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Old 04-12-2017, 06:44 PM   #61 (permalink)
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Just to confirm the CV (Charge Voltage?) phase would mean maintaining a set voltage and slowly dropping the amperage until it reaches zero right? Something that a charger would do, but not regenerative braking.
Exactly.

Soo .. You let Regen stop a bit more away from the ends .. for safety .. thus the 3.5-4.2 window .. and if you want to do more topping at the upper end .. CV with BMS , at lower and more controlled charging rates/conditions.

Note .. amps don't have to actually go all the way down to zero .. it's a logarithmic decay function .. soo it might be 'good-enough' to just stop them at something like around ~2A or so ... continuing down to 2ma , 2uA , etc .. just has rapidly diminishing returns .. Very little value.

Besides .. for cell longevity it's best not to push 100% top to bottom very often (or at all) .. and you gain soo little % comparatively.

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Thanks for the very in-depth reply with measurements and everything.
Happy to help

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Originally Posted by IamIan
about ~332mm front to back .. more if you rise up some.
After I played around with it in my head and re-read what you wrote this section got me thinking. I just grabbed the tape measure and if we raise it above the bar on the bottom of the box that the stock pack mounts onto we could easily get 390mm front to back
Exactly.

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maybe we could trim the inside of the junction board a bit?
Definitely possible .. probably around ~20mm or so can be trimmed without any issue .. just takes time .. and you'll want to be sure to have some type of mounting / bolting method to attach it to your case/box .. depending on the details of how much and where you trim.

- - - - -

By far the 'easiest' direction to push out .. is toward the passenger side .. Like Mudder did in fitting Leaf cells .. and Peter did in locating his BMS .. Do your up a bit over the rail .. which gains to a bit of room in both the front and back of the back .. to get your 14 cells per row going front to back.

If you kept the terminals facing up toward roof .. you could fit your 3 rows (148x3=444mm) side by side in the ~480mm of space from passenger side to the junction board .. and if you trim another ~20mm off the junction board .. you're up to a max of about ~500mm .. leaving you a good 500-444 = 56mm ... if you put 2 air paths between the 3 rows .. each 10mm wide .. you'd still have 36mm left for the two sides of your box/case.
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Old 04-13-2017, 02:56 AM   #62 (permalink)
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Exactly.
If you kept the terminals facing up toward roof .. you could fit your 3 rows (148x3=444mm) side by side in the ~480mm of space from passenger side to the junction board .. and if you trim another ~20mm off the junction board .. you're up to a max of about ~500mm .. leaving you a good 500-444 = 56mm ... if you put 2 air paths between the 3 rows .. each 10mm wide .. you'd still have 36mm left for the two sides of your box/case.
I am 99% sure this is what I will end up doing.

I worked on the BCM Interceptor today and got the checksum working. Its a little different than what I had learned a checksum usually is in that the first bit always has to be a zero. This can be achieved by adding all the numbers up and taking the 2's compliment. This is what a checksum usually is, but for the Insight you then have to make sure the first bit is zero. Easy to achieve with a bit-wise AND of the sum and 0x7F.

I also set up code to modify the 2 packets that carry the voltage. If you index the 12 byte packet from 0 to 11 these are bytes 3 and 4 in the $87 packet. I did not change any other bytes, or anything on the $AA packet. If you are looking at Peter's code, he indexes only the 10 bytes that carry data and doesn't index the first (package type) or last (checksum) bytes so his indexing is from 0 to 9, and in his code they are bytes 2 and 3.

I set up inputs so that I could have it either
1) not modify the data and let is pass through
2) Modify it to 0 bars (packet 3 = 0x11 and packet 4 = 0x6A)
3) Modify it to 4 bars (packet 3 = 0x12 and packet 4 = 0x32)
4) Modify it to 19 bars (packet 3 = 0x15 and packet 4 = 0x6F)
5) Modify it to 20 bars (packet 3 = 0x16 and packet 4 = 0x3C)

I only included these four levels since they were in Peter's code. I was unable to find a complete list of what the other SOC levels are, so if you know where that data is located I would be grateful for a link.

I read the bytes received from the BCM and had it repeat back to me what it was sending onto the MCM after everything was calculated so that I could see what was being sent and confirmed that the sent bytes were correct based on the inputs and the checksums were correct.

I did have some noise problems and messed with the code a bit, so at 1 point I did have it slowly count up to about 16 bars and at another point I had it count down to 0 bars, but have been unable to reproduce these.

In the most recent version that appears to be working the battery gauge on the dash never changes. It stays set at 4 bars, which is what it was at before. When the SOC is set to 0 it does put on a few bars of charge and then when the SOC is changed to anything else, the charging stops. I tested this a few times and it worked every time, so its doing something right, but not what I expected.

Does the BCM data not update the dash SOC display? Am I missing something?

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Old 04-13-2017, 03:19 AM   #63 (permalink)
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This is over my head, but I thought the dash display was controlled by the MCM, on the METSCI line? Here's a post where Peter talks about that, this and the next post down: Analysing the BCM/MCM Signals
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Old 04-13-2017, 03:49 AM   #64 (permalink)
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This is over my head, but I thought the dash display was controlled by the MCM, on the METSCI line? Here's a post where Peter talks about that, this and the next post down: Analysing the BCM/MCM Signals
I have combed through the thread which is where I got most of my data and Peter is able to force the display manipulating the METSCI line, however I wasn't able to find any info on just the BCM Interceptor being able to update the SOC gauge. The BCM sends data to the MCM on the BATTSCI line and I had assumed that the MCM then forwarded the SOC data (along with a bunch of other info) to the display. I had assumed that the BCM simply listened in on this info, but I guess it is more complicated than that.
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Old 04-13-2017, 05:35 PM   #65 (permalink)
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So I did a little investigating today. Because I had found that the car turns on a couple bars of regen when the third and fourth bytes of the $87 packet are modified to $11 and $6A (and when it is parked), I started just paying attention to these bytes. Below I will refer to these bytes as the SOC word.

As previously stated, the values that Peter uses in his BCM interceptor doesn't change the SOC gauge on the dash, but the MCM does react to them. I set up my arduino so I could see the incoming SOC word from the BCM and had a switch which allowed me to either pass through the SOC word form the BCM, or modify the SOC word so that it was 116A which would turn on regen. I then turned on regen and recorded how the SOC word changed. It turns out that the values that I found can be used to modify the SOC dash display. When I set up the arduino to change the SOC word to the values below, the SOC gauge changed to the number of bars after it. The words that don't have a number of bars after it were recorded in that order so the top ones should be 5 bars and the bottom one 6 bars, but I did not verify them. The arduino I was using for logging froze, so I missed the data between 6 and 9 bars. The 7 and 13 bar values were guesses that I made.

I didn't do any more since I think something broke or fried on the arduino I was using for logging. It will start up, but every-time I start the car it freezes, so maybe one of the components that makes it immune to noise fried? The reset button also doesn't reset it. It was a cheap chinese clone of an arduino that I purchased a few years ago so that doesn't surprise me.

023C = 4 bars
023B = 4 bars
024D = 5 bars
024E
024F
0250
0251
0252
0253
0254
0255
0256
0257 = 6 bars
025F = 6 bars
026F = 7 bars
0326 = 9 bars
033B = 13 bars

These bits don't drive the display directly. For example if you have it set to show 4 bars and change the SOC word to 9 bars, after a second it shows 5 bars, and then after a second it shows 6, and so on until it reaches 9. So its not the MCM blindly copying the SOC data and using that to drive the display off of the METSCI line. It seems that there are some flags hidden in these bytes and some of them cause the MCM to update the dash and some don't.
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Old 04-14-2017, 02:38 AM   #66 (permalink)
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Wow. Way over my head but interesting to read how you all are planning your conversions.
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Old 04-20-2017, 10:46 PM   #67 (permalink)
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Well, the DMV finally got the paperwork straightened out so I was able to take it for a spin today. My pack seems surprisingly strong, and even with a few hills I did not see any recals, so that was nice. I was surprised at how differently it drives than my wife's prius, and now totally see the attraction of MIMA, so that is a must at some point. I don't notice any transitions into or out of lean burn at any point, so I will have to do some reading here on that. When the OBDIIC&C PCB gets here that should help too.

I haven't been able to work on analyzing the BMS serial communication since my one arduino nano died and I decided to go with slow shipping from china for the Mega. I also haven't been able to prototype the BMS slave circuits due to the same slow shipping. Parts have arrived, but not enough to start.
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Old 04-20-2017, 11:24 PM   #68 (permalink)
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In the meantime, I think your assumptions about the hopelessness of your pack may have jumped the gun.

...

That may be all you need to discover you have a surprisingly strong pack.

...
I haven't been keeping up with this thread, but just read the last post by Op, and can I say I told you so? LOL.
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Old Yesterday, 11:29 AM   #69 (permalink)
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can I say I told you so?
Sounds like you already have

I just hope it sticks long enough for me to get the lithium swap done
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Old Yesterday, 03:45 PM   #70 (permalink)
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I just hope it sticks long enough for me to get the lithium swap done
From the little experience I've had so far with these packs, I'd say you have a very high chance it will. If it does start complaining again, just a full balancing grid change should keep it happy for several more months.

I think you did stick level work on your's? So you should be good for a while. I've found good results with pack level deep discharge for packs that have deteriorated beyond what a full balancing grid charge will fix. But stick level work/pack level deep discharge shouldn't be necessary more than say once a year or so.
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