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Can any battery be trickle charged with low amperage?

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barythrin

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Not being that fluent in electronics, I don't quite understand trickle charging other than pulses and not overcharging a battery. I have two devices that I'm wanting to play with but I lack the proper adapter right now. I do however have a "universal" adapter that isn't made for powering high amp electronics, it only puts out 500mA while this device to run would like 3A.

If I put this 12V 500mA charger to this device and leave the device off, would it be able to safely charge the battery or am I completely misunderstanding the technology? Most of what I read out there doesn't seem like it's a good idea and would thus result in me purchasing another adapter or modifying one if I can find it with the right tip. Call me lazy or cheap, but was just trying to use what I have vs going out and overpaying for two possibly non-working power supplies to test unknown condition laptop. (i.e. our goodwill I'm sure would be thrilled to sell me some power adapters but I recall them wanting around $15/ea in as-is condition).
 
Carbon-zinc cells have been recharged since at least the 1920s. You can get some of the capacity back, but it's not as good as a secondary (rechargeable) cell.

It's not a good idea to attempt to recharge primary alkaline cells, unless you have a low-current pulsed charger designed for that specific purpose. Using, say, an ordinary NiCd charger can cause leakage of the potassium hydroxide electrolyte or buildup of gases in the cell--not very nice. In general, the results aren't very good if you're trying to rehabilitate a fully-discharged battery. There are rechargeable alkaline batteries (RAM), but they're labeled as such.

Lithium primary cells (e.g. the ubiquitous CR2032) can be downright dangerous if recharging is attempted, as they contain metallic lithium.

And there are many cells manufactured as rechargeables and labeled as such. But each has its own particular charging style (e.g. pulsing, current limiting, etc.) so it's not a good idea to mix charger types with cell types.

Neither alkaline nor lithium primary cells self-discharge, so they're great for long-life low-current long-term performance. As far as I know, all rechargeable cells have some level of self-discharge.

Hope this helps.
 
Hi
I don't think you question is clear enough.
Are you intending to connect a wall wort
to a lap top that normally has a 3A supply?
If that is so, you'll most likely burn out the
wall wort.
These supplies are not current limited. When
it says 500ma, they mean if you connect to
something that draws more, it will take out
the safety link and shut down before going up
in flames.
Dwight
 
I have to admit, that along with Dwight, I was a little puzzled by the question, so I attempted to answer it by taking the post title literally, namely, "Can any battery be trickle charged with low amperage?". I tried to answer in the general case as best as I could for any battery, be it a Le Clanché cell, Weston cell, or nickel-iron rechargeable.

However, if what you're trying to say is that you've got laptops and other gizmos that normally take their own "brick" power supply, it's generally true that if you apply the nameplate (on the device) input DC voltage, charging will be handled by the circuitry in the device and that you shouldn't have to worry about the current issue. So if your laptop says "14VDC" on the input jack, that's what you should apply--it doesn't have to be from the power supply that originally came with the unit. Make sure that your supply has ratings adequate for the job.
 
Most laptops I've seen require somewhat more than 12V; if it does require more than that you probably won't charge the batteries at all with a 12V wall-wart, regardless of the current ratings.
 
@barythrin: Just for education's sake, I would like to point out that the title's reference to "trickle" charging is normally something specific and different from what you seem to imply. A trickle charge is usually thought of as one that the battery can sustain without over charging. In other words one that can be left on indefinitely. I seem to recall that the old Radio Shack battery book, suggested something in the neighbourhood of 120ma for NiCd cells. That would mean that you should use around a 100 ohm resistor in series for a 12 volt battery. Perhaps someone with better knowledge and memory can confirm or correct this amperage. Generally, charging through a load limiting resistor (just put it in series) is a safe way to go that will protect both the charger and the chargee.

Also, as Mike pointed out, if the charging voltage is not higher than the intended charge then no electricity will flow. Think of that as having two warm objects touching each other. If one is hotter than the other, then heat will flow and warm up the colder one. If they are both the same temperature, then they will remain that way.

Anyway, that probably isn't directly useful to you in this case, - there's a lot to consider with batteries and charging. Like other have said, more information is needed, but it's not looking good so far. :)

PS: The word "goodwill" isn't really the first that comes to mind when talking about $15 for a laptop charger. That's a bit steep for an as-is kind of store. No?
 
Rule of thumb for charging NiCds is usually 10% of Ah rating, i.e. 120ma for a 1200mAh cell.
And yeah, around here "Goodwill" (;-) ) & SallyAnn etc. charge around $5.00, but as Chuck is wont to say, YMMV.
 
Yeah precisely, Goodwill computer store here thinks they're a computer store usually and sell their donated crap for close to retail prices as they can. It's really a shame lately, they USED to be a nice store for cheap gizmos, now they're just another discount electronics store.

To answer the questions, yes I'm implying a laptop and a handheld device that both want x volts and higher amps and was contemplating whether a wall wort with the correct voltage but a lower max amp output could still charge the device battery, while keeping the device off (i.e. not having it pull the amps to run but if it would still charge the battery but at a 4th of the normal charging rate). Unfortunately I don't know the type of re-chargeable battery either have which apparently is more proprietary than I realized. I didn't try it and never have before (well maybe as a child with small variance) but was just curious. I always shy away from sharing adapters or buying things that don't have adapters for that reason.

Last night I ran out to some other crap thrift stores that still have thrift store prices and bought a few adapters that fit one of the devices and one that gives out the right volts and amps and was intending on chopping up the combo, hoping the polarity is internal positive and winging it that way which should be fine assuming the adapter touches the right parts. This is what I was incorrectly calling a trickle charge (slowly trickling voltage into the battery instead of charging it at full power) .. I realize that's not really the right term or technology reference though.

Today I bettered my potential results finding an odd little recycler store that has a warehouse of boxes of crap in the back and found a universal laptop power supply that offers the right outputs for either gadget I was staring at recently for $20 which is an acceptable price to me. The problem I was having was typically all the chain stores around here have universal power supplies for $40-99 which is much more than the devices I'd play with cost.

I guess my theory was based on laptop batteries (Li-Ion), for instance a device that came with a 1200mA battery can still use a 2400mA battery with the right voltage and it would just have a longer running time right (watts?). I thought perhaps the opposite was true still but maybe as pointed out it wouldn't have enough amps to push the power into the battery? But yes 12v is the one handheld appliances requirement, the other was 19v.

I think I'm good with the universal charger though now, but still wanted the education for myself and perhaps others that stumble upon this thread :)
 
A small nitpick: batteries are rated in mAh (milliamp hours) or Ah (Amp hours), not mA; mA refers to the current that the device uses, and mAh says how long that battery can supply that much current.

Watts are also the power that the device uses, just like light bulbs (nothing to do with the battery), and are essentially the voltage times the (milli)amperage.

So, A 1200 mAh battery would theoretically power a device that uses 600 mA (0.6A x 12V = 7.2 Watts at 12V) for 2 hours (1200/600); a lower wattage device would run longer.
 
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doing some digging online for used batteries can be worth it if you don't find anything reasonable around. Personal sellers or discount/coupon hunting for sites can be worth it. I like to rebuild and resell laptops as a hobby and have found it more many great deals with a little searching! I love bargain hunting.
 
Hi
I think there is some confusion as to what a wall wort
is and a charger is.
A charger is a circuit that controls the current and voltage
for a particular battery. The power pack you plug into
a laptop is not a charger, it is a power supply. The charger
is in the laptop. A charger can be as simple as a Dc power supply
and a current limiting resistor.
Now, how about using a wall wart for a laptop power supply.
If the wall wart is rated for a lower current than what the
laptop expects for charging, you'll most likely burn out the
wall wart.
The wall wart is not a supply that has an active current limit.
If you try to draw more current from it than it is rated for,
it will simply over heat and open the primary winding.
It expects the load to control the amount of current that
it is using.
Using a voltage less than the expected voltage for charging
will not charge.
I'm hoping I'm making some sense here.
Dwight
 
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