2.5 amp charger

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JamieWlcox
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2.5 amp charger

Post by JamieWlcox » Mar 17, 2018 5:29 am

I have recently blown a few Chargers due to the polarity being on the opposite sides of a one way plug. So I have bought a resistor kit to fix the Chargers

After fixing I wanted to check the output voltage and amps to ensure proper use because I used a .33 ohm resistor which should have been a .1 ohm resistor I wanted to double-check the output

After doing so I checked all 3 chargers one of which the factory Seal had not been broken all measured between 56 and 59 volts. The Chargers were 2.5 and 3.0 amp Chargers

My question is they are putting out between 19-20 amps with no load
What am I confused about here how does a 2.5 amp charger put out 20 amps.
The battery is also charging to 57.4 volts that seems kind of high to me for a 48 volt battery

dustNbone
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Re: 2.5 amp charger

Post by dustNbone » Mar 17, 2018 9:38 am

If there's no load on them (no battery connected) then they're not outputting any amperage at all.

Current is measured inline with a load, no load, no current.

A fairly good explanation here:

https://www.powerstream.com/how-to-measure-current.htm

As for the voltage, it depends on the battery. Generally 48V batteries are 13 or 14 cells in series. 13 cells is usually around 54V fully charged, 14 cells is around 58V. Alot of 14S batteries are labelled/marketed as 52V, but not all.

It sounds like you have some chargers at each voltage, it would be good to determine which one is the correct one for your particular battery to avoid over charging it.

markz
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Re: 2.5 amp charger

Post by markz » Mar 17, 2018 1:58 pm

I did something similar with a little wall charger for rc toy.
I was trying to balance charge my ebike pack manually.
With snipped charger leads, I connected wrong and the output decreased in voltage and would never turn on. So garbage.

I then bought a Wii charger from Value Village for $3 it had a rated voltage that suited my needs but the amp rating was like 3A or something. So I was even more careful now, triple checking where I alligator clipped the leads. Hooked it up, and read 8A. I was like Whoooaaaaaaaaaaaa. I will go back and find another adapter and monitor is closely.

I am waiting on a balance charger from Gearbest. For now the unbalance is doable, its not far off.

markz
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Re: 2.5 amp charger

Post by markz » Mar 27, 2018 8:20 pm

I recently bought a couple thrift store $3 HP chargers, 32V 0.625A and 30V 0.333A. I figure I would do a 4.0V/cell on 8S and 3.75V on 8S then finish them off with the weezy wimpy I-Max B6 for balance.

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amberwolf
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Re: 2.5 amp charger

Post by amberwolf » Mar 28, 2018 5:53 pm

markz wrote:
Mar 27, 2018 8:20 pm
I recently bought a couple thrift store $3 HP chargers, 32V 0.625A and 30V 0.333A.
Those sound like their printer / all-in-one power supplies, rather than chargers. If so, they probably aren't usable as chargers, as all of the ones I've tried out use "hiccup" current limiting, so they just shutdown when connected to a battery that needs charging (rather than a full one, or one so nearly full that current draw is negligible or well within the max spec of the PSU).


(well, actually some of them just die when their current max is exceeded, either because of an onboard fuse that blows, or some other component that explodes).

markz
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Re: 2.5 amp charger

Post by markz » Mar 28, 2018 9:09 pm

Purchased from Value Village
HP 0957-2242 - Deskjet
HP 0957-2286 - Photo All-in-one

You are right Amberwolf, both are printer power supplies, so I donated $6 to V.V.
Next time I will google the model #'s right in the store.
amberwolf wrote:
Mar 28, 2018 5:53 pm
Those sound like their printer / all-in-one power supplies, rather than chargers. If so, they probably aren't usable as chargers, as all of the ones I've tried out use "hiccup" current limiting, so they just shutdown when connected to a battery that needs charging (rather than a full one, or one so nearly full that current draw is negligible or well within the max spec of the PSU).


(well, actually some of them just die when their current max is exceeded, either because of an onboard fuse that blows, or some other component that explodes).

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