Questions about an adopted off-grid system (with pics)

**ron_jeremy** · 08-06-2018, 04:56 PM

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**jflorey2** · 08-06-2018, 05:08 PM

Originally posted by ron_jeremy

My wife & I live off-grid in the Vancouver, BC, area (island on the Georgia Strait). Our home is a 'typical' house (1600 sq ft / 150 sq m) not a cabin. However, we (like to) live life as if we are connected to the grid. We work from home, so there are multiple computers, tablets, cell phones, even a file server running/ (or charging) all day, along with a home wifi network, 5GHz point-to-point antenna, etc. Additionally, there is music playing from my stereo pretty much all day, & at night there is one or sometimes two TV's playing Netflix, etc. We also have a full home theater system (projector, 1kW multi-channel amp, subwoofer, etc) that gets used once in a while.

I've adopted the current solar/battery system that was installed when the house was built about 2 decades ago.

I understand the basics of the system in that the solar panels provide power to the batteries which in turn powers our house. We also run a 4000W continuous power rated generator to charge the batteries (via 30A connector plug) a couple times a week (the inverter is set to accept generator power for 7 hours each time we run it). This is, as my wife has told me, how things have always been done. She knows nothing else.

Good news is that -
Batteries look like they are in good shape (so you've been taking care of them)
Inverter and charge controller are decent

Bad news is that -
Solar is woefully undersized. You've got 600 watts there; you want at least 2000 to maintain that battery bank. As it is the solar is more of a "battery maintainer" that will keep the batteries healthy when you are away and not using the system.

How do I know when the batteries are low & I'm supposed to run the generator if the panels are not providing enough juice?

Best way is via a battery monitor; that will tell you what capacity the batteries are at. You then charge when they hit some level (say 50%.) You would need to buy and install it.

A not-too-bad way is via voltage. A voltage of about 2.1 volts per cell (when there are no loads on the battery) means you should charge. So that means when the overall voltage goes below about 25 volts.

How much power are we receiving from our panels (at any given time)?

About 400 watts if everything is working. Your charge controller should have a way to display either power (easy) or amps (then multiply by battery voltage to get power.)

What settings on the Trace inverter or Xantrex solar charger should I look at to see if they're correct or maybe need to be adjusted?

The big ones are charging voltage levels and current limits; get a manual, look them up and let us know what they are. Given that it's been working for a while they are probably OK as is.

BTW that's a fairly "smart" inverter and can do things like start your generator for you.

Which components could use an upgrade? If so, upgrade to what?

Upgrade to a ~2000 watt solar array. Use high voltage (i.e. cheap) panels and match them to your charge controller. Your controller will pass a max of 60 amps, which means a 2000 watt array will just about max it out (your effective power will be about 1600 watts.)

If you want to go higher than that you can but you will need a second charge controller. Since we don't know what your loads are (watt-hours per day) it's hard to say.

**Sunking** · 08-07-2018, 02:39 PM

Never mind, deleted my post. Just way too much wrong and not worth my time trying to help someone who has no idea what they are doing.

**ron_jeremy** · 08-07-2018, 02:51 PM

Originally posted by Sunking

Never mind, deleted my post. Just way too much wrong and not worth my time trying to help someone who has no idea what they are doing.

Hey Sunking, no problem at all -- but thanks for the consideration.

**ron_jeremy** · 08-07-2018, 03:34 PM

Originally posted by jflorey2

Best way is via a battery monitor; that will tell you what capacity the batteries are at. You then charge when they hit some level (say 50%.) You would need to buy and install it.

A not-too-bad way is via voltage. A voltage of about 2.1 volts per cell (when there are no loads on the battery) means you should charge. So that means when the overall voltage goes below about 25 volts.

Would it be possible to use a clamp meter that measures DC amps/volts (like a Klein CL900) to check the condition of the batteries?

**ButchDeal** · 08-07-2018, 03:41 PM

Originally posted by ron_jeremy

Would it be possible to use a clamp meter that measures DC amps/volts (like a Klein CL900) to check the condition of the batteries?

the only real way to check the batteries is with a specific gravity tester.

**jflorey2** · 08-07-2018, 04:13 PM

Originally posted by ron_jeremy

Would it be possible to use a clamp meter that measures DC amps/volts (like a Klein CL900) to check the condition of the batteries?

No. That will only tell you charge (or discharge) current.

A battery monitor will tell you how much charge (in coulombs) is left in the battery; you can easily convert that to kilowatt-hours. Most have a simple "percent remaining" display.

As BD mentioned an SG tester will also tell you a lot about the state of the battery.

**ron_jeremy** · 08-07-2018, 06:14 PM

Originally posted by ButchDeal

the only real way to check the batteries is with a specific gravity tester.

Good to know -- thx very much for taking the time to help.

**ron_jeremy** · 08-07-2018, 06:15 PM

Originally posted by jflorey2

No. That will only tell you charge (or discharge) current.

A battery monitor will tell you how much charge (in coulombs) is left in the battery; you can easily convert that to kilowatt-hours. Most have a simple "percent remaining" display.

As BD mentioned an SG tester will also tell you a lot about the state of the battery.

Thx for the continued help. Do you recommend a particular battery monitor? Also, is this a function that might be built in to our inverter? I've just started to dive into the manual...

**jflorey2** · 08-07-2018, 07:09 PM

Originally posted by ron_jeremy

Thx for the continued help. Do you recommend a particular battery monitor? Also, is this a function that might be built in to our inverter? I've just started to dive into the manual...

I have used the Trimetric and the Outback Flexnet DC; they have worked OK. For you I would recommend the Trimetric since it is standalone and does not need to be paired with a charge controller or inverter.

The inverter you have does not have a battery monitor. It is something of an ancient inverter but it was a very good one; they are rugged, reliable and very programmable. It will take you days to understand the manual simply because it can do so much.

**ron_jeremy** · 08-07-2018, 08:26 PM

I'll be ordering the Trimetric TM-2030-RV as seen here.

I'm looking at the panels over at the cdnsolar.ca site. I'd prefer to get aw many watts as possible, but will have to examine our current mounts to see if we can keep them of if they need to go. Should I be simply looking to get the most watts per panel? How many kW should I get (2kW, 4kW, 6kW, etc.) while still staying in line with the rest of our system (batteries, electronics, etc.)? I am fine with upgrading minor electronics if required.

**bcroe** · 08-07-2018, 10:23 PM

Before buying anything, you should generate a lot of numbers of what is happening and what you
would like to happen. Measure your energy usage and time of day needed. Battery capacity, your
typical level of discharge. Contribution of the panels, in summer and in winter.

In a nutshell, it appears to me you are generator powered with batteries to even out the gaps. The
solar is so small so as to barely be able to maintain the batteries when nobody is home and everything
is turned off. That may be fine, what do you want to change? Bruce Roe

**ron_jeremy** · 08-07-2018, 10:40 PM

Originally posted by bcroe

Before buying anything, you should generate a lot of numbers of what is happening and what you
would like to happen. Measure your energy usage and time of day needed. Battery capacity, your
typical level of discharge. Contribution of the panels, in summer and in winter.

In a nutshell, it appears to me you are generator powered with batteries to even out the gaps. The
solar is so small so as to barely be able to maintain the batteries when nobody is home and everything
is turned off. That may be fine, what do you want to change? Bruce Roe

Thanks for the thoughtful reply. I am trying to learn as much about off-grid solar as I can.

Yes, we are definitely 'generator dependent', but I'd like to greatly reduce the time between generator runs, especially in the summer months. Id be ok with installing as many panels as we can afford.

We don't have a power usage meter (like as found on grid-tied homes), so how would we go about measuring our typical energy usage per day/week/month? Is this something the inverter can tell us? If not, I am willing to buy whatever is required.

**Mungy** · 08-07-2018, 11:08 PM

Does anyone kow anything adverse about Think Green Solar

Questions about an adopted off-grid system (with pics)

Questions about an adopted off-grid system (with pics)

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