LiFEPo4 sitting several months NOT hooked up = freaking about self discharge = Brick?

[danewguy]

Mike90250, I'm truly sorry about that. That didn't even cross my mind. Since the link was from the actual manufacturer I got it from I was just trying to show what it was I had.

I'm on the road without a computer and just my phone so I didn't know how to just show a picture.

Seeing as how I was kinda shedding negative light on that very same company it never occurred to me. Honestly. I'm not malicious. Just probably naive and maybe not too bright.

Thanks for your patience with me.

[Raj]

LFP batteries are shipped at 50 to 60% SOC. They have a 1% discharge per month, so like Sunking said, they can go for a year without charging. 27KkWh is about 560AH at 48V so they are discharging about about 6AH per month. That's like nothing.

You really need to get a voltmeter reading so you know where your at. If you want to charge them, and they probably don't need much, I would get a 48V 3 amp LiFePO4 charger like this one ( http://www.batteryspace.com/Smart-Ch...CE-listed.aspx ) and give them 4 to 6 hours charging.

I wouldn't charge them any higher than 60% SOC until they are put into service. I believe you want the voltage between 52 and 53 volts while they are waiting to be installed.

[Willy T]

The problem here is no one knows if the BMS system is active and what it's Parasitic Load drain on the battery is. The Cell boards, Controller and Disconnect solenoid could all be drawing power on top of the self discharge.

Besides knowing the Voltage it would also be nice to know the temperature of the batteries since they are sitting outside.

[danewguy]

Hey guys,

I switched on the enclosure today and I'll list the exact results below. The display has 2 buttons side by side that each cycle through a top or bottom row of basic info. Without a manual, I assume they reflect the top and bottom level of batteries inside??? Or maybe they both represent the whole so you can check two different numbers at once. Cause both rows said the exact same thing as I cycled through both buttons.

" 0 A "
" 0 W "
" 52.4 V "
" 66F Tmp "
" 1.0 Ah "
" 52 Wh "
" E F "
" 0% Fuel "
" 0% SoC "
" 0 A "

I'll also attempt to upload the pictures I took. A couple of things I noticed immediately was:

A) condensation on all the cross bars bridging cells. (stupid question, but how do I wipe them off without shorting anything out or electrocuting myself???)

B) the black squares on every 3 cells (8 on each level = 16 total) (the BMS Sensors???) were all blinking, even though I had the battery bank turned off.

C) the top row and the bottom row had 24 cells each. So the whole bank has a total of 48 cells. (Is that 1 cell for each of the 48V that the system is?)


I went by Home Depot and got a $99 Klein Multi Meter. - Depending on your advice I'll try to check the cells tomorrow. From the looks of the inside of the enclosure I'm not sure how many of the bottom row I can actually reach.

I'm still trying to figure out where I can actually go buy a 48v charger in person instead of having to order one online and wait. Even if I have to drive an hour away to get one. But if this thing is "dead" would there be any special instructions or specific charger to trying to revive it before officially pronouncing it a lost cause?

Thanks

[danewguy]

[Mike90250]

get to a golf course that has cart sales. even a cheap 48V battery maintainer will be better than nothing. And at only 48V, it looks like you are close to having nothing, Even the BMS (which is always on and bleeding power away on this pack) says 0% charge. With the cells low, you dont want to charge them very fast at all, and if below freezing temp where the battery is, you CANNOT charge the cells till they are above freezing (all the way through the pack)

[danewguy]

OK. Aside from getting a 48v charger, what Amp, or Amp rating should I be looking for?

[Raj]

No, it's not 1 volt per cell. It looks like you have 48 180AH CALB's 16 in series times 3 in parallel. A 540 AH bank. I also looks like the bank is at 52.4 volts. Measure it with the meter and see.

[karrak]

I don't think you have to worry about the state of charge of the battery, the overall battery voltage of 52.4 volts equals 3.275 volts/cell (52.4/16) which is around 50% full. Worth confirming with your multimeter. You can make the measurement by placing one of the multimeter probes on the end of the cable coming from the battery to the fuse and the other going to the current sensor.

It is more than likely that the fuel gauge will not start reading correctly until the battery has had its first full charge.

I see several issues with the design and construction of the electronics but they can be looked at later.

Simon

[karrak]

I switched on the enclosure today and I'll list the exact results below. The display has 2 buttons side by side that each cycle through a top or bottom row of basic info. Without a manual, I assume they reflect the top and bottom level of batteries inside??? Or maybe they both represent the whole so you can check two different numbers at once. Cause both rows said the exact same thing as I cycled through both buttons.

" 0 A "
" 0 W "
" 52.4 V "
" 66F Tmp "
" 1.0 Ah "
" 52 Wh "
" E F "
" 0% Fuel "
" 0% SoC "
" 0 A "

This is what I think these figures probably mean
"0 A" is the current going into or out of the battery, zero in this case as the battery is disconnected
"0 W" is the power going into or out of the battery. It is equal to the current x battery voltage
"52.4 V" is the overall battery voltage
"66F Tmp" is the temperature. It would be interesting to know where the temperature is being measured. The sensor should be in the middle of the battery pack so it is measuring the battery temperature not just the temperature in the cabinet.
"1.0 Ah" I would think is something to do with the amount of energy drawn from the battery. I would think that this is reset to zero when the battery is fully charged.
"52 Wh" Is the same as the Ah drawn but expressed as power (battery voltage x Ah)
"E F","0% Fuel" and "0% SoC" are all different ways of showing the amount of energy left in the battery. I would think these figures have no meaning until the battery is fully charged at which the SoC and % Fuel should be set to 100%.

A) condensation on all the cross bars bridging cells. (stupid question, but how do I wipe them off without shorting anything out or electrocuting myself???)

This is a worry, you can see it has already cause some parts to start corroding. I would get the battery out of the damp and dry it out with a fan heater or a hairdryer. Make sure that all the electronics are thoroughly dried out! Be careful not to heat the batteries to more than 100^oF.

B) the black squares on every 3 cells (8 on each level = 16 total) (the BMS Sensors???) were all blinking, even though I had the battery bank turned off.

The black squares are the BMS sensors. If the whole unit had been well designed they should have been turned off when the main switch is off. Hopefully they do not draw much power. If all the electronics draws around 4.5W, and it should draw less than that it would take a year to flatten the battery.

C) the top row and the bottom row had 24 cells each. So the whole bank has a total of 48 cells. (Is that 1 cell for each of the 48V that the system is?)

Has been answered by Raj

I went by Home Depot and got a $99 Klein Multi Meter. - Depending on your advice I'll try to check the cells tomorrow. From the looks of the inside of the enclosure I'm not sure how many of the bottom row I can actually reach.

What is the model of the multimeter?

I'm still trying to figure out where I can actually go buy a 48v charger in person instead of having to order one online and wait. Even if I have to drive an hour away to get one. But if this thing is "dead" would there be any special instructions or specific charger to trying to revive it before officially pronouncing it a lost cause?

I would hold off on the charger. If your multimeter measurement confirms the 52.4 volts that the BMS is showing you then the battery should be OK and not need to have an emergency charge.

Simon

[Willy T]

The Voltage looks ok, ( 52.4 ) I'd bump it up a little and watch it drift back down. The charger won't make much difference unless you intended to use it daily., a 10 amp would be fine. To dry it out, I'd get a fan and move the air around, assuming you had it covered up and it trapped condensation. Using aluminum for Interconnects and Buss Bars would have never been my choice, you can already see galvanic corrosion and cankering on them. One has to assume that at least some of the contact areas have it under them and are compromised. Even the top picture shows there has been condensation on the connections, I'd be trying to figure how it got in there. Over time you'll have lots of problems.

Good Luck.

[danewguy]

Wow. Thanks for all the input guys. It is all invaluable!

The Klein Mutli Meter is model MM2000 from Home Depot. Seemed to have decent reviews.

The Enclosure has spent the winter still in its shipping crate and under a tarp. It's just starting to flirt with spring weather here, and NC is just humid anyway. Although we have had a whole lot more precipitation than usual lately.

I'm gonna go out today and get a charger. I want to use it for a few days and keep an eye on the changes, and so I can sleep at night. When I go back inside the cabinet I'll throw a fan at the insides too.

Due to all the things that have to be done preceding it's initial official use, it may be 2-3 months yet. In the end the battery will be in it's own cinder block insulated room (that I have to build) along with the wall of invertor/charge controllers, etc.

[Mike90250]

Only charge it for a couple hours, then stop and check things . My bad, I'd thought you said you measured 48v, but I'd misread your post. So it's not ultra critical. But if the batteries in the center of the bank are still below freezing (I don't know the local temps) you can't charge lithium batteries below 0 C

[Sunking]

Hey guys,

I switched on the enclosure today and I'll list the exact results below. The display has 2 buttons side by side that each cycle through a top or bottom row of basic info. Without a manual, I assume they reflect the top and bottom level of batteries inside??? Or maybe they both represent the whole so you can check two different numbers at once. Cause both rows said the exact same thing as I cycled through both buttons.

" 0 A "
" 0 W "
" 52.4 V "
" 66F Tmp "
" 1.0 Ah "
" 52 Wh "
" E F "
" 0% Fuel "
" 0% SoC "
" 0 A "

OK all this info is bogus except the Voltage and Temperature. Everything else from the BMS is gibber jabber garbage. At 52.4 volts is an INDICATOR the pack voltage is OK. It does NOT MEAN all the cells are OK. You need to measure and record every cell voltage on a spread sheet. Then look at them all and find the highest and lowest cell voltages. If the range is .05 volts are less you are in fairly good shape, and your BMS might be able to balance the cells. If the range is greater than .01, then you will need to disassemble them, and reconnect all of them in parallel and walk away for a day to let them equalize. Look very carefully for any queer cell voltage. If you find one get rid of it before it blows a cell. A queer cell will be one radically different than all the others, especially any 3 volts or less. If any are at 2.5 or less, you have problem. At 52.4 volts hopefully you will not find any cell less than 3.25 volts or greater than 3.3 volts.

A) condensation on all the cross bars bridging cells. (stupid question, but how do I wipe them off without shorting anything out or electrocuting myself???)

OK this is not very good news, but not a show stopper. It means the batteries were improperly installed, and you need to fix it. Whoever installed them did not use an Anti-Oxidant grease. Bad mistake and poor workmanship. Buy you a small tube of San Chem No-Ox-Id A Special grease. Remove all the intercell-bus bars off the batteries, and apply a light coat of the grease. VERY LIGHT COAT. Be sure to put a light coat on the battery term post. Also use it to coat all wire skinners before compressing terminals. Do this and you will never have any corrosion problems for 50 years.

Pro-Tip: Put the grease in a pan and heat it up until it melts. Then brush on bus bars and dip wire skinners. Also apply a light coat to all power connection points. Again a VERY LIGHT COAT

B) the black squares on every 3 cells (8 on each level = 16 total) (the BMS Sensors???) were all blinking, even though I had the battery bank turned off.

C) the top row and the bottom row had 24 cells each. So the whole bank has a total of 48 cells. (Is that 1 cell for each of the 48V that the system is?)

OK this tells me you have a 16S3P battery. 16S means you have 16 cells wired in series. Each cell is 3.2 volts. So 16 x 3.2 = 51.2 volts aka 48 volt battery. 3P means 3 in parallel. You have Vampire Bleeder Boards with cell temp monitor, the curse of any BMS. You have one Vampire board to Bleed 3 cells in parallel, and you have 16 Vampire Boards. Need to know what BMS and Vampire Boards you have to tell you what the Blinking Light means. You should be able to figure it out yourself. Otherwise tell me what make and model they are.

I went by Home Depot and got a $99 Klein Multi Meter. - Depending on your advice I'll try to check the cells tomorrow. From the looks of the inside of the enclosure I'm not sure how many of the bottom row I can actually reach.

You must measure every cell. Otherwise sale everything you have and get rid of it. You have 16 voltage measurements you must make. One measurement will read 3 cells in parallel. But you must know what each cell voltage is before you can do anything. If they are out of balance, you have a major project on your hands. Refer to above about putting all cells in parallel and walk away for a day.

I'm still trying to figure out where I can actually go buy a 48v charger in person instead of having to order one online and wait. Even if I have to drive an hour away to get one. But if this thing is "dead" would there be any special instructions or specific charger to trying to revive it before officially pronouncing it a lost cause?

Thanks

Very bad idea at this point. You need a charger that can interface with your BMS, and you need to know what the Bypass Current is of the Vampire Boards. Your batteries have sit for a long time. The Vampire Boards bleed your batteries 24 hours a day at different current rates. That throws your batteries out of balance. Most Vampire Boards can only make very small corrections of about 150 ma to 500 ma. We have no idea what you have. For each 1 AH out of balance takes 7 hours to correct with a 150 ma Vampire Board. You have a large battery with 3 parallel cells of what looks like 180 AH total. It is very likely you could have as much as 20 AH out of balance. It would take your BMS 133 hours to balance, and can only do that if it can communicate with your charge to limit current to what the Vampire boards can handle. If you exceed that limit, you will severely over charge over half of your cells and damage them, and/or start a fire. This is why you must know the cell voltages before you do a thing as that will determine your corrective action plan. Don't take it lightly. At a minimum your batteries are at risk if you make a mistake. At most your life and property is at risk.

[danewguy]

Ok. Dude, ur a master! Thank you. Sincerely.

So, new updated plan... tomorrow I chart out and log each individual cell and then I'll post back for ya'lls thoughts.

I did find a couple of chargers online that have integrated BMS. If I were to need to get one of those then at that point I guess I'd need to figured out how to hook it into the battery bank's.

It appears that my current BMS is this one here:

http://minibms.mybigcommerce.com/tem...er%20Guide.pdf