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creeky 08-05-16 08:57 PM

One month update.

Did a full cell check after letting the batteries rest last night.

Cell voltage - count
3.96 - 1
3.97 - 29
3.98 - 42

Total 72 cells. All cells within .02. This is fine. I suppose I could bump up the low one.

I am coming to full charge every day. Haven't missed a day. Yet.

The morningstar TS-MPPT-60s (2) continue to function as per program.

I have a BMS solution from China available that I am pursuing. Not sure I really need one though. Guess we'll see what it all costs.

Right. That's it. Enjoy the summer all. It's finally raining here. I harvested two hot peppers today. Made a great salsa with local yellow beans, corn and cucumber. Huzzah!

stevehull 08-06-16 06:44 AM

Creeky - time for a recap (from you) as you enjoy your harvest and bask in your fine accomplishment..

I feel a little responsible as I was one of those who encouraged you to "do this" when you were initially feeling a bit overwhelmed with the entire situation (5/29/2016).

What I read is that the initial time to do this was not at all what you expected and progress was far faster.

So, in retrospect . . .

What price is good to buy a Chevy Volt battery pack.

Where were you "lucky". For example all cells appear to work No damage to physical parts. Some of us may not have such luck.

How much time did you spend on disassembly and did you really need to do all that.

If you were to start again, what would you have concentrated on?

How many specialized tools were needed (lets not count voltmeter).

A lot of discussion was on BMS - but it seems like this may be unnecessary?

Safety - I know that this is "low" voltage, but sweaty hands/fingers on 48 V with a lot of amperage behind it can create a nasty burn!

Other issues import to recap on . . . .

Lastly, I infer that you have about 1 kW in panels. Might be helpful to describe more clearly your PV infrastructure. It is VERY clear why you replaced your old lead acid storage.

Thanks in advance as you now have singular knowledge that is very valuable.


creeky 08-06-16 10:52 AM

Thanks Steve. I appreciate the encouragement. Warning, I do enjoy a slight deprecation of intent. It makes the story more interesting (to me anyway;).

I couldn't speculate on cost. It really is location dependent. Where I am, I saved a few thousand dollars over any other option (by size from 3 to 5k? By original budget I'm a bit under. And with 2.5x the capacity). There are benefits to being diy and an early adopter. smile. I have yet to sell off all the replaced assets. But having sold some of them; right now I sit somewhere below $155/kw. Installed.

From what I've read I was not "lucky". My experience seems to be standard. What was lucky was finding the battery pack at all.

I didn't spend much actual time on dis/reassembly. It occurred over two weeks/a month primarily as I had other obligations. I would do it exactly the same way if I had to do again. Of course, being my second time, the schedule would be greatly compressed. smile.

There were no specialized tools. I used a 10mm socket head on an electric drill and a voltmeter. I also used a socket wrench with a 10mm socket. Oh and some screwdrivers/pry bars. All pretty standard stuff.

To charge I was very fortunate that I have two Morningstar ts-mppt-60s. And two 1kw panel sets. This allowed me to use one controller/set for test charging the lithium batteries. And I was able to keep my electrical system online while I did so. It also allowed me to flash eeproms. Set new previously unheard of charge control limits etc with the security of knowing I had a fall back position.

For SESS (solar energy storage systems) I don't believe a BMS is necessary in the short term. And I have a month and 120 kws of power created and distributed to back that up.

In the long term I do believe that a BMS will be a good idea. Simply for peace of mind. If you can monitor your batteries online. Hopefully from a remote location as I travel a fair bit. This would be a good thing.

Also. If I was going to use more of the battery I would want better control. Charging to 80 and discharging to 30% offers a huge high/low safety net. I may want to go higher this winter when the days are short. A sunny day to 4.1 per cell vs 4 would give me another day of cloudy weather storage.

As mentioned. The inverter will shut down at 3.2v/cell. The solar controllers not only charge to a set point that has proven accurate. But there is a high voltage disconnect setting.

Safety - Its the same with any wiring you do. House. Battery. Car. Stereo. There are more dangerous jobs that I do. My tractor can easily do great damage. My tablesaw. Chop saw. Cook stove. Vegetable slicing.

Measure twice cut once. Look up and live. Etc. I imagine here we are talking to the converted. DIY demands clear thinking.

If I was to do it again I would make better protection for the cell bus bars. And probably wrap the handle of the socket wrench. Bicycle tube would work well methinks. Hmm. Think I just added something to my "still to complete list."

And yup. It turned out that the solutions I needed were accessible from online resources. Primarily from the electric bike and rc crowds. Also, early on GM released more info and there were some neat presentations given. Clues were found!

There was also some good info from other folks who have tried similar things. Nobody who did exactly what I did. But close enough. I was able to share with some of those folks too. Which feels good.

My explorations with Morningstar have always been rewarding. They are great folks to work with. And I appreciate their help. Plus. To be able to reprogram a 5 year old controller to an entirely new chemistry. In large part due to Morningstar continuing to update software and firmware for these products. Speaks very highly for them.

A tip of the hat goes to my buddy John. I'm not an electrical wizard. And I usually have to do things a few times before it "clicks." So having him help out was good.

<B>All the pointers here</b> were really helpful. You'ze all made things easier for me. Much appreciation.

While I'm handing out kudos I'd better mention my girlfriend. She who rode in the truck. She who listened to untold hours of ideation. Maybe we should have a moment where pause in celebration of our significant others ;)

You know. I guess us DIYers are like bulls in china shops. We charge in where others fear to tread. Sure, there's an element of original thinking / solution creation in what I did here. But its not the first time. I mean I over paneled my solar panels to controller initially because it made sense. later the idea was supported "officially." I put my panels on dock hinges for seasonal adjustment. Still one of the best ideas I've seen for mounting small panel sets. Cheap. Strong. Durable. Efficient. Proven particularly useful in the winter. Who knew?

And of course there are tonnes of great ideas on this site. From you folks who have done the same. Charge on! (yes that is a deliberate pun)


Creeky. The somewhat knowledgeable about one fragment of the lithium solar world. ;)

stevehull 08-06-16 05:26 PM

Great idea to use an old bicycle inner tube on the socket wrench . . . .

Great review. There must be at least a few brewski bottle tops popped!


creeky 08-10-16 09:24 AM

Well. No brewski's. But some general dancing about with my hands in the air.

Had a record 7200w/day a few days back (blowing past the previous record of just over 6kw). largely because I ran the a/c. used the induction hob to make supper. watched a movie. listened to music. ran the dishwasher. all after dark.

Hit a record low on the battery voltage. 45.43 according to the tristars.

Which is crazy to me. Seeing as "full" is 48.36. And "empty" is 42. So half of the power available? Of course some power was used during daylight hours.

And. Sunny day. Summer. Fully recharged by 1 p.m. Huzzah.

Heat wave today. No doubt some a/c use coming up. Better get to my chores.
Anybody else watching the Perseid meteor showers? Thu/Fri night looks awesome.

pinballlooking 08-10-16 09:39 AM

Very nice…
We use 5-6.5 KW overnight. We have used over 100 kw hours in a day but about 76 kw has been the highest this year so far.
Keep in mind we charge our Volt from empty to full two two three times a day that is 12 kw hours each charge.
People’s usage sure varies.

creeky 08-10-16 09:53 AM


Being a single guy living off grid in a moderate manner certainly helps. The 7.2kw day was my girlfriend visiting. Making her supper. Keeping her cool. Entertaining her. She loves movies. Doing the dishes.

Even with leaving the internet on 24/7 now. With idle draw of 40w/hr. (Okay. I upgraded the firmware on my IoT plugs. They read voltage/watts now. 36.512w is the current usage). I typically use around 3.5kw/day.

An all electric vehicle would be a joy. (Your Volt use is an inspiration.) I'd like a little 3 wheeler with room for 2 and good sized trunk.

I can expand to 6 kw panels with my current controllers. So I think I could fit in another 12kw battery pack.

Chores. Oh ya. Back at 'em.

creeky 09-01-16 09:44 AM

2 month Lithium report

The cells continue to check out exactly at the voltage spread noted in my first test.
I have 1 cell at .02 lower than the highest. Many cells .01. And most cells within .003v. There has been no change I can see.

My power use has been:

My 2kw off grid system produced
July: 140,210 watts
Aug: 129,710

for a total of 269,920 watts produced.

A/B (I have two 1kw panel sets and two controllers)
July: 73470/56240
August: 84740/55470

Note that the panel sets produce unevenly due to two factors.

One: the panels are set at different angles. The first set is adjustable and is currently (sorry) at 30 degrees (now that it is fall I'll be adjusting to 45 degrees). The second set is fixed at the "winter" angle of 60 degrees.

The fact that I am usually fully charged before noon also means that one controller will typically pick up most of the day time loads. For reasons I don't know of, the adjustable panel set carries most of these loads.

Of note:

I also saw 1023w being produced by my "summer angle" 1kw panel set. That this number was produced from 8 year old panels is interesting. This is a record high for my panels. I was "overpanelled" at 12v. But at 48v I can add up to 4kw more panels should I wish to. While overpanelled I frequently saw "current limiting." The high number comes after a good rain storm washed the panels.

I also set a personal record. One day power creation of 8.12kw. I ran the dishwasher on "high temp wash." smile.

My power use is dropping dramatically as I am not using the a/c unit in the studio anymore. Sigh. Today is the first day in months I don't have the doors to my studio wide open for the fresh morning breeze. It's too cold!

jjackstone 09-01-16 05:56 PM

Just wondering if you live somewhere with a lot of cloud cover. I would expect about 10kwh production per day from a 2kw array. Just a quick average of 5 good hours of sun per day times your 2kw array. That would produce around 300kwh per month. I realize that your panels are not all at optimal angle but 50% of rated seems a bit low. I did a quick check on Pinballlooking 12.5 Kw array and using the same 5 hours of sun per day and his production numbers are pretty much what I would guestimate for the month. Anything I overlooked in your system or is my math wrong? Thanks, JJ

jjackstone 09-01-16 05:57 PM

Ah, maybe you're only measuring what goes back into the batteries each day since you are off grid. JJ

creeky 09-01-16 06:55 PM


Originally Posted by jjackstone (Post 51571)
Ah, maybe you're only measuring what goes back into the batteries each day since you are off grid. JJ

You got it JJ. I'm usually recharged before noon. Most of my power use is during the sunny times.

In fact. My solar production will drop now that I don't need the a/c. During the transition to the new battery I was able to get by with just 1 kw.

Sadly Oct/Nov/Dec are very cloudy in my area. And I need the extra kw then.

creeky 09-05-16 08:52 PM

A note on lithium:

I just microwaved some stuff for a snack. 5 minutes of microwave time.

Battery pack voltage pre-microwave. 47.95. Post microwave. 47.79.

Amount of voltage sag. None observed.

I'm only posting this to bug guys with lead acid battery packs. smile.

randen 09-12-16 12:39 PM

Chevy volt pack for S-10 EV
3 Attachment(s)

It very good that your having some good results with your pack. Thanks for sending over the bits. I'm still accommodating the 2 Chev volt packs for the truck.

The aluminum box will contain about 5 kws and will be placed where the spare tire went between the frame rails.

The OEM battery box will be placed between the frame rails ahead of the rear axle.

The focus right now is plumbing for liquid cooling/heating the packs. Followed by the installation of the main contactors.

Thanks again for sending the pcs.


creeky 09-12-16 04:59 PM

Looks awesome Randen. That is going to be some incredible truck. You'll have to capture some smoke off of the tires on the first drive and send it to me. ;)

Happy to see some of the excess parts from my pack finding a new life. I'm thinking I will turn the old shell into bird or bat houses. But that's a project somewhere in the future.

Happy to report I had my first heavy use (tv, dishwasher, etc) but low sun day. Made almost 8 kw on the sunny day following (not home at the time) easily refilling the batteries.

CFECO 09-14-16 01:12 PM

Great story! I am building an Electric off road buggy using Motorcycle suspensions, golf cart drivetrain ( For Now) and a Chevy volt battery ( 48v) for power. I have one 48v section which I am also trying to use for my camp trailer "House Battery," using a 48v to 12v voltage reducer. Anyway if you have any 48v battery sections left over I would be interested in them...

creeky 09-14-16 01:50 PM

CFECO I have two 48s left over. Not sure if I'm hanging on to them for other projects or selling them. But AZ is a llloooonnnnggggg way away from me. Not economical to ship.

Look forward to seeing your build tho. I'm going to have a poke at a small "solar barge." In part so I can dock at my girlfriends and get around the dock regulations. Smile.

I have started doing a bit of research on building a trike. I look forward to seeing how your build goes together.

creeky 09-14-16 02:17 PM

Btw. It's a dark and cloudy day here. At mid afternoon the sun started breaking through the cloud. I saw 1068w from an 8 year old 1kw panel set. Angle set to 30 degrees. So not optimal for this time of year at my latitude.

Kind of interesting. As I've noted elsewhere. The "rated" max for panels this age should be 930w.

Maybe lens flare off a cloud edge amping up the solar incidence?

Also. I'm fully charged at mid day. Seems like all it took was a bit of breaking cloud. Lithium rules!

creeky 11-20-16 08:11 PM

Quick update: 4 months.

Perfect, even astounding performance. I have had up to 5 days in a row at less than fully charged. While I reduced use to 2-2.5 kw/day the pack only went as low as 43.5v. With 48v "fully charged." My low cutoff is 40.5. One sunny day and I was fully recharged.

This 5 day gap is primarily due to the efficiency with which the batteries recharge.

By ex. After 3 days of not being fully charged. Down to 44.5 at the lowest. I ran the dishwasher on a partially sunny day. The system made just over 6kw off my 2kw panels. And finished fully charging under better sun the next day.

This kind of use is just not done with lead. Absolutely proves lead is dead.

Morningstar controllers continue to work well. I am seeing a few anomalies. Including odd resets (with no reset actually occurring), loss of internet connection (stats still available via MSView), temp reading popping up to 25 and then returning to actual. Yet the wires are attached securely. Meh. Its still charging perfectly, charge values have not changed.

With the onset of winter and short days comes freezing temps. The batteries (off grid application) are stored in an out building with no heat.

A hacked together box of polyiso insulation and R values around R30 along with the inverter being inside the box has been enough to keep battery temperatures around the 10C mark. Yesterday I sealed the box better with some spray foam. I did have considerable gaps at one corner. Just in time for two weeks of cold sub 0 weather. Should be interesting to watch.

Sadly, I'm traveling this winter. I will be unable to monitor the performance of the insulation and inverter heater setup in keeping the batteries above 5C during the depths of winter as I will be shutting the system down.

Still. How nice is that. Just discharge to 3.85/cell then shut down and leave it. Take that lead!!!

stevehull 11-21-16 03:24 AM

Creeky - good to hear from you about the update. Chuckled to read "lead is dead" . . . . (and I agree).

Regarding keeping the batteries from freezing. Can you install them such that you get some ground heat? I realize that your deep ground temp in your Canadian "tundra" is probably 40 F (?).

Thought experiment . . . Am thinking of a box on the ground with 1/2 inch foam insulation below it. Above the box and on the sides are 6 inches of foam insulation (much more insulation). The net gradient of heat will be up from the ground, into the box, with little heat escaping.

We all know that the Li-ion batteries suffer terribly from cold - and the colder it gets, the worse it gets. Is it possible to build such a physical box that keeps cells above 32 F (0 C)?

That all said, how much heat (i**R) is "generated" during charging and discharging. Can wrapping all up in R30 trap that heat?

Great project!


creeky 11-21-16 10:56 AM

Steve. Great idea about the basement storage. Sadly, my property is river bottom. In the spring I get significant ground water. The soil is very soft. If you drive into my back field the only thing keeping you up is the grass mat. It's a pretty cool feeling.

I'll digress. Last spring my insurance agent came into the back field and parked in front of a straw bale thinking that it was a sign of a parking area. Sadly it was a sign that the area in front of it was grass free. She sunk up to her axles. I wasn't home. She had to walk the mile to the neighbors to get a tractor to get her out. ha ha ha. I laugh.

Thus, I am unable to build a basement or cooler room. That would be ideal. And I recommend that to anyone doing solar. Put your batteries in the basement!

So far my polyiso box is working. I'm running the experiment for a wee bit longer. So we'll see what we see.


1) I have seen no heating from battery use (unlike lead where I could keep the batteries warm just by running a heavy load). Previous to the box building if I ran the dishwasher, batteries that were 10C to start were 10C to finish. This surprised me.

Now that I've boxed the batteries I saw 10C to start and 12C to finish. I think this is due to the inverter being in the box. Even at 94% efficient it is generating considerable heat. Over a 100 watts of heat from one cycle of the dishwasher. Another 100 watts should be lost to heat daily with regular use. A good insulated box and I might be worrying mostly about keeping it cool. (I jest of course).

2) according to the literature lithium batteries see very little degradation of useful power with temp change. Very much unlike lead. However at below 5C you will get increased degradation of the anode material. Effectively shortening the lifespan of the battery. Hence the need to keep your batteries warm.

Dendrites be damned. Looking forward to seeing that problem fixed.

creeky 12-02-16 09:03 PM

Fun with heat

Having fun with keeping the batteries warm. Turned out I had a huge hole in my insulation. Got that fixed. Redid the lid. Etc. Will post an update in a few days on what temp the batteries are staying at.

So at below 0C the batteries "plating of metallic lithium can occur on the anode"? I've been pretty close to 0C. So far so good though. The inverter as a heater is working at least for late fall/early winter.

Yup, I did it again

Lucked out. 2015 pack this time. 17kw of goodness. The battery packs appear identical to the previous gen. So not sure what or where the .5kw comes from.

Next I'm planning to try a high voltage install. Something around 120v. Maybe Sunny Boy? Hmmm. All to drive a minisplit. Should be a fun experiment.

pinballlooking 12-03-16 12:00 PM

This is very cool. Each year after 2012 they made the battery pack a little more dense. They did not list this because they did not redo the EPA estimate. But each year had a little more range.

creeky 12-03-16 12:23 PM

I can find a lot of posts where folks are assuming the 17.1kw was a software tweak but LG appears to say they updated the chemistry. I'll go with that.

What I find amusing: My 2014 battery was dated May 2014. My 2015 pack was dated August 2014. Ah model years!

The 2015 pack was perfectly balanced. That was really cool to see. 3.71. I reset my reader to three decimal points just to see how far that goes. But as of right now. 96 cells at 3.71.

Hopefully I can find a 2016 pack. Would love to tear that down.

stevehull 12-03-16 01:30 PM

How much for this recent pack of cells?


creeky 12-03-16 02:53 PM

Gee. I'm starting to feel a bit guilty about the cost of these things. And wonder if I shouldn't be keeping my big mouth shut ...

This pack is in, torn down and verified for something around 120/kwh. The economics is real good. Tho. This is not including labour. Only material costs. Battery, shipping, incidentals (ie. supper out for she who is patient).

So let's keep this on the down low. Grin (is there anything worse than an olde guy misusing slightly out of date slang?)

randen 12-03-16 06:34 PM


Information for you.! You can discharge while the pack is -25 Deg C. but don't ever charge until the batteries are above 0 Deg. C . Metallic plating of the anode happens only while charging below zero. Discharging is fine at sub-zero temps.

While the pack is discharging the cells will produce a little bit of heat. Albeit with reduced capacity.

Enlist the services of the arduino to warm the space before any effort is made to charge. The batteries should last a long long time.

FYI with a little shopping and negotiating I got mine for a little less.


creeky 12-04-16 04:04 PM

Thanks Randen. The temp info is important for anyone considering this project.

My price is $C. And includes shipping/taxes etc. The first pack I bought worked out at under 100/kw. This second one. They're just so rare. I didn't mind coughing up a bit more for the 2015 an hour from home. Sadly I don't have access to the US wholesale market. Those guys have lots of batteries. More likely to move on price.

How'ze your truck doing? Burned any rubber yet?

randen 12-10-16 06:21 PM

Chevy Volt battery
5 Attachment(s)

Yep made some very good progress. Both Chevy Volt packs are in. I had some trouble with the DIY motor controller and that kept me scratching my head for a few weeks. I'm happy to report that issue is wrestled to the ground.

In the photos is the installed pack. Painted and sealed ready for action. I like to utilize aircraft hardware, nutplates and other fasteners just seem more user friendly and robust. (better for mantainance) The large connector with the 1/2 twist lock is used for aircraft batteries, that will handle some current!! The truck box was re-installed and all is back to original condition.

The truck was introduced in 1997 along with the famed EV-1. As it rolled of the assembly line it had a lead acid pack at 16Kwh and 1400 lbs. (a true lead sled) This was later up-dated with a Nimh pack at 29Kwhs and 1043Lbs.

Today the numbers are Lithium Ion at 34Kwh and 875Lbs.

Couldn't resist went for a little drive. The parameters for the motor controller are yet to be tuned. Sounds funny tuning an electric motor.??

Its kinda spooky backing out of the garage with absolutely no sound.

The truck is currently charging to ready for tomorrow for a couple hours of tuning the parameters. THEN maybe some rubber toasting.


creeky 12-10-16 09:00 PM

I'm lookin' for some smoke ... off the tires that is.

I just shut down the farm. It's going to be tough living in the city. Hydronic floor heat. 24/7 grid power that I didn't make. No wood chopping. No morning fire in the woodstove. No long cold walks. No howling coyotes. Sigh.

Anyway. The last two days as I shut down the systems the batteries were in their box with the inverter on "idle." Initial temp was 5C. By day two they were down to -2.

The inverter doesn't generate enough heat to keep the batteries above 0 with no load. It was also quite cold. The past two days saw a high of 0. Low last night was -10.

The battery box never did get finished. I had 3 sides at R30. And 3 sides at R12-15. So there is that.

If I decide to go back to full four season use I will add an electric heater. And a charger. I would be able to charge and heat for say an hour every few days off the generator just to keep things tidy.

Having said that. The lowest fall/early winter voltage level was that 43.6 I think I reported earlier. And I went 5 days several times without making it to full charge.

All without using the generator or an alternate charge source.

So I consider this a stupendous success. My previous lead acid battery required charging virtually every day during this time of year. The reasons are not just the shorter days. Its the very cloudy weather we get here.

Now I await spring. The battery after two days on "idle" is at 47.25. This is too high. I was hoping to get it down to 3.8 or 3.7/cell (not 3.9). So I may hop out to the farm now and again and just turn on some lights. Use the inverter. Enjoy a "ski" day.

Now to start the "solar boat" plan. And build a few high voltage systems with the new pack. Happy holidays to all.

Lithium rules!

creeky 03-04-17 11:05 AM

1 Attachment(s)
The new 12s monitors are in and tested.

Well. I have to say these things look way better than I had hoped. And how nice is it to be able to measure all 12 cells at once.

After testing I find them very sensitive and accurate. tho, to be fair, the gauges of their accuracy are probably less accurate than this new monitor itself.

So 'nuff talk. On to the test:

taking a 6s 24v cell I attach the monitor.

I watch for two days to see if its drawing down any one cell more than another. After two days my conclusion is: not that I can see.

I then attach a 24v battery charger from an electric lawnmower. Hook up and begin charging. As I charge all cells to 4v. I notice that cell 1 is consistently .02 lower than the other cells. Is this an indication that cell 1 is carrying the monitor load?

Note: I have set the monitor to light an led at a cell voltage of 4.00

As the charger brings the cell voltage up (9-10 hour process, this charger isn't very powerful) I check in from time.

At 9 that night my girlfriend yells up the stairs "your monitor is flashing" I go down, one cell is flickering to 4 down to 3.8 up to 4. Battery voltage is 23.8. I leave the battery on charge for another hr. Most cells are now 3.99 to 4.02. Lot of flickering up and down of the indicated voltages. Battery voltage is 24. I disconnect the charger.

The next morning battery voltage is 23.9

I leave the monitor on for a week watching the cells. Cell one is .02 lower than the others. After a week its .04 lower than the others. Most of the cells are showing some decline (.02) in voltage. Whether that is settling or what I don't know. Cell 6 is still at 4. And the led is still lit. Indicating that the battery voltage is fully charged.

Result: it only takes one cell v to trigger the led. the monitor works well as a warning device of cell imbalance.

I will look at how the 8M cell monitor users dealt with the monitor drawing all the power from one cell and modify.

that's it. Huzzah. Another step forward in lithium cell tech for off grid use.

PS-I had to buy 5 to get one. Took over 6 months to find a supplier. anyone want one?

creeky 03-07-17 03:28 PM


Originally Posted by creeky (Post 50830)
wait until somebody releases a parallel inverter for 60hz.

Found a couple. Man the chinese inverter companies are coming out with a lot of new equipment.

First, from europe: Victron Quattro parallels.

And I'm going to try a Helios from Cnbou. Fingers crossed.

creeky 03-14-17 03:14 PM

Just a quick update (I know. I always say that.)

The 12s cell monitor does appear to draw down off all cells. The first monitor I tested appears to have one cell measurement .02v lower than the others. The 4 other monitors (I brought in 5) all appear to be more accurate.

However, the cell voltage readings from the Bm12s are not super accurate. Close enough for the funny papers.

I am out of 2015 battery modules. So now to find more packs.

creeky 03-25-17 09:13 AM

Well. Turns out only the one monitor seems to draw poorly from the cells. The 4 others are okay. So I've kept the one bad one and relegated it to intermittent monitor duty. And sent some of the others out into the world.

Now I may have found a BMS. Stay tuned.

randen 03-26-17 08:56 AM


What are you going to use all this stored energy for now. What appliances are you operating with it. LED lighting??? better yet mini-split??


creeky 03-26-17 09:33 AM

Hey randen, how'z the truck?

Being off grid I'm pretty energy thrifty. So I do have all LED. Along with a zigbee network that turns lights on and off with timers/sensors.

And I've been selling battery packs. Turns out lots of folks want small battery systems for cottages, but don't want to spend thousands of hours doing research. Driving for days to pick up and collect. All to spend dozens of hours testing and configuring. Who knew?

Fingers crossed. I'm building a 30kw pack this month. Should be fun. And with the bigger pack comes more monitoring with finer resolved "system integration?" So that extra bit of work/problem solving keeps me interested.

creeky 03-26-17 09:38 AM

Oh. And mini split. GREE Crown 9kw soon to be ordered!

creeky 04-20-17 02:22 PM

Aaaaaa. Just bought a 2016 pack. Gonna tie it to a Schneider Connext 80/600 at 60v.
10 panels. 450v?

What am I thinking? Smile.

Edit/add on:
And pack prices are up 40% this year. I gotta stop talking about this.

Fionn 06-12-17 10:53 AM

Great project and writeup.
Are you still happy with the Chargery BMS?
I'm looking at the BMS16.

creeky 06-12-17 11:23 AM

I used the Chargery BM. Just the monitor. They aren't terribly accurate. I measure with a voltmeter when I want an accurate measurement. And then recorded the difference from the BM to the voltmeter. So far the error seems stable. Painful workaround but...

You may have seen this fellow on endless-sphere. He's making the Chargery BMS look pretty good. Especially as the new version comes with some nice add ons. Bluetooth et al.

TYVA BMS seems similar.

creeky 06-22-17 07:41 AM

One Year Update:

Well, I'm jumping the gun on this a bit. But in celebration of SPA day (solar power appreciation) I tested my lithium cells to monitor cell drift/balance.

Here's the result

To wit, after one year we have these results:
* no cell drift. None. Zip. Zero.
* efficiency far surpassing expectations
* no maintenance other than monitoring
* = happy Creek

And I've found a nice niche product to sell. SESS with lithium. I call them PowerWings.

And a big shout out to all who have helped. You folks are the best. Thank you.

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