Griot's Battery Manager Junior - does it ever finish charging?

Last week I was given a barely used Battery Manager Junior II from a former 328/360 owner, who's waiting for his 430. The battery in my 328 is an Interstate MT34R, about a year old. I drive the car once a week (more or less) and have never had dead battery issues. But, I figured it would be easier on the alternator to keep the battery topped up, so I started using this battery tender a couple of days ago.

There are three lights on this unit -- 'power' (red), 'charging' (yellow), and 'maintaining' (green). Obviously the red power light is always on when it's plugged in. The yellow 'charging' light is on when I connect it to the lighter socket. After two days, it still isn't in 'maintaining' mode -- i.e, the third/green light on.

How long does it take to top off a good battery? I took the car for a short drive today (~10 miles) and had it out Tuesday, so I don't see how the battery could be that drained. There's no alarm, no radio, etc. -- the only draw is the clock.

Anyone used one of these?

 

Not sure if this helps or not. I purchased a Batterty Tender Plus and used it this week. It took about 16 hours to charge battery. I too drive the car on average once per week, thus my battery was not dead at time connecting the charger.

 

Jon,

Try connecting it directly to the battery and see what happens. Your lighter socket might have a bit of oxidation internally and is not providing a good connection.

Barry

 

I use a battery tender from Sears. It takes about 12 - 16 hours to fully charge and hold a battery at that charge. The reason is that it's only a 1.5 Amp device, not a 10 or 50 amp device like a dedicated battery charger (which does a quick charge in 1 - 2 hours, and 50 amp charge for trying to start right away.) I would just plug it in and forget about it. (Don't forget to unplug it prior to taking the car out!)

 

That could be. However it came with the lighter connection only. I'll have to track down the other connection hardware.

True, the thing makes an annoying noise when it's hanging out the door and you're cruising at highway speeds.

 

If your battery retains enough juice to start the car, then I don't think the alternator cares about the state of your battery. It is spinning anytime the engine is so the wear on its bearings are the same, and is putting out 14v regardless and all the electrics of your car are being powered by the alternator. The regulator keeps things in check. Diodes may fail prematurely if you're always putting in a totally dead battery and having the alternator charge it up, but since you said your battery never gets too low even without the battery tender, then I think you could skip using it unless you're going to park the car all winter or something.

 

That is made by Yuasa, and is a well made charger:
http://www.yuasabatteries.com/chargers.asp

Here are the instructions for use:
http://www.yuasabatteries.com/pdfs/Safety_Inst_12v_Charger.pdf

What you are describing is odd though. It should charge in no more than 4 or 5 hours for a car that is regularly driven...often less, much less, perhaps one hour. That is a 900ma charger, and I used to use a 1.25amp (1250ma) charger through the cigarette lighter socket on my 87 328GTS and it would charger very quickly, always within one hour.

I think what I would do is verify that your lighter socket is working correctly, (which it seems since the yellow charging light is on) and also check the fuse, both in the fuse panel, and also in the cigarette light adapter (yup, there is usually a fuse inside them). I would also go so far as to clean your battery terminals too.

Something is not right. If it still acts up, call Griot's, everything they sell comes with a lifetime warranty so they will exchange if for a new one, or give you store credit. That is why I shop there, they really have great customer service.

Dave

 

Jon--the first time I plugged my battery charger in it took like 2 full days for it to show charged. Now after a drive it only takes a few hours each time....

 

I am not familiar with your device, but some of them are never finished as they continuosly monitor and trickle charge as necessary.
You should check the level of charge of your battery separately from the activity of the charger.
There are some inexpensive load testers that will give you the voltage of the battery and then by simply pressing a switch you apply a load on the battery and they will measure the battery ability to take the load.
This will give a good idea of the health level of your battery.

 

Yes, there is a fuse in the lighter adapter - check that one, too, and it looked fine. The actual lighter element (that you'd use to light a cig) gets hot, so the socket is 'live'.

That's what I suspected -- guess I'll find out.

 

This one is not a trickle charger -- it's designed to stop charging once the battery reaches an 'ideal' state of charge.

Still, it would be good to know the actual voltage...

 

I would agree Jon, give it another couple days, then give Griot's a call.

 

Update: the green 'maintain' light is on. It took three days (drove the car twice this weekend, though).

All is good.

 

Great news...

 

Good news indeed. I guess the slower charging is possible due to the small size. 900ma is usually used for motorcycle and ATV batteries. I have one that is similar, and I use it on my motorcycle.

Not a big deal, and because of the lower charging rate, it is likely charging your battery more completely. For example, if I connect up my 15 amp charger (which is microprocessor controlled, just like my 1.5amp Griot's charger) it gives the full charger indication immediately. If I connect up the Griot's 1.5amp, it will charge for another 30 to 40 minutes before giving the full charge indication.