lowering/adjusting chargers current (SOLVED...!)

[ev tocak]

Hi all ,is there a way to adjust current in this type of chargers ?
http://www.ebay.com/itm/LiFePO4-Bat...88270?pt=Battery_Chargers&hash=item4177d16e8e

 

[dnmun]

not really unless you know what you are doing.

 

[ev tocak]

maybe a few pictures would help :?

 

[Matt Gruber]

what amps do you want and what does it show on your DVM?

 

[dogman dan]

If that one has the adjusting pots in it, I don't see them. That's typical for the less expensive chargers. You get what you get. I have found as they age, they will put out less voltage. I never saw one that put out the amps they say on the label. 5 amps might only do 3 in reality, even when hooked to a very depleted battery.

You want to lower it? Bet it's lower than you think already.

 

[ev tocak]

hi Matt n dogman , I would like it to be below 3A .right now its putting out 5+A on the picture battery is almost full

 

[Matt Gruber]

easy to cut amps by adding extra resistance in series. not elegant, and won't impress engineers, but it can work.
i use a spool of awg20 wire because i have it lying around.
Teh Stork points out that stainless steel wire, awg15 that he found, is 41x the resistance of copper! So i plan to get some ss wire because it should be easy to adjust amps by sliding an alligator clip along a shorter length. a foot? a yard? 10 yards? it will be an experiment and your charger may or may not work properly. Mine all work fine.

 

[dogman dan]

Something external like that might work fine. I don't know a way to tweak one without the adjustment pots. Just make sure it doesn't resist enough to get red hot.

Sell it and get a cheaper 3 amps one?

 

[heathyoung]

No-one else saw the shunt resistors on the output?

3 X 3w wirewound beasties... I bet they are in series with the negative, and all in parallel, remove one and see what happens.

 

[ev tocak]

No-one else saw the shunt resistors on the output?

3 X 3w wirewound beasties... I bet they are in series with the negative, and all in parallel, remove one and see what happens.

heathyoung...,
your advice was spot on 8) ,indeed they are in series with negative ,parallel with positive .after removing 1st one current dropped to around 3.5A ...2nd and its 2.7A
Later on i will put variable resistor to further fine tune * charging current
so there u go Matt.... no need for 10yards of ss wire!
"JOKE"


Thanks for the effort heathyoung ,i really appreciate it!

 

[Matt Gruber]

good job!
kudos to heath! i learned what to look for too!