I just destroyed $500 worth of batteries by doing nothing.

Barbar0ssa

Solar Enthusiast
Joined
Mar 3, 2021
Messages
77
They never overcharged and never were heated beyond 90f. They were magically over discharged.

I followed the previous advice and charged each one up to about 3 volts (till the cell was taking less than an amp). Now they're all in parallel and I am charging them to 3.1.


PXL_20210908_222716954.MP.jpg
 
Last edited:

sunshine

Solar Addict
Joined
Apr 24, 2020
Messages
456
Maybe owners of these batteries should reconsider the container they use to build or store in since there is reported v leakage to the case. some cases are the negative terminal,
A plastic tub as in op's photo, even with drainage holes, may provide a current path across batteries in series at any sign of moisture.
 

Barbar0ssa

Solar Enthusiast
Joined
Mar 3, 2021
Messages
77
Maybe owners of these batteries should reconsider the container they use to build or store in since there is reported v leakage to the case. some cases are the negative terminal,
A plastic tub as in op's photo, even with drainage holes, may provide a current path across batteries in series at any sign of moisture.
I am definitely a newbie. Right now they are in parallel and the cases are positive on these cells. Do you see a risk in this current resurrection attempt?

How should I contain them?
 

OM617YOTA

Solar Enthusiast
Joined
May 27, 2021
Messages
112
Is that tape across the top of the cells? Is it ESD tape, by chance?

I ask because ESD tape is conductive.
 

sunshine

Solar Addict
Joined
Apr 24, 2020
Messages
456
How should I contain them?
It just looks like a accident waiting to happen holding these batteries, series connected across the top, when they are sitting in water proof containers. If not a total short, may cause the BMS to behave erratically if water gets in and covers the base.
Lead acid batteries are ok because of zero conduction through their outer cases up to just below the terminals.

How should you contain them?
Need someone with these batteries to advise since I am still on lead acid.
Those photos in your post may change the general common practice of tub storage.
 

fblevins1

Solar Enthusiast
Joined
Aug 14, 2021
Messages
92
Ugh - ditch those clip leads. Make proper connectors, even for something as simple as this.
I use clips for my battery sense terminals but all it is drawing is 16 mA so no big deal. I think as long as the OP is monitoring the current the connection will be OK, but....clips can slip and where they go when they slip could be a problem, so you ain't wrong. I admit when I was doing testing I was having to move things around a lot and it was easier to use clips, but once I settled on a configuration, from there it was heavy gauge and torque those connections down. Sometimes you have to be a bit of a gun slinger and get the job done.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,434
Location
Rural NE Ontario Canada
I am definitely a newbie. Right now they are in parallel and the cases are positive on these cells. Do you see a risk in this current resurrection attempt?

How should I contain them?
You are doing fine, taking it nice & easy, from your update they seem to be behaving. There is no chemical leakage or anything and very little to worry about at this stage.

Once you get the cells up to 3.650 (I would stick to 3.600 myself) and fully saturated (meaning taking <2A) and stop charge current. The cells WILL SETTLE which is perfectly normal & expected behaviour. They will likely drop to about 3.500 from 3.600 within 1 hour or so, give or take a bit. They will usually continue to settle till around the 3.400-3.450 mark where it will slow considerably as the LFP Working Voltage range is 3.000-3.400.

Once this is done, I would setup the pack temporarily with the BMS and discharge the battery pack to cutoff, then recharge through the BMS till it reaches full at a respectable Amperage. 150AH Cell can typically take a Max of 0.5C or 75A charge rate. 20-40A Charge rate would be as high as I would go "for now" while determining their condition.

You are getting there !
The dents are concerning BUT they are NOT a "stop the show deal" either. Here's the acid test on that one... When charging at a higher amperage the cells heat up (normal & expected) and the higher the amps the warmer they get. With ESS cells @ 0.5C it's never crazy ! EV Grade Cells @ 5C Charge Rate = another matter ok. We are dealing with ESS cells here, so staying "in context". You will want to check the cells during Higher Amp charging feel the sides etc, they should be consistent / constant... a Hot Spot = Warning Flag ! You WILL NOT GET THAT with Lo Amp Charging, it has to be at least 0.25C and the temps should be notable within 1/2 hour or so. Be diligent & watchful !

Even 3 years ago, various shrink wrap colours were used by manufacturers, some had different properties (toughness/thickness/UV Stability etc) and it was not uncommon to see a variety. The majority of companies have now settled in a standard type/class which is why most are blue-skinned now. The material can be bought in rolls, it is available as a Heat Shrink or adhesive wrap.

If you are concerned about Cell Separation & Isolation as well as lining a Casing if it is Conductive, then I suggest using what is appropriate for the purpose and not some bodge option from a Buck Store some folks suggest... Please have a look at this.
https://diysolarforum.com/threads/lifepo4-cell-separator-material.28023/

Hope it helps, Good Luck
Steve
 

Barbar0ssa

Solar Enthusiast
Joined
Mar 3, 2021
Messages
77
What wonderful feedback and information! Thanks so much!

I have been charging at about 15w for a few days now and it will probably take another week to fill at this rate but I'm not in a hurry. Every 24 hours or so I measure the pack and it is at 3.2v and I'm sure it will stay there for days.

PXL_20210912_221218522.jpg
 

upnorthandpersonal

Administrator
Joined
Dec 25, 2019
Messages
2,253
Location
63 degrees North, Finland
Do you have any suggestions of what to use in place of those clips? Only asking because I am waiting for this very power supply to arrive.

Ring terminals on both sides (battery and power supply). The plugs at the power supply screw off to attach a ring terminal behind, like is done here:

a4649387-200-IMG_1088.jpg
 

A.Justice

Swears he didn't start that fire.
Joined
Sep 12, 2020
Messages
608
Location
TN
While I am running 15w the wire gauge should be ok (I think) but you are right I will put on rings. Parts on order.
It's not just about the wattage or amperage running through the cable. Those clips add a point of high resistance, and can mess up the voltage reading inside of the power supply, causing your cells to over, or under, charge.
 

Barbar0ssa

Solar Enthusiast
Joined
Mar 3, 2021
Messages
77
Well, I made some 12 awg leads with ring terminals and it made quite a difference without changing anything else!

Before:
PXL_20210916_003014751.jpg

After: PXL_20210916_004008211.jpg

Looks like 3.6 days to charge the remaining 80% at this rate. Should I keep charging at 10 amps or should I decrease the current setting?
 

A.Justice

Swears he didn't start that fire.
Joined
Sep 12, 2020
Messages
608
Location
TN
Well, I made some 12 awg leads with ring terminals and it made quite a difference without changing anything else!

Before:
View attachment 64835

After: View attachment 64836

Looks like 3.6 days to charge the remaining 80% at this rate. Should I keep charging at 10 amps or should I decrease the current setting?
My power supply tapers off as it gets towards 3.6v. I leave mine on the full 10 amps (actually I leave it on 9a, so I'm not maxing out the power supply) and by the time it's almost charged it's down to 1-2a.
 

Horsefly

Photon Sorcerer
Joined
Dec 12, 2020
Messages
918
Location
Denver, mostly
My power supply tapers off as it gets towards 3.6v. I leave mine on the full 10 amps (actually I leave it on 9a, so I'm not maxing out the power supply) and by the time it's almost charged it's down to 1-2a.
It probably won't be popular here, but I think I should throw this out: The quality of the leads and the ring terminals vs. alligator clips can make a difference, but not much and not the way most people think.

If you think about it, you have your charge source set to the right voltage, and you connect it to your cells. No matter how good the connection is or how good the wires are, there will be some resistance in the wire and therefore some voltage drop between your charge source and the cells. Ok, fine.

As time goes by, the difference between the voltage of the charge source and the voltage of the cells goes down. By definition (ohm's law) the current between the two goes down. Eventually the cells and the charge source are at the same voltage, so there is no current between the two, so there is no voltage drop on the wire. That means that the cells are charged to what you have the charge source set to, no matter how tiny the wires are that connect them.

So, what does using really good ring terminals and really big wire do for you? It allows the process to go a bit faster. Does it make the end result any better? Absolutely not.

This discussion (about charging your cells initially) is not at all related to how you deploy your cells to an operational system. It is critical that the connections and wire be appropriate to minimize the losses in your system. Different situation, different answer.

 

Bob B

Photon Sorcerer
Joined
Sep 21, 2019
Messages
3,379
It probably won't be popular here, but I think I should throw this out: The quality of the leads and the ring terminals vs. alligator clips can make a difference, but not much and not the way most people think.

If you think about it, you have your charge source set to the right voltage, and you connect it to your cells. No matter how good the connection is or how good the wires are, there will be some resistance in the wire and therefore some voltage drop between your charge source and the cells. Ok, fine.

As time goes by, the difference between the voltage of the charge source and the voltage of the cells goes down. By definition (ohm's law) the current between the two goes down. Eventually the cells and the charge source are at the same voltage, so there is no current between the two, so there is no voltage drop on the wire. That means that the cells are charged to what you have the charge source set to, no matter how tiny the wires are that connect them.

So, what does using really good ring terminals and really big wire do for you? It allows the process to go a bit faster. Does it make the end result any better? Absolutely not.

This discussion (about charging your cells initially) is not at all related to how you deploy your cells to an operational system. It is critical that the connections and wire be appropriate to minimize the losses in your system. Different situation, different answer.
I agree with pretty much all of that .... but would add that one of the things that causes the cells to be damaged during top balance is loss of patience .... so lets crank up the voltage on the power supply a little to speed things up.

The other thing is .... hey, I'm not getting anywhere near as much current as I should be .... so, lets crank up the voltage a little to get more current.

I was having problems with getting the current I should be from my power supply .... replacing the crappy alligator clips pretty much doubled my current.
 

Bob B

Photon Sorcerer
Joined
Sep 21, 2019
Messages
3,379
It probably won't be popular here, but I think I should throw this out: The quality of the leads and the ring terminals vs. alligator clips can make a difference, but not much and not the way most people think.

If you think about it, you have your charge source set to the right voltage, and you connect it to your cells. No matter how good the connection is or how good the wires are, there will be some resistance in the wire and therefore some voltage drop between your charge source and the cells. Ok, fine.

As time goes by, the difference between the voltage of the charge source and the voltage of the cells goes down. By definition (ohm's law) the current between the two goes down. Eventually the cells and the charge source are at the same voltage, so there is no current between the two, so there is no voltage drop on the wire. That means that the cells are charged to what you have the charge source set to, no matter how tiny the wires are that connect them.

So, what does using really good ring terminals and really big wire do for you? It allows the process to go a bit faster. Does it make the end result any better? Absolutely not.

This discussion (about charging your cells initially) is not at all related to how you deploy your cells to an operational system. It is critical that the connections and wire be appropriate to minimize the losses in your system. Different situation, different answer.
I agree with pretty much all of that .... but would add that one of the things that causes the cells to be damaged during top balance is loss of patience .... so lets crank up the voltage on the power supply a little to speed things up.

The other thing is .... hey, I'm not getting anywhere near as much current as I should be .... so, lets crank up the voltage a little to get more current.
So ..... the crappy leads can definitely affect the outcome.

I was having problems with getting the current I should be from my power supply .... replacing the crappy alligator clips pretty much doubled my current.
 

Horsefly

Photon Sorcerer
Joined
Dec 12, 2020
Messages
918
Location
Denver, mostly
I agree with pretty much all of that .... but would add that one of the things that causes the cells to be damaged during top balance is loss of patience .... so lets crank up the voltage on the power supply a little to speed things up.

The other thing is .... hey, I'm not getting anywhere near as much current as I should be .... so, lets crank up the voltage a little to get more current.
So ..... the crappy leads can definitely affect the outcome.

I was having problems with getting the current I should be from my power supply .... replacing the crappy alligator clips pretty much doubled my current.
Yep. Not understanding can lead to not good results. Agree with you completely @Bob B. However, understanding can make it so the intermediate and final results make sense to you. Ohms law is your friend. ;)
 
Top