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Re: Quick charge project

Posted: Thu Apr 11, 2019 1:24 am
by martii
triangles wrote:Nice work! Glad to see someone working at figuring out how things work on the FFE.
I'm using this great tool called SavvyCan - will find out soon what bytes change during charging session as now I know what ID to look at.

So it looks like only bytes 3 and 4 are changing during charging session. Those must be displayed capacity.

Image

B4 is counting up quickly after it comes to an limit b3 goes up and b4 starts from beginning

Image

There is something going on with B6 also. To be sure I need to look at it when car is full and empty. I have a feeling B6 might much less accurate SOC.

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edit:
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So this was CAN capture from 1100s charging session at 32A 240V.
Session started at B3 0x01 B4 0xE5 - this gives hex 01e5 = 485 decimal
Session ended at B3 0x02 B4 0x58 - this gives hex 0258 = 600 decimal

So I think true value is div. by 10 - this would give 48.5% to 60% in 1100s - looking legit.

Once again I'll check those values when car is full and empty to be 100% sure.

I don't know how many kWh went into the battery at this time but I'll find out - will be playing with this capture file and this awesome tool more.

Cheers,
Martin

Re: Quick charge project

Posted: Sun Apr 14, 2019 3:57 am
by martii
Here is fully charged car:

Image

So car screen shows 100% charge - but:

B3 and B4 says hex 0384 = dec 900 so SOC is 90%
B6 on the other hand says hex C8 = dec 200 so div by 2 gives 100%. This must be the info car displays as no other values change that much during charging.

So now I believe B3 and B4 is real SOC as Forscan shows that cells are at 4.06V and B6 must be displayed SOC.

I'll confirm that once again when in way different SOC like closer to 10% displayed. Then I should see B6 as 14 hex.

Martin

Re: Quick charge project

Posted: Sun Apr 14, 2019 6:04 am
by Dobrinia
Very interesting! continue,
if you need something to test or participate - I am ready

Re: Quick charge project

Posted: Sun Apr 14, 2019 11:09 am
by martii
If you have ability to dump can frames - help is always welcome.
Dobrinia wrote:Very interesting! continue,
if you need something to test or participate - I am ready

Re: Quick charge project

Posted: Thu Apr 18, 2019 10:26 am
by Sebuś
I have a very empty battery pack if you want to drop it :)

Re: Quick charge project

Posted: Sat Apr 20, 2019 3:13 am
by sefs
Guys,

Per cell voltages (min and max actually) don’t exist on the EV CAN bus natively, only through diagnostic queries. What I did was capture what IDS was sending to get the min and max cell voltages, and then just make a for loop to constantly query that every 100 ms or so. That, as well as getting info from the charger, were the only messages I needed to query directly. Everything else I could pick up passively through the EV CAN bus.

Re: Quick charge project

Posted: Sat Apr 20, 2019 4:12 am
by martii
Sefs,

Can you ask for voltage of any cell or you just can get min-max?

Re: Quick charge project

Posted: Sat Apr 20, 2019 4:45 am
by sefs
martii wrote:Sefs,

Can you ask for voltage of any cell or you just can get min-max?
I just read the maximum difference between the cells. So the math I did was I read the min cell voltage diagnostic parameter, and then added the maximum cell difference diagnostic parameter to get the max cell voltage. This was across the whole pack, not individually per cell. I don't remember if in IDS you could query every cell or not (I believe you could), but there is a limit to how much "active querying" you can do through the diagnostic CAN message; so it is good to limit what you are actively requesting.

Re: Quick charge project

Posted: Sat Apr 20, 2019 5:16 am
by martii
I've been trying to sniff what Forscan does and it's sending some requests as it shows cell min voltage.

One more question - during the AC charging is the charging power given somewhere in CAN frame or I would have to calculate like amps times pack voltage?

Re: Quick charge project

Posted: Sat Apr 20, 2019 7:00 am
by sefs
martii wrote:I've been trying to sniff what Forscan does and it's sending some requests as it shows cell min voltage.

One more question - during the AC charging is the charging power given somewhere in CAN frame or I would have to calculate like amps times pack voltage?
AC charging power (AC volts and AC amps) are only present through the diagnostic request. I had my display setup to request these messages when I was parked and I pressed "C". You don't want to be constantly requesting these signals while you're driving, as there really isn't a need. I had AC volts, AC amps, available amps, and AC frequency setup to be queried for. Set these up as the only messages to be queried by ForSCAN, then log the traffic. They should be in the 0x7 range. 0x7 range is reserved for the diagnostic traffic, both send and receive. I sent you a PM with some more info.