Topic: trickle charger question

[Alan F.]

is there a specific difference between a trickle charger and any other 'wall transformer' type 'power pack'?  my trickle charger is rated at 500ma and has a switch for 6 or 12 volts....  is there a difference between this unit and any other power pack rated at 1/2 amp and  12 volts?  is it possible to use one of these other units as a trickle charger?

[Gordon]

500ma is 1/2 amp.  The main difference, which you'll have to check on the units themselves, is whether or not they automatically switch to a tending mode when the battery reaches full charge, or if it just keeps charging until you turn it off or unplug it. 

[Tim2005]

I found from using them for electrolysis that some (/all?)  of those "wall transformers" aren't regulated like a battery charger would be. A battery charger attached to a heavy load will still put out 1/2 amp and say 14 volts. Put a wall transformer under the same load & both the voltage & current will go up quite a bit, then it gets rather warm & packs up. I'm not sure whether a flat battery is sufficient a load to affect it like this, but suspect it is - if you try it I'd suggest you measure the volts & amps it's putting out when connected to the battery.

[Alan F.]

I'm talking about a cheap trickle charger like this one: 
And not a float charger or a 'Battery Tender' type unit or any of the smarter charging units like that.
But thanks for mentioning them, it'll certainly enrich the thread for somebody.

So if I construct a simple voltage regulator circuit maybe that would improve the operation of the common 'wall transformer' into a trickle charger....
Perhaps more intensive internet research is required?  I'm not the only cheap/creative bastard out there...

[Alan F.]

This page has considerable information, but is not specifically motorcycle battery oriented: http://cs.yrex.com/ke3fl/htm/TRICKLE.HTM

This looks like a cheap way out of buying a real 'battery tender'  http://www.bakatronics.com/shop/item.aspx?itemid=697

[jkot55]

Walmart has a motorcycle trickle charger/maintainer for about 20 bucks. 

[Alan F.]

Walmart has a motorcycle trickle charger/maintainer for about 20 bucks. 

And there's always this at Harbor Freight too: http://ww2.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42292
Looks like it's a simple wall transformer with the float circuit added inline...
-Alan

[Gordon]

Okay, I'm confused now.  Your original question seemed like a very basic question about the nature of battery chargers, which is what I responded to.  Now you're talking about taking an already cheap "wall transformer" type charger and altering it to do the same thing as another already cheap wall transformer battery tender?

Nevermind.  I think I just answered my own follow-up question...   

[bucky katt]

i have a battery tender plus, the same charger that bmw puts their stickers on and sells as a bmw brand. i've used many different chargers but this is the best one so far. i have one for the bike and one for the lawn tractor

[Alan F.]

....you're talking about taking an already cheap "wall transformer" type charger and altering it to do the same thing as another already cheap wall transformer battery tender?

Yes, that's my question.  (Cheap is a very relative term these days, isn't it?)

I have a few chargers from cell phones, or telephone answering machines or video games or whatever.....

Some of them are rated at 12vdc, 500ma

That's where the question comes in, "could these become useful to maintain a bike battery?"
"Would a simple in-line circuit make them useful for this purpose or will they work as is?"

Thanks for your input.

[Kevin400F]

I guess it would depend on the actual voltage output of the generic transformer.  A "nominal" 12V rated output might be higher or lower than a purpose-designed battery charger, which needs to put out something over 13V to actually charge a 12V battery (as one of the linked articles above pointed out).  Measuring the no-load output of the generic transformer might not tell you the real story, so your best bet is to hook it to your fully-charged battery, which should be reading about 12.4 volts +/- at rest, and see if it raises the voltage a bit.  If it does, it oughta "trickle" just fine.  Watch it to make sure it doesn't overcharge....as you probably know, the more sophisiticated battery tender-type units go into a "float mode" which drops the voltage down to a point that prevents overcharging.

[Deltarider]

I used to charge with similar cheap chargers. Results were disappointing and one even developped the nasty habit of smoking in the process. For good charging - that means to get the last electron in there safely - you need a multi-stage charger (I/U Phase U1-U2 Phase is the keyword). For motorcycle batteries, this is the very best: http://www.getgeared.co.uk/SAITO_Intelligent_ProCharger.
Every time, I'm impressed how well it charges (safely!) and how long afterwards my battery hold it's charge. I use it for all my batteries now. It's cheaper ordering it from mailorder www.louis.de in Germany (less than € 50,-), but I gave this link so you can read all about it (Click instructions and find out about what is important in charging (p8-11). It's not just about voltages but about what voltage when in a sequence of time.) Oh... and forget about leaving the battery attached. It's not necessary at all, if you do a charge-cycle say every 5 weeks.

[TomC]

Hi Chargers
     I have a 12volt 400ma charger from some device that went into the trash. It actually has an open circuit voltage of about 18 volts. I have added a 330 ohm resistor in the circuit. This resistor was handy. I use this charger to get very discharged batteries charging again. I also find it useful for charging in the winter as it will take weeks to charge a some what discharged battery. I hook up the charger and check the voltage ever week or so.
     My concern is that a discharged motorcycle battery will draw to much current when discharged. I have been given a couple of similar chargers. Next time my motorcycle battery gets discharged I will hook one up with a amp meter in the circuit and see. My preferred charging system is a day with dry roads and the temperature above freezing by 10 degrees.

....you're talking about taking an already cheap "wall transformer" type charger and altering it to do the same thing as another already cheap wall transformer battery tender?

Yes, that's my question.  (Cheap is a very relative term these days, isn't it?)

I have a few chargers from cell phones, or telephone answering machines or video games or whatever.....

Some of them are rated at 12vdc, 500ma

That's where the question comes in, "could these become useful to maintain a bike battery?"
"Would a simple in-line circuit make them useful for this purpose or will they work as is?"

Thanks for your input.

[MötleyRöx]

I bought 4 battery tenders on amazon for less than 100 bucks.
$22 each!
That's cheap in my book.   

[Alan F.]

I bought 4 battery tenders on amazon for less than 100 bucks.
$22 each!
That's cheap in my book.   

That's a pretty good deal for the genuine article.