Lishen 272 Ah Top Balance and Capacity Test

[WA5IDX]

I finished the top balance on my cells ( via cells in parallel) and built a temporary battery to add the BMS units and then check them out and "final" battery balance.

After charging to 14.2V overall and waiting for the current to go to zero, I turn the PS off. After resting ( circa 48 hours), things settled out with only a 7 mv delta.

I'm happy so fsr.................... now to move this 100 Lb block into the Airstream.....

 

[cinergi]

Cell 4: 284.0Ah

 

[blutow]

Just finished my first individual cell test on my lishen 272’s. 287 Ah at about 6.5a discharge. Started at 3.62v and finished at 2.62v (cut off for tester set to 2.5v, but it has a bit of voltage drop).

 

[Bud Martin]

Nice result.

 

[blutow]

Nice result.

Yeah, I'm loving the performance from these lishen cells. I've already tested all cells in 12v packs with pack results over 280Ah at higher discharge rates, so I don't expect any of the cells to test under 280. I'm testing individual cells to possibly improve matching a bit. Delivery of my van is delayed, so I've got some time to burn before I'll be ready to install batteries.

 

[prowess1993]

I got a question,, I’m new to the solar game. I recently received the Lishen 272 cells. My setup is pretty simple, 4 cells, 12v. I’ve top balanced and capacity tested them twice and got good results, 282 ah and 283 ah. I’m using them now and one cell is off from the others. Under load or changing can range anywhere from 5 mv to 50 mv depending on the amp draw. Typically the load is between 3 and 40 amps. The other 3 stay within 1 mv of each other. Is it normal for a cell or two to be off in that range?

 

[blutow]

I got a question,, I’m new to the solar game. I recently received the Lishen 272 cells. My setup is pretty simple, 4 cells, 12v. I’ve top balanced and capacity tested them twice and got good results, 282 ah and 283 ah. I’m using them now and one cell is off from the others. Under load or changing can range anywhere from 5 mv to 50 mv depending on the amp draw. Typically the load is between 3 and 40 amps. The other 3 stay within 1 mv of each other. Is it normal for a cell or two to be off in that range?

From what I've seen watching my cells:

They stay nice and tight (under 5mv) in the meat of the voltage curve (between ~3.05v - 3.45v). When I hit ~3.5v on the high end or ~3.0v on the low end, cells start to depart. The closer they get to 2.5v and 3.6v, they move apart further.

If you are seeing 50mv differences in the sweet spot of the voltage curve, I would suspect a bad connection somewhere on the battery. See if any of your bus bars are warm. Try cleaning terminals and apply noalox and reassemble.

 

[John Frum]

My cells diverge at ~26.2 volts on discharge ~15-20mv and converge again to ~3mv at 26.1 volts.
Same on charge at ~26.2 to ~26.3.
No clue why.

 

[jharkin]

After setting up for the capacity test, I drained the batteries to the normal 100% capacity value of 13.3 volts from the Top Balance value of 14.5 volts. Since there is very little energy in this area of the curve, it didn't take long. 3.9 Amp-hours were drained. The capacity meter was reset. I was able to find a combination of loads that gave me 0.2C or 54.4 amps via a Giandel 2200 watt and a space heater and several incandescent and LED lights.

Your premise is flawed. If you let the cells sit unloaded for 24 hours they would have naturally settled to rest at 3.37~3.4 volts per cell (about 13.5 for the pack). The discharge you did actually used some of the usable capacity and you started your test only 98% full or so.

 

[blutow]

Cell #2 - 288Ah

 

[prowess1993]

From what I've seen watching my cells:

They stay nice and tight (under 5mv) in the meat of the voltage curve (between ~3.05v - 3.45v). When I hit ~3.5v on the high end or ~3.0v on the low end, cells start to depart. The closer they get to 2.5v and 3.6v, they move apart further.

If you are seeing 50mv differences in the sweet spot of the voltage curve, I would suspect a bad connection somewhere on the battery. See if any of your bus bars are warm. Try cleaning terminals and apply noalox and reassemble.

Thanks, I’ll try that. What is noalox

 

[blutow]

Thanks, I’ll try that. What is noalox

Used for electrical connections to resist corrosion. Typically used for aluminum wire connections, but some apply it to prevent corrosion on the cell terminals. Aluminum and air don't mix well, results in near immediate oxidation that may not be visible, but will affect the connection.

Noalox®

Noalox®

www.idealind.com

 

[Just John]

Thanks, I’ll try that. What is noalox

It's a compound used to prevent aluminum from corroding very rapidly by blocking air contact. When aluminum and copper meet, all of the corrosion occurs on the aluminum due to galvanic corrosion. When they started using aluminum wiring in houses in the 1970s, it was discovered to cause quite the fire hazard. Aluminum oxide is a much worse conductor than copper oxide, and the chemical reaction called galvanic corrosion causes it to form. Google it.

You just need a light coating to block air contact, preferably right after you clean the contacts. Noalox, ox-gard and many other name brands exist specifically for this.

 

[prowess1993]

It's a compound used to prevent aluminum from corroding very rapidly by blocking air contact. When aluminum and copper meet, all of the corrosion occurs on the aluminum due to galvanic corrosion. When they started using aluminum wiring in houses in the 1970s, it was discovered to cause quite the fire hazard. Aluminum oxide is a much worse conductor than copper oxide, and the chemical reaction called galvanic corrosion causes it to form. Google it.

You just need a light coating to block air contact, preferably right after you clean the contacts. Noalox, ox-gard and many other name brands exist specifically for this.

Thanks! I’m new to all this solar and DYI battery. It’s fun. I’m looking through the forum for a clear directions on cleaning the terminals but I can find anything. What is the best, simplest way to clean battery terminal?

 

[John Frum]

What is the best, simplest way to clean battery terminal?

There is little consensus on this question.
I used green scotch brite followed by contact cleaner and finally ox-guard.

Ox-Gard Anti-Oxidant Compound

Ox-Gard Anti-Oxidant Compound contains prime grade zinc and is formulated with metallic zinc to create a compound that enhances electrical and thermal conductivity which is used on high power crimp connections and stud bolt mountings. When the connection is tightened, the grease is displaced...

www.gardnerbender.com

It worked for me.
If I hadn't had the contact cleaner I would have used isopropyl alcohol.

 

[Just John]

There is little consensus on this question.
I used green scotch brite followed by contact cleaner and finally ox-guard.

Ox-Gard Anti-Oxidant Compound

Ox-Gard Anti-Oxidant Compound contains prime grade zinc and is formulated with metallic zinc to create a compound that enhances electrical and thermal conductivity which is used on high power crimp connections and stud bolt mountings. When the connection is tightened, the grease is displaced...

www.gardnerbender.com

It worked for me.
If I hadn't had the contact cleaner I would have used isopropyl alcohol.

I used a little wire wheel attachment on my Dremel tool to clean off what looked like glue or something from a couple of mine, otherwise I used the buffer pad (basically a felt pad) with some 99.5% IPA (Isopropyl Alcohol). Like you said, various flavors of scotch brite, very fine grit sandpaper, acetone (contact cleaner) have all been reported to work well. They certainly seemed to work on mine (just watch out for stray cat hairs). My advice is don't go hog wild on the Noalox or Ox-Gard, you just need a very thin layer to protect it from contact with the air. I put it on with my finger, you can basically feel it on there, but really can't see it on there. I'm in the desert, it would be much more noticeable if you live in a high humidity environment. Both houses with aluminum wiring that convinced me of the necessity were in Florida, as well as the Union electricians I watched use it for a huge commercial installation with their comments "It's required for the inspection".

 

[Javalord1]

Trying to be as thorough as possible, I've Top Balanced and Capacity Tested my first battery build.

I received the cells on 2/11/21. My cells did not come as consecutive numbered items (see table below). I'm assuming this is a sign that they were hand-selected as being similar to each other as all other parameters where identical on the stickers.
View attachment 37167
Many who purchased 272 Ah cells in the same time frame as I received cells labeled as 280 Ah cells. My cells arrived with better hardware - studs and serrated nuts.
View attachment 37169

Here is the setup for the capacity test.
View attachment 37172

Here are my list of cells, and voltages out-of-the-box, after Top Balancing and after shut-off of the Overkill Solar BMS with default settings.
View attachment 37170
After setting up for the capacity test, I drained the batteries to the normal 100% capacity value of 13.3 volts from the Top Balance value of 14.5 volts. Since there is very little energy in this area of the curve, it didn't take long. 3.9 Amp-hours were drained. The capacity meter was reset. I was able to find a combination of loads that gave me 0.2C or 54.4 amps via a Giandel 2200 watt and a space heater and several incandescent and LED lights.

The test ran till the BMS kicked out. The results are:
275.2 amp-hours
3513.4 watt-hours
5:06:18 of time

I'd say that's pretty close to a 0.2C test as I'll ever be able to do again!
Would anyone have any issues with the variability of the voltages in the chart above? Thanks.

 

[MrM1]

Wondering

Noalox vs No-Ox-Id A-Special.

I have No-Ox-Id, I'd have to go buy some Noalox. Which would u use on your Lishen Cells?

 

[Just John]

Wondering

Noalox vs No-Ox-Id A-Special.

I have No-Ox-Id, I'd have to go buy some Noalox. Which would u use on your Lishen Cells?

I'd use what you already have.
I have seen no compelling evidence that any brand is better than any other.
Since I had none, I bought Ox-Gard because it was cheap (under $4).

 

[Inq720]

I'd use what you already have.
I have seen no compelling evidence that any brand is better than any other.
Since I had none, I bought Ox-Gard because it was cheap (under $4).

Is this commonly used? I've not seen this on the forum... or hadn't noticed it.