Charging Current: 500 mA vs. 100 mA?

[adamlau]

AC Charger #1 for Flashlight #1: 6V DC 100mA
AC Charger #2 for Flashlight #2: 6V DC 500mA

1. What happens when we use AC Charger #1 for Flashlight #2? Longer charging times...?
2. What happens when we use AC Charger #2 for Flashlight #1? Battery overheating resulting in...?

 

[Mr Happy]

1. You may possibly damage the charger or even the flashlight. The flashlight will pull too much current from the charger causing it to overheat and activate any safety cutout it contains.
2. Most likely everything works fine. The charger is over specified for the job at hand and simply copes with capacity to spare. But don't risk it in case the plug polarity is different.

 

[VidPro]

wait a minute
if he uses a 500ma charger on a battery set in a light thing that intended to have 100ma very slow charge occuring, it might go into overcharge and ruin the batteries.

more often your safer to use the slower charger on the faster item, cause it will just take forever, not overheat anything.
also
your often safer to Change batteries to HIGHER capacity within a device (better battery pack), using the same chemisty, and the same charger (cause that too is slower charge rate)

but reality, untill you know what is IN the light itself to control the charging , or if there is any control at all, and untill you know the capacity and type of battery your charging, we couldnt much make a blanket statement.

because there is Often somone who actually HAS and uses the same devices, if you would tell us WHAT exact items your referring to and the makeup of the items, a better descision could be made , or guessed at.
also we need to know the makup of the "CHARGER" your referring to, is it a standard wall wart, li-ion charger, or an actual terminating charger?
what is the battery chemistry? li-ion ? ni-??? what is the cell configuration?

 

[Mr Happy]

It's true, there are things we don't know, about the exact models of flashlight and charger for example.

Even so, given the information stated and taking it at face value, both supplies (wall warts?) are described as 6 V DC. Assuming both supplies are regulated (possibly an unjustified assumption), the excess current rating doesn't matter. A 6 V 50 A supply will deliver just the same amount of electricity into the designed load as the intended 6 V 100 mA supply would do (because the supply voltage is the same in each case). As long as the voltage remains at 6 V, more current is not going to be delivered and the batteries are not going to be overcharged or overheated and nothing is going to blow up.

On the other hand, if the load expects to draw 500 mA and the supply can only provide 100 mA, then the supply is going to be overloaded and is likely to suffer. It could simply suffer nothing worse than a drop in voltage and fail to deliver what the load is asking for, but it might overheat and burn out its circuitry. It is much more risky to have an under sized supply than an over sized supply.

Consider that your household 120 V outlets can supply 15 A if asked for (they would supply 1000 A if the breaker didn't trip). Yet you plug in a battery charger that only asks for 100 mA or less. Does it concern you that the outlet has a huge excess current available?

(Just to be clear, I am not recommending or advising to use the wrong charger with the wrong device. This is all a purely theoretical discussion.)

 

[VidPro]

ya but . . .
if its charging some 3 or 4 ni-mhy , and your average wall wart, there will always be a battery to power supply voltage differential, the higher amp wall wart will supply higher current.
if there is a TAPER due to the differential becomming smaller, then no problem, but lots of these cradle chargers are "current controlled" based on max output of the wall wart itself.

i am sure your science is correct , for some exacting specs, but wall warts used on cradle charging and in light charging doesnt use science they use slop , and it works out great .

there usually isnt enough current flowing neer end of charge to do any damage, and they sloppily change voltage and therfore current, depending on load and voltage., the lower rated ones push less current than the higher rated ones, when used in the loose CV (constant voltage) way for slow charging.

oh com'on, dont confuse me with the facts , wall warts dont use facts. Switching supplys might use more facts. so there is things we must still know.

 

[Mr Happy]

Quite valid points. So to cover myself, let me say again just for emphasis:

I am not recommending or advising to use the wrong charger with the wrong device. This is all a purely theoretical discussion.

:thumbsup:

 

[VidPro]

I am not recommending or advising to use the wrong charger with the wrong device. This is all a purely theoretical discussion.

:thumbsup:

yup and that is what the OP is stuck with unless they pull out thier meter, and find out what really happens.

but i DO fully agree with you on the fact that overdriven power supplys of BOTH types (switching and magnetic) will fail over much time when attempted to be driven at thier max or even "speced" outputs.
i have a few that used with the devices they came with, have melty cases from poor ventilation and parts that didnt last, like capacitors that blow, or transformers that char.
along with agreeing with the rest of it, either way you go, unless you check what happens and stay within (or even below) specs for the junk, there could be some minor problems.

 

[bcwang]

I agree with Mr Happy. Scenario 1 is bad and will probably result in a broken/overworked charger and possibly damaged flashlight. Scenario 2 should work if the flashlight just needs the right voltage and will pull current based on internal resistance or some other factor. As long as the adapter has a minimum current rating of what is needed, it should work. Now there is the part of the plugs being the same size and same polarity as well.

By the way, nice Terminator you've got there. I've got an 04 myself, completely stock though.

 

[adamlau]

...if you would tell us WHAT exact items your referring to and the makeup of the items...also...the makup of the "CHARGER"...what is the battery chemistry? li-ion ? ni-??? what is the cell configuration?

Referrring to the FreePlay Jonta and Indigo. Freeplay is currently moving to a universal mini-usb charger format, however my units (ordered direct from Freeplay within the past month) came equipped with the 6V 500mA and 6V 100mA wall chargers, respectively. I was hoping to use a Coby CA-989 800mA adapter for both, as well as for a Dorcy 1MCP (9V 300mA). The Jonta is powered by a rechargeable NiMH (voltage unknown, I will have to contact Freeplay Customer Service) and completes a charge cycle in 4 hours. The Indigo is powered by a rechargeable 3.6V NiMH and completes a charge cycle in 15 hours. From what I gather thus far, I may as well play it safe and charge each light with their respective charging units.

 

[VidPro]

The Indigo is powered by a rechargeable 3.6V NiMH and completes a charge cycle in 15 hours.

and is probably using a "dum" charge method of 15 hours at .1C 100ma , and would ruin the battery at 500ma. if they had put in it a termination method , or limitation method , but its unused, then that would be the only way to feed more into it.

the other one charging at 500ma , might be using a cutoff , a max voltage internally (even if the initial input is 6V) or a termination of the cells charge, because its a "smart charge" rate . it would probably handle a 100ma, BUT with the appropriate smart charge internally the 500 should work good.

you probably have 2 totally diffferent "methods" of charge in the devices, assuming they didnt mix things up.