So educate me

[Bubber]

What is the real difference between a battery tender jr and a battery charger?

 

Since the last battery I put in the bike was a AGM type I am wondering what it is I should be using.

Read articles about desulphering and all kinds of technical stuff.

 

Just need to know in layman's terms what to do or at least an explanation of what each kind does and if it is important to me or not.

 

Let the technical guys come back first and then you can let the insult fly.

[frankd]

Steve,

 

A battery tender charges with a lower voltage, usually about 13.6 volts. This low charge rate prevents the battery from being overcharged or boiled, but prevents the battery from sulphating, and it actually restores the battery (within reason). A battery charger usually will charge a battery until the voltage gets up to about 15 volts, and after it gets completely charged, you can hear the battery gassing (bubbling). An AGM battery doesn't self discharged as quickly as a conventional lead/acid battery. A lead/acid battery in good condition self discharges approximately 1% per day. An AGM battery self discharges about 1% per month, or about 1/30 as quickly. Of course, you have to remember that your bike does have a small drain on the battery all time for the clock and radio memory. If you have a burgler alarm, you have to consider that also. In a perfect world, an AGM battery would like a little higher charge voltage than a conventional lead/acid, but let's not worry about little things. I live a little south of you (Near Joliet, IL) but with the mild winter we've had this year and with the AGM battery, my bike hasn't spent very much time on the tender. In the first part of the winter, I had it on the tender for a couple of weeks, but with the frequent rides I've taken, it hasn't been on the tender since early December. I think it was about 5- 6 weeks between my last two rides, and the bike cranked over just like it was ridden yesterday. Yesterday, it probably ran 1 1/2 hours and I'm not going to worry about charging it unless April gets here before I ride it again.

 

Hope that helps,

 

Frank D.

[MasterGuns]

A battery charger is just that; an electrical unit for charging a dead or almost dead battery. Once it is fully charged it must be disconnected.

 

A tender is a smaller, probably a 1.5 volt "maintainer". It can remain connected to the battery for prolonged periods of times and never be disconnected. At least not until you decide to take a ride. A tender simply maintains a charged battery that will set for long periods of time without being charged by a charger or the bike's charging system.

 

At least this is the way I'd explain the difference

 

Herb

[flb_78]

Yup, I'll pretty much echo what was said above. A charger will charge even if the battery is fully charged. It will cook a battery.

 

A Battery Tender, or battery maintainer can be left hooked up. Once the battery is charged, it will shut itself off or lower the amperage down automatically to keep from cooking the battery.

 

I personally have a Schumacher Battery Maintainer from the Evil Empire of Walmart. It was around $20.

[KIC]

Make sure you get a quality tender that shuts off when it reaches peak charge. I got one that didn't shut off totally and made a dual pig tail to keep my 2 TW200's charged. All of a sudden I am constantly filling them with water and the new batteries lasted less than a year. Same with my KLR560. I don't keep any of the bikes on one all the time now, I just plug one in if it has sat for a while and then unplug it after a day or so.

[darthandy]

Make sure you get a quality tender that shuts off when it reaches peak charge. I got one that didn't shut off totally and made a dual pig tail to keep my 2 TW200's charged. All of a sudden I am constantly filling them with water and the new batteries lasted less than a year. Same with my KLR560. I don't keep any of the bikes on one all the time now, I just plug one in if it has sat for a while and then unplug it after a day or so.

 

Sounds like somebody packaged a "trickle charger" and passed it off as a battery tender. A tender will adjust its charging rate and voltage based on the battery's condition. A trickle charger will just keep charging until it is unplugged. It does the same thing as a regular charger but at lower levels. You can still "boil off" a battery with a trickle charger...it will just take longer. Battery Tender jr. and CTEK are two good units that come to mind, although I'm sure there are others.

[OldBear]

Sounds like somebody packaged a "trickle charger" and passed it off as a battery tender. A tender will adjust its charging rate and voltage based on the battery's condition. A trickle charger will just keep charging until it is unplugged. It does the same thing as a regular charger but at lower levels. You can still "boil off" a battery with a trickle charger...it will just take longer. Battery Tender jr. and CTEK are two good units that come to mind, although I'm sure there are others.

 

Yup, either that or your units defective. I've got tenders on both the BMW and the Wing all the time through the cooler months. That way there's never a worry and they're always ready to go. Have done so for several years now with NO problems whatsoever.

[Snaggletooth]

That was one of my concerns when I bought my DEKA AGM from Bohannon Battery back in '09. I have a battey charger that cuts down the charge level from the low setting (2a) when fully charged but had just purchased a Battery Tender Jr. the year before and was concerned about using it on the AGM.

 

I spoke with Joshua at Bohannon about it and he said the Tender Jr. wll work fine for keeping the battery topped off after a full charge for long term storage, but not for charging a discharged battery. The Tender Jr. does shut off, float, when fully charged.

 

Now the deal is I can't say how well the Tender Jr. works on an AGM because I have never found a need for it. I had wired up the quik-disconnect harness to it when I installed it and never plugged it in. Even when I stored the battery inside of the first couple winters it did not discharge enough, only from 12.8 to 12.6, over the winter to require any charge maintance.

 

Can't beat that.

 

Mike