[POLL] On-Board Charger and DC/DC Converter

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kiev

Well-known member
Joined
May 3, 2015
Messages
2,337
Location
The Heart o' Dixie
Preventative Measures: See 12V Aux Battery Test in this post

This poll is open to everyone, please indicate if you have experienced a failure of either the On-Board Charrger or DC/DC Converter or the 20A fuse in the MCU or None (no failure).

If possible describe the condition of your 12V Aux battery at the time of the incident such as the age e.g. 4-yr old OEM, or Brand spank new or recently replaced 6 months ago, etc.

Please list the typical amount of battery maintenance that was done, e.g monthly, semi-annual, annual, never, and what procedures were done, such as checking of the fluid level and topping off, any periodic top-up charging with either float or dedicated 12V chargger, cleaning of terminal blocks, etc.

Here's a little form that you can copy and paste into your post and fill in the blanks. If you want to be anonymous you can send me a PM or email and i'll just use your data to tally without any names.
kenny 1st_dot house (at) mchsi 2nd_dot com

Just looking for clues and trends of why over a dozen charrgers have failed in a somewhat tight time window after 5-6 year of running okay.

-----------------
1. Year and mileage on your iMiev:

2. OBC failure experience:


3. 12V Battery Condition, Age:


4. 12V Battery Maintenance Frequency and Procedures:


5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car):


--------------
 
p.s.

My theory is that a weak or old 12V battery could let the DC/DC converter, the main contactors, any of the 12V supply relays, or the little boost gate driver power supply inside the OBC, to have a hiccup. Unfortunately any of these will result in a huge and catastrophic electrical spike in the OBC if it occurs during charging.

So my thoughts are to not try to get every last bit of life out of your Aux battery like we used to do with ICE cars. And this is especially true if you don't have time to keep up with periodic checking and maintenance. Consider it cheap insurance to just replace it after 3 or 4 years. And probably a good idea to spend a little more for higher quality brand, or even pay out the nose for an OEM--they do seem to work well and last a long time (but risky to push them to the end in our case).

An ICE car can tolerate a weak 12V battery better than an EV. Unfortunately some have had to learn the hard and expen$ive way.

If you are still driving around on the original OEM Aux battery, then you are living on borrowed time for some expensive repair parts, just my 1¢ worth, bandwidth is half-price today...
 
1. Year and mileage on your iMiev: 2012, 43k or so.

2. OBC failure experience: none


3. 12V Battery Condition, Age: about a year, replaced by Mitsubishi dealer with OEM? battery.


4. 12V Battery Maintenance Frequency and Procedures: None, but dealer checks it.
 
1. Year and mileage on your iMiev:
2012 35K miles


2. OBC failure experience:
OBC Failure During Charging, 20A 400V fuse blown inside inverter housing. Replaced with ots dcdc converter and chademo charger. Car has been running great for 1000 miles+ since failure.


3. 12V Battery Condition, Age:
Original, (6 years old) seemed strong, never discharged.


4. 12V Battery Maintenance Frequency and Procedures:
Never let fluid levels get low, never let discharge below 11v.


5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car):
Always used the KWH limit on my open evse to hault charging at around 80%. Never pulled the AC plug to shut off.
 
1. Year and mileage on your iMiev: 2012 - 55,000 km CHAdeMO

2. OBC failure experience: None

3. 12V Battery Condition, Age: Car was bought used but assume 6 years

4. 12V Battery Maintenance Frequency and Procedures: After sitting for about 3 months, car wouldn't go into Ready mode. Battery dead.

Battery when charging wasn't drawing enough current from charger. Removed cell covers from battery cells and filled with distilled water. For the past 6 months, the battery now keeps its charge for extended period of time, but after reading this it would appear that a new battery should be included in my service budget for this car which after 2 years has been zero.
 
1. Year and mileage on your iMiev: 2012 - 91,000

2. OBC failure experience: Filter caps and 20A fuse blew at 80,000 miles, 6 yrs old

3. 12V Battery Condition, Age: Healthy V and CCA at 6 yrs, replaced along with OBC, still in use on another vehicle.

4. 12V Battery Maintenance Frequency and Procedures: Watered at least once per year, consumption was low.

5. No timer use, but unplugged during L1 charging a few times.

My 12V lived a hard life with extended accessory use and many ICE jump starts, but OBC/DCDC failed overnight on a normal L2 recharge in mild weather.
 
1. Year and mileage on your iMiev: 2014, ~20kmiles

2. OBC failure experience: none, but now always lift up rear hatch when charging L2 since learned of the problem on this forum. Thank you all so much !!


3. 12V Battery Condition, Age: original


4. 12V Battery Maintenance Frequency and Procedures: the iMiev is mostly parked these days, since we also have the Volt and the Boltev. When parked, 12v negative is disconnected and a cheapy HarborFreight Solar trickle charger is attached. But the solar trickler was recently found dead, so disconnecting the 12v was a big help. The 12v had gone to low SOC a couple of time, when forgot to remove the OBDII Bluetooth transceiver.
 
1. Year and mileage on your iMiev: 2012 with 134k km

2. OBC failure experience: OBC failed at 133k km. four days before the charger failed my experience was that the car would charge at a very slow rate for a few minutes before charging would shut down (This happened at three public l2 chargers) For the next three days charging worked normally. The last succesfull charge before this all happened was L1 plugged into the 15 amp socket of an RV. Car was in direct sun.


3. 12V Battery Condition, Age: Battery replaced by dealer at 120k km.


4. 12V Battery Maintenance Frequency and Procedures: No maintenance done on original. I had no issues with the performance of car with original battery

5. Do not use a timer on my charging. Normally charge until full or end charge by removing j1772 from car. I have probably unplugged the charger from the wall first (120v 12a) but that is not my normal practice.
 
i've added a 5th question concerning interruption of AC power during charging, if you could go back and edit your responses for this, thanks.
 
1. Year and mileage on your iMiev: 2012, 69,500 miles.

2. OBC failure experience: Charger failed during an overnight charge using a home charging station.


3. 12V Battery Condition, Age: Original battery.


4. 12V Battery Maintenance Frequency and Procedures: Water level was still between the Min and Max marks
and was reading over 12 volts with a voltmeter. I changed the battery at the same time that I swapped out the charger with a used unit.


5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car): I have occasionally shut off the charger by pulling the J1772 connector before the charger had shut off, but only on a rare occasion.
 
!.) Year and miles: Two cars, both 2012's one with 35K, the other with about 30K

2.) OBC Failure Experience: None on either car

3.) 12 Volt battery condition & age: Both replaced with Mazda Miata AGM batteries. The first one when the car was only about 3 years old because it had been in storage for about 10 months and the original battery was very weak when it was returned to service, the second car got a new battery proactively when it was 6 years old because of what I read here on the forum - Battery still seemed strong . . . . but it was 6 years old and no doubt on borrowed time

4.) 12 volt battery maintenance: - Zero. Never needed to add water, never trickle charged either one, though I probably should have on the car that was in storage . . . . but I didn't

5.) Charging history incidents: None that I can recall. For several years, we seldom charged either car to full - Maybe once every 6 weeks or so. Seldom need a full charge the way we use these cars. We can go several days, making 6 or 8 or 10 mile trips and then recharge to 80% or so when we get down to 20% or so. Lately we've been making more freeway trips and we have been letting them recharge to full most of the time

Because of all the recent failures reported here, we pretty much quit L2 charging completely a year or 15 months ago. One car recharges L1 at 12 amps using a modified OEM Panasonic EVSE and the other car uses a bone stock EVSE at just 8 amps. It's pretty hot here for 6 months or more and my 'theory' is that the added heat from L2 charging might be responsible for many of the failures. For the first 5 or 6 years when we were using L2 maybe 50% of the time, it was limited to 12 amps (2880 watts) max. Can't recall if either car has ever been recharged running 'full blast' at 3.2 Kw

Don
 
This may be of interest to people on this string:

As the owner of a 2012 IMIEV I recently received a letter from Mitsubishi.

...... " due to potential low durability of the capacitors on the circuit boards in the On-Board-Charger (OBC), the capacitors may short and cause the high voltage fuse in the Motor Control Units MCU) to blow. As a result, the drive battery may not be charged by regular charging and the 12V battery may not be charged. When this occurs, the power unit and 12V battery warning lights will turn on."

Mitsubishi is extending the warranty for the OBC to 10 years / unlimited miles.

TSB-19-54-016

Letter dated September 2019.

Mitsubishi Customer Relations; 1-888-648-7820 M-F 7AM.-4PM. PT

Stay charged my friend
 
I have 2 of them...

1. Year and mileage on your iMiev:

Car 1: 2012, 40,000 miles

Car 2: 2012, 21,000 miles

2. OBC failure experience:

Car 1: None

Car 2: None

3. 12V Battery Condition, Age:

Car 1: 1 year +, on second battery - currently a Bosch blue series battery from Costco (Honda Insight Gen 2 equivalent)

Car 2: 3 months, on third battery - currently a GS Yuasa black series battery (Honda Insight Gen 2 equivalent)

4. 12V Battery Maintenance Frequency and Procedures:

Car 1: nothing other than driving car normally

Car 2: nothing other than driving car normally

5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car):

Car 1: Very occasional abrupt charge interrupt (charge fail), less than 1% of charges, always left to charge fully after full charge cycle, J1772 plug disconnected first. Normally a mains power RCD trip actually. I think the couple of times this has happened have been in the winter months - i.e. colder.

Car 2: Very occasional abrupt charge interrupt (charge fail), less than 1% of charges, always left to charge fully after full charge cycle, J1772 plug disconnected first. Normally seems to be due to the very sensitive RCD on the wall L2 charger I think. I think the couple of times this has happened have been in the winter months - i.e. colder.


None of these two cars have been ChaDEmo'd more than about 5 times in their lives, car 1 is charged of 240 Level 1 domestic outlet, car 2 is charged by a level 2 240v wall charger... which is more or less the same thing actually.

Car 1 is used every day, charged 3 times a week or so, car 2 is charged once per week typically.

Zero failures on either car so far... they have been totally reliable. I somehow put this partially down to the UK mild climate that's also not overly dry, and the fact that the cars are almost always charged overnight when it's cooler, and re-charged normally at 2 bars or so.. i.e. full cycling.

Currently running another 2 hybrids, both 10+ years old, and no battery failures or glitches so far there either.... let's hope it all stays that way.

Have had the 12v batter go flat about 4 times on car 2, so far no issues there...
 
1. Year and mileage on your iMiev: 2010 80xxxkm

2. OBC failure experience: currently working thru failure. 3k capacitors blown, and something else.....


3. 12V Battery Condition, Age: looks new(car is 1year old to me)


4. 12V Battery Maintenance Frequency and Procedures: voltage is 12.14 after a month of so of sporadic chad charging.


5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car): i did notice the charger socket both sides had some dark scorching unknown if from shorting or just dirt.
most days typical day is 40-60kms of travel so its charged overnight with the odd balancing charge in the morning(for about a hour or so)
outside that button is always pressed to disconnect(metal handle with leaver impossible to remove without pressing)
 
Hi Folks,

In a week will have had Maeve for two years.
Maintenance has been wash, wax, wiper blades.
Recently both rear tires started to need topping off about once a month, may try
replacing the valve stems. Or having tires re-seated on the rims.

1. Year and mileage on your iMiev: 2014 with 15,900 miles.

2. OBC failure experience: All good.

3. 12V Battery Condition, Age: Excellent, 1.5years old, AGM from Braille, B3121

4. 12V Battery Maintenance Frequency and Procedures: None.

5: Charging history, any incidents of abnormal interruptions such as loss of AC mains, or pulling the AC plug to shut off (as opposed to pressing the J1772 button or automatic shutoff by the car):
) Open EVSE charging interface, 240V, 12A rate.
) During hot weather we set it to charge after the day has cooled off, and only charge to about 80%.
) We live in a rural area that regularly has power glitches of several seconds, a few minutes, hours, and one time five days.
One evening I connected the J1772 and the next day the car was not charged. We had lost power for a few minutes, which interrupted the charge cycle, and it did not auto-restart.
) During a couple power outages a 300 watt inverter connected to Maeve has kept a couple LED lights on, the router live, charged a phone,
for about a 100 watt load.
For longer outages a 1000 watt inverter is connected to the 1982 diesel Toyota pickup with big, dual AGM batteries for powering the fridge or freezer.

Does anybody know if the 2014 models for sure have the newer OBC?

Thanks and good health, Weogo
 
1) 2012 I-Miev. 71,000 Miles
2) Yes. Charging failures occasionally for 2 months. Now won't charge. Trying to diagnose.
3) Replaced 12V battery 1 year ago due to going bad.
4)
5) Background: In January 2019 (7 years old) the battery really started to lose range and was becoming a problem. We thought it might have something to do with our summers that are routinely over 100 degrees. Then when on the highway it got the "turtle" lights and I slowed down from 60MPH to about 5mph. Dealership took it for a month and then shipped it to California for 4 months. My wife wrote letters that didn't really have any effect until she copied the National Transportation Safety Board and said it was a "safety" issue dying on the highway. Amazingly we had the car with a new 330V battery within 2 weeks! No charge.
So, a few years back the car wouldn't charge with the 240V charger. I never diagnosed that problem and have since only used the slow 110V wall charger. A couple months ago some nights we found it didn't charge but the next night is was okay. 2 days ago it stopped charging altogether.
For some reason the OBD reader can't find the car data/codes. The reader says "Failure to connect to the car". I plan to look through all the threads to see if this is a symptom anyone else has experienced and if it could be related to the charging issue.
Today I opened the DC-DC inverter and looked at the capacitors and resistors and everything seemed good to me. All fuses were good. There was some dark marks on the cover that probably came from the wires from the transistor off-gassing from getting too hot but they still looked alright.
So does anyone know how to diagnose this without a code or anything looking obviously bad?
 
Try a different scantool or OBDII dongle to get the DTC codes; don't know where to start without that.

Check the condition of the 12V battery, unless it has been kept fully charged all the time, then it may be degraded.
 
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