PV1
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Re: Extra battery connection

Tue May 30, 2017 11:41 am

There are two resistors. The pre-charge resistor is located inside the battery pack. It is used to slowly bring the high-voltage bus up to pack voltage when starting the car (slowly being 1-2 seconds).

When the car is shut off, a discharge resistor, located in the Motor Control Unit (MCU, also known as drive inverter), will slowly (over about 10 seconds, I believe) bleed off all voltage on the HV bus after the battery pack disconnects.

Given that it read 0 volts, I don't believe the discharge resistor burnt out, so good news there. The only thing the dealer should have to do is reset the code and you should be good to go.

In previous discussions on this forum, myself and others have stated to use contactors to disconnect 2nd battery packs. The contactors should get their power from the same feed that drives the main pack's Positive (+) contactor. This way, the 2nd pack won't connect until the HV bus is charged and the main pack connects. It will also allow both packs to charge together and be connected/disconnected at the same time, and would hopefully avoid this issue going forward.
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gisli
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Joined: Sat Dec 03, 2016 5:31 pm

Re: Extra battery connection

Fri Jun 16, 2017 2:56 pm

GOOD NEWS!

I managed to reset the error WITHOUT the help of the local dealer, thanks to this diagnostic tool :
http://www.diagnostic-world.com/pages/m ... tem_105904
Now I don´t have to worry about producing more error codes as I can always reset them myself.

The extra battery is now connected and has been charged in parallel connection to the main battery. Now I am connecting some measuring equipments before I do the first "hopefully" long test drive. I will post the results.

kiev
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Re: Extra battery connection

Fri Jun 16, 2017 4:02 pm

Wow, that is great news. i'm glad you found a tool that would do the reset. does it also reveal any of the stored information from the car's memory, etc. over the can bus/diagnostic connector? Thanks for sharing, all info helps gain a better understanding...
kiev = kenny's innovative electric vehicle

JoeS
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Re: Extra battery connection

Fri Jun 16, 2017 5:23 pm

Fantastic! Thank you gisli. Where did you end up connecting to the main battery?

I got this far in pursuing the i909 unit, available for NA i-MiEVs, but haven't finished reading the fine print. No time now...

http://www.icarsoft.com/web/icarsoftus/allproducts/mazdascantools/2012/201212/2012122912256kg3yn_1.html
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siai47
Posts: 351
Joined: Fri Jun 14, 2013 5:54 pm

Re: Extra battery connection

Sat Jun 17, 2017 6:27 am

You Cannot connect the additional battery to the inverter as you are bypassing the main contactor which is located in the battery pack. Bad things will happen unless you have a way to connect the additional pack after the "ready" light is on and disconnect it before the "ready" light is off. In addition, the I-MiEV battery is a lot higher voltage (just over 360 volts when fully charged) than the 322 volt battery you are using. I don't know what type of batteries you are using but if Li-Ion you will surely be overcharging them to a dangerous level. The only correct place to tap into the battery is inside the pack before the contactors. Or, if a Chademo equipped car, through the Chademo power cables. The codes you got most likely were because the car thought the main contactor was stuck closed. Remember, there are lethal voltages inside the pack so I am not recommending you go inside. However, if you match the voltages, the external pack will work if wired correctly---I have done it.

gisli
Posts: 10
Joined: Sat Dec 03, 2016 5:31 pm

Re: Extra battery connection

Sun Jun 18, 2017 4:07 pm

kiev wrote:Wow, that is great news. i'm glad you found a tool that would do the reset. does it also reveal any of the stored information from the car's memory, etc. over the can bus/diagnostic connector? Thanks for sharing, all info helps gain a better understanding...


Yes, the unit can read error codes and clear them. It has also the "read data stream" function where I can see values from all the sensors in the car.
About the stored information in car´s memory, at least I have seen data from the BMS like the actual Ah capacity of the battery.

gisli
Posts: 10
Joined: Sat Dec 03, 2016 5:31 pm

Re: Extra battery connection

Sun Jun 18, 2017 4:11 pm

JoeS wrote:Fantastic! Thank you gisli. Where did you end up connecting to the main battery?

I got this far in pursuing the i909 unit, available for NA i-MiEVs, but haven't finished reading the fine print. No time now...

http://www.icarsoft.com/web/icarsoftus/allproducts/mazdascantools/2012/201212/2012122912256kg3yn_1.html


I am still connecting directly to the motor inverter but I only switch the extra battery on when the main battery is switched on. I am doing this manually but later I will add a relay that is controlled with the same signal as the main battery relay.

gisli
Posts: 10
Joined: Sat Dec 03, 2016 5:31 pm

Re: Extra battery connection

Sun Jun 18, 2017 4:47 pm

siai47 wrote:You Cannot connect the additional battery to the inverter as you are bypassing the main contactor which is located in the battery pack. Bad things will happen unless you have a way to connect the additional pack after the "ready" light is on and disconnect it before the "ready" light is off. In addition, the I-MiEV battery is a lot higher voltage (just over 360 volts when fully charged) than the 322 volt battery you are using. I don't know what type of batteries you are using but if Li-Ion you will surely be overcharging them to a dangerous level. The only correct place to tap into the battery is inside the pack before the contactors. Or, if a Chademo equipped car, through the Chademo power cables. The codes you got most likely were because the car thought the main contactor was stuck closed. Remember, there are lethal voltages inside the pack so I am not recommending you go inside. However, if you match the voltages, the external pack will work if wired correctly---I have done it.


The extra battery is based on Li-Ion cells Sanyo NCR18650GA 3500mAh - 10A, connected 88 Serial and 6 Parallel that is exactly the same number of cells in series as in the car battery pack.
The 322 V was just the charging status of the extra battery and of the car battery when I connected them in the beginning. Now I have fully charged them in parallel and both packs are approximately 360 V.
I think it will be ok to connect directly to the motor inverter as long as I switch on the extra pack only when the car battery is switched on.
I am not connecting through the Chademo power cables because later I am planning to be able to run the car either on the extra pack or the car batteries or both in parallel. With the Sanyo cells I am able to pull 60 A according to the cells data sheet. Therefore I can drive the car with power up to aprox. 18 kW only with the extra pack. This pack is around 5 - 6 kWh so it should give aprox. 50 km extra range.

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