Battery charging question on hybrid

[MJL]

So I probably already know the answer but wanted to ask to see if I missed anything. I went out of town for 3 weeks and of course truck went into sleep mode. I pre connected my trickle charger (1A) and had my wife plug it up 5 days before I came home. The trickle charger is connected via pigtail directly to battery terminals and I have it run just in front of rear seat so I don't have to raise seat to access (mute point). After 5 days I checked voltage at battery and it showed 11.89 V. Would have thought after 5 days I would see 12v plus.
I disconnected charger and put my bigger charger 2A on it using the under hood connections...by end of the day just about 13V.
So my question(s) is 1A over 5 days just not enough and is there any reason under hood vs direct pigtail on battery would offer different charging solutions.....I don't think so but asking anyway........reason I ask is one connection would be pre battery management sensor (under seat) and under hood is post sensor.....or was 1A just not enough to get me over 12V

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[Ozarkbeard]

I use a 2A maintainer and connect it under the hood. When I remove it, I reset the BMS.
A forum search of thread titles for reset BMS will show how to do this, if not familiar.

Never had a battery issue on my Hybrid.

 

[The Real Maverick]

So I probably already know the answer but wanted to ask to see if I missed anything. I went out of town for 3 weeks and of course truck went into sleep mode. I pre connected my trickle charger (1A) and had my wife plug it up 5 days before I came home. The trickle charger is connected via pigtail directly to battery terminals and I have it run just in front of rear seat so I don't have to raise seat to access (mute point). After 5 days I checked voltage at battery and it showed 11.89 V. Would have thought after 5 days I would see 12v plus.
I disconnected charger and put my bigger charger 2A on it using the under hood connections...by end of the day just about 13V.
So my question(s) is 1A over 5 days just not enough and is there any reason under hood vs direct pigtail on battery would offer different charging solutions.....I don't think so but asking anyway........reason I ask is one connection would be pre battery management sensor (under seat) and under hood is post sensor.....or was 1A just not enough to get me over 12V

That is weird data.

Third possibility:

The first attempt with the 1A charger had a malfunction or user error (example not connected firmly, or not plugged in for the full 5 days).

Ever see "National Lampoon's Christmas Vacation"? Clark's light display didn't work as expected because the lights were on a switch in the house. Just sayin' something does not add up.

Bad connection or user error, or cord was on a light switch.... something's not right.

1A should have done the trick. Maybe the charger had an internal malfunction or human error.

 

[MetalsGeek]

Some chargers are better than others, so it's hard to say anything worthwhile here.
However, you should put your charger on the vehicle side of the BMS sensor instead of directly on the battery. Easiest way for this is via the underhood connection behind the red plastic cover.
I have a Noco G3500 (3.5A) charger with status LEDs to show charge state and when it converts to float mode. On the Maverick, it never gets there. The load of all the computerized goodies waiting for commands and running environmental tests keeps this from happening. Some day I may try to measure this load and post it. I'm guessing maybe 150 mA.... which seems like a LOT to me.

 

[agmonaco]

Someone please explain why you need to charge this battery if the truck sits for an extended time? Is there some sort of phantom drain? Seems strange the main power battery does not maintain the 12 volt one if that was the case. The engineering of this system seems to be an issue.

 

[Darnon]

Someone please explain why you need to charge this battery if the truck sits for an extended time? Is there some sort of phantom drain? Seems strange the main power battery does not maintain the 12 volt one if that was the case. The engineering of this system seems to be an issue.

For safety reasons the HVB is electromechanically isolated when the vehicle isn't on. So there's no provision for it to charge the 12V when not in operation.

 

[MavTime]

So I probably already know the answer but wanted to ask to see if I missed anything. I went out of town for 3 weeks and of course truck went into sleep mode. I pre connected my trickle charger (1A) and had my wife plug it up 5 days before I came home. The trickle charger is connected via pigtail directly to battery terminals and I have it run just in front of rear seat so I don't have to raise seat to access (mute point). After 5 days I checked voltage at battery and it showed 11.89 V. Would have thought after 5 days I would see 12v plus.
I disconnected charger and put my bigger charger 2A on it using the under hood connections...by end of the day just about 13V.
So my question(s) is 1A over 5 days just not enough and is there any reason under hood vs direct pigtail on battery would offer different charging solutions.....I don't think so but asking anyway........reason I ask is one connection would be pre battery management sensor (under seat) and under hood is post sensor.....or was 1A just not enough to get me over 12V

I had a Noco 1A charger maintainer and it did take a long time to get it charged, but 5 days should have done it, so maybe it was how you had it connected. The positive should be to the positive terminal and the negative needs to go after the "black block" BMS sensor either on the cable but past the sensor or to body ground. That way the BMS senses the charge. I did upgrade to a Noco 2A that is always wired into the truck, but it still takes 2-3 days to get to solid green. Also interesting that when I test it at full it is above 12 or 13v, or if I charge it with truck cables disconnected to get it to the fullest charge, the moment I hook it back up to the truck the voltage drops like the truck has a shunt or regulator that reduces voltage to 12 point something. FYI

 

[TNFurb]

I use a 2A maintainer and connect it under the hood. When I remove it, I reset the BMS.
A forum search of thread titles for reset BMS will show how to do this, if not familiar.

Never had a battery issue on my Hybrid.

I have just connected my 2A trickle charger via the posts under the hood. Pic below. My question is why does this method require resetting the BMS? Are these points not “before“ the sensor attached on the battery post that’s under the rear seat?

 

[Darnon]

Honestly I think a lot of people are too fussy about the BMS, especially on the charging side. If anything the BMS would think the battery is undercharged and just try to charge it more.

 

[The Real Maverick]

Some chargers are better than others, so it's hard to say anything worthwhile here.
However, you should put your charger on the vehicle side of the BMS sensor instead of directly on the battery. Easiest way for this is via the underhood connection behind the red plastic cover.
I have a Noco G3500 (3.5A) charger with status LEDs to show charge state and when it converts to float mode. On the Maverick, it never gets there. The load of all the computerized goodies waiting for commands and running environmental tests keeps this from happening. Some day I may try to measure this load and post it. I'm guessing maybe 150 mA.... which seems like a LOT to me.

In my tests the vehicle consumes 12v power for the first 90 to 95 minutes after key off and doors locked.

After 90 - 95 min mine draws nothing.
In those first 90 minutes it consumes 0.62 AHr pretty consistently three nights in a row. But always in the first 90-95 minutes.

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