How to decrease charging current?

I want to decrease the charging current of a Desi UPS.

The guy who build this, said something about moving the one of these wires

There is also a Charge out switch on the board.

Overall view of the UPS

http://i.imgur.com/S2HjjcK.jpg

Although I can't be very sure in your particular ups but I can tell you a simple trick.

There are two diodes that form a full wave rectifier. Disconnect one of them and your current would reduce to roughly 50%. However it will also reduce the output voltage which may create a problem for the charging cycle to reach its end point.

Try it and see. You can always reconnect later if it does not work.

Aurangzeb

disconnecting the diode will affect the rectification ?

I think he said something about the yellow or blue wire. these wires are related to transformer IMHO.

its most probably the yellow wire,, which has 4 options at 5 Amp steps of 5-10-15-20 A... mine had the same setup..

PS; the ups looks made of quality stuff but very poor build quality..

[quote=“farhan_ds, post:4, topic:21159”]

its most probably the yellow wire,, which has 4 options at 5 Amp steps of 5-10-15-20 A... mine had the same setup..

[/quote]

So I should move it toward position 4 or position 3 ?

[quote=", post:, topic:"]

PS; the ups looks made of quality stuff but very poor build quality..
[/quote]

With surgeries I have performed, it had to look that way... ;)

Cover is usually removed...

Blue wire can't control charging since it is for the panel meter. Most likely it is yellow wire which needs to be shifted to position 4.

If you are not sure or you don't want to take any risk, you need to get an AC voltage meter and do some measurement as follows:

1) Remove AC input, output and battery. Then remove the transparent cover from the terminal block on the transformer.

2) Connect battery and then AC input. While UPS is charging, measure the voltage at 5, 4, 3,2 and 1 with respect to 6.

3) If voltage at 5 is lower than voltage at 4, then shifting the yellow to 4 will decrease the charging current.

0V is common, Connect 220V to charging. Connect 250V to inverter out.
Deeper most or first one is 0V or neutral. It is start of winding so is single wire. Outer most is 280V or 5th one. It is end of wire hence it is single wire. These can also be identified by checking resistance with a digital meter. Resistance between 0V and 190V is 2.7 ohm and it is 4 ohm between 0V and 280V. (Value for voltages and resistance are just for example. Actual may be different. Voltage and charging can be increased and decreased by shifting connection to nearby loop. The one having highest volts have the lowest charging current, so shift wires accordingly by checking volts. I’ve attached pictures for better understanding

Regards

[quote=“waqar789, post:7, topic:21159”]

0V is common, Connect 220V to charging. Connect 250V to inverter out.
Deeper most is 0V or common. It is start of winding so is single wire. Outer most is 280V. It is end of wire hence it is single wire. These can also be identified by checking resistance with a digital meter. Resistance between 0V and 190V is 2.7 ohm and it is 4 ohm between 0V and 280V. (Value for voltages and resistance are just for example. Actual may be different. Voltage and charging can be increased and decreased by shifting connection to nearby loop. The one having highest volts have the lowest charging current, so shift wires accordingly by checking volts. I’ve attached pictures for better understanding
Regards
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[quote=“yousaf465, post:5, topic:21159”]

So I should move it toward position 4 or position 3 ?

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with the 5 amps steps, its your choice what type of charging rate you want..usually its 5 amps step if your peak charging is 20 amps max.

[quote=“farhan_ds, post:9, topic:21159”]

with the 5 amps steps, its your choice what type of charging rate you want..usually its 5 amps step if your peak charging is 20 amps max.

[/quote]

At the current position, it is charging at ~25A. which is too high IMHO.

[quote=“waqar789, post:7, topic:21159”]

0V is common, Connect 220V to charging. Connect 250V to inverter out.

Deeper most or first one is 0V or neutral. It is start of winding so is single wire. Outer most is 280V or 5th one. It is end of wire hence it is single wire. These can also be identified by checking resistance with a digital meter. Resistance between 0V and 190V is 2.7 ohm and it is 4 ohm between 0V and 280V. (Value for voltages and resistance are just for example. Actual may be different. Voltage and charging can be increased and decreased by shifting connection to nearby loop. The one having highest volts have the lowest charging current, so shift wires accordingly by checking volts. I’ve attached pictures for better understanding

Regards

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Thanks for explanation, at the time of installation, UPS technician said something similar.

Can't see the pictures...

Here are the pictures, I think I wasn't able to attach them in my previous post, all you need is a digital ammeter and there you go, you can also install a simple switch for variable charging according to loadshedding situation u5ata3uv.jpggaze3yhy.jpg

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Values with reference to position 6

Position 5 : 216V

Position 4 : 235V

Position 3: 257V

Positon 2: 279V

Connect Invertor @ position 4 and charger @ position 2 Have you taken these values on battery backup or through AC source?

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[quote=“waqar789, post:14, topic:21159”]

Connect Invertor @ position 4 and charger @ position 2 Have you taken these values on battery backup or through AC source? Sent from my LT22i using Tapatalk

[/quote]

as suggested by @Ijaz Ahmed I measured these while UPS was charging. So i should move yellow wire to which position ?

Moving away from 5 towards 2 will gradually reduce the charging current. Set it at the point where you get the desired charging level.

First of all differentiate between the charging and invertor wire going towards the pcb board, mostly ups technicians join them together and connects to a single loop of transformer output loop, secondly don't rely on colours check their voltages again on AC source and mark them accordingly, now connect inverter wire which you distinguished in first step to 235V of transformer out and connect charger wire with 279v or rhe highest voltage wire coming out of the transformer wirring. Remember, check charging current when battery is at lowest set point, also check inverter output voltage when its working in inverter mode, do all these things but lifting off all your load from UPS. Regards

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