Two outlander packs with single simpBMS coding help.

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bigmotherwhale
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Two outlander packs with single simpBMS coding help.

Post by bigmotherwhale »

Hello

Im trying to run two outlander whole packs on a single simp BMS
I have a man in the middle can bus bridge copied from here https://github.com/knoxsp/OutlanderCanH ... Middle.ino

I want to send the balancing commands only from the BMS to the second pack wile ignoring the rest of the jabber.
can someone help me modify the code so i can do this, im no good at programming at all.
Thanks
bigmotherwhale
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Re: Two outlander packs with single simpBMS coding help.

Post by bigmotherwhale »

Im still struggling to get this to work, The SimpBms only recognises about 15 cells on start-up and it slowly rises to 20, If I reset the cell count it will turn on the contactor for about an hour until it errors again. I was using an UNO to do the man in the middle function but I thought it might be too slow so i bought a mega2560 but I still have the same issue. I am using two 8mhz MCP2515 modules to do this btw.
If i run a single pack through the Arduino, it doesn't fault, I tried changing the “if (millis() - cleartime > 10000)” to a higher number but that seemed to cause weird issues. Can anyone help? im seriously considering using a switch to share time on the canbus between the packs but i really dont want to do that. I have seen other people modify the simpbms code on here to use two packs via an additional port.
bigmotherwhale
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Re: Two outlander packs with single simpBMS coding help.

Post by bigmotherwhale »

If anyone wants to know, I switched to a 16mhz MCP2515 module on the output and the problem went away.
m.art.y
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Re: Two outlander packs with single simpBMS coding help.

Post by m.art.y »

bigmotherwhale wrote: Wed Jun 08, 2022 10:26 pm Im trying to run two outlander whole packs on a single simp BMS
As far as I know this sort of configuration is problematic and not advisable. I also had 2 packs and decided to rewire them into single pack with 2P configuration. A lot of work but for the peace of mind. Apparently the charge/discharge currents are not predictable between 2 separate packs wired in paralel and reguire extra safety meausures of sort.
Side note, does uno or mega accept 2 can transcievers to work as man in the middle? I used Due for that.
bigmotherwhale
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Re: Two outlander packs with single simpBMS coding help.

Post by bigmotherwhale »

I have it up and running and have had no current sharing issues i cant imagine why you would have any? both packs are wired identically, packs currently sitting at 8mV Im only charging or discharging 6 Amps from each pack maximum, seems like an insignificant amount for a battery like this.

The Uno and Mega limit on SPI modules depends on the CS pin allocation and processing power / latency as far as im aware, obviously a chip with an integrated CAN is much preferred, but i had some modules kicking about.

Im going to switch to a Simp bms version with two CAN busses eventually there is the "spaceballs" version of simp bms thats being developed as well as a teensy 4.0 version of Simp.
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