My build thread

[timselectric]

Started charging.
Just one charger for now. I'll add a second one tomorrow, if necessary.

 

[Crowz]

Hope they all fall in line when charged!

 

[timselectric]

They will, but I don't know how far off they will be at the beginning of balancing.
This is why I was running the test, for as long as possible.

 

[ksmithaz1]

Theory is always nice. Then again 56c/KWh is outrageous.

 

[timselectric]

Well, things never go as planned.
I have to do a service call today. So I will have to delay the charging.
Because I want to be here to monitor the balancing.
No big deal. I'll still get it done. But I was hoping for a relaxing day off.
It's always something. lol

 

[Brucey]

More money more panels+batteries

 

[timselectric]

So, I shut off the charger and went to work this morning.
Sun has been bright all day.
Come home to 97% SOC. lol

 

[timselectric]

Balancing is just beginning (3.45v).
Largest delta is currently 122 mv. (Oldest battery)
I'm sure it's will expand, as it starts climbing the knee. But so far, I can't complain.

 

[timselectric]

Well, that delta got up to 178 mv , before I realized that balancing was turned off on that BMS. lol
Back down to 83 mv now.
I checked the others and they are all on. I don't remember turning it off, or why.
But oh well, all is good now.

 

[timselectric]

Garage system is full, balanced (LFP), and equalizing (SLA).
House system shunt thinks it's reached 100%, but we ain't there yet.
Still taking 5kw in, At 56v.
Worst delta is 115 mv.
Highest cell is at 3.505v

 

[ricardocello]

Well, that delta got up to 178 mv , before I realized that balancing was turned off on that BMS. lol

Should have relied on "Inertia", sheesh.

 

[OffGridForGood]

Well, that delta got up to 178 mv , before I realized that balancing was turned off on that BMS. lol
Back down to 83 mv now.
I checked the others and they are all on. I don't remember turning it off, or why.
But oh well, all is good now.

that is great information, thanks for doing that test!

 

[OffGridForGood]

Should have relied on "Inertia", sheesh.

Then he would also be relying on 'Self Balancing' cells too... oh yeah guess this test is another data point Against so-called self balancing...

 

[timselectric]

Oldest battery is in OVP.
Delta at 233 mv
Everything is working as it should.
I'm not going to intervene.

 

[NCislander]

Oldest battery is in OVP.
Delta at 233 mv
Everything is working as it should.
I'm not going to intervene.

Those JK BMS w/Active Balancing work really well. I've been happy with mine (Copied Yours)

 

[timselectric]

That delta isn't a runner, it's a stragler.
Average cell voltage in the battery is 3.519v and the stragler is at 3.348v

 

[OffGridForGood]

That delta isn't a runner, it's a stragler.
Average cell voltage in the battery is 3.519v and the stragler is at 3.348v

My current batch of cells came in, and this time I ordered a group of 20 cells: 16 for the next pack-build, and 4 spares to allow swapping out any outliers from a couple packs. I put a post-it note on any pack that shows an odd-ball cell at high or low SOC and note which cell it is, the delta etc. Now with some spare cells I will try swapping around and then see how it does. Later the four crappiest cells can be made into a portable 4s pack for the MPP 1012 mobile set up.

 

[ricardocello]

That delta isn't a runner, it's a stragler.
Average cell voltage in the battery is 3.519v and the stragler is at 3.348v

I hate those stragglers, but I've only got one. I ignore it, better things to do.

 

[timselectric]

My current batch of cells came in, and this time I ordered a group of 20 cells: 16 for the next pack-build, and 4 spares to allow swapping out any outliers from a couple packs. I put a post-it note on any pack that shows an odd-ball cell at high or low SOC and note which cell it is, the delta etc. Now with some spare cells I will try swapping around and then see how it does. Later the four crappiest cells can be made into a portable 4s pack for the MPP 1012 mobile set up.

That stragler already has a post-it note on it. lol
I noticed that it was struggling before.

 

[timselectric]

I hate those stragglers, but I've only got one. I ignore it, better things to do.

Yeah, it's not a big deal.
It only shows itself at times like this. (Long duration between full charges)

 

[JJJJ]

That stragler already has a post-it note on it. lol
I noticed that it was struggling

Lol. Been there done that. My recent rebuild replaced a group of older cells. One is a sleeper and just couldn’t keep up with the team.

 

[timselectric]

That delta is at 235mv now.
It won't get any worse, as bulk charging is complete (57v).
Now, I'll just see how long it takes to balance.
The rest of the batteries are doing great.

 

[timselectric]

The next biggest delta is 7 mv.
So the other batteries are already balanced.

 

[timselectric]

All in all, it was a great test.
The only issue was the one cell, and I already knew about it.

 

[Zwy]

That is the point, for what it costs for meter charges, it might be cheaper to unhook from grid.

The Kwh used can be expensive. In November, we used 18 Kwh from grid and in December even with 3 weeks of fog, we used 404 Kwh from grid and that is mainly due to laundry when in grid bypass. That might be all the grid power we need until next November/December.

Correction, I see tonight we only used 134 Kwh from grid in December, the 404 Kwh was in the column to the left in SA and is Battery Discharge for the month.

Using the example from that post, generator cost for fuel is $0.23/Kwh. Right now, I'm paying $0.17755/Kwh with a $25.08/month meter charge or basically $300/year.

422 Kwh would cost me $74.92 for the Kwh plus $300=$374.93 for the year. That comes to almost $0.89/Kwh. For the 422 Kwh/year, it would cost $97.06 for fuel using the generator. Can one purchase a generator and maintain it for $278/year is the question.

With the correct grid usage for the year of 152 Kwh, the cost would be $300/year for meter charge and $27 for the Kwh used comes to $327 per year. That makes the cost of grid power $2.15/Kwh.

Those are high priced Kwh.