SimpBMS With Original Tesla Wiring Harness

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JapanPowerWall

New member
Joined
Dec 30, 2016
Messages
11
Hi everyone, I currently run an off-grid14kWhPowerwall using a2013Nissan Leaf batterywith 2.8kWp of solar panels on the roof. And its served me and my familygreat albeit the few low SOC scares in rainy season...Been running for almost 1 year without any major issues.

However, Irecently came acrossa whole 201485kWh Tesla Model S battery pack for the incredibly cheap price (relatively)of 600,000Yen or just around 5,800USD on yahoo auction. For the whole pack! I just couldn't let it slip away especially at that price. Soooooo, I now have 16beautiful Tesla modules sitting in my living room almost making a hole in the floor (and my wallet)


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I currently have nine 315W JAsolar PV panelscharging the Leaf modules Via aVictron SmartSolar 150/85Tr MPPT unit. A Victron BMV-712 Smart for SOC and power monitoring and finally a Cotek SP-2000-124 2kVa inverter. All equipment has been working every single dayflawlessly, except for the Cotek inverter. Its a long story but to keep this short I got a Victron MultiPlus 24/3000/120V as a part of the system upgrade, replacing the Cotek Unit.

I've deiced to use 14 of the 16 Modules in the main system leaving 2 modules for other projects. I was going to go 48V but that would require getting a Victron Quattro which I thinkwould be excessive and expensive. So 14 modules in parallel for "24V".

After reading a ton online I decided to purchase a SimpBMS for monitoring and keeping the Tesla Modules safe. I wanted to use Batrium BMS for its nice GUIbut since each Tesla module has its own series and parallel connections I would need a satellite board for each module making the total cost outrageous. And since the SimpBMS uses the original Tesla battery slave boards which handles cell monitoring,balancing and temperature via two thermistors in the pack, everything becomes quite simple. I have all the parts for the upgrade ready, waiting to be installed, except for the SimpBMS, thats still being shipped.

Today I've been trying to figure out how the slave boards connect andcommunicate via the daisy chained wiring harness. Let the record show, I'mvery confused....

Does anyone have a diagram on how these would connect to 14 paralleled modules then terminate into a SimpBMS with only 4 wires?

I was able to figure out that the originalTesla harness uses a Molex type connector with 5 sets of two pins connected together in each slave boardfor a total of 10pins per connector. I made a pinout diagram of the connector


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Now what confused me is the SimpBMS wiring diagram for Tesla modules. It shows only 4 wires going into the SimpBMS board with only 2 modules worth of connectors shown as the example. Because only two modules were shown as an example I don't know how the rest would connect....
How can I usethe original Tesla wiring harness? How do I go from 10 wires on the Tesla harnessto only 4 on the Simp?


Thanks in advance guys.
 

CarelHassink

Member
Joined
Oct 21, 2017
Messages
148
OK, you have the complete original serial connect cable from busbar??
16 connectors, and the connector to the main master bms??

colours are grey green yellow blue red
grey is not used
blue/yellow are can low/can high
red = pos
green = ground
Molex 4 pole connector to board connector J1
check manual
Green to pole 1
Red to pole 2
Yellow to pole 3
Blue to pole 4

In my photo I used double power leads Red/Green
I clipped off grey cable ends
I used single Blue/Yellow,

If you do not get a signal on your serial monitor, perhaps swap blue/yellow position, using a Molex pin extract tool.

I have managed 32 modules to work with SIMPbms, running out of modules, we believe you can use 64 modules max, but never had that many in stock...

My advice it to go 48V, and make a stack of 2Sx 8P, have a fuse in the 2S connector to isolate a failing string
Perhaps have look at the MPIIPLus 48V 5000 series + a Cerbo GX device + Smartshunt
if 5 Kva is not enough go parallel depending on the max load you can have on 1 phase in Japan.

best Carel


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JapanPowerWall

New member
Joined
Dec 30, 2016
Messages
11
CarelHassink said:
OK, you have the complete original serial connect cable from busbar??
16 connectors, and the connector to the main master bms??

colours are grey green yellow blue red
grey is not used
blue/yellow are can low/can high
red = pos
green = ground
Molex 4 pole connector to board connector J1
check manual
Green to pole 1
Red to pole 2
Yellow to pole 3
Blue to pole 4

In my photo I used double power leads Red/Green
I clipped off grey cable ends
I used single Blue/Yellow,

If you do not get a signal on your serial monitor, perhaps swap blue/yellow position, using a Molex pin extract tool.

I have managed 32 modules to work with SIMPbms, running out of modules, we believe you can use 64 modules max, but never had that many in stock...

My advice it to go 48V, and make a stack of 2Sx 8P, have a fuse in the 2S connector to isolate a failing string
Perhaps have look at the MPIIPLus 48V 5000 series + a Cerbo GX device + Smartshunt
if 5 Kva is not enough go parallel depending on the max load you can have on 1 phase in Japan.

best Carel


image_ksocbv.jpg

image_dqnqhk.jpg

image_yewurw.jpgimage_civndt.jpg

image_nktxvc.jpg

image_kxwoez.jpg


Thanks for the reply! Yes, I have the complete original serial wiring harness from the Tesla pack. I harvested all the components like the contactors, shunt, fuses, etc.


Can I use the original wiring harness as is? Do I need to follow the number markings on the connectors corresponding to the modules? The original series cable has connectors alternating from 16, 1, 15, 2, 14, 3, 13, 4, etc. Can I just connect it like 1, 2, 3, 4, 5, 6,..?
 

CarelHassink

Member
Joined
Oct 21, 2017
Messages
148
TESLA bms-cable mod for SIMPbms.

any number of connectors can be modded to connect to J1 on SIMPbms board,
matching your application,
even or odd numbers: max 1-64 modules.
The bms doesn't care for the set-up of your battery bank all in serial, parallel whatever, bms is safeguardingat cell-level

link for the Molex mini-fit seriesextraction tool:
https://uk.farnell.com/molex/11-03-0044/extraction-tool-mini-fit-jr/dp/525080

cheap crimptool Engineer PA-09 >>eBay
or
Molex:
https://nl.rs-online.com/web/p/crim...Jeqsm8mK_jn6Q8BYwpRoCu2sQAvD_BwE&gclsrc=aw.ds

Knipex use partnumber for your search in your location:
https://www.knipex.de/crimpzangen_fuer_miniaturstecker_parallelcrimp?v=4918&sku=975426


best Carel


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JapanPowerWall

New member
Joined
Dec 30, 2016
Messages
11
Thank you, this helps a lot. I do have one another question though, do I need to do anything to the remaining 2 connectors at the end of the loop? Since Im using 14 out of 16 modules the last two connectors are unplugged and left.
 

CarelHassink

Member
Joined
Oct 21, 2017
Messages
148
Yes, take these two unused connectors out, if not connected the loop is not working

Must be simple, same procedure as disconnecting the Master bms board connector,
flip out retainer peg ( the little white plastic thing) with a small screwdriver.
disconnect at the correct counted number of serial Molex connectors

use the Molex extraction tool

best Carel
 

JapanPowerWall

New member
Joined
Dec 30, 2016
Messages
11
CarelHassink said:
Yes, take these two unused connectors out, if not connected the loop is not working

Must be simple, same procedure as disconnecting the Master bms board connector,
flip out retainer peg ( the little white plastic thing) with a small screwdriver.
disconnect at the correct counted number of serial Molex connectors

use the Molex extraction tool

best Carel
How to I know which data wires to connect? I know to connect the positive and negative wires together but which blue and yellow do I connect?
 

CarelHassink

Member
Joined
Oct 21, 2017
Messages
148
+++++++++++++++++++++++++++++++
In my photo I used double power leads Red/Green
I clipped off grey cable ends
I used single Blue/Yellow,

If you do not get a signal on your serial monitor, perhaps swap blue/yellow position, using a Molex pin extract tool.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

well, already answered that,
in my very first reply


You have a 16 connector bms cable,
planning to use only 14 for your storage battery, that leaves you 2 connectors and some cable already crimped with Molex pins

perhaps dismantle 2 connectors ( using a Molex extraction tool) to make a single connector lead
If you use the Molex extraction tool, you don't have to crimp Molex pins, since already ready, to re-use.

My take would be to:
1) make a single module connector cable to a 4pole Molex mini-fit, connect it to J1 of SIMPbms
2) this is your "tester"
3) hook up to your SIMPbms board with a usb cable to laptop/pc, and open a serial monitor
4) start testing all your modules, check if all cells are in balance, check for problems like big Delta V values
( to make this a bit easier I clip off the retaining clip of the molex connector
that connects to the Tesla cmu-boards, (easy connect&pull-out))

5) this way you get a feel for how the bms works, and learn to use the settings / readings
6) read the SIMPbms manual....


There's a nice example of a Tesla storage battery build with Victronby another member of this forum
check this entry:
https://secondlifestorage.com/showthread.php?tid=7966
all credits of the buildto Jens.

best regards, Carel
 

JapanPowerWall

New member
Joined
Dec 30, 2016
Messages
11
CarelHassink said:
+++++++++++++++++++++++++++++++
In my photo I used double power leads Red/Green
I clipped off grey cable ends
I used single Blue/Yellow,

If you do not get a signal on your serial monitor, perhaps swap blue/yellow position, using a Molex pin extract tool.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

well, already answered that,
in my very first reply


You have a 16 connector bms cable,
planning to use only 14 for your storage battery, that leaves you 2 connectors and some cable already crimped with Molex pins

perhaps dismantle 2 connectors ( using a Molex extraction tool) to make a single connector lead
If you use the Molex extraction tool, you don't have to crimp Molex pins, since already ready, to re-use.

My take would be to:
1) make a single module connector cable to a 4pole Molex mini-fit, connect it to J1 of SIMPbms
2) this is your "tester"
3) hook up to your SIMPbms board with a usb cable to laptop/pc, and open a serial monitor
4) start testing all your modules, check if all cells are in balance, check for problems like big Delta V values
( to make this a bit easier I clip off the retaining clip of the molex connector
that connects to the Tesla cmu-boards, (easy connect&pull-out))

5) this way you get a feel for how the bms works, and learn to use the settings / readings
6) read the SIMPbms manual....


There's a nice example of a Tesla storage battery build with Victronby another member of this forum
check this entry:
https://secondlifestorage.com/showthread.php?tid=7966
all credits of the buildto Jens.

best regards, Carel



Thanks for the suggestions and your help. I think I got itnow...

I just want to make sure I'm understanding everything correctly in order to not to blow anything up..

I made a diagram of how I thinkeverything connects, I'dreally appreciate it if you could take a look and make sure I have it right...


image_hpvyhh.jpg


 

CarelHassink

Member
Joined
Oct 21, 2017
Messages
148
Your end of the loop is wrong: blue and yellow are never connected.

why open the loop anyhow,
leave original cable connections intact,
that's the beauty of having the original Tesla bms cable,
sure to know it has been working while still attached to donor-car

just shorten it from the master bmu side (big connector) to match your needs

best Carel
 

ClassicStyleATX

New member
Joined
Sep 10, 2021
Messages
2
I apologize for reviving a necro thread, but I'm a bit inexperienced here and there's great info here!

This is a very rough diagram of what I'm planning to do with my Tesla model S batteries in an EV I'm building. I based this plan around Carel's images earlier in this thread.
battery BMS wiring.png

I don't know a lot about how CAN works, so I don't know if I must create a loop out of the wiring, and if so, how far back up the chain must the loop go? Can I just loop it within the final box, or do I have to go all the way back to J1?

Thanks!
 

ClassicStyleATX

New member
Joined
Sep 10, 2021
Messages
2
I think I got the answer to this by finally understanding the diagram attached below. So long as the 3 pin comes from the last battery in the series, I should be good.

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