I've mounted a battery tender and have it hooked up for winter storage. It's a 1.5 amp charger/maintainer. Been there for four days now and still showing as charging. How long should it take to reach fully charged on a "good" battery? I would like to see it switch over to the "maintaining" phase before winter is over.

 

You just think its good. Evidently the maintainer doesnt think so yet...i have run into this and wouldnt worry about it, once it comes up it maintains it faster after that...just goes to show you how many people think a battery is good(myself included) when in fact its not a 100% and this is what causes alot of electrical gremlins on cars today. Starting a car has nothing to do anymore with the proper condition of a battery. Imagine how you home appliances etc would work on 90volts instead of 110v......but all the lights work...

 

Hello,

As you know there is parasitic drain even with everything switched off and is why a battery goes flat in only a few weeks of non-use. Try disconnecting the battery from the car while using the tender. If you still see it charging there may be a dead cell keeping it from fully charging. If it switches to maintain then there is an issue with the car's circuits. The real way to test for excessive parasitic drain is with an multitester while each circuit is disabled by removing its fuse. I suspect it's battery-related.

Good luck,

Steve

 

I have used Battery Tenders for all my vehicles, cars and bikes,for possibly 15 - 20 years..since they came out. All my cars, and my bike use them...they work I second the idea of the fault being within the battery. Have a good electrical shop check the battery and charging system. If the battery is a year or so old, it shouldn't take more than an hour or so to go to the green light.

 

I agree with the above statements. Your battery probably has some issues. My cycle battery usually is good within about 4 hours (alt. barely keeps up with the light on at 5k rpm). I would disconnect the tender as you can cook 'em by making them work that hard. They are only designed for small charging and maintaining. Not keeping the battery going. You don't have the interior light or any other loss item (security) on do you? Clock shouldn't take enough to effect it.

 

Nothing is on but bonnet is up. Perhaps it's not got a good enough ground connection? But then it shouldn't show as charging according to the literature.

 

Correct a tender won't show its charging unless it has a good connection.

 

Thanks for the suggestion about disconnecting but it is the type of unit meant to be mounted under the hood and has ring connectors, no claps so it's hard to connect it without bolting it to the positive cable end.

 

if the bonnet is up and the bonnet open is on in the message center with the key on, then with it off the car wont go to sleep. close the hood and setting the alarm will(should) yield less than a 30milliamp draw on the system<thats nothing

 

Are you using a "smart" charger? I use the CTEK 3300 on my Porsche. With the intelligent chargers, if you don't see a change in status after 24 hours or so, it's an indication the battery is bad. Smart chargers can renew bad batteries by deep cycling between draining and refilling the charge several times, but if that's happening, you should see the charge status change periodically between states.

 

I tried to find that CTEK unit but everyone was sold out around here...the Schumacher unit I got is small enough to bolt onto the back of the battery box. It does say that the 1st cycle may take a while but each successive cycle will be shorter.

 

i use a smart charger on my cadillac which i just put on it today.
what i do is it stays connected 24/7 and is usually in maintainer mode, however i also have the car still connected so that the computer doesnt loose its memory (dead/unplugged battery for a period of time sometimes causes cadillacs to need to be reprogrammed by the dealer)
regardless of the computer i would rather have it plugged in and a smart charger on it, i was even thinking of having a timer on it this winter so that it is only turned on 6 hours a day.
mine is a eliminator charger by motomaster list on it is $120-140 i think..i got it on sale for 50-60 last year, it even has a battery recondition mode.

 

Update. Battery is good, I had a bad ground connection. It's hard to find one in such a limited space. Connected both the ring leads directly to the battery terminals and 3.5 hours later I had the "maintain" indicator light up.

 

Good to hear.

I have the Deltran Battery Tender model on my STR and like others stated it went green in about 3 hours. Kind of a pain when the battery is in the trunk.