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Discussion Starter #21
Here's a photo of the LTO 84-cell batteries fitted into the IPU case.
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It was a lot more organized before throwing in the grid charger harness, which is to be used for testing purposes. This changer harness could be trimmed down substantially, but it will remain intact just it case someone else could ever use the harness as-is. The BCM and MCM are joined together with the mounting tabs bolted together. Double-sided tape is holding the BCM/MCMs in place atop a sheet of clear Lexan suspended atop a standoff above the batteries. The tops, i.e. bottoms of the upside-down BCM/MCMs, are flush to the IPU lid.
 

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Discussion Starter #22
Art, with GreenTecAuto, told me there were 4-5 Honda Fits used for testing purposes well past when all the other vehicles were taken back. The cars were each driven 150,000 miles in Arizona and NewMexico. Even with all the harsh conditions, when the batteries were tested they were found to have only 5% degradation relative to new batteries. Used in our Insights, these batteries should last a very long time! This is is a good thing because I'm not sure where we can take them whenever it's time to get rid of them. I'm guessing many of us older folks won't be around when that time comes!
 

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Moving between 18, 17, 16, 15, 14, and 13 has no effect on voltage readings, they stay in the range of Bvo 149 and Mdv 161. At 12 and below the voltage readings are nonsensical with reading in the Bvo 157 and Mdv 8 range. For 19 and above, code P1576 occurs. The unequal voltage reading do not seem have any ill effects. If I'd started out displaying Mdv instead of Bvo, then I wouldn't have known anything was amiss.
I'll think about this, we may well need to revisit the resistors with some nice new 1% tolerance types.
You seem to be only just in the allowable P1576 voltage differential zone so something is a bit wonky.
They should be closer together..
 

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I don't think Toshiba was making the 22Ah cells back when the Fit EV was coming out, could be wrong*, but... I thought they were rated, or at least called, "20Ah" - that's what they're being sold as, aren't they?...
Yes, you are correct. I misspoke. I do like your analysis :)
 

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^ The more I thought about it the more I realized that knowing the original rated capacity is critical to knowing how much the cells have degraded, which is pretty important. And then, when it comes to these LTO cells, it's looking like they do indeed have phenomenal cycle life, which bodes well for their second lease on life in Insights...
 

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Eric, there is lots of capacity testing data in this thread:


particularly at the end of the thread.

I fear we are hijacking Tim's thread :(
 

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Discussion Starter #30
These are all good questions and I'm happy to share what I have learned so far. The LTO pack has been charged four nights straight with more energy put into the pack each time than what’s taken out during a 40 mile daily commute. This is a graph for the lastest charge, from 197 to 218 volts.
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For some reason, changing is interrupted whenever the G1 charger attempts to cross above 202V at the 1070 mA change rate. To prevent this interruption, the cutback voltage was set to be 201V. At this point the charge rate was reduced to 347 mA. At 202.7V, changing was momentarily stopped so the charge rate could be re-adjusted to 1070 mA. Charge rate as again cutback to 347 mA above 213V. This charge rate reduction resulted in a 0.5 Voltage reduction.

The battery pack has demonstrated almost identical voltage profiles during each charge cycle, which includes the flatter section in the 198 Volt range. The Voltage vs. Time relationship is very linear above this section of the curve. At 1,070 mA, the slope is around 16 minutes/Volt and at the 347mA charge rate the slope is about 39 minutes/Volt. Total energy into the pack at these upper Voltage levels was a little more than 1.4kWhr.

After charging ended, with the car sitting in the garage all day, the voltage settled to 216V. The following shows the pack discharge cycle to 168 volts, which took about 11 hours.
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Discharge current at 216V was 1,987 mA and at 197V the discharge current was 1,893 mA. I was hoping to get a broader voltage/discharge-current profile, but this attempt was aborted due to technical difficulties using the multi-meter. The energy meter, with clamp-on Hall sensor, arrives this evening, which will make things a lot easier. The total energy-out should then be readily available as opposed to having to do the calculations using voltage/discharge-current profile along with the data log file.
 

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Discussion Starter #31
The benefits of grid charging these LTOs are considerable.
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Having some fun practicing to better manage both battery and fuel consumption. This was on a familiar 1.8-mile loop where I normally exercise after-hours on my road bike. Half the loop is mild climb and half is descent. Average speed was about 36 mph. The routine for each loop: lean burn on the ascent, averaging 15 amps assist, for about 1:45, followed by about 1:00 engine off coasting on the descent, followed by about 15 seconds of neutral idle, for purge, at the bottom of the descent. Based on another 7 miles of driving home on the interstate following this test and still showing 150 mpg, the business-park loop test was estimated to be in the 170 mpg range. I'm finding that some of what's learned on the business loop is transferrable to normal diving situations. I accidently keyed-off before taking this photo, so the starting high-voltage was lost. I think it started out about 213 Volts and at the end it was only down to 189 Volts.
 

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Impressive but I see you haven't upgraded the BCM Replacer software ;)
You still have the avg V error etc.
Or have you and it's still got that bug?
 

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Discussion Starter #33
I haven’t upgraded the software yet, but as you can probably tell I have been reading the manual and adjusting a few settings. I haven’t broken anything yet. I’ll have more fun with it whenever I have some spare time. You probably noticed the tap voltages are still dead on.
 

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Fascinating. It has been pretty clear for a while that these huge LTO packs would change the MPG calculus entirely. At will the car can be converted to PHEV mode, causing the fuel economy to reach incredibly high levels. Because of the car's light weight and aerodynamics, I predict that it will far exceed cars like the Clarity. IMA C&C, or MIMA, will allow the measured use of the battery energy to retain lean burn and ICE off-loading for considerable distances depending on the extent of the normal detractors.

I fully intend to do some of this type testing myself, just as soon as I get some time, my illness clears, and my wife has a quiet day with her dementia. Ah, the joys of old age.

BTW, you can actually measure the mileage by switching your display to the kilometer/liter gauge. That gauge doesn't top out nearly as quickly as the MPG gauge. You can then use a quick conversion factor. You can keep a "gift" 4 function calculator in the car for quick conversions ;)
 

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Discussion Starter #35
JIME, Thanks for the suggestion of switching to metric. It doesn’t seem the resolution would generally be as good, but when it’s off scale above 150 mpg, the metric resolution is infinitely better!
 
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