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BAE-200 Powerwall
#11
If you are mixing 14s Lithium Ion and 16s LiFePO4 in parallel, they should be ok together, but I wouldn't let it run wild without testing on both the top end and bottom end of the voltage range to make sure everything agrees.

Using an APC you don't really have much customization of charge termination voltages so do keep a close eye. Personally I would want to limit both the top end and bottom voltages to try and extend life of the cells and give myself a little runway for saftey.

If you have a multimeter with a USB logging capability or a few CellLog that actually record data, you can capture what is happening during the APCs max charging and float voltages assuming you are charging using the APC and not just using it as an inverter.
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#12
I found a hack to add a variable resistor to adjust the top voltage on the APC. The low voltage cutoff is not adjustable but seems to be around 40V so for 16s lifepo4 that is 2.5V  per cell which should be OK, on the 14s 18650 that will put me at 2.85V a tad lower than I like. I  think if i build a 13s pack instead of a 14S for the 18650   and set my top voltage to 54V the top voltage per cell for the 16S Lifepo4 will be 3.3v  and Lipo at 4.15, the low will be 2.5V for the Life and 3.0V for the 18650.  This seems like a good compromise  to keep both  cell types within their safe operating voltage.
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#13
Please post more details about the variable resistor modification / hack... I wouldn't mind trying that myself.
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#14
(08-24-2018, 05:49 PM)Crimp Daddy Wrote: If you are mixing 14s Lithium Ion and 16s LiFePO4 in parallel, they should be ok together, but I wouldn't let it run wild without testing on both the top end and bottom end of the voltage range to make sure everything agrees.

Using an APC you don't really have much customization of charge termination voltages so do keep a close eye.  Personally I would want to limit both the top end and bottom voltages to try and extend life of the cells and give myself a little runway for saftey.

If you have a multimeter with a USB logging capability or a few CellLog that actually record data, you can capture what is happening during the APCs max charging and float voltages assuming you are charging using the APC and not just using it as an inverter.

No mixing on the same system. Really bad idea. Each system will need their own charge controller and inverter or you will lose capacity to the lowest denominator. This simple math fellas.  Is it possible? Theoretically yes. is it smart? Fuck no.
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#15
Does anyone know what the total series count is on these BAE A123 modules? 12s?

I just got mine... but don't have time to crack them open just yet. I wanted to do a complete charge/discharge cycle as assembled to see how much life is left in these things.

(08-26-2018, 05:51 AM)Solexx X Wrote:
(08-24-2018, 05:49 PM)Crimp Daddy Wrote: If you are mixing 14s Lithium Ion and 16s LiFePO4 in parallel, they should be ok together, but I wouldn't let it run wild without testing on both the top end and bottom end of the voltage range to make sure everything agrees.

Using an APC you don't really have much customization of charge termination voltages so do keep a close eye.  Personally I would want to limit both the top end and bottom voltages to try and extend life of the cells and give myself a little runway for saftey.

If you have a multimeter with a USB logging capability or a few CellLog that actually record data, you can capture what is happening during the APCs max charging and float voltages assuming you are charging using the APC and not just using it as an inverter.

No mixing on the same system. Really bad idea. Each system will need their own charge controller and inverter or you will lose capacity to the lowest denominator. This simple math fellas.  Is it possible? Theoretically yes. is it smart? Fuck no.

Im not here to argue, but you are being a bit extreme.  If you know what ur doing and design it right, it's fine.

I've done it, and ive seen it done before plenty of times.  You don't need a separate charge controller or inverter.

Even with differently chemistry such as lead acid... it really is fine, all that happens is the bank with a lesser resistance ends up dishing out more current than the other.  With both in parallel, they just end up equalizing anyways.

Control the top and bottom voltages so they are within a SAFE range of both packs and then give yourself a little more headroom.

The key take away is that you don't want to draw high currents, at low drain currents, it's a non issue and both bank stay equalized.  If you are uncomfortable with it don't do it.  

I'll agree that it's not ideal, but it does work just fine.  The only thing I would do is have separate combiner switcher and separate BMS per bank.  I did this when I had two separate battery banks.  Bank A (LiFePO4) and B (6v deep cycle lead acid), both 48v total pack voltage, and I ran both in parallel for ages before I decided to retire the older Lead Acid stuff.
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#16
yes its a 12s8p pack
below is some pictures of teardown


When you take apart I found out if you cut the negative nickel strip and cover the negative tip of cell with electrical tape you reduce the risk of shorts to almost zero. You have to do them all at one time(both sides) and continue to slowly take apart. Its alot of extra work but the only safe way to do it. I had 2x96 packs to take apart, the first one was where I had all the problems, the second pack where I covered all the negative tips with electrical tape it went smoothly with no incidents. 


On this picture, the first cell you can see a small hole on the insulation where a short occur. The next 2 cells are the same cell of where a short occur and then a fire started. When the short punctured the cell , the pressure started to escaped and then the fire started. I poured water on it and it put it out but reflash when you stop pouring water. Fire will finally die out when the all the pressure has escaped. Have alot a water available just in case, to at least keep the cells cool down until the pressure dies down. 
 

As far as MAH, of the close to 200 cells the majority where in the 1700/1800 in one pack 1500/1600 on the other pack, but a few as low as 1400 and some as high as 1900. Still usable, they all performed well on the charger, charge and discharge quickly and most seem to hold there charge. I used the opus btc3100 to test them, you have to open up the charger and there is a small switch you have to toggle to 3.7 volts. I had to buy some 26650 holders (about 8 for 5 dollars) .
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#17
@jonyjoe505

Thanks for the post and for the photos they were very helpful. I'll be sure to follow your advice.

My plan was to leave two of the 4s chunks alone to make some 12 volt packs and use the rest for smaller projects. Excited to have some Pb compatible voltages.

Thanks for the test report too, I guess I was being a bit overly optimistic hopefing for close to the 2300mah but I guess 30% average degredation isn't bad... My packs have a 2008 date on them, I'll test and see what I get.

I'll probably test he full module as it first just to see what how it preforms.
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#18
(08-31-2018, 03:16 AM)jonyjoe505 Wrote: yes its a 12s8p pack
below is some pictures of teardown


When you take apart I found out if you cut the negative nickel strip and cover the negative tip of cell with electrical tape you reduce the risk of shorts to almost zero. You have to do them all at one time(both sides) and continue to slowly take apart. Its alot of extra work but the only safe way to do it. I had 2x96 packs to take apart, the first one was where I had all the problems, the second pack where I covered all the negative tips with electrical tape it went smoothly with no incidents. 


On this picture, the first cell you can see a small hole on the insulation where a short occur. The next 2 cells are the same cell of where a short occur and then a fire started. When the short punctured the cell , the pressure started to escaped and then the fire started. I poured water on it and it put it out but reflash when you stop pouring water. Fire will finally die out when the all the pressure has escaped. Have alot a water available just in case, to at least keep the cells cool down until the pressure dies down. 
 

As far as MAH, of the close to 200 cells the majority where in the 1700/1800 in one pack 1500/1600 on the other pack, but a few as low as 1400 and some as high as 1900. Still usable, they all performed well on the charger, charge and discharge quickly and most seem to hold there charge. I used the opus btc3100 to test them, you have to open up the charger and there is a small switch you have to toggle to 3.7 volts. I had to buy some 26650 holders (about 8 for 5 dollars) .

Thanks for the tear down photos. Curious, when you discharge tested the A123 LifePO4's with the OPUS BT-C3100 V2.2, what did it use for the termination voltage when the voltage switch is set to 3.7? Same voltage as for LiIon's?
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#19
I finally tore apart the packs myself. The first too me a little over half an hour, the second only fifteen minutes. They were much easier to disassemble than I thought.

Turns out they are from TTC (Toronto Transportation Commission) buses. I bought them from batteryhookup in California when sadly they began their journey only 30 minutes away from me. LOL



Here are a couple of pics of my process.

 
 

Looks like I can leave them in their packs and just cut the packs to my desired voltage and build a housing for them. Done.

 


Does anyone know where I can get more of these?
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#20
A bit OT on the thread but I think its worth an answer

Solexx X : I run LiFePo4 and LiIon together in parallel. I have been doing that for almost 2 years now with NO problem what so ever. 14s LiIon and 16s LiFe match each other really good.
Yes you need to beware of top vs end voltage. yes you need to beware of how the SOC curves are on both of them.
Is it doable? Yes
Is it the best option? No
Is it for everyone? No
Does it work for me. Hell Yes Wink

And yes i have 1 bms per chemistry and all that to make sure they are handled properly.
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