philou
Posts: 6
Joined: Mon Sep 10, 2018 6:43 am

Re: Any tips to damaging the main battery?

Tue Sep 11, 2018 5:32 am

Totally agree with JoeS, this is totally un-ethical !
I'm just giving ideas, from a technical point of view. I wouldn't try any of these ideas, I'm sure the engineers thought of that and probably have means of finding any artificial degradation to the battery (doesn't the BMS log each charge ?). Seeing the price of the battery, I wouldn't try to destroy it on purpose, that's just too risky...

kiev
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Location: The Heart o' Dixie
Contact: Website

Re: Any tips to damaging the main battery?

Tue Sep 11, 2018 6:28 am

This is all technical "what-if" chatter--no need to worry about hypoethical fouls.

The LTC6802 cell monitoring chip doesn't provide for arbitrary discharging, it only provides for balancing. It can be used if a cell in the series get over charged, then the balancer circuit can discharge that cell by passing current thru a bleed resistor.
kiev = kenny's innovative electric vehicle

philou
Posts: 6
Joined: Mon Sep 10, 2018 6:43 am

Re: Any tips to damaging the main battery?

Tue Sep 11, 2018 6:49 am

Yes it does, see datasheet page 26:

DCCx
Discharge Cell x
x=1..12
0=turn off shorting switch for cell ‘x’ (default); 1=turn on shorting switch

The hard pard would be, how to get access to the SPI of the LTC6802 !

kiev
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Re: Any tips to damaging the main battery?

Tue Sep 11, 2018 7:43 am

Ok sure there is a memory register bit that controls the fet driver, and if you could write to the chip, you could toggle the bit.

But without direct physical access to the LTC chip (remove the pack and open the covers), this would require knowing the EV-ECU CAN buss commands that talk to the BMU, then the BMU commands on the second CAN buss to the CMUs, then the translation of those commands in the firmware of the microcontroller, which could actually send memory bit register data to the LTC chip. To me that is only Hypothetically possible...not a very useful objective for the amount of reverse engineering that would be required.

Plus there is a DTC that will be thrown if a balancer is ON when it is not supposed to be:

http://mmc-manuals.ru/manuals/i-miev/on ... 000ENG.HTM
Last edited by kiev on Tue Sep 11, 2018 10:10 am, edited 1 time in total.
kiev = kenny's innovative electric vehicle

Gorfllub
Posts: 75
Joined: Sat Aug 04, 2018 6:08 pm

Re: Any tips to NOT damaging the main battery?

Tue Sep 11, 2018 9:57 am

I changed the subject title on the first post.

A simple change in wording.

Now feel free to list of battery damaging things so we all know what to stay away from.

philou
Posts: 6
Joined: Mon Sep 10, 2018 6:43 am

Re: Any tips to NOT damaging the main battery?

Wed Sep 12, 2018 5:35 am

Gorfllub wrote:I changed the subject title on the first post.

:lol:

wmcbrine
Posts: 363
Joined: Wed Apr 29, 2015 10:26 am
Location: Laurel, MD
Contact: Website

Re: Any tips to damaging the main battery?

Thu Sep 13, 2018 6:55 am

Gorfllub wrote:I don't feel bad about it in the absolute slightest. Warranty work keeps my fellow technicans employed. I am certain our dealership generates as much revenue in warranty work as retail work. Maybe even more. It actually helps my local economy.

It might benefit the dealers, but clearly it penalizes the manufacturer.

Gorfllub
Posts: 75
Joined: Sat Aug 04, 2018 6:08 pm

Re: Any tips to NOT damaging the main battery?

Thu Sep 13, 2018 11:18 am

That's OK. Its in their budget. They don't mind one bit.

wmcbrine
Posts: 363
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Location: Laurel, MD
Contact: Website

Re: Any tips to NOT damaging the main battery?

Thu Sep 13, 2018 5:01 pm

Gorfllub wrote:That's OK. Its in their budget. They don't mind one bit.

Like how the banks don't mind when you rob them, because they're insured?

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