fyi: local wal-mart has 800maH charger for $20

[se7enty7]

comes with a quick connect attachment so you don't have to remove your seat everytime...

my local super-walmart has these, but the normal one didn't... course the normal one is about to shutdown


they also had helmets, disc locks, true motorcycle gloves, etc....

[Rema1000]

I have the 850mA Wal-Mart one.  A couple of problems:

The "quick disconnect" looks like the standard SAE 2-pin connector:


This is cool, since you can re-use the connector with a heated vest or whatever.

On the SAE 2-pin connector, one pin is going to be ground, and the other will be +12v hot.  Obviously, you want the exposed male side to be ground, and the shielded female side to be hot.  

If the SAE 2-pin is running to your heated vest, there's no problem.  But if it's running to a +12v charger, then there is a problem:  since you have to hook the +12v from the battery to the +12v from the charger, one side or the other has to have an exposed +12v prong. The question is: would you rather risk shorting the battery, or the charger.  The battery is more expensive.  And if shorted, the battery can make a bigger mess.  The charger can only produce <1Amp, but the battery can produce 40-210 amps for an instant.  If shorted, the battery will make a bigger mess!   And the charger is only a concern when it's powered-on, but the bike battery is always "on".

Unfortunately, the makers of this charger were only thinking in terms of their charger, so the +12v lead from the charger is shielded (making the +12v prong from the battery unshielded).  The connector on the bike does have a protective cover, but in my case, the plastic cover broke off in the cold of January. The exposed +12v prong touched the bike frame and shorted the battery . Luckily, I was planning on replacing the battery anyways :guns: .  OK, I'll admit that I should have had a fuse in there!

So if you buy the Wal-Mart charger, I'd recommend cutting the wire by the charger, and flipping the two wires around, and crimp/solder. That way, the connector on the bike will have the +12v wire on the shielded, female side.  You'd also want to use tape to mark the black battery clamp "red", and vice-versa.  Also, you'd want to add an inline fuse onto the battery pigtail.

Another shortcoming I've had with this charger, is that it won't charge completely flat batteries.  My car battery was drained due to a door ajar.  I connected the Wal-Mart charger, and the single LED didn't light up.  This is supposed to mean either "battery is all charged", or "there is no battery connected".  So I assumed that the battery was good, checked the fuses (all good) and called the dealer.  The dealer diagnosed a dead battery , and I was out a $150 towing fee.

I saw the same thing later with a friend's dead battery (he left the trunk unlatched while on vacation); same problem: the Wal-Mart charger wouldn't charge it at all.  My friend hooked-up a "dumb" charger for a few minutes, which happily charged it, then he switched back to using the Wal-Mart smart charger, which finally recognized that a battery really was attached, and started charging it.


After all that, I'd look at a Battery Tender Jr. if I were buying again.  I don't know whether it is designed any better, but I'd at least look at it.

[se7enty7]

I've got a walmart charger (goes down to 2amps only though..) it's like 2 amps, 6 amps, or 12 amps... or something like that... THAT will charge a dead battery.  

The motorcycle charger ONLY does 850mah..... which isn't enough to charge a totally dead battery...


but yeah I would get a better connector.  Radio shack probably sells on that is totally shielded on both ends..

[Rema1000]

Oh, you're right, I was talking about the 850mA charger.

[Kerry]

Is a brand  new battery with electrolyte freshly added considered to be a "dead" battery?  :dunno:

I used my Battery Tender to give the initial charge to a battery like that.  (My first and only replacement battery ... so far.)  It probably took 24 hours or more, but it worked.

[Rema1000]

Yeah, I also used the Wal-Mart 850mA charger to charge a brand-new battery (shipped dry, and I added acid).  That worked (I left it connected for a couple of days) :wtf: !?.  But twice, I tried charging a car battery that was completely flat (from having the lights left on), and the "charging" LED did not light.

Perhaps the charging light didn't come on for the new motorcycle battery either; but maybe it was charging anyways?  Or perhaps there is a difference between a new motorcycle battery and a flat car battery. :dunno:

[ghettorigged]

Isn't a car battery much LARGER than a moto one?  :dunno:  I would think that a normal moto charger would only 'warm' an already charged car battery.

I also have a walmart charger. Schumacher Battery Companion. It does charging & tending. $17.95 + tax

[Rema1000]

Isn't a car battery much LARGER than a moto one?  :dunno:  I would think that a normal moto charger would only 'warm' an already charged car battery.

An 850mA charger adds charge to the battery at a rate of 850 milliAmpres per hour, while a 10A car charger adds at almost 12 times that rate.  The battery will get "full" 10 or 11 times slower with the smaller charger, but it will still get charged (eventually).  But you're right, there is some static loss of charge (a battery just sitting will slowly lose charge), but I'd guess that it's less than 10mA, much less than the 850mA of the m/c tricklecharger.

I have a large deep-cycle boat battery that I run part-way down with a trolling motor, then charge-up again with the 850mA charger... it's done charging within a few days .

[se7enty7]

okay... I actually bought the charger tonight.  It's 750mah btw.


also the cord on mine... the neg end is exposed on the BIKE side... so yeah.. don't touch the charger end to anything.. it would be kind of hard to short it out though..

[crash]

hrm

the only charger i saw at walmart was the 1.5A 6/12V one.  if i use it, will it hurt the gs batery?

[Rema1000]

The "rule of thumb" I've heard is to try to stick to 10% of total capacity, or a 1.1A slow-charge for an 11amp-hour battery.  If you've got an aftermarket battery, it may have a higher rating, making 1.5A okay.  

In any case, if the battery doesn't get hot when charging, then it's probably okay.  Getting too hot causes the plates to warp, until they short.  The flatter the battery is when you put it on the charger, the more heat will be generated when you first hook it up.  I think that you could use a much higher amperage charger provided that the battery isn't very flat; or if the battery is quite flat, then only use the charger for a few minutes at a time, and give the battery a minute to cool off in-between.

For example, when you hook a car battery directly to a flat motorcycle battery: the car battery is capable of putting-out a huge amount of power.  There is nothing preventing it from charging the motorcycle too fast.  If the voltage is significantly different, the motorcycle battery will get hot.  But this is not really a problem, because you wouldn't hook-up the batteries together for more than a few minutes (*).

Using a tricklecharger is really just to make it impossible to accidentally charge the battery from flat to charged, too fast.  I'd say that as a tricklecharger for my OEM battery (1.1Ah), less than 1.1A is perfect, 1.5A is probably acceptable, 2A is marginal... and 2.5A or more is not really a trickle charger anymore; 5A is just too darned much.

(*)If you want to charge a very flat battery from a charged battery, or you have a huge charger (say 10A), you could run the current through a 10W or 15W lightbulb on the way to the battery.  As the lightbulb approaches its rated wattage, its resistance increases.  This limits current to 850mA or 1.25A.

[Rema1000]

Another shortcoming I've had with this charger, is that it won't charge completely flat batteries.  My car battery was drained due to a door ajar.  I connected the Wal-Mart charger, and the single LED didn't light up.  This is supposed to mean either "battery is all charged", or "there is no battery connected".  So I assumed that the battery was good, checked the fuses (all good) and called the dealer.  The dealer diagnosed a dead battery , and I was out a $150 towing fee.

I saw the same thing later with a friend's dead battery (he left the trunk unlatched while on vacation); same problem: the Wal-Mart charger wouldn't charge it at all.  My friend hooked-up a "dumb" charger for a few minutes, which happily charged it, then he switched back to using the Wal-Mart smart charger, which finally recognized that a battery really was attached, and started charging it.

Update/more info:  
I have the 1.5A "Vector" charger from Wal-Mart.  Again, today, I needed to charge a completely flat battery (a 750mAh 12v gel-cell, unused for 18 months).  The battery read 4 volts.  I hooked up the Vector-brand Wal-Mart charger, and the "charging" LED didn't light.  A voltmeter still showed only 4 volts; the charger wasn't supplying anything.

Then I took a little 9v battery and touched the positive terminal to positive on the big 12v, and took a screwdriver and momentarily touched the ground on the little 9v to the ground on the big 12v.  Immediately, the charging LED on the Vector charger lit-up.  Now, a voltage probe reads 12.8v (supplied by the charger), and the battery is charging (even if a little faster than desirable, at 1.5A).

Apparently, the 1.5A Vector charger needs some voltage across its leads, before it's charging computer decides that there really is a battery there (somewhere above 4v but below 9v appears to be the threshold).  On the negative side, this made it useless when I had completely run-down the car battery (dome light on).  On the positive side, the charging leads are not hot when they are not connected to a battery, so there is no danger of accidentally shorting them to each-other.

[Mandres]

Another shortcoming I've had with this charger, is that it won't charge completely flat batteries.  My car battery was drained due to a door ajar.  I connected the Wal-Mart charger, and the single LED didn't light up.  This is supposed to mean either "battery is all charged", or "there is no battery connected".  So I assumed that the battery was good, checked the fuses (all good) and called the dealer.  The dealer diagnosed a dead battery , and I was out a $150 towing fee.

I saw the same thing later with a friend's dead battery (he left the trunk unlatched while on vacation); same problem: the Wal-Mart charger wouldn't charge it at all.  My friend hooked-up a "dumb" charger for a few minutes, which happily charged it, then he switched back to using the Wal-Mart smart charger, which finally recognized that a battery really was attached, and started charging it.

Update/more info: 
I have the 1.5A "Vector" charger from Wal-Mart.  Again, today, I needed to charge a completely flat battery (a 750mAh 12v gel-cell, unused for 18 months).  The battery read 4 volts.  I hooked up the Vector-brand Wal-Mart charger, and the "charging" LED didn't light.  A voltmeter still showed only 4 volts; the charger wasn't supplying anything.

Then I took a little 9v battery and touched the positive terminal to positive on the big 12v, and took a screwdriver and momentarily touched the ground on the little 9v to the ground on the big 12v.  Immediately, the charging LED on the Vector charger lit-up.  Now, a voltage probe reads 12.8v (supplied by the charger), and the battery is charging (even if a little faster than desirable, at 1.5A).

Apparently, the 1.5A Vector charger needs some voltage across its leads, before it's charging computer decides that there really is a battery there (somewhere above 4v but below 9v appears to be the threshold).  On the negative side, this made it useless when I had completely run-down the car battery (dome light on).  On the positive side, the charging leads are not hot when they are not connected to a battery, so there is no danger of accidentally shorting them to each-other.

This is an interesting idea, the battery on my new bike is doornail-dead, 0.1 volts.  The PO had let the bike sit, untouched, for a year and a half.  After filling the cells with distilled water  I bought a 1.5A  trickle charger today, hooked it up, and got the same problem.  Apparently with too low/no load the charger doesn't recognize that a battery is hooked up.  I tried your 9v battery trick and got a similar result; the charging light comes on and the juice starts flowing.  Unfortunately, the charger shuts off again as soon as the 9v is disconnected.  I'm not going to leave the 9v hooked up for more than a second (exploding Duracell anyone?) so this charger is basically useless for my situation.  The battery is probably trash anyway, but I thought that maybe I could breathe some new life into it.  Anybody know any other tricks for bringing a battery back from the grave?  The wal-mart ES12BS is $50.00 now and I'd rather buy a riding jacket.

-M