openinverter forum

Has anyone tested the Gen2 Prius DCDC converter to see what the maximum input voltage is?

I know the Gen3 is limited to around 230V and needs a modification to some resistors to allow it to work with higher voltages.

I’ve had a look inside my Gen2 inverter today and the input fuse is rated at 600V 30A and the capacitors are rated to 400V so just wondered if anyone had tried applying 300V+ to see if it works.

Since the #4 pin of C5 can modify the DC-DC output, I would think it could be used for that purpose at higher voltages. While I have not seen anything authoritatively published on it, those Toyota engineers are smart and I bet that is exactly how they use it; to maintain the desired "12v" output over a range of HV bus voltages.

tom3141 wrote: ↑Sat Aug 22, 2020 6:37 pm I know the Gen3 is limited to around 230V and needs a modification to some resistors to allow it to work with higher voltages.

Actually Gen3 is limited to 310Vdc! Tested.

Interesting! My peak pack voltage is around 320V, I might just have to try it with the Gen2 DCDC and see what happens

tom3141 wrote: ↑Tue Sep 01, 2020 6:59 pm Interesting! My peak pack voltage is around 320V, I might just have to try it with the Gen2 DCDC and see what happens

Actually my DCDC shut off at exactly 315Vdc. I have this documented here:
viewtopic.php?f=14&t=51&start=50#p948

Did you end up testing the gen 2 dc-dc with your 320v battery? Just realised that it might be an issue for my battery which will have a similar peak voltage.

LRBen wrote: ↑Wed Feb 17, 2021 7:49 pm Did you end up testing the gen 2 dc-dc with your 320v battery? Just realised that it might be an issue for my battery which will have a similar peak voltage.

Sorry for the delayed response. I didn’t end up trying it as I had another DC-DC from my Enova inverter that I knew worked at the higher voltage.

tom3141 wrote: ↑Wed Mar 24, 2021 2:58 pm Sorry for the delayed response. I didn’t end up trying it as I had another DC-DC from my Enova inverter that I knew worked at the higher voltage.

That's ok, decided to change my pack configuration anyway so it now has a voltage range that won't worry the dc-dc converter.

So I tested a gen2 today at 288v (80s pack that needs charging) and no dice. So it’s a lower than a gen3

Dumb questions:

1 - Can you rip the DCDC block out of a Prius Gen2 or 3 and use it with nearly-zero modification?

I.E. People are still buying DCDC converters, should I just recommend they buy this? Even the whole inverter is still cheaper than buying a DCDC anywhere else, just as long as you're not stuck with the bulk of using the whole thing.

2 - Can you parallel the DCDC? I'm considering heating options, and, honestly, just easy and dumb solution is to use several 1000W 12v heater elements as the cabin heater. They just need more than one DCDC. Again so see above, how easy is it to just yank that part out of the inverter?

I pulled out a DC-DC converter from the bottom of a Gen2. All that matters is getting the cooling sorted. 4 TO-264 transistors want cooling, then the transformer, diode pack and output choke. Will try if I can rig something up.
Only downside regarding space requirement: you're dragging that small 3-phase inverter for A/C along which is on the same board.

johu wrote: ↑Fri Apr 02, 2021 7:45 amOnly downside regarding space requirement: you're dragging that small 3-phase inverter for A/C along which is on the same board.

Not the MG1 or MG2 inverter, some tertiary inverter?

Pics would help. If not me, then, everyone else I'll be explaining it to :p

MattsAwesomeStuff wrote: ↑Fri Apr 02, 2021 9:31 am Not the MG1 or MG2 inverter, some tertiary inverter?

Aircon pump.

SciroccoEV wrote: ↑Fri Apr 02, 2021 12:16 pmAircon pump.

Ahh.

Speaking of, has anyone reverse engineered that yet, and put it into use?

Hoping that eventually it all goes into a single board, single solution.

The 3ph for the AC compressor is controlled over the "BEAN" (?? have no clue) network. I have not seen, likely partially because I did not look hard, any information on the protocol.

Some testing today on the Prius Gen2 DC-DC

Conditions: VCU & Inverter logic "On", C5 Pins 1&3 tied to B+ terminal on a 12v battery, B- to the Inverter case, then applied some High Voltage to the HV Battery input.

Results:
- DC-DC "activates" at about 170v (120v on the high-high link)
- 14.1v was the max voltage supplied by the DC-DC to the 12v
- DC-DC provided stable output to over 360vdc applied at the HV Battery input
- Grounding Pin#4 of C5 terminates the DC-DC output while grounded

Due to lack of focus, I did not catch the "high-high" link voltage during the test, but it was somewhat lower than the HV "battery" voltage.

High-high link? I thought the dc convertor took its power straight from the dc bus? I’m running mine stand alone anyway so it definitely get full pack voltage. Also to date I’ve not killed it by Running without any additional cooling then the aluminium box it lives in, time will tell,

ZooKeeper wrote: ↑Fri Apr 02, 2021 10:20 pm - DC-DC provided stable output to over 360vdc applied at the HV Battery input

Are you saying here that it works with 360vdc applied?

MattsAwesomeStuff wrote: ↑Fri Apr 02, 2021 9:31 am Pics would help. If not me, then, everyone else I'll be explaining it to :p

Roughly everything above the fuse is the DC-DC converter, everything below the tertiary A/C inverter.
All components need cooling and the center tap of the transformer must be grounded.

Just looking for the v sense resistor network now, looks like it’s on the underside

Ok I have found one voltage divider which runs off to the control chip a rear on top of the board it’s 4 120k (1203) (r631 r632 r633 r634 r634) and a 3.14k (approx can’t read code) (r635) which would give a reference voltage of about 1.5v from a 200v input so it’s believable. I don’t think I have anything to loose by trying to change the values here.

Also a second divider network here, 4 x120k (1203) on the bottom of the board (r301 r302 r303 r305) and 6.4K (approx code too small to read) on top (r305)

Nice find! Maybe one is for the threshold and one for regulation?

Hopefully, testing will tell just doubt I’ll get to it this weekend( have updated some of the values above after getting my glasses out but still can’t read the small ones!

tom3141 wrote: ↑Sat Apr 03, 2021 8:23 am

ZooKeeper wrote: ↑Fri Apr 02, 2021 10:20 pm - DC-DC provided stable output to over 360vdc applied at the HV Battery input

Are you saying here that it works with 360vdc applied?

I just re-ran the tests with new batteries in the meter and yes, the DC-DC was charging 14.1v @ 0.91A with 340vdc applied to the battery connections.

WOW!

<Edit: Video linked>