Can't trickle charge the 12v battery

[PilotMark]

Thinking I'd like to occasionally charge the 12v battery or maybe even desulphonate the battery, I cut the holes found plugs and then it did not charge.
I have a battery minder trickle charger/maintainer.
The 12 volt was at 12.57 and 54%
I had an odbii attached and running torque on my android phone.
I noticed there was a difference between the torque reading 11.7v and the fluke (12.57) at the attach points.
The car is off and I took off the red cover on the + and attached the battery charger to the steel post then the copper under the red cap.
Over the next 30 mins the 12v went down to 47% charge with the car off and the charger connected.
I gave up for the night and plugged the car in and it started to charge the 12v battery within a min or two.

The battery minders are 12v 1 amp output. I use them on my ice cars and they have worked well.

What am I missing?

Do I need to use a battery charger not a maintainer?

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[devmach-e]

If I had to guess, the battery minder wasn't actually working.

 

[HuntingPudel]

Another guess is that the OBD-2 reader is somehow keeping the car awake and the car is drawing more than the tender is providing. ?‍?

 

[TheVirtualTim]

Use a regular charger. I do know (from personal experience) that if the battery is low enough for the car to throw errors, a battery tender (in my case a 4 amp rate) wasn’t enough to charge it. I had to switch to a regular charger with a 10 amp rate.

 

[Mach-Lee]

Thinking I'd like to occasionally charge the 12v battery or maybe even desulphonate the battery, I cut the holes found plugs and then it did not charge.
I have a battery minder trickle charger/maintainer.
The 12 volt was at 12.57 and 54%
I had an odbii attached and running torque on my android phone.
I noticed there was a difference between the torque reading 11.7v and the fluke (12.57) at the attach points.
The car is off and I took off the red cover on the + and attached the battery charger to the steel post then the copper under the red cap.
Over the next 30 mins the 12v went down to 47% charge with the car off and the charger connected.
I gave up for the night and plugged the car in and it started to charge the 12v battery within a min or two.

The battery minders are 12v 1 amp output. I use them on my ice cars and they have worked well.

What am I missing?

Do I need to use a battery charger not a maintainer?

Don't leave Car Scanner/Torque running or it will drain the 12V battery. You need to hit the red disconnect button and quit the app before walking away for the night. I recommend unplugging the OBD adapter when done to be safe.

The car is going to use way more than 1 amp of battery to stay awake running the OBD, so a 1 amp battery charger won't keep up with that.

 

[RickMachE]

The car is off and I took off the red cover on the + and attached the battery charger to the steel post then the copper under the red cap.

Just to be clear, did the battery minder indicate it was connected properly?

Positive to positive, negative to negative?

I use a 3amp just fine, or a 1.25amp.

 

[johnnycombo]

I’ve found that a 16amp or better charger works the best, also do not use a desulfatotion on a battery connected to a car, disconnect first, newer desulfate chargers won’t activate if connection is sensed by the charger.

 

[AliRafiee]

Just curious, is the negative actually connected to the battery?

 

[Mach-Lee]

Just curious, is the negative actually connected to the battery?

Yes...

 

[Snakebitten]

Don't leave Car Scanner/Torque running or it will drain the 12V battery. You need to hit the red disconnect button and quit the app before walking away for the night. I recommend unplugging the OBD adapter when done to be safe.

The car is going to use way more than 1 amp of battery to stay awake running the OBD, so a 1 amp battery charger won't keep up with that.

This ^^^^^

Having the car off, but Carscanner connected to the OBD can drain that little H3 pretty quick.

(I unwittingly did just that today)

I was sitting at my desk in the office today when FordPass sent me 2 notifications at 1:42pm

I hadn't been at work very long. Had parked at about 11:20 am.
Barely longer than 2 hours before receiving the alerts.
The battery settled at ~12.6 volts as I walked away.

At 1:39pm, 2 minutes before FordPass triggered the alerts, the voltage had just dipped below 12.0 volts. (11.99)

You can see the steep drop in voltage on the chart, representing the drain of having the OBD awake.

You can also see that the BMS immediately enabled the DC/DC converter and tapped the HVB for charging the little H3 back up.

 

[PilotMark]

Thanks for all the feedback.
I think with the ODBII plugged in and the Torque app running it was drawing more than 1amp charge.
I'm done for now but will be using a battery charger tomorrow night to see what happens.
I'm going to try it again with the 1amp maintainer without the odbii and without the app running constantly.

The experiment continues.

I'll post the results.
Thanks

 

[Snakebitten]

I think 1 amp will outpace the natural drain of a "Resting" Mach-E. I say resting because a modern connected vehicle doesn't actually sleep.

So that little H3 should gain voltage tonight, if all else is normal with the car.

 

[Shayne]

Use a regular charger. I do know (from personal experience) that if the battery is low enough for the car to throw errors, a battery tender (in my case a 4 amp rate) wasn’t enough to charge it. I had to switch to a regular charger with a 10 amp rate.

Chargers are too smart for their own good. When the Mach wakes up the charge can think it is a huge phantom drain and error out with something wrong with the car. Switched to 15 amp LG.

 

[someone22]

But can you actually charge directly on the battery terminals? Most modern cars have a BMS and estimate the state of charge using coulombic measuring not just voltage sensing.
Desulfators don't work, not sure if someone had a positive experience with them. You can just as well "revive" a battery by charging it. I tried several brands on at least 10x batteries (cars, motorcycles) and the only change was that it made the situation worse in some cases.

 

[RickMachE]

But can you actually charge directly on the battery terminals? Most modern cars have a BMS and estimate the state of charge using coulombic measuring not just voltage sensing.
Desulfators don't work, not sure if someone had a positive experience with them. You can just as well "revive" a battery by charging it. I tried several brands on at least 10x batteries (cars, motorcycles) and the only change was that it made the situation worse in some cases.

Those posts aren't the battery... They work fine.

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