coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Battery current sensor

Tue Sep 08, 2020 11:30 pm

I'm considering modifying the main battery current sensor output to allow use of higher capacity cells in the imiEV battery case.

The current sensor seems to come out on 10-pin connector C26. Anyone know where this connector (male and female) can be purchased?

Does anyone know the consequences of modifying (reducing) the value of current read? For example, will this affect the maximum motor power?

Also, does anyone know what the high and low control values are about? I assume that there are actually two sensors, both output 2.50 V at zero current. My guess is that one has 10x the resolution of the other, and so the other has 10x the range of the first. I assume that the two have to agree within certain tolerances or there would be a trouble code produced.

coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Battery current sensor

Wed Sep 09, 2020 11:18 pm

The current sensor itself:

Image Image

The blue and green paint was just something the owner used to keep track of the connectors and where they go.

Edit: the large number 710... seems to be the world's most high resolution date code (with the leading 7 for the Beijing factory). Possibly down to the tenth of a second, unless I misread the datasheet. Or maybe there is a check digit.
Last edited by coulomb on Thu Sep 10, 2020 7:45 pm, edited 1 time in total.

kiev
Posts: 1232
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Battery current sensor

Thu Sep 10, 2020 4:12 am

Thanks for posting the picture--that's a first time to see the sensor. i'll have to look for an LEM datasheet.

So you are looking for the connector and mate for the oval-shaped [rounded rectangular] housing to make a break-out box for the wiring?

DHAB
High performance Dual range (high/low range outputs) current sensor +/- 1000A,suitable for high performance Battery management system.

Their website doesn't list the S/18** part, but i see you beat me to it...

Why do they not identify the mating connector on the datasheet? how useless is that
Last edited by kiev on Thu Sep 10, 2020 4:41 am, edited 3 times in total.
kiev = kenny's innovative electric vehicle

coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Battery current sensor

Thu Sep 10, 2020 4:28 am

kiev wrote:i'll have to look for an LEM datasheet.


Here is one: https://www.electronicsdatasheets.com/d ... format=pdf

So you are looking for the connector and mate for the oval-shaped housing to make a break-out box for the wiring?

I would have said more rounded rectangle, but now that I look again, there does seem to be a very slight curve on the long edges. It's one possibility I'm thinking of. Especially before I knew about the two outputs, thinking two resistors might do it :twisted:

coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Battery current sensor

Thu Sep 10, 2020 7:41 pm

> Oval-shaped housing

Oh, I see what you mean, the connector as pictured. That's buried inside the battery box; most inconvenient. I meant connector C-26 on pins 2,3,7,8. C-26 is just outside the battery box. It's a standard looking connector, though still likely hard to find.

kiev
Posts: 1232
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Battery current sensor

Fri Sep 11, 2020 4:41 am

i would guess it's a JAE connector since so many others are from them. Is pin1 populated?

Here's my notes on C-26:
1
2 CS +5V
3 CS CSIG
4 BMU AutoNumber OuT
5 BMU CANH

6 Shield Ground
7 CS LSIG
8 CS C Ground
9 BMU AutoNum IN
10 BMU CANL
kiev = kenny's innovative electric vehicle

coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Battery current sensor

Fri Sep 11, 2020 7:49 am

kiev wrote:i would guess it's a JAE connector since so many others are from them.

It seems to have a Sumitomo logo at the back top left corner:

Image

Is pin1 populated?

Yes. Blue with single silver stripe. I can't immediately see where it goes.

Here's my notes on C-26:

Thanks.

coulomb
Posts: 223
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Battery current sensor

Sat Sep 12, 2020 9:29 pm

For completeness, here is the location of the sensor in one of the battery teardown photos (thanks, Dani!). It's normally hidden under a plastic cover that holds the five star-point ("dummy") connectors, and the world's largest CAN bus termination resistor.

Image

This area is located towards the front left of the car. [ Edit: the current sensor is measuring the negative end of the battery, before the main negative contactor. ]

Here is the plastic cover with the termination resistor and current sensor (just dangling as it's removed from the pack):

Image

Close-up.

Image

The "12" on the end may indicate 120Ω:

Image

kiev
Posts: 1232
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Battery current sensor

Sun Sep 13, 2020 4:48 am

Thanks for marking the current sensor location; i have looked at Dani's great pack pictures often so that is a big help to identify what's in there.

i've seen the CAN buss termination resistor called out on a FSM wiring diagram, but didn't realize how significant it was. Kinda like adding a large bladder tank to control water hammer in plumbing lines. i guess Mits wanted a big one to let everybody know that they sure-as-hell TERMINATED that thang.
kiev = kenny's innovative electric vehicle

PV1
Site Moderator
Posts: 3066
Joined: Fri Apr 27, 2012 4:22 pm
Location: Pittsburgh, PA

Re: Battery current sensor

Mon Sep 14, 2020 6:47 am

coulomb wrote:I'm considering modifying the main battery current sensor output to allow use of higher capacity cells in the imiEV battery case.

Would this be a necessary step? I seem to recall that the BMS will slowly recalculate total battery capacity to allow larger capacity cells and that no modifications were necessary.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015
"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

Return to “Batteries and Battery Management”