2008 e4 batt display shows ~50% but battery measured 13.0V

On the 2008 e4 with gel batteries this is the 2nd time I noticed the dash display shows much less than full after leaving it plugged in for a few days( ~4 days ). I was surprised today to see ~50% charge on the display but I unplugged it and took it out for a quick turn to the store. It seemed peppy and could even feel a little tire slip on acceleration from a stop so I was thinking the display is off. I got home, put the 2 wiper blades on my ICE truck and then went back and checked the batteries on the GEM. I measured 2 batteries and they both came back with 13.0 volts so pretty darn full.

I was hoping for better results than the Zivan on the 2002 which even with the lithium battery will slowly drain off charge if I don’t throw the master disconnect when it sits for a week.

The charger blinks mode 14, has the black dot on part num sticker and when plugged in went right to the 6 amps indicator(walked up to 6). Now, maybe 3 hours later it’s at 3amps and showing blinking green which says it’s in the finishing phase of charge yet the display still shows ~50% charge.

So does the DQ and 2008( T4 controller ) still need the master disconnect thrown once the charge is complete instead of leaving it plugged into AC power?

Without a BMS to intertupt the power, IIRC the DQ goes into a trickle or float charge (battery chemistry determines which) mode after completing the charge.

Sounds like someone set the soc right after it came off charge so the batteries never had time to dissapate the surface charge

It’d been getting used Mon-Wed with maybe a 2-3 mile loop and then a 1 mile loop and then on the charger and unplugged the next day. This type of low SOC indication seems to show up when the vehicle doesn’t get used for a few days but is left connected to AC power. I will experiment over the next few weeks with unplugging it in the AM whether it’ll be used that day or not and see if this issue shows up again. IIRC the SOC is triggered by sensing battery voltage increasing from charging and than stability of top charge. I’d just figured it was fine just being left plugged in but it seems it is not.

I don’t think the DQ’s have a maintenance cycle - I also do not think they “restart” a charge unless unplugged. I could be very wrong and this has been debated many times.
But, I know at least three people here that have reported dead batteries after sitting on the charger during the winter

Wow, I would have thought DQs were so much better than Zivan and at the very least would have had a “restart” mode.

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I went out and checked and the display is now showing fully charged. It seems it doesn’t inch its way up it just jumps from the last state to the fully charged state.

I also noticed that there’s no longer any charge currents and the display is blinking red on the Fault Indicator. I should have looked at the blinking pattern but I think it was just a steady on…off…on…off. So maybe these batteries are not just a year old or something else is going on.

one flash is “High Battery Voltage Detected”

yes and this is why I was thinking the batteries have aged more than one or two years. Good batteries don’t generally hold higher voltages while worn batteries will or that’s what I’ve observed.

I’ve been surprised to see my SOC meter go down a number of clicks just on a ~4 mile day but I’ve not been monitoring the battery voltages. I’ve really only had it on the road for something like 2 weeks. I had been lead to believe they were good batteries and was planning on moving them to the 2002 e4 before I sold it. After seeing the SOC go down so much on a little 4 mile trip had me thinking about leaving the Leaf pack in the 2002 and finding a different pack to put into the 2008 e4.

When Bat switch is ON the DC Converter is also active.
Has anybody put a meter on it to see how much it draws at idle?

One reason not to leave the Main Bat Sw ON.

I’ll have to look into that. Maybe there is a hack with a small DC-DC converter just to keep whatever 12V thing is needed instead of lighting up the whole main converter. I know my 2002 is a power sucker just sitting there but I figure by 2008 there would have been improvements. Guess not.

You and @inwo should chat about that SDI 22s pack we used as a bridge for steve. :slight_smile:


I measured 2 batteries and they both came back with 13.0 volts so pretty darn full.

Did you not measure all- individually? I saw similar display readings on mine, turned out I had 2 bad batteries. They would charge up, but would deplete rapidly. Replaced those two with two new and all is good. Not sure about the charger state changes, but the trickle theory never worked on my 02. If I don’t use the gem for more than a week, I turn off the battery switch.

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I had measured individual batteries twice previously and not seen anything but a difference of a few hundredths of a volt so I concluded all the batteries are operationally equal at this time.

My latest configuration was that I fully charged it( or the charger stopped(with OV error though) and batteries had ~13.0V on them. I’d thrown the main disconnect over the past 5 days of non-use.
Yesterday I did ~3 miles and today, after putting ~2 miles on it I measured all the batteries and they showed 12.49V so I reset the display SoC to 65%. Then I drove it another mile or so and checked a battery and saw it was at 12.25V so I went to adjust the SoC to 45% but couldn’t figure out how to set the ones place so it ended up being set to 49%.

I should have made a measurement on all batteries in this low SoC state but forgot and now it’s on the charger charging at 6A which started at ~3:00p and I will try to check on the hour what the charge state shows on the charger.

Late to this thread. The charger will restart but it is between 10 -14 days. Frequently when there is a power disruption the charger will go into fault mode, blink red and not restart. This is why some people have dead batteries over the winter. The soc is not a volt meter, but as mentioned keeps track of watts in and watts out. If batteries stat to age or have a bad one, the gauge will come out of sync. Each bar has an amount of watts associated with it, as the watts pass thru the bars drop. With older batteries their charge will drop faster then the bars. You can have 40% of bars and go into low voltage turtle mode. You can adjust the bars to go down quicker to be more accurate with older batteries. Also the gauge does not count watts drained with key off. The Gem can drain the batteries all the way down but when you turn it on, it will show full charge.

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Good stuff LG! I didn’t know it’s an actual coulomb counter and keeps track of power. Maybe besides the SoC option in the display the BAT option is for the batter capacity. I will have to search and see what those other options are for.

It’s kinda strange that gel batteries which hold a charge at ~13.0V for days would drop so quickly with less than 10 miles of driving. From what I read about gel batteries, their steady state voltage is a good indication of aging.

The charger is still showing 6a after 2 hours… I should have put my KiloWatt meter on the thing to see how much is going into the batteries.

Ya, these vehicles seem to have lots of parasitic power losses… If it’s all in the DC-DC converter maybe there’s a switch or a relay I can install and use when it’s parked over night.

When you say 6a, where are you measuring that?

The indicator LEDs on the DQ charger are amps. the bottom one is 6a from what I read. As the batteries charge and the charge mode changes so does the indicated amperage. I have to guess that the 6A is on the output side of the charger.

They are percentages. The bottom light is 100% and about 11.5a

I use the word “stages”.
There is nothing implied or expected when used in that context.

Well shoot, when I looked it up the DQ manual called it ammeter so I figured it was charge current.