 2000wt inverter generator for 4 years and always ran great, sold it to a camp host who had no power. Our plan was to buy 2 2800 yamaha inverter generators and parallel them in order to have plenty of power to run our ac unit on our travel trailer. Found out the yamahas are not parallel compatiable. Long story, I know. Bought the honda and it runs very good, but it is a gas hog compared to the champion. It is just a bit quieter then the champion but not much. In hind sight, I paid $2100 for 2 hondas and could have bought 2 champions for $1250. If the honda's last twice as long as the champions they will be worth it if not I should have stayed with the champions. Yes, I like the hondas and I know others swear by them but if they don't last twice as long as the champion, I'll swear at them to.


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