RE - Pack Seperation
weber wrote: ... We will also have 12 vacuum contactors for pack breakup. These Andersons are mainly so we don't have to deal with unfused bolted connections when lying underneath the vehicle installing or removing battery boxes.
If your using 12 will that be 2 in each of the
6 battery boxes?
Do you isolate both pos and neg in the battery pack box?
What type of "vacuum contactors" will you use?
Sounds costly. Would they need to be 100A with 1200Vdc Isolation?
The Coils to pullin the contactors are you tinking of 12VDC?
What coil current would they need?
So if they are normally open then you need the Aux ACC battery to be charged/ready to turn them all (12) ON.
Also if the Aux 12VDC lost connection to battery packs the isollators would drop out most likely while current passing causing arcing in contactors as they release.
Would it be worth having a fast Solid-state relay in the circuit too to kill current first?
This would prevent arcing in contactors and help them last such an event.
It could have the blead resistor across it for charging the DC bus capacitor bank in the Motor drive and 12V Bat Charger.
... can't remember if you where to have a 12V battery or just DC/DC. re dual Meanwell DC/DC's to be used for floating a 12V battery.
If you haven't got a battery you might need a hand crank generator to get power to bring in all the isolators.
weber wrote: in other topic...
It would be a nice feature, so if you can see a way to make it work ...
RE
BMS circuit with the "LINK IN" or "LINK OUT" signals
For the LINKIN signal on Neg Battery BMU pcb in each pack add:
, add a 1uF Cap to GND (to allow diodes time to turn on)
and diode to GND and diode to Vcc as MSP430 can only take 2mA in its pin diodes.
Then a 10kohm 1/2W (1000V) resistor then followed by
100mA trip PTC resistor 1000Vdc/650VAC so when normally operating at 50ohm it wont effect the 10K + 75Kohm (x2)circuit path.
As the PTC will take 1/4 second to turn off the diodes need to be over 0.1A and if there Vrrm is 1000V they're still low cost and do the job.
LINKOUT on POS end BMU with similar addon but diode to Vdd not Vcc.
You could fit them to the edge of the PCB's with axial diodes not surface mount. Making it tidy and tough is always a challange though.
Then I would also totally isolate LINKIN and LINKOUT from the connectors with relay contacts 1000Vdc isolation. So another couple of relays.
Considering all the connectors, wiring, relays and vacuum contactors, it might be worth having a Battery-Pack PCB to help with signals distribution.
I guess your plan of the end BMU having the extra opto may become redundent and could be moved to this PCB with the LINK protection.
So your battery boxes would have in and out connectors with
IN(0V, 12V, COM+, COM-)
OUT(0V, 12V, COM+, COM-)
LINK-POS, LINK-NEG
BAT-PACK-POS, BAT-PACK-NEG
After considering all those extras (plus the LINK wiring) maybe it's not worth the cost to verify where the fault is when it could be either the contactor or anderson plug (or the circuit its self).
The more built in diagnostics, the more commercially viable the design would be considering the automotive OEM market. (If the cost doesn't blow out)
I hope some of that is helpful. Helps me consider the options of + 300Vdc EV approach.
(edit 10K + 75Kohm (x2))