Gen 1 DC/DC Converter and HV Junction Box

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nlspace

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Jun 6, 2017
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i opened up a Gen 1 DC/DC Junction box and have some findings to report.

It is a simple and dumb box with no CAN buss service--basically 4 big ass Panasonic relays, a Panasonic High Voltage isolation board to measure the HV DC during Chademo Quick Charge, a Denso DC/DC converter to charge the 12V starter battery, and a HV Interlock daisy chain that will inhibit the vehicle systems unless all six of the HV connectors are inserted into their respective positions, and 4 HV fuses. It's a heavy unit weighing 39.8 lbs with the PTC, A/C, Inverter, DCQC, and Pack harness cables connected.

The DC/DC converter unit is a separate box inside the box, and it will be somewhat difficult to reverse engineer because the reference designators are missing on some of the circuit boards.

The interlock system is powered by the M/C relay activation thru fuse #73 that supplies 12V to pin 6 of J12; it can be bypassed using a jumper between pin 6 and pin 5 of the J12, i.e. using a jumper inside the box from the Inverter (Green taped pair) Light Green wire socket to the Pink wire socket of the PTC Heater (Violet taped pair).

more details as they are discovered.
 
Wiring colors for F11 and F12 connectors.

Jp690rN.png
 
Dala said:
More info on this unit found here: https://openinverter.org/forum/viewtopic.php?f=4&t=1532

Dala;
Not being a electronics savvy person - a basic question;
Could this be another "scavenged" part of Gen1 Leafs that could fairly easily be converted to a FLA/AGM battery bank charge controller? (Maybe even bump up the charge voltages to 24/48 VDC systems?)

Just curious as there are so many parts of these Gen1 Leafs (motors/motor controllers/inverters/etc) that would seem to be great DIY projects - when the battery gives out (with no "Fenix" to offer a fix!!).

BTW, have you made progress on V2X with your solar system - another great use of older Leafs with decent batteries.
 
Marktm said:
Dala;
Not being a electronics savvy person - a basic question;
Could this be another "scavenged" part of Gen1 Leafs that could fairly easily be converted to a FLA/AGM battery bank charge controller? (Maybe even bump up the charge voltages to 24/48 VDC systems?)

Just curious as there are so many parts of these Gen1 Leafs (motors/motor controllers/inverters/etc) that would seem to be great DIY projects - when the battery gives out (with no "Fenix" to offer a fix!!).

BTW, have you made progress on V2X with your solar system - another great use of older Leafs with decent batteries.

I would say the best use case for a DC/DC converter would be to use them in an EV conversion.

V2X updates incoming later, offtopic here :p
 
The PWM frequency is 8 Hz, and the duty cycle for 13V (13.5%) and 15V (55%) is shown here from the FSM, but most of the users who have bench tested this unit have indicated an opposite control, with higher duty cycle causing a lower voltage--what's the real answer?

SWAnOnv.png
 
i found an error in the POWER SUPPLY, GROUND & CIRCUIT ELEMENTS, aka PG section of the FSM for the High Voltage connector polarity for the Quick Charge harness into the DCDC Junction Box. This may be why Jim H. burned up his first DCDC when doing bench testing (reversed the polarity) mentioned in his video, https://youtu.be/ipEzK1yzxHY?t=6723

Comparing with the Vehicle Charging Section, VCS of FSM shows the error:
2Cc6ZIC.png


Another wiring diagram in the EVC section but with the correct polarity:
F6qmRMj.png
 
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