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Small Cabin Forum / Off-Grid Living / putting together a Solar set up.
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# Posted: 10 Jan 2018 17:42 - Edited by: bronco_ed

Well it has been a while but I finally hooked up the Chevy Volt battery to the bus bar!
Double checked the wiring again and turned on the inverter, the green light came on(a good sign ;) so I plugged in a small Milwaukee buffer to see if I had power to run something.
That portion is working.

I then downloaded the Victron app, and turned the battery disconnect to the on position and the controller has power, another good sign!

I used phone app to connect to dongle... updated firmware for dongle and then controller made a couple configuration changes I am sure of.

At this point I have the rest of the equipment (wires/panels) I just need to put in sun and connect.

I will make a drawer or find a cabinet to house the components.

I ordered one of Creeky's harnesses and battery monitors to use. At a later point I may buy the BMS he is now offering.

Getting to see what happens when the sun hits the panels... It is cold and absolutely no sun right now but... I am thinking about setting the panels in the yard to see if the panel will pull anything from the daylight that is available.

Just curious...

I still have reading to do to start getting familiar with the controller settings etc... I think I am on the right track.


# Posted: 10 Jan 2018 18:00


# Posted: 13 Jan 2018 16:07

Hey guys. Well. what a great adventure bronco_ed. Congratulations. Especially on the Victron stuff. Makes a real solid system. You should be set for a decade or more.

Ya. Have I got some tales to tell too!

I got a bunch of lithium batteries at a different voltage. i won't talk about that yet because its all pretty experimental ...

Anyway. Just got the custom inverter in. Hooked it up. Everything works. I just saved a bunch of battery cells from having to languish at the wrecker! And I had a bunch of fun figuring it all out.

Complete with adventure trying to communicate with a factory in China. Those folks are doing amazing work.

Next summer I will be using this system at home. The current (ha, never gets old) system already has a new home to go to. So another summer. Another test!

Btw. If anyone is interested. I have 24v systems for small camps and campers coming out in a few weeks. Prices around $1-2k. I also have a few 48v systems getting ready. I'm having trouble keeping 48v in stock. Sheesh. So if you're looking for summer 2018 let me know.

And just to add a BMS tale. I had a customer have his cells go way out of wack and in a big hurry. I'm not sure. But I suspect somebody got to fiddlin'. Anyway. He had 3 cells go .3v out of balance. (just happens to add up to 12v. and he just happens to have an old 12v inverter. coincidence?)

He calls me up. Pretty worried. And for good reason. That's way too far out. So I lent him a RedWing BMS. Long story short. A week later his cells are within .009v. Huzzah.

So anybody thinking of building with more than two modules. Buy a RedWing. Maybe not today. But soon. I have a spring special on. Free harness!

Oh. And I just built a system with one of the new Victron inverters. Man that dongle is cool. I had been told it would be backwards compatible with the older inverters. But that turned out to be a ... er ... not correct. dang.

With the new inverters you can set your voltages for disconnect etc. But the old inverters were already set to acceptable ranges. meh.

It is kind of fun to look at the daily stats chart in history tho.

Happy solar everyone.

# Posted: 15 Jan 2018 12:35


Am I interpreting this correctly... When charging a lithium battery it is important to bring the battery to desired level of charge. Then to discharge to desired level. I am using longevity specs. It is undesirable to use float when charging a lithium battery, it is best to draw battery down then recharge.

Since float is a parameter in the victron controller that can be set...should float be set at the lowest discharge level? Or below to null it's operation?


# Posted: 15 Jan 2018 18:00


BMS = Battery Maintenance System?

# Posted: 15 Jan 2018 19:54

Hey ILFE. Long time no hear from. I was thinking of you the other day. Hold on. I'll come back to that. BMS for me is Battery Management System. Basically a BMS manages the cell voltages. Some folks are even using them for lead acid batteries now. It improves battery longevity.

Bronco_ed. Lithium really doesn't care. For longest life you leave 10% at the bottom and 10% at the top. So for the LG Chem cells you're looking at 3.4 min. and 4.0 top. If you look at the charts you'll see lithium in the NMC format tends to drop (power capacity wize) quite quickly at around 3.5. So I try to stay away from the bottom.

At the top the researchers are saying 4 is best for long life. I use 4.03. I have no idea how I came up with that. ha ha ha. But its true.

Most of the algorithms for solar controllers (good controllers) have something like "self learning" built in. So my Victron controller is set for 6 hrs of "absorb" at 4.03. But I find that it drops to "float" after about 15 minutes. So I set my float at 4. (Oh ya. That's why I put the absorb value to 4.03. Now I remember. Ah getting old!)

There're a couple of reasons for a high float, but basically, if the float value is higher the sun will provide more of the actual load power during the day. A lower float will draw down the battery even while the sun is out. A higher float forces the sun to run your loads.

ILFE. The reason I was thinking about you goes back to the discussion of water filters. You posted your local design for water filtration along with links to a video. Most of us around here are using bigger, fatter sand bed filters.

One night I'm in bed thinking, unusual I know, and I realized one advantage to your taller thinner water filter was that it put the water through a deeper sand bed.

So maybe it processed less water, and did it slower. But in effect probably cleaning the water better.

Well done that!

# Posted: 17 Jan 2018 17:36

Thank you!

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