charging a battery through the ps2 port

[spyghost]

hi,

i came across this device from a4tech which has the ability to charge up to 2 nimh 1400mah batteries from the ps2 port of a pc...
**broken link removed**

is this a safe way of charging such kind of battery? according to one website i found earlier (forgot the link) that the ps2 can source up to 100ma max...

 

[Exo]

A battery gets charged with current limited, so 1400mAh batteries don't get charged with 1400mA, probabely just 80mA or so

 

[pike]

That all entirely depends on the battery internal resistance. sounds feasible to me. I've seen USB cell phone chargers around to..

 

[bogdanfirst]

i have got a usb phone charger. :lol:
on my main board it says that the max current on the PS/2 port is 500mA protectd by poly fuse. though it doesn't say that it is that much on each port or on both.
now, it doesn't matter the capacitance of the battery, it matters the current you charge them with. but the gihter tha capacitance the longer it takes to charge.
now, i have seen wireless mice and kb`s that charge directly on the port. some charge even when the computer is off, because the power suply of the computer has got a standby of 5V and something like 0.5-1A.
so i think that you could use that charger. but look at how much current your charger, keyboard and mouse use, and see if you don't draw too much. my guess is that you can safely use 150-200mA for the batteries.

 

[spyghost]

well, honestly i bought already the set. i've already charged 4 batteries (those that come with the set)

my mobo documentation/manual does not come with the electrical specs of the ports. the sticker on the battery charger only says that only 2 1400mah of nimh batteries can be charged. no warning of any damage whatsoever if other rechargeabvle batteries were used.

as of now all i can say about this set is that its great specially the keyboard layout. (no promotion/advertisement intended)

 

[bogdanfirst]

hm....regarding the 1400 mAh batteries. i think that the charger has some sort of timer inside so that it stops the charging after some time.
by using other capacity of batteries you can overcharge/undegharge them.

 

[RonH]

Max PS/2 current

I actually asked ASUS what the max current for the PS/2 was and I got this reply back.

Dear Customer :

Thank you for contacting ASUS Customer Service.
My name is Paul, and I would be assisting you today.

The standard specification of PS/2 is 500mA

Thank you for using ASUS products and services !

Paul

ASUS Customer Service Center (Shanghai, China)
*If you have any suggestion or complaints about our tech support service, please contact with our TSD assistant Manager and director directly for help.

 

[bogdanfirst]

see.....i told u! about the 500mA :lol:

 

[spyghost]

hm....regarding the 1400 mAh batteries. i think that the charger has some sort of timer inside so that it stops the charging after some time.
by using other capacity of batteries you can overcharge/undegharge them.

isn't it there are so-called charging algorithms for batteries? what i am wondering about is that there is an LED that is bright when the battery is worn out (drained) or dim when the battery is fully charged. this occurs at random spans of time...

 

[bogdanfirst]

hm...i don't know about the led.
but what i was saying is that there are chargers that have a constant current source and a timer.
this way a constant current goes trought the batteries and for a specific amount of time adjusted by the capacity.
since the charger is set for 1400mAh, it charges them for a specific time.
i once bought a charger that was designed for 1000mAh batteries. it stopped charging after about 5 hours. the instructions were not clear. it was said that after the batteries were charged, the charger went to trickle mode charge. what i understood from this was that the charger knew when the batteries were charged and stopped the charging. so i wanted to charge 2000mAh batteries. and the charger stopped too soon. then i understood that it had a timer.
anyway, can you say here what it is written on the instructions?

 

[spyghost]

well, here is a link to the manual:
**broken link removed**

take a look at page 3 (english language). in bold, there is something like Receiver works as charger:

another observation that i had was this... the LED becomes dim as time passes up to a point where it would already be OFF. if another battery is placed (either a used battery or a dead battery, the LED would remain bright until it is fully charged)