Battery Maintainer?

[ofdfiremedic]

Has anyone else had problems with a battery maintainer on their vehicles? I have the Battery Tender Jr. and the issue currently is the unit stays on "charge" mode for over 24 hours and is never entering the "float/maintain" mode. Makes me think there is some draw on the vehicle preventing it from realizing the battery is charged. To answer a few questions... Yes the battery is good (tested), Yes the unit is hooked up correctly (proper lights). No I won't daily drive the car, so save the "just drive it everyday!" comments.

 

[John G.]

Your battery tender might be defective; try a different one.

 

[sad]

Yes there are parasitic draws on the system. I have no clue if they’re enough to make a battery tender think it cannot achieve a float/maintenance charge.

Do you have it hooked directly to the battery in the trunk?

 

[ofdfiremedic]

Yes there are parasitic draws on the system. I have no clue if they’re enough to make a battery tender think it cannot achieve a float/maintenance charge.

Do you have it hooked directly to the battery in the trunk?

I do.

 

[Confuzed1]

You did read the instructions that came with it right? It only puts out .75 Amp...

TIME REQUIRED TO CHARGE A BATTERY:
The Battery Tender® Junior charges at a rate of 0.75 Amps (0.75 Amp-Hours
per hour). The Battery Tender® Plus charges at a rate of 1.25 Amps (1.25
Amp-Hours per hour). Therefore, a fully discharged 15 Amp-Hour battery will
take approximately 16 hours or 9.6 hours respectively, to recharge to 80%
capacity with a Battery Tender® Junior or a Plus. Some large automotive or
marine, deep cycle type batteries may take several days to fully recharge

 

[ofdfiremedic]

You did read the instructions that came with it right? It only puts out .75 Amp...

TIME REQUIRED TO CHARGE A BATTERY:
The Battery Tender® Junior charges at a rate of 0.75 Amps (0.75 Amp-Hours
per hour). The Battery Tender® Plus charges at a rate of 1.25 Amps (1.25
Amp-Hours per hour). Therefore, a fully discharged 15 Amp-Hour battery will
take approximately 16 hours or 9.6 hours respectively, to recharge to 80%
capacity with a Battery Tender® Junior or a Plus. Some large automotive or
marine, deep cycle type batteries may take several days to fully recharge

Of course, the battery is fully charged however, so after 24 hours, it should have switched to float mode, furthermore it should have been flashing green at "above 80%" which it remains on red (charging mode).

 

[sad]

I do.

Maybe a battery disconnect switch is in order.

All of my tenders achieve float, but we’re talking things with no parasitic loss (tractor, Atom, mower)

 

[MikeD1]

I have not had that problem with my Tender Jr. and the Hellcat. It goes from charging (red light) to 80% (red + flashing green) then solid green (maint mode).

I did have this issue with my old M45s tho, it would never get past the flashing green status even when I replaced the battery on the car.
Dealership insisted there was no unusual draw, but the car was never 'right' IMO. If the car was not driven 2 or 3x week, the battery would go too low to start it, had to keep a tender on it all the time.

I would try the charger on another vehicle & see if it cycles correctly, that will eliminate the issue being the charger itself.
Could also be a bad cell (or going bad cell) in the battery which is very possible on a '16 (I had to replace mine 18 months ago for that very issue).

 

[Confuzed1]

Of course, the battery is fully charged however, so after 24 hours, it should have switched to float mode, furthermore it should have been flashing green at "above 80%" which it remains on red (charging mode).

I don't know about the Junior models.

I have one of the bigger dual port ones that put out 1.25 Amps per lead. I don't have a red light...(I don't think I do)...its either one solid yellow (charging) or both the yellow and green flash (over 80%), then to green only (fully charged and maintaining). If my battery is even slightly low, it will flash both yellow and green for at least 12 hours....maybe longer before it shifts to full green. If it were only putting out .75 of an Amp...I imagine it would take quite a lot longer. There's always some draw on the battery anyway on these cars when shut down. I'd give it another day and see what happens. If nothing changes as mentioned...either the charger you have is bad, or the "good" battery you have...isn't.

EDIT: - Or good suggestion by MikeD1....try it on a known good car and battery if you have one and see what it does.

 

[ofdfiremedic]

Thanks everyone, I will dig deeper into it, wasn't sure if this was a widespread issue with these units. Considering the Tender Jr was the bottom priced unit I was a little concerned I got a dud.

 

[Deano]

Is it possible your battery while charged was not as full as you thought?
My Tender Jr. functions correctly. However, sometimes it takes longer .

 

[ofdfiremedic]

Just to double check, I drove the car up to Advance, they ran the tests on the battery again and show the battery fully functional and healthy. I may have to opt for a higher amp tender. 🤷🏻‍♂️

 

[MikeD1]

What does the volt meter read as you are driving around ?

 

[ofdfiremedic]

What does the volt meter read as you are driving around ?

13.9-14.1

 

[MikeD1]

That's pretty normal. I'd try testing the Tender on another vehicle next, it could be defective.

 

[ofdfiremedic]

That's pretty normal. I'd try testing the Tender on another vehicle next, it could be defective.

Will be testing tonight once the other vehicle comes home!

 

[Jungle Cat]

Hook it up under the hood in the proper place. I had the same issue with the regular battery tender when I hooked it up to battery in trunk. It gave me fits. I Hooked it up under the hood and went to green pretty quick. I don’t know why that is it just is.

 

[Deano]

I wonder why. I have hooked mine up front or back on 3 different cars with no change.

 

[MikeD1]

I wonder why. I have hooked mine up front or back on 3 different cars with no change.

X2, I have used both (lately just directly on the battery) and have noticed no difference in how it charges.

Before the 1st battery went bad, it died at the dealer during an oil change & they hooked their charger directly to the battery.

 

[Yoguard]

Has anyone else had problems with a battery maintainer on their vehicles? I have the Battery Tender Jr. and the issue currently is the unit stays on "charge" mode for over 24 hours and is never entering the "float/maintain" mode. Makes me think there is some draw on the vehicle preventing it from realizing the battery is charged. To answer a few questions... Yes the battery is good (tested), Yes the unit is hooked up correctly (proper lights). No I won't daily drive the car, so save the "just drive it everyday!" comments.

I use the same one. I have two and the 1st one I put on the car stayed constantly charging. I thought it might be bad so I switched it. Still stayed red on charge. After looking on their website, I noticed it charges at a 0.75 clip (slow). After 3 days it turned green on trickle. Dummy me....