openinverter forum

I am not sure if this was already documented here somewhere. If so please consider this only a documented "how to" from me...

A friend lent me a HV contact box out of Nissan Leaf Gen1. He said i should try confirming if it works by simple DIY means. When i googled around in true engineering spirit i noticed this particular DCDC is documented on various sites and videos, however not with schematics or wiring diagrams...
I used some photos and wiring from here: http://myimiev.com/forum/viewtopic.php?t=4533
Starting with connection of the 12v positive terminal to battery
And then GND the case back to battery negative terminal
I connected HV directly to DCDC input wires. Then referring to plugs F11 & F12
Terminal 3 and 11 would need +12v for Battery power supply
Pin 1 needs a PWM signal 9Hz 50% duty to it Well it was all good and well with the wiring obtained online, however i noticed that DCDC starts as soon as i provide 12V to pins 3 and 11 of connector and provides 14V power to charge 12V battery.
When i added 9Hz PWM to pin 1 of connector F11 i got following result:
PWM voltage
80% 13,10V
70% 13,40V
60% 13,70V
50% 14,00V
40% 14,30V
30% 14,70V
20% 15,00V
If i remove PWM from pin 1 i again get 14V on DCDC output. Also i tested the output with 14V 85A load (9x H4 light bulbs and 60Ah Pb battery) and DCDC provided true and steady 14V power.

Great reference! Will pin it. Or if you want, copy paste it to wiki

Oh snap, I just received gen1 motor package on friday and was thinking shame I have no use for this huge dc-dc box..
(outlander charger route planned..)

Maybe it will have some use after-all

Great post! Thanks

The Nissan manual also indicates the PWM signal is 5v.

I have checked that PWM signal straight from a UNO pin does control the DCDC voltage.

mackoffgrid wrote: ↑Fri Apr 09, 2021 12:15 am The Nissan manual also indicates the PWM signal is 5v.

I have checked that PWM signal straight from a UNO pin does control the DCDC voltage.

Yes. I used both direct 5V PWM and MOSFET amplified to 12V.

I did not play with precharge startup however. I just connected 360Vdc directly on to the DCDC input and it worked immediately with only 12V on pin s 3 and 11. I did not need to use PWM to get 14V. I expect you would need to use PWM also to start precharge relays in a proper way?
Would someone confirm that?

arber333 wrote: ↑Fri Apr 09, 2021 6:24 am I expect you would need to use PWM also to start precharge relays in a proper way?
Would someone confirm that?

I'm not sure if I understand what you're asking?

In the LEAF the DCDC converter or (PDM) is connected to the main high Volt bus so it gets it's pre-charge off the main pre-charge for the whole car which is in the Battery module.

In my project I just wanted the DCDC converter so I cut the PDM in half, and managed to keep the water jacket intact.
viewtopic.php?p=24025#p24025

hello everyone, the controller limits the power by current, which is measured by sensors, and if you change the readings of these sensors?

Can I have the part number of the module?

Renegate2020 wrote: ↑Mon Jan 31, 2022 4:19 pm Can I have the part number of the module?

292C03NA0B

After disassembling the block, it seems to me that the use of pin 11 is not necessary. only pin 3 (+12v) and pin 1 (pwm) can be used. Pin 11 connects to the high voltage relay, not to the dc/dc box

Hi guys
I've been working on this too for a little while and just today got the dc-dc 12V charger working by applying only 12V to pin 3.
As mentioned it gives 14.15V to the battery with no other input.
While this is another step forward for me I have a couple of questions.

First, I noticed the DC-DC converter was making a noticeable squealing noise. Not loud but it had me concerned so I turned it off again and thought I should ask here.
Has anyone else noticed the same?
Is it normal?
Is it because I'm not controlling the voltage with a PWM on pin 1?

At first I was taking the 12V for pin 3 from the battery being charged via a 12V bulb (in case I'd cocked up the wiring) so it was more like 14V going to pin 3.
To check if this was causing the issue I tried again using a 2nd 12V battery with the neg going to the dc-dc frame and the pos going direct to pin 3 but the result was the same.

Second, 14V is around normal for the output of an ICE alternator so provided the dc-dc converter is happy with no input on pin 1 is there any reason to change it?

Thanks guys.

So I put a smallish load on the 12V battery and tried again and after a few minutes the squealing sound quietened a lot. The dc-dc converter was sending approx 5A at 14.05V (under load) and seemed happy. I'm happy this is OK so unless someone says otherwise I'm going to go with only supplying 12V to Pin 3. I might put a resistor in line to reduce the voltage from 14V to 12V but I suspect it won't matter.

Alibro wrote: ↑Thu Mar 17, 2022 8:30 pm So I put a smallish load on the 12V battery and tried again and after a few minutes the squealing sound quietened a lot. The dc-dc converter was sending approx 5A at 14.05V (under load) and seemed happy. I'm happy this is OK so unless someone says otherwise I'm going to go with only supplying 12V to Pin 3. I might put a resistor in line to reduce the voltage from 14V to 12V but I suspect it won't matter.

Yes, all DCDCs i know of hate to work unloaded. You need to at least provide a small load like a light bulb. Otherwise they release angry sounds...

does anyone know what minimum voltage is needed for the input to make it work?
All instructions indicate the pin numbers at the entrance to the main large box, but what if only the dc/dc itself is in the hands?
on which of the four wires to apply + 12, and on which pwm?



I can answer everyone for the future myself. Connect a 12 volt battery to the output, supply a high voltage to the input, supply +12 volts to the blue wire. That's it, the output will be 14 volts.

Is that module in the photo the dc-dc converter from inside the PDM?

Alibro wrote: ↑Wed Jun 01, 2022 5:05 pm Is that module in the photo the dc-dc converter from inside the PDM?

yes. today I checked by applying only 240 volts to the high voltage input and it started perfectly, 14.03 volts are produced at the output.

Yes I was able to get mine working but it's still inside the PDM
I'm not sure it is important to control the voltage as I think the 12V battery is happy enough at 14V.
Have you tried getting the Gen1 240Vac on board charger working stand alone?

Alibro wrote: ↑Wed Jun 01, 2022 6:52 pm Have you tried getting the Gen1 240Vac on board charger working stand alone?

yes. it works great. but for the initial start, the output must have a 12 volt battery. after starting the battery, you can remove it and use the DC/DC as a power supply

Romale wrote: ↑Fri Aug 12, 2022 1:05 pm yes. it works great. but for the initial start, the output must have a 12 volt battery. after starting the battery, you can remove it and use the DC/DC as a power supply

Would you mind sharing how and the code? I messed about with it for a couple of weeks but didn't really know what I was doing.

Alibro wrote: ↑Sat Aug 13, 2022 11:32 am Would you mind sharing how and the code? I messed about with it for a couple of weeks but didn't really know what I was doing.

I gave the picture above. plug in a 12 volt battery to the output (this is mandatory!!) then put a high battery voltage on the input. put +12 on the blue wire from the battery connected to the output. that's it. it will start

Romale wrote: ↑Sat Aug 13, 2022 8:02 pm I gave the picture above. plug in a 12 volt battery to the output (this is mandatory!!) then put a high battery voltage on the input. put +12 on the blue wire from the battery connected to the output. that's it. it will start

Sorry, I was asking if you have got the on board ac charger charging the HV. I've seen the dc to dc working myself and as you say it is fairly simple.

Alibro wrote: ↑Sat Aug 13, 2022 8:19 pm Sorry, I was asking if you have got the on board ac charger charging the HV. I've seen the dc to dc working myself and as you say it is fairly simple.

no. I don't have a charger. I expect to charge the battery through the inverter itself and the motor. this is implemented in the software.

Has anyone used it without connecting it to the car's cooling system?

Renegate2020 wrote: ↑Wed Sep 14, 2022 8:02 am Has anyone used it without connecting it to the car's cooling system?

We removed it from the junction box assembly and ran it with just a finned heatsink and some airflow from our radiator fan and it's been fine.

I wouldn't run it for long with no cooling at all though. Any power conversion component generates heat.