JoeS
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Joined: Thu Dec 15, 2011 5:47 am
Location: Silicon Valley, California

Driving Without OBC/dcdc

Well, it's now my turn. Long story, sorry -

On March 15, six weeks after the expiration of the OBC ten-year warranty on my i-MiEV, the car stopped charging in the middle of an overnight charge well before the Remote programmed to stop around 13 bars. The car now doesn't charge using J1772 but goes into READY and drives just fine but shows a red battery symbol and displays the amber car symbol with exclamation point through it. Verified that the car charges properly using CHAdeMO.

Cleaned up the rear underbody compartment (ten years worth of grime) and pulled the lid off the MCU and the fuse was blown, indicating that I now have the dreaded OBC failure.

Called up the local Mitsubishi service department and asked them to look up the sale date of my i-MiEV by VIN, which turned out to be the end of January 2012. When I suggested it might be the OBC and would they still honor the warranty, the person was emphatic that the 120-month warranty had expired and the car was no longer covered. :!: I asked about the OBC replacement and he confirmed the ballpark number of $5K. He recommended that I bring the car in and they'd take a look at it and not to believe anything I read on the Internet regarding the possible problem. When I asked how much the diagnosis would cost he said around $200. Thank you, 'bye.

I needed to continue using my i-MiEV as at the present time I really need it for towing the trailer and I didn't want to mess with the OBC just yet, After all, recently member @tewharaunz had been driving around without a working obc <http://myimiev.com/forum/viewtopic.php?t=4946> and a few years ago a member in Michigan(?) had installed a CHAdeMO charger at home and put in a charger for the 12v battery (couldn't find his post) and drove around without a functioning OBC as well.

So, I installed a larger (than the Noco) LiFePO4 12v battery with Heltec balancer and which I feed with a small Meanwell power supply and I have not only continued driving the i-MiEV daily using a CHAdeMO station in town but I have now picked up a 10kW Seton (Edit: correction, Setec) dcfc charger (both CHAdeMO and CCS) which operates just fine off my garage 14-50 outlet. Life is good and the i-MiEV continues as a daily driver in my hectic life.

In the meantime, I finally installed the trailer hitch on my Tesla so I can afford to lay up my i-MiEV for a while and am finally about to pull the lid off the OBC and hope to see what let the smoke out.

It occurred to me that even if I pull out the OBC that I will want to continue driving the i-MiEV (the wonderful Tesla Model S is a misapplied vehicle for local driving IMO), so I thought I'd first prepare for that. It seems to me that there are two things that I would need to do:

1) Connect a bypass for the plumbing to keep the coolant flow going through the system without the OBC in place
2) Spoof the CAN bus so it doesn't shut down the i-MiEV with the connectors to the OBC open (thank you jray3)

Two questions for this group:

a) Anything else I would need to do to drive around without an OBC physically in place?
b) How exactly do I spoof the CAN bus so I can continue driving?

TIA
EVs: Two '12 Wht/Blu SE Prem., '13 TeslaMS85, three 156v CorbinSparrowsLi(NMC), 24v EcoScoot(LiFePO4)
EV Conversions: 156v '86 Ram PU, 144v '65 Saab96, 48v1kW bike
RIP(2021) ICE: Orig.Owner '67 Saab96V4, '88 IsuzuTrooper; '76 MBZ L206D RHD RV
kiev
Posts: 1778
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Driving Without OBC/dcdc

My guess is that the OBC only gets powered up during charging so there is no CAN buss activity during READY.

To test this you could just unplug the connector to the OBC and see if it goes to READY or not and throws a code. If it works then you could proceed with the plumbing bypass.
kiev = kenny's innovative electric vehicle
JoeS
Site Moderator
Posts: 4168
Joined: Thu Dec 15, 2011 5:47 am
Location: Silicon Valley, California

Re: Driving Without OBC/dcdc

kiev wrote: Mon May 09, 2022 12:30 pm My guess is that the OBC only gets powered up during charging so there is no CAN buss activity during READY.
To test this you could just unplug the connector to the OBC and see if it goes to READY or not and throws a code. If it works then you could proceed with the plumbing bypass.
Kenny (kiev), thank you for this. I'll give it a try in the next few days. I don't suppose that a disconnected OBC will have any effect on CHAdeMO charging as the dc-dc doesn't work anyway? I'll try that also. More significantly, I need to take the lid off the OBC and see what it looks like inside.

Afraid this is still on the back burner relative to everything else going on here as the kludged i-MiEV is fully usable for now.

Edit:
I'm afraid that I'm reinventing the wheel as I found Michigan's charliejuliett's post Eliminating Mitsu's Onboard Charger/DC-DC Converter. I tried contacting him a number of times over the years to see how things worked out long-term, but haven't had any response.
EVs: Two '12 Wht/Blu SE Prem., '13 TeslaMS85, three 156v CorbinSparrowsLi(NMC), 24v EcoScoot(LiFePO4)
EV Conversions: 156v '86 Ram PU, 144v '65 Saab96, 48v1kW bike
RIP(2021) ICE: Orig.Owner '67 Saab96V4, '88 IsuzuTrooper; '76 MBZ L206D RHD RV

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