vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Fuel gauge vs tortoise

Sat Jan 04, 2020 12:46 pm

Due to an illness and then a hurricane, I let my car sit in an enclosed garage with what I thought was a full main batty and a disconnected aux battery for over a year. Replaced aux battery, car went to ready status ok, but fuel gauge showed no bars. Put car on charge, charger kicked out within a couple hours with fuel gauge showing only 2 bars. Hooked up charger again, kicked out after a few minutes now showing 3 bars. Drive car, got about 5 miles per bar, brought her home with zero bars but no tortoise. Range shows 1 mile. Put her in ready state, put headlamps on. After 4 hours I figure that should use another bar. (1kWh). After about 30 mins tortoise came on and then when I checked after an hour tortoise had disappeared. So had READY indicator. Lights still bright after 1.5 hours. Shut her down and then back in ready mode .. tortoise and READY came back but after a few mins both went off. Decided to start charging cycle and not sure where that will end up. Do I have a malfunctioning gauge, or a bad main battery? Car has only done 25k and it's a 2012.

vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Re: Fuel gauge vs tortoise

Sat Jan 04, 2020 1:18 pm

Well after starting a charge cycle, the charger kicked out after a few minutes and now it will only stay in charge mode for a few seconds. Each time the charge starts normally .. The Orange and green are on, the cooling fan comes on, then after 30 secs or so the charger goes into ready mode. So I can't even get her to one bar.

kiev
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Re: Fuel gauge vs tortoise

Sat Jan 04, 2020 2:04 pm

Sorry to hear about your troubles.

From your symptoms it sounds like you might have a defective Onboard Charger OBC and a blown fuse in the MCU.

We have a big thread about all the folks with that failure, and lots of information about the OBC, fuse, etc.

Mits has extended the warranty to cover the OBC out to 10 years just like the pack.


When you bought a new aux to replace the old one, did you charge it first?

When you go to READY, does the 12V aux battery voltage go up to 14.4V?

There is a 30 Amp fuse under the cover of the Motor Control Unit MCU in the rear engine compartment that will usually fail when the OBC fails. This will cause the 12V aux to not get charged when the car is in READY. So when you ran your test it could be that the new aux got discharged. If so recharge the aux and the car should go to READY if the pack is not too low. With a good strong aux then you may be able to get the pack to charge, if the OBC is not failed. The DCQC Chademo would still work to charge even if the OBC has failed. Otherwise you might need a tow to a dealer for a new OBC and fuse.
kiev = kenny's innovative electric vehicle

vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Re: Fuel gauge vs tortoise

Sat Jan 04, 2020 3:23 pm

Well the new aux was sitting for about a month before install but I figured it would charge with the main pack. And yes I probably ran it down some when I had the lights on. So I removed aux and have it on a charger now. When it's fully charged I will put it back in car and see what happens. Just hoping it's not a bad main battery. Your input was most enlightening!

vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Re: Fuel gauge vs tortoise

Sat Jan 04, 2020 5:04 pm

Charged aux out of car, put it back, car is now taking a charge. But if dc-dc box is shot then aux will not be charged thru main while charging or driving right? And it will run down leaving me stranded even if main is still good?

Car purchased in FL is in Bahamas voiding Mits warranty according to fine print. So I will need to swap out box myself. How hard is that?

kiev
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Re: Fuel gauge vs tortoise

Sat Jan 04, 2020 5:18 pm

Sounds like good news!

You will need to measure the voltage on the aux while in READY to determine if the MCU fuse has blown, but if your pack is charging then that means the OBC is okay, and i would guess that the fuse is likely okay also or the car wouldn't charge.

i use a little plug-in USB phone charger that has a digital voltmeter display--just plug it in the cigar lighter socket and reads the aux voltage.

It appears you just had a weak aux that couldn't supply the necessary power to enable charging the pack.
kiev = kenny's innovative electric vehicle

vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Re: Fuel gauge vs tortoise

Sun Jan 05, 2020 6:58 am

Back to square one .. Car was still charging when I went to bed (about 2 hours in) but gauge showed zero bars with flashing pump. Got up this am charger had kicked out but only 3 bars showing. Hooked up my RC LIPO charger to aux and it read 14.2V. Checked charger again it had clicked on while I was hooking up LIPO charger. After 20 mins charging a tiny RC battery, aux went to 13.1, charger had kicked off again. Removed charging handle, turned ignition to ready, aux voltage went back to 14.2V.

So I conclude no problem with OBC or DC converter. Either gauge is way out of whack, or main won't take more than 3 bars. How do I tell?

PV1
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Re: Fuel gauge vs tortoise

Sun Jan 05, 2020 10:59 am

At this point, I would invest in an OBDLink LX bluetooth and the Android app Canion. This will allow you to see what the cell voltages are within the pack. The pack may simply be way out of balance.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015
"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

kiev
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Re: Fuel gauge vs tortoise

Sun Jan 05, 2020 11:18 am

It does appear that the OBC and DCDC are working okay, possibly the 12V aux is weak or needs a good long charge at 14.4 to desulfate the plates. Take it out and charge it up on the bench so acid doesn't overflow in the car.

With the car being out of service for so long, it may be that the EV-ECU has gotten confused or lost some memory values about the capacity of the pack. It keeps track of all the current flow in and out of the main pack while charging or driving, and it has a baseline value for how much capacity the pack contains. So it will cut off charging if it thinks the capacity has been reached. When you put the aux back it in might reset any error codes and wake up.

The other possibility is that one or more cells is weak and holding down the rest of the pack from being charged fully.

If you could get a ScanTool LX obdii dongle and the android canion app, you would be able to view the individual cell voltages to determine what is the status of the pack.

Otherwise you could drive down to 2 bars and then charge the car, and do this several times to see if the systems will wake up and come back to life.

i have posted in another thread about pulling the MCU cover to read the pack voltage with a voltmeter when you turn the key to READY mode. It is a dangerous high voltage task that requires much care and attention to detail, but that could provide another clue about the pack.
kiev = kenny's innovative electric vehicle

vh2q
Posts: 37
Joined: Fri Dec 18, 2015 12:39 pm

Re: Fuel gauge vs tortoise

Sun Jan 05, 2020 12:02 pm

I charged the aux on the bench last night using my house inverter set for lead acid open cell, 20A charge rate in stage 1 til it got up to voltage, then held at 14.4 V with controlled amps for an hour, then float for about 15 mins. It was reading 13.1V this morning after being plugged in all night, where is was held at 14.2V at least a few hours. It's a new battery so I think it's fine. It could be the charger or the electronics that control when the charger lets go.

Would like to know whether the tortoise mode is triggered by main batty voltage, or by the software logic that keeps track of amp hours in and out. I got the tortoise icon after I drove it to zero bars yesterday. I am hoping the data in the memory is messed up and not a main batty fail.

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