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It might help if you explained what this pack is from; I assume it is from your Phoenix SUT, shown in the second photo.

It appears to have 101 prismatic cells, all connected in series (mostly by short bars, with the occasional bit of cable to connect sections of the pack), and of course also wired with a tap to every cell for the battery management system (BMS). If they are the Altair Nanotech titanate lithium-ion (LTO) cells that Phoenix was supposed to be using, they should have a nominal voltage of about 2.40 V/cell, for a total of about 242 volts for the pack.

If it was the 35 kWh pack, then each cell (and the pack) must have about 145 amp-hour capacity.... but then I have no idea how they thought they could fit the promised 70 kWh optional pack. If it was the 70 kWh pack, then each cell (and the pack) must have about 290 amp-hour capacity.

The BMS appears to be included in the pack, along with the usual contactors and fuse.

There is no visible provision for cooling or heating, either liquid or by air.

What else are you trying to figure out?
 

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Discussion Starter · #3 ·
How to revive them. Most effectively. Separate into 6 cells -s and charge each slowly, then with bench charger at ???v and amp.? I leaning towards that.
Glad you mentioned cooling. There is a water cooling system onboard. I'll grab a pic underneath in a min. I dropped that solo.this morning and had to take a quick minute. Thanks for you help.
 

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Discussion Starter · #5 ·
I do not see any evidence of ever having cooling to batts. Just motors and charge about V management stuff. Possibly because of the type? LTO crastaline cells, very little metal content. Could it be that they do not get very hot? Supposed to bd fast charge so im curious for sure. It is spaced up from floor of tray.
BRAD, WOULD YOU CONSIDER THIS A GOOD BATTERY SYSTEM?
D
 

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How to revive them.
If you need to revive them, that seems to imply that they are currently dead? You are talking about breaking the string down into 6 cell groups and charging each group by itself - but to what end? If they are going to go back into the vehicle, that would be a very strange approach. If you are going to be using the battery bank at their 6s nominal voltage, why not rewire them all into a parallel arrangement and do them all at once? And why exactly would you want a 14.4v nominal battery (if Brian is correct about the cell voltages; and I am going to just assume that he is).

There is something interesting going on here, but it is not yet clear exactly what it is.
 

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Discussion Starter · #7 ·
Musical instrument Electronic instrument Audio equipment Electrical wiring Electronic engineering Musical instrument Electronic instrument Audio equipment Electrical wiring Electronic engineering Hood Automotive tire Grille Trunk Bumper Audio equipment Electronic instrument Musical instrument accessory Technology Automotive exterior so at the front 1st pic I have .9v. at the opposite end of pack w same positive location, 2nd pic.3.2v. and at middle groukind point 3rd pic, 2.3v. This mean anybthing to anyone. Could i just hook up my charger from my boat to this thing? It does have a Ilithium setting? Or am i just totally talking stupidly? Im a charter boat captain. Kind of learning curve here...d
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It means you have some dead cells. I don’t believe you can use a 12v lead battery charger for this. They usually put out about 14.5 volts. Mane 4 in series to jump start them up above 50% but if what was said previously then you need a charger deigned for this chemistry
 

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Discussion Starter · #9 ·
I'm thinking that the cells will be able to balance if charged separate 13.8v groups of cells, 6s. Then let them SIT for a day and charge again. Then parralel the charged and balanced modulesback as designed. Then hook the whole system up to j1772 smart charger and hope for the best. I be charged one 6s module to 9V. From star V of 1.1V. It dropped to 8.7V over an elapsed 30min period after taken off charge. Then it seemed to hold steady. I'll charge the same tomorrow and I think that will work. As always any info is appreciated.
By the way there are exactly 101 cells.
D

It means you have some dead cells. I don’t believe you can use a 12v lead battery charger for this. They usually put out about 14.5 volts. Mane 4 in series to jump start them up above 50% but if what was said previously then you need a charger deigned for this chemistry
Duly noted thank you. I used a charger that has a lithium setting. For 12volt car/ boat baths. As a trial run. I removed 5 s cells after considering 6s. So an 11v-12v module @ 2.2v- 2.4v per cell. This may be wrong, as the system seems to be built on a 6s format. However the staggered effect when reintroduced with overlap may help balance out cell voltage overall? My goal for now is to achieve 9volts retained, each 5 cell s module. Then connect as original , same format, and charge the entire pack.
 

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Discussion Starter · #10 ·
As for the charger...
I have two Eltek 3kw "valerie" HE charges onboard. It seems to mme they were not starting charge likely due to the BMS and CAN protocols. If I unhook the BMS and same from chargers, I may be able to charge with the brains built into th onboard charger? Until I can get enough voltage in the pack for the system to accept charge via J1772 inlet.
 

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Discussion Starter · #11 ·
If anyone sees a Fatal error in my reasoning please, somebody stop me.! 😐 these components have no manufacturer or integration support, they actually Cannot... support the particular units used.
 

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Discussion Starter · #12 ·
The folks at CosLight who made the BMS units used and the BVT-H units , 6 of those probably can huh? Bingo. China or Korea would likely not be constrained in by whatever is dampening any helpful motivations by Phoenix MC , Altair nano, Eltek to a lesser degree, and BQM. All US companies. I don't know. Worth a shot.
Im going to almost certainly require updated can program and a synchro motot(s) controller. The one on board is stamped "expermental useage only" do not replicate. Marching on....
D
 

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This shows the voltage across a set of ten cells in series, with essentially zero voltage. These should be at 24 volts nominal, so if the typical operating range is 1.8 to 2.85 V/cell then ten should run something like 18 to 29 volts depending on state of charge. There is presumably at least one completely failed (open circuit) cell in there somewhere. A discharged but okay cell is at about 1.8 volts; near zero voltage means dead, not just discharged.

I suggest checking each cell individually to see which ones are bad... in the whole pack. There are 101 cells, but it will still take less than an hour if those are exposed points at each terminal for the meter probes, or if the BMS taps are all accessible to the meter probes.
 

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If the LTO cells are not salvageable, and you can find prismatic cells in a close enough size, you could entirely replace the cells in the same pack. You would only need about 75 LFP (LiFePO4) cells or about 67 cells of other lithium-ion chemistries, but you would have to make the BMS work with fewer cells and different cell voltages... or replace the BMS.
 

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Discussion Starter · #15 ·
Well I'm getting to them . Had to build as tentbfir shade and get the whole he's y thing up on a flat top . It's 150° in the darn shade here in sw FL.! Anywho...
Yes I ha be checked randomly. I.3, 1.2 1.7 1.8, .9v, ect... So yes I will test each one per like you recommend. Possibly group them by condition. I did charge 5 cells in Series for about 30mins with a smart charger on lithium setting. 10 min cycles. Restarting in test mode each time. Brought them to 11.1V. Module V. This held for 3 hrs. Then began falling off 11V per hour until they balanced at 8.8V and holding. I'll let them rest then charge again tonight slow. Hopefully that will do it! This test batch was the lowest, 2 of them were .9 V. But they balanced...
What do you think about charging in parallel if they don't balance in series?
 

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What do you think about charging in parallel if they don't balance in series?
Good cells can be charged in parallel, and most EVs have two or three cells in parallel... but if one is bad, it's not a good idea. I would want to get them sorted out before parallel charging anything.
 

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Discussion Starter · #17 ·
Well i have the pack and tray up on a 4x8 utility trailer, just in case I have to haul it to a n EV friendlier stare for service. Just kidding Florida is fine... i was tired of leang down.
Anywho...
The LTO cells were reading .1v and some read .07V. I got tired of a writing each down. .47V was the highest module V reading .
So I have charged two- 6 cell modules and they are holding charge. I hooked a trollling motor to each module in order to discharge under load. That seemed to cause them to take higher charge and retain the voltage afterwards.. I used a automatic 100amp charger with STNRD, AGM, and LITHIUM battery type settings. 6v 2a, 12v 30a, and 12v 100amp choices for output.. Initially volts were reading. 0.32V > across the Module!
So I used a 6v -2amp setting and the charger "cycled' up and down for about two mins untill it began to charge at 6v 2a. Stopped charge afger 1hour and they read 8v. Let SIT overnight and then did same thing- 1hour at 6v 2a because they had discharged to 2..1v aacross the module (6s). Then let SIT for 30 mins and hit start 100amp cycle for 1min. Twice. Overnight they settled...volts @10.1v early next day. Loaded module and discharged it to 7v. Hooked modules back too the Charger - set on auto lithium setting- set to the 30 amp smart setting, untill charger said "Ready" and went into maintenance mode. Checked module with a good volt meter-- 13.8v. EXACTLY. On the money.
As of now 4 Hours later at 3:30pm, (modules have been disconnected from charger) each module reads 13.35V.
7:20pm -- 13.2V and 13.1V... > So I gave each module another 2 mins jump @ 100amp start mode and they are back at 13. 8v. Nice. I'll find out in the morning. Hope fully I have a recipe that works .
Only15 or so more modules to go....
 

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Honestly I thought this pack would be bricked and charging them would be dangerous but looking into lithium titanate cells; unlike most other lithium cells, can be stored at 0 volts and be perfectly fine. All of the cells should come up to their normal capacity and function after you charge them up.

@CaptD I think you have a good plan reviving the cells as you have been doing just make sure not to overcharge them, the lithium setting on your charger might be too high for LTO cells.

Article: Effect of Zero Volt Storage on Commercial Lithium Titanate Cells - Effect of Zero Volt Storage on Commercial Lithium Titanate Cells - IOPscience

Makes me want to find one of these trucks with a dead battery and try to pick it up cheap...
 

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Discussion Starter · #20 ·
Thanks for the link. Once I disconnected every piece of hardware and all the leads, leaving only the batteries in series and parrrelell, the entire pack is taking a charge. It started (with two testers attached -neg ground in the middle) cycling through 2.4v and rapidly dropping to.37-.55v. It would not On out and Then, a rapid increase to 2.2-2.5v. Now it's steady- ish. Reads 9.8v and rising but some times nothing. I hope this is balancing cells. we shall see. My fingers are crossed
D
 
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