The BYDs from Batteryclearinghouse have arrived.

[Supervstech]

I am contemplating going up to 2.7v per cell... but I don’t think exceeding 2.65 is a good plan...

if it hangs in well at 28, I may take it to 29.2... and see where they settle at the recommended top charge of3.65 before tempting fate...

 

[jasonhc73]

Hmmm

I am working on them 24v at a time, I will charge to 26.4 one day, then up to 27.2 then to 28 then to 28.8
test each cell voltage after I stop charging and log it on my notepad.
So far, no weak cells, no voltage drop after charging...

I don’t want to damage any cells, so I am being very slow charging.

Keep in mind these are used batteries and being recycled for a reason. I'm not at all worried about the one cell I found as being crapped out by manufacturers specs. I let the little ISDT BatteryGo try to balance for a couple of hours, kind of like using a sippy straw to drink from a horse tank.

Right there at that 20% is where I want to keep my bottom end, and going past 90% serves very little to adding usable energy.

 

[Maast]

It's been a week since I got mine and I'm still busting my hump getting them down to the basement. I knew they were going to be heavy but holy crap, they're HEAVY - I should have been thinking of "they're as heavy as picking up two 80lb sacks of concrete at the same time"

To make matters worse I've got a 20 inch lip on the small exterior basement door hatch so I have to put them in a wheelbarrow, push it around the side of the house and down a slope and then manhandle them through the door onto another wheelbarrow I've put blocking to get it level with the hatch lip then squeeze inside, wheel it over to where the holding stack is and pick them up, shuffle over a couple steps then stack it. I'm no bodybuilder hulk but I'm no girlyman either and after I've moved 3 of those I'm flat done for the day and my back is screaming at me.

 

[Keith C]

Thanks for the info Jason.

T'wer me I'd keep all your batteries in service. That allows you to UPS your entire house thru utility failures. 22 hrs! Just cut back a little during a blackout and you'll have 24 hour cycle-ability. That lets you run a generator for a couple of middle-of-the-day hours to keep the place running smoothly, even thru days of blackouts. Perhaps an ice storm or maybe the Aussie style of too much wind or solar on the grid causing instability and a system-wide collapse.

I assume you're BMSing each 48V set?
If so what are you using for 'a bunch of BMSes'?

 

[Keith C]

Geez Maast! At least this method will prevent us from seeing you like a squished bug under a pack at the bottom of a dark, narrow, creaky, stair case.

 

[batteryclearinghouse]

Jason.. any chance you can get some ballpark temperature numbers that your seeing when you cycle them?

The heat sinks do not applying any pressure on the cells to keep then compressed. The two green strapping bands that do that.

There someone who has separated them into two 12 volt battery packs and re-strapped them back together into two different packs. They left the bus bars in place, but it got me thinking about the potential of tapping the individual cell terminals for a bolt.

It's hard to explain but the slight expansion we are talking about when the straps are removed comes from the sides of the cells when the pressure is released.. not the Top or Bottom.

BYD does make batteries for buses. The ones we are all talking about are from a solar farm deployment.

 

[Steve_S]

Jason.. any chance you can get some ballpark temperature numbers that your seeing when you cycle them?

The heat sinks do not applying any pressure on the cells to keep then compressed. The two green strapping bands that do that.

There someone who has separated them into two 12 volt battery packs and re-strapped them back together into two different packs. They left the bus bars in place, but it got me thinking about the potential of tapping the individual cell terminals for a bolt.

It's hard to explain but the slight expansion we are talking about when the straps are removed comes from the sides of the cells when the pressure is released.. not the Top or Bottom.

BYD does make batteries for buses. The ones we are all talking about are from a solar farm deployment.

Hi Guy !
"still standing by on what you find out from UPS etc" LOL... hesitantly anxious ? maybe.
I would like to know if you do figure out if it's possible to tap the terminals for bolts (I'm not holding my breath though) because that would make more things possible without a doubt.

Good to hear the cells do not expand on "all sides" which is what it looked like in that breakdown Video. Although I would still be somewhat concerned for the exposed cell sides being protected from "injury" but that can be resolved easy enough. I can just picture laying the cell pack down on a surface and a nail or screw being under there and damaging the cell side walls. You know "stuff happens" dept. operate by Murphy under his laws.

 

[jasonhc73]

I discovered one of my cells, in one of the packs is a poor performer.

While all the cells in my 2 pack series (16S) are happy around 3.210, one is sad and down to 3.193.

What difference do 17 millivolts make, you say?

It means the entire set shows up to the inverter as 51.088V instead of 51.360V.

A chain is as strong as it's the weakest link and a battery voltage is the voltage of it's lowest cell times how many cells it has.

In my BYD pack, you get what you get, if you leave it in the pack. Dismantling will certainly result in a higher total V for the inverter to work with.

If I dismantle the pack, in the end, I get to remove the dud cell and ultimately have a 16S3P setup instead of a 16S4P. Or just leave the dud in the pack and not go to the 0% DOD, just artificially set the lower limit on the BMS.

I have 64 cells of BYD (8 BYD packs). I am able to see and monitor 24 cells for now, and by the end of the week will have all 64 monitored.

Now, just wrap your mind around this - my cost vs "Battleborn" = 3/64th = or less than 5%(4.69%) of the cost of something new. It takes 4 Battleborn to equal 1 BYD pack.

 

[jasonhc73]

Jason.. any chance you can get some ballpark temperature numbers that your seeing when you cycle them?

The heat sinks do not applying any pressure on the cells to keep then compressed. The two green strapping bands that do that.

There someone who has separated them into two 12 volt battery packs and re-strapped them back together into two different packs. They left the bus bars in place, but it got me thinking about the potential of tapping the individual cell terminals for a bolt.

It's hard to explain but the slight expansion we are talking about when the straps are removed comes from the sides of the cells when the pressure is released.. not the Top or Bottom.

BYD does make batteries for buses. The ones we are all talking about are from a solar farm deployment.

I am seeing nothing above room temperature. Last week I discharged them under max load, and that was the only time it was warmer than room temperature. Under normal load, they are just room temperature.

Temp sensor1 (T1) is ambient, Tempsensor 2 (T2) is stuck onto the B- blue at the terminal.

 

[Maast]

You gonna aggregate the cells into groups like Poz did? Any weak cell will be helped out by its brothers in its group. An active balancer would help too.

Weak cells are why I'm going to test each module so I can identify the weak cells so I can spread them out among the two 'layers' and I've got a spare module so when I find the worst one I can pull it.

Going to take forever to test each module though. And I'm still waiting for my Meanwell psp-600-27 power supplies from ebay to show up to charge these things. Ordered on the 16th and still not here.

 

[jasonhc73]

You gonna aggregate the cells into groups like Poz did? Any weak cell will be helped out by its brothers in its group. An active balancer would help too.

Weak cells are why I'm going to test each module so I can identify the weak cells so I can spread them out among the two 'layers' and I've got a spare module so when I find the worst one I can pull it.

Going to take forever to test each module though. And I'm still waiting for my Meanwell psp-600-27 power supplies from ebay to show up to charge these things. Ordered on the 16th and still not here.

Once a cell is weak it is weak, this is the first cycle with the bms on. A damaged LiFePo4 is a one way process. There simply is no way to "fix" it, but it is easy to work around it.

I've been cycling for two weeks daily. And monitoring each cell with 20 measurements, the top end charges the cells to capacity and my weak cell matches the rest all within 1 or 2 millivolts. Yesterday Will put up a video at battleborn and the Ceo really made it clear showing why it is not very important to be concerned about balanced. And why once it's "broke" it can't be fixed.

 

[batteryclearinghouse]

Measuring the internal resistance on that battery pack as compared to others would be interesting to see. It might give some insight if the lower cell is having an impact or not.

 

[Maast]

Once a cell is weak it is weak, this is the first cycle with the bms on. A damaged LiFePo4 is a one way process. There simply is no way to "fix" it, but it is easy to work around it.

True, but having cell groups will help 'average out' weak cells and give you a greater range of charge/discharge instead of being limited by the weakest cell.

 

[Keith C]

17mV? I think your math is screwed up? 17mV doesn't make any difference. That's probably typical.

Maybe you meant 51.360 - 51.088V = 272mV? That's significant!

 

[Keith C]

Hi Jason. Nice setup there. Thanks for the tour! Rosco's a cutie too.

Have you found a way to stop those *&#$*MPP inverters from beeping insanely every time you push a button? I want to beat on mine every time theybeep. Hell, my neighbors probably want to beat on it too! (What were they thinking??!)

With those 5048s what's the most current you expect them to draw?

Do they both try to charge the batteries at the same time if on-grid, or do you leave one off and the other on charging?

It looked like you only had about 4 wires going to the battery cell taps connector. What am I missing? Are you using the original connector? If so what's the mating one you found that works?

 

[jasonhc73]

Hi Jason. Nice setup there. Thanks for the tour! Rosco's a cutie too.

Have you found a way to stop those *&#$*MPP inverters from beeping insanely every time you push a button? I want to beat on mine every time theybeep. Hell, my neighbors probably want to beat on it too! (What were they thinking??!)

With those 5048s what's the most current you expect them to draw?

Do they both try to charge the batteries at the same time if on-grid, or do you leave one off and the other on charging?

It looked like you only had about 4 wires going to the battery cell taps connector. What am I missing? Are you using the original connector? If so what's the mating one you found that works?

USB cable to a computer and the software. No beeping! Try program 18 off, that might turn off the button beeps.

I did a max load test already, 35 AMPS A/C which pulled 92 amps DC from my battery pack.

My MPPs are in parallel, so everything is synced with the settings, except one setting, program 11, utility charging. One can be 10 and the other 20 amp, the battery gets 30 amps. The software from the computer fails most of the time on that one setting. But the beeping panel works every time.

I used a plumbing pipe to connect to the batteries. 1/2 inch L series. (L has thicker walls than M or N) . I cut them about a hands width long, pressed the ends together, and drilled a hole. Then hammered them onto the battery terminal. A very snug fit. I used 1/0 copper welding cable.

 

[jasonhc73]

Measuring the internal resistance on that battery pack as compared to others would be interesting to see. It might give some insight if the lower cell is having an impact or not.

Now that I have a monitor on each cell, it's neat to see the entire pack show the voltage exactly 16 times the lowest cell. I would like to know the resistance of each cell also. But that means taking all the covers off to measure each cell, right?

 

[jasonhc73]

True, but having cell groups will help 'average out' weak cells and give you a greater range of charge/discharge instead of being limited by the weakest cell.

The entire pack measured voltage is exactly the lowest voltage cell multiplied by how ever many cells are in the series.

Get an enormous parallel set and it quickly becomes irrelevant.

48V 880 AH is enormous. Limit the measurement to 75% of the new capacity, and 48V 660AH is still enormous.

 

[Keith C]

Thanks for the answers! I'll try 18 but I remember the instructions saying "set this this way and all alarms will be silenced" only to find it ONLY silenced alarms not the heinous beeping.

How did you get to each cell to monitor it?




Do I only see 4 wires? For 8 cells? Are you using the original connector or something else?

 

[jasonhc73]

Thanks for the answers! I'll try 18 but I remember the instructions saying "set this this way and all alarms will be silenced" only to find it ONLY silenced alarms not the heinous beeping.

How did you get to each cell to monitor it?

View attachment 4680


Do I only see 4 wires? For 8 cells? Are you using the original connector or something else?

You see the top half of a ten pen molex Micro-Fit 3.0 connector. The top half are the odd cells, 1-7, right to left, the bottom half are the even cells, 2-8, right to left.

The two empty spots on the left are not connected, those two go directly to the 24v case fan.

I used the connector on the left, it is a machine wire insert part, I had a very hard time getting the crimped wires installed.

The 3 parts on the right are these molex parts:

The molex parts:
https://www.molex.com/molex/products/datasheet.jsp?part=active/1729531001_ACCESSORIES.xml
https://www.molex.com/molex/products/datasheet.jsp?part=active/1729521001_CRIMP_HOUSINGS.xml



I just made 6 connectors in the time it took me to crimp 8 wires just now with the right parts!