Battery charging

[Rob S.]

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I have this Sears unit. When I hook it up, the middle (charging) light comes on, and the battery slowly starts bubbling. After a few hours, the right (charged) light comes on, and the battery has quieted down some.

If I then unhook and re-hook the charger up again, the "charging" light comes on, and the battery bubbles at full speed. It will then take about an hour for the "charged" light to come on.

Why doesn't the charger quickly detect that the battery is already charged?

I'll be leaving Suzy unattended for two weeks in the spring, and I'm trying to decide whether to leave her plugged in for that time. The Sears unit is a "fully automatic...charger and maintainer", but I only use it a few times a year, and always disconnect it once it shows "charged".

BTW, I recently started the bike right after charging her, and I couldn't believe how quickly it fired up. She usually starts quickly, but this was ridiculous! I didn't even hear the starter spin - the instant I touched the button she was running.

Being so difficult to remove the battery just to check electrolyte levels, I'm afraid of boiling it dry (it's an old school, old style battery).

[posplayr]

Crappy charger?? Did you pay more than $20 in this century for it?
do you have a model number? Then find the manual. You sound like you are overcharging at a high C rate

[tkent02]

If your battery won't hold a charge for two weeks either it's way past it use by date or something on the bike is discharging slowly. Fix it.
I leave my bikes for three to five weeks every time I go to work, none of them are even a little bit low when I get back. If I don't get around to it they might go two or two and a half months unused, it's never a problem. Hell my 750 fired right up in December after sitting unused since June. No charging required, the starter turned the engine very well.

Unless you are still using a regular old lead acid battery. If you are swap it out for an AGM, it is absolutely worth it.

Edit - Reading your post again, you are using a lead acid battery. Even a cheap off brand Chinese AGM battery will not spew acid all over your frame, does not need to have it's level checked, they do not leak down internally when left unused, and they last for years longer than the old school batteries. The cost something like $30 - $50 on Amazon, or spend a little more and get a quality name brand one, they still don't cost much considering all of the advantages. I left a bike sitting for four years with an AGM battery installed, when I got around to riding it the battery still had a strong charge and it worked just fine.

[posplayr]

Apparently this is the manual; 2Amp charger if he has it set correctly. It has a 12V(2A) /6V(4A) switch.

http://i.sears.com/s/d/pdf/mp-tc/10049435/prod_1688140212

[Rob S.]

No switches on the charger, it's all automatic, even detecting between 6 or 12 volts, with a light for crossed cables. It's so involved that I've only removed the battery once, several months after buying the bike. All the cells were low, a couple by more than half! (Even so, she started and ran flawlessly.)

With my Z1, I used to remove the battery frequently to rinse the exterior and check the levels. Hinge open the seat, unhook the two battery cables, and voila!

Now, I've got to remove the seat, unbolt and displace the gas tank, then unbolt and remove a frame crossmember. And it's only that easy because I ditched the stock airbox.

My charger is nearly identical to the one you posted - mine has no voltage/amp switch, no switches of any kind. After it shows "charged", the green 'charged' lamp slowly pulses on and off, indicating maintenance mode.

Suzy's charging system works beautifully, knock on wood.

[jabcb]

That is a pretty big charger/maintainer. The Battery Tender that I use is around 0.75 amp.
I am not surprised that you can see some bubbles.


I use one maintainer for a bunch of batteries. Leave it on a battery for a day or two, then move on to the next. Each battery gets charged up a few times during winter.


Not a scientific observation, but batteries seem to last longer if I charge them up only occasionally as compared to leaving the tender on all winter.

[Rob S.]

...I only use it a few times a year, and always disconnect it once it shows "charged".

I am not surprised that you can see some bubbles.

Not a scientific observation, but batteries seem to last longer if I charge them up only occasionally as compared to leaving the tender on all winter.

With the removal of the right side cover, I can see the battery, but not electrolyte levels. I hear the bubbles.

Removal of the battery on my Kaw was so easy, I never charged the battery while it was in the bike (and I rode it for a while with a dead charging system). I miss the big Z.

[John Park]

I have an old school charger from the selenium rectifier era; 6 or 12v with an amperage gauge. It likes to charge a car battery at about 4 amps, but I use a signal light bulb in series and it runs about .75 amps on a m/cycle battery. This has worked for me for decades and you can't beat the cost of the 'resistor'.

If a charger doesn't have an ammeter on it, I won't even take it as gift.

[tkent02]

Battery chargers, how twentieth century.

[posplayr]

I have an old school charger from the selenium rectifier era; 6 or 12v with an amperage gauge. It likes to charge a car battery at about 4 amps, but I use a signal light bulb in series and it runs about .75 amps on a m/cycle battery. This has worked for me for decades and you can't beat the cost of the 'resistor'.

If a charger doesn't have an ammeter on it, I won't even take it as gift.

The only downside of a built in Amp meter, is having to know what it means .
maybe a voice activated bluetooth app to interpret the amp meter reading would be useful?

[argonsagas]

Any good battery that is given a full charge should be no cause for concern if left unattended for two weeks.



If you have access to one, you could try a load-tester for the battery, which will give you a good idea of its condition.

That said, why not just try charging it and then check the voltage immediately afterwards?

Leave it for a few hours, then check the voltage again

(The initial reading is just to get a confirmation that it is fully charged and after a brief time it will show a lower voltage)

.Leave it overnight and then check it once more.

The initial voltage reading will likely be close to 14 volts.
Second reading will be in the 13s
By next day the third reading will have dropped nearer to 13, and likely just a bit under.

Check it again on another day (a fourth check) and the reading should be just about the same as the third one.

If it is significantly lower at any stage, then you have a concern about a drain on the battery from some connection, or the battery is failing.

You can charge it up once more, with the cables removed from both terminals, and repeat the checks. If the voltage holds steady, then you have a drain problem. If it drops, it is time to replace the battery.

[tkent02]

If it is significantly lower at any stage, then you have a concern about a drain on the battery from some connection, or the battery is failing.

Not really failing, just normal aging. Lead acid batteries leak a little bit of current internally, even when they are new. It's called auto discharge, and it's why they need to be recharged periodically if they are in a vehicle that is not being used. As they age the auto discharge rate goes up, after a few years it gets bad enough that it really makes sense to get a new battery rather than keep messing with it. If it won't hold a charge for a month it's pretty much done. You could milk it a while longer by charging it all the time but what a pain in the butt. Eventually it will get so bad it won't hold a charge for even a day.

One of the biggest reasons to use AGM batteries is that the auto discharge rate is so low that it just doesn't matter, they can literally sit unused for years and not lose much of their charge. My 750 sat in a storage locker since last June, just fired it up last month, the starter cranked hard. Had one AGM that sat in a bike four years, it still showed full voltage.


The other reason for even good batteries to lose their charge is something on the bike drawing a tiny current when it's shut off. Something like a clock, or a voltmeter that's connected all the time, or maybe something else on the bike that's not working correctly. More common on modern vehicles with digital stuff, but an old bike could do it too.

[Grimly]

[ATTACH=CONFIG]43975[/ATTACH]

I have this Sears unit. When I hook it up, the middle (charging) light comes on, and the battery slowly starts bubbling. After a few hours, the right (charged) light comes on, and the battery has quieted down some.

If I then unhook and re-hook the charger up again, the "charging" light comes on, and the battery bubbles at full speed. It will then take about an hour for the "charged" light to come on.

Why doesn't the charger quickly detect that the battery is already charged?

I'll be leaving Suzy unattended for two weeks in the spring, and I'm trying to decide whether to leave her plugged in for that time. The Sears unit is a "fully automatic...charger and maintainer", but I only use it a few times a year, and always disconnect it once it shows "charged".

BTW, I recently started the bike right after charging her, and I couldn't believe how quickly it fired up. She usually starts quickly, but this was ridiculous! I didn't even hear the starter spin - the instant I touched the button she was running.

Being so difficult to remove the battery just to check electrolyte levels, I'm afraid of boiling it dry (it's an old school, old style battery).

There's something askew with that charger - toss it in the trash. Just go down to Lidl or Aldi and get one of their semi-smart chargers for 20 dollars or so (they're based on one of the CTek models and are actually really good vfm). I still wouldn't leave one of them unattended for a couple of weeks - nor any charger, no matter how smart it is.

[Rob S.]

...I still wouldn't leave one of them unattended for a couple of weeks - nor any charger, no matter how smart it is.

Agree with that.

[mrbill5491]

IF you can see and hear it bubbling, its over charging already ie to fast of a charge. Battery does best at a slow rate of charge. Dump the Sears charger and go get a float charger/Maintainer from Battery Tender. Then again just get a AGM. Mine is going on 4 years old and still cranking away. Doubt that my float charger has been on it more then 2 hrs in the last four years. It only goes on for a few minutes if the bike has been sitting for a couple weeks.