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Discussion Starter #1
I've been muddying the other LTO Conversion threads, so here's one dedicated to my approach.
I started out with 72 cell build using a Peter Perkins 30% hack, OBDIIC&C, BCM interceptor & fooler, but have reverted back to OEM with 60 LTO cells.

Voltage wise, this is in the OEM ballpark and I can use the BMC to monitor these cells similar to how the stick voltages are monitored. (every 6 cells opposed to every 12) and I'm also using the PTC strips to monitor battery temp.

I put about 2k miles on the 72 cell setup, and I've put under a mile on 60 cells. Tomorrow comes the real test.
 

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Discussion Starter #2 (Edited)
more pictures

Since I have only 5 PTC strips as opposed to 20, I'm using a 22
Ohm resistor in series for compensation.
 

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Discussion Starter #3

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Discussion Starter #4
more pics

Here's the wiring:

Battery packs in series, Neg from battery 1 Positive from battery 5

white = pack 1 negative post
blue = pack 1 split
yellow = pack 2 negative post
green & black = pack 2 split
blue & red = pack 3 negative post
blue & yellow = pack 3 split
green & white (tied to green & red)
green & red = pack 4 negative post
green = pack 4 split
black = pack 5 negative
green & yellow = pack 5 split
red = pack 5 positive post
 

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....but have reverted back to OEM with 60 LTO cells. Voltage wise, this is in the OEM ballpark and I can use the BCM to monitor these cells similar to how the stick voltages are monitored.
I'll be curious to hear how the pack works out vis-a-vis the BCM's top-end charging, or whatever, just how it works with background charging, what state of charge range you're getting out of it, how you manage the top-end manually (if that's your plan), etc...

As far as I know the conventional high end voltage cutoff for your pack will be around 162V (2.7V X 60 cells), possibly up to 168V (2.8V x 60). With a stock NiMH pack and management, typically I see around 164-170V at the main, top-end background charge cutoff point (nominal 70.2% state of charge). And as you probably know, regen is still enabled beyond that, and the actual loaded high voltage cutoff is around 190-192V... So you'll have to be doing something to circumvent charging above that 162 to 168V range, at least I'm pretty sure you'll have to, to prevent damage, perhaps, but certainly to facilitate longevity(?). Kind of a mystery.

I'm not sure how much overcharge these cells can take without doing damage. If they can take short bursts of overcharge you might be fine without doing much of anything, in terms of management at the high end. Voltage will ramp up very quickly once they reach about 2.65V - so given that the BCM will 'pos recal' somewhere around 170V/17V at tap level, resting, or maybe around 174V at about 7 amp charge, there probably wouldn't be too much overcharging possible once your cells are full...

Anyway, I hope you report back after you get some miles logged... Good luck...

Oh, one more thing: Seems like you might want to get a hold of one of the BCMs that don't allow regen after a pos recal. I think the older ones pos recal to a nominal 75% and then allow another 6% or so of charging, while the newer ones(?) - or at least some of the BCMs - simply pos recal to 75% or maybe a nominal 80% and then regen is disabled. The latter seems like it would work better with your situation, or what I interpret to be your situation, that is...
 

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I foresee a few issues with this and personally think your pack voltage will be too low, especially when cold and at a lower soc. I did point this out in the other thread..

IMHO it will give poor performance at the low end and be in danger of overcharging at the top end.

I presume you are removing the fooler and interceptor?

Be interesting to see how you get on.. Fingers crossed.

The operating range for the SCib cells from the Toshiba site is 1.5-2.7V, for the full range. If one left a little margin for a non BCM managed pack, then say 1.6-2.6V.

Therefore for 60 cells, the range is:

60x1.6V=96V
to
60x2.6V=156V.

This of course assumes that the 23Ah cell referenced on the Toshiba site has the same specs as the Honda cells. See no reason why not since they have the same LTO chemistry,
 

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^ He won't be able to maximize use of the big cells - but he should still be able to get at least stock usable capacity out of them, before voltage gets too low and the car forces charging... Plus, the real low voltage isn't really 1.6V - that's like saying the real low end voltage on NiMH cells in the Insight is say 0.9V. It's really more like 1.1V... And the high energy LTOs are around 2V - so that might work OK with the ~120V loaded cutoff. As far as I know the BCM will call it quits around 144V resting - so that gives us a range between 144/60=2.4V at the low end, when the car will force charge, and call it 2.6V at the high end. That's probably still a good amount of usable capacity, between 144V and 156V... It will throttle around 132V, so 132V/60=2.2V. That seems workable - the nominal is 2.3V, and with such big cells 50 amp discharge isn't going to pose much of a burden and make voltage sag much, especially since he's only got 60 cells instead of the 120 stock - so resistance will be a lot lower...

I think the real issue is going to be managing the top end... Or at least that seems to be the most questionable part of this, in my mind...
 

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I too think the voltage range is going to be too low, but he'll just have to give it some experimental time to see how it works. There will be some usable capacity, perhaps as much as the stock pack. BTW, when I was doing some of my initially evaluation, I was seeing about 3V of loaded voltage drop at indicated 70A. For 2 packs, he would see about 2V if he can draw the current at lower pack total voltage.

The use of 2 packs does raise interesting possibilities. If the top end could be managed properly with perhaps a bit of simple "fooling" electronics, and IF that allowed something like stock capacity, this would be an easy mechanical configuration to deal with. Peter's new BCM replacer may just provide the programing needed.
 

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....I'm not sure how much overcharge these cells can take without doing damage. If they can take short bursts of overcharge you might be fine without doing much of anything, in terms of management at the high end. Voltage will ramp up very quickly once they reach about 2.65V - so given that the BCM will 'pos recal' somewhere around 170V/17V at tap level, resting, or maybe around 174V at about 7 amp charge, there probably wouldn't be too much overcharging possible once your cells are full....
Was just perusing some older talk about LTOs and revisited some Toshiba testing videos. One is an overcharge test. The tests are on Toshiba's high power 2.9Ah cell, but I'm guessing the 20Ah high energy cell probably behaves similarly at the top-end...

In any event, they subject a full cell to a 1C charge for 90 minutes. The thing that catches my eye, that seems most relevant to the day-to-day potential risk/degradation level overcharging in the car environment, is what happens between the start of overcharge and 21 minute mark (they only show a few intervals, 21 minutes being the second one).

At the start, cell is 22 degrees C (72F), voltage is 2.8V and increases pretty quickly, like to 2.84V in only the handful of seconds that the video includes. By the 21 minute mark, cell temp has doubled and voltage peaks at 4.54V.

One question is, How much 'degradation' happens during this period - then, How much of this period would an LTO, faced with stock Insight battery management, actually experience?

I have no real idea how much degradation happens. It doesn't look debilitating. It's not catastrophic. 44 degrees C (111F) is pretty hot, but not that hot. I'm guessing there might be some electrolyte breakdown - I think I've read that before, regarding high voltages on whatever lithium-based cell that uses typical electrolytes... I don't see any swelling during this first interval - unlike the next one in the video.

This is 21 minutes of absolute overcharge at a 1C rate. I'm guessing you'd be able to use the cell as normal after this abuse, maybe you'd see some degradation in performance if you really looked hard... Just a guess though...

The second part of the question is, How much of this interval, of this overcharge, might the LTO cell experience in the car, subjected to the car's stock management?

In general, it would likely be only a fraction of this interval...

3.2V at cell level (192V/60 cells) is the max the car will allow under load, yet, except for when the cells are truly full, I don't think an LTO pack will get close to that value (fewer cells, lower cell-level internal resistance and pack resistance, etc.).

The other issues have to do with how the BCM decides when the pack is 'full', such as allowed full resting voltage (something like 170/17V when the BCM pos recals to 'full'), different pos recal loaded voltages, such as about 174/17.4V at about 6.5 amps; and possibly nominal state of charge calculations/determinations (this idea might become a problem)...

I think I'll have to leave this second question for later, or as food for thought... Here's a link to the videos: https://www.scib.jp/en/about/index.htm#con1
 

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Was the rest of the sub pack not saveable? Someone had mentioned taking one cell out and leaving it at 71 cells. That should work with a fooler in place right?
 

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Discussion Starter #12
So, if I'm understanding correctly, you're using the stock MCM and BCM to monitor//control these Lithium cells?
Correct, the MCM/BCM are getting real battery tap voltage values and temperature from the PTC stips. I'm not sure how accurate the battery temperature is with my setup, but my battery temp showed 10 Celsius this morning, consistent with outside temps, and 15/16 Celsius after the cabin was warmed up.

From the photos it looks like the module is a solid block, is there any cooling in place here?
No cooling in place at the moment, but I might place the OEM fan under the two larger packs and have it force air under the tray. Not sure if it's even necessary, even on my trip to Texas these things didn't even get warm to the touch.

I'll be curious to hear how the pack works out vis-a-vis the BCM's top-end charging, or whatever, just how it works with background charging, what state of charge range you're getting out of it, how you manage the top-end manually (if that's your plan), etc...
I have a powerlab6, but I didn't use it to balance out these packs. Instead, I used my grid charger to bring up overall voltage, and then drained 4 of the 5 packs using an incandescent bulb until all packs were the exact same voltage. I'd like to print some of the boards that nothingtoseehere designed, and then I'll put together a harness that will allow me to easily use the powerlab6 to balance out individual cells. Right now, I don't even think this will be necessary, all of the cells are the same voltage.

I foresee a few issues with this and personally think your pack voltage will be too low, especially when cold and at a lower soc. I did point this out in the other thread..

IMHO it will give poor performance at the low end and be in danger of overcharging at the top end.

I presume you are removing the fooler and interceptor?
I'll talk voltages toward the end of this post, but yes, the fooler and interceptor have been removed. I'm using the ObdIIc&c to monitor the system and I can easily reach back and flip the switch if I see anything alarming.

Was the rest of the sub pack not saveable? Someone had mentioned taking one cell out and leaving it at 71 cells. That should work with a fooler in place right?
In my opinion, no it's not salvageable. insightbuyer has suggested simply bypassing bad cells with solder and a jumper wire, but I'm not remotely comfortable with this approach. First, these things are extremely difficult to separate without damaging the cells (and I don't want to leave bad cells in my car). Second, there's not much material to solder onto the welded tabs - plus soldering a gauge of wire big enough to handle this current would be very cumbersome. Now, splitting the pack? No problem, but I'm not going to separate these cells.

The other issues have to do with how the BCM decides when the pack is 'full', such as allowed full resting voltage (something like 170/17V when the BCM pos recals to 'full'), different pos recal loaded voltages, such as about 174/17.4V at about 6.5 amps; and possibly nominal state of charge calculations/determinations (this idea might become a problem)...
eq1, thanks for putting this post together - you've got a lot of good questions. Thus far, this thing is performing exactly the way I had dreamed that it would. The battery indicator gauge has not wavered outside of 17-19 bars. Battery voltage has consistently been in the high 150's and it's not dipped below 149 (which I only achieve after full assist for quite some time). The highest I've seen on full regen was 167. I had one of my best work commute MPG's today too, a tough task in Nashville traffic. If my ObdIIc&c is accurate with its readings, I really think I found an ideal LTO/Lithium approach.

I may ease back into the IMAC&C eventually, but I'm really REALLY enjoying my car just as it is right now. I thought about disassembling my Logitech G27 racing wheel and retro-fitting the paddle shifters to my Honda steering wheel to be used for assist/regen. wouldn't that be a trip!
 

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Another "lazy" I phone. Pictures are laying down
 

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Discussion Starter #15 (Edited)
figured I'd add a quick reply, since I've put over 1200 miles on my 60 cell LTO setup (with OEM MCM/BCM)

I've had no problems thus far, and I'll probably go ahead and button everything up in the back next week.

EDIT: I swear these pictures are right side on on my local machine, no idea what's happening in the upload process. ugh.
https://photos.app.goo.gl/7YR8imCTLwdgiHvN8
https://photos.app.goo.gl/rAk75uvmh12fWKSM8
https://photos.app.goo.gl/WpENGKiwXnibxhQNA
https://photos.app.goo.gl/99XfhPDVkCVcWaGj6
 

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figured I'd add a quick reply, since I've put over 1200 miles on my 60 cell LTO setup (with OEM MCM/BCM). I've had no problems thus far, and I'll probably go ahead and button everything up in the back next week.
Have you tried counting amp-hours - with your OBDIIC&C - to see how much capacity you're able to use before stock management shakes its head? How about max assist and regen? What kind of voltage range are you seeing day-to-day, and how about voltage sag and spike on assist and regen usage?

Inquiring minds want to know...
 

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I really like this. I think more miles have to be put on this setup to test it, and maybe SOME cooling of some sort would be beneficial, but like you might have figured out the lithium battery solution for these cars for low tech DIY types like myself.

I can't see in the photos how like securely the batteries are anchored down; are there brackets or anything you've used to hold them in place?
 

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Discussion Starter #18
Have you tried counting amp-hours - with your OBDIIC&C - to see how much capacity you're able to use before stock management shakes its head? How about max assist and regen? What kind of voltage range are you seeing day-to-day, and how about voltage sag and spike on assist and regen usage?
Inquiring minds want to know...
157 volts is where it's usually at. If I'm really hammering on the accelerator, it will slowly dip down to about 147 and climb a volt or two. I can't get it go any lower before redlining the tach, so I think it's got more capacity than I'm able to take from it. I'm going to put the 30% MCM (and my Imac&c) back in when I get the time to do so. on max assist, it will reach up to 180v for a few minutes and then settle back down below 160.

I really like this. I think more miles have to be put on this setup to test it, and maybe SOME cooling of some sort would be beneficial, but like you might have figured out the lithium battery solution for these cars for low tech DIY types like myself.

I can't see in the photos how like securely the batteries are anchored down; are there brackets or anything you've used to hold them in place?
Thanks, I like it too! I'm going to install the OEM battery fan below these batteries when I have the chance to pull this all apart again. There's a channel of space between the bottom of the batteries and the tray that will make a nice air passage, but I really don't think it's necessary. I feel around the base of the batteries after any extended trip, and they've always felt ambient.
Here's pics from my photo gallery that depicts how the batteries are anchored. https://www.insightcentral.net/forums/members/3009-atheos-albums-lithium-lto.html
 

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This is a video on YouTube please watch. Whenever you hear the word cow bell From Christopher Walken please Substitute the word cowbell for LTO . Then you may understand how bad I would like to hAve The conversion . The same is true for Pegasus .you guys with all the brains 👍------- I just love it !!!------
 

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