Modifying a RCT2000VA UPS with an External charger

thehuman said:
The problem here I understand is the cheap ups charger even though it may be a 10amp charger is most probably a 2 stage charger
Current limited to x amps
Voltage limited to 27.6 volts
It does not charge battery to 28.8 v for an hour and then drops down to 27.6
Click to expand...

As far as I know the RCT 2000 comes standard with two series connected 9Ah batteries..
MAX charging current for a normal 9Ah SLA is 2.7A.

How can it have a 10A charger?

See pdf below

View attachment RT1290.pdf
 
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Can someone please try and get a diagram circuit for the ups. This will help us to bypass the internal charger.
Which company can we ask to maybe get the manual or diagram
 
Got the Manual. Thanks. It's 2.72A MAX charging current. As I predicted. Not 10A....

They have made allowance for bigger Ah batteries though...they have an option of an additional current sense resistor in parallel with R14...more current then...

Interesting design. Love to get my hands on one
 
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Again loadsheding for me will switch pc on 18:00 and take a look
Ok
Check figure S 3 B
R71 and r14 is parallel can increase the value of both to limit current to nothing
 
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Note to KOPITE.

Send the thing here to me. Let me sort out and do the simple mod and check it out. You take internal batteries out and pay postage both ways. Done and dusted. Any work I do on the thing I will share here on MBB. And the labor is free.

We all need to learn here. Plus I have equipment that can monitor and do stuff.

Ball is in your court.
 
amongstthevotingfodder said:
Note to KOPITE.

Send the thing here to me. Let me sort out and do the simple mod and check it out. You take internal batteries out and pay postage both ways. Done and dusted. Any work I do on the thing I will share here on MBB. And the labor is free.

We all need to learn here. Plus I have equipment that can monitor and do stuff.

Ball is in your court.
Click to expand...

This i think will be the safest
 
thehuman said:
Again loadsheding for me will switch pc on 18:00 and take a look
Ok
Check figure S 3 B
R71 and r14 is parallel can increase the value of both to limit current to nothing
Click to expand...

Those two resistors are in parallel. And they are both 3W low Ohm resistors. That tells me they are handling the actual current going from internal charger to internal battery/s. Design probably has a transistor base emitter junction waiting for 0.6V to switch on...and then current limits. Gut feeling.
 
Or maybe I should just buy a RCT 2000. Don't need it though. Check it out properly. Mod it and sell it to a Customer here that hates blackouts...problem is I will not have any takers.

Enough.
 
amongstthevotingfodder said:
Got the Manual. Thanks. It's 2.72A MAX charging current. As I predicted. Not 10A....

They have made allowance for bigger Ah batteries though...they have an option of an additional current sense resistor in parallel with R14...more current then...

Interesting design. Love to get my hands on one
Click to expand...

I had a close look at the circuit board and I noticed there is a resistor missing. Looks like they left it like that intentionally.
 
amongstthevotingfodder said:
Note to KOPITE.

Send the thing here to me. Let me sort out and do the simple mod and check it out. You take internal batteries out and pay postage both ways. Done and dusted. Any work I do on the thing I will share here on MBB. And the labor is free.

We all need to learn here. Plus I have equipment that can monitor and do stuff.

Ball is in your court.
Click to expand...

I can send it, but the Mrs will complain for a few days.
If you can send me something to go on with or if anyone in cpt can donate something to me in a few days then i will ship it off to you.

Any takers........
 
Some components sometimes optional . What is the resistor id ?
 
amongstthevotingfodder said:
Those two resistors are in parallel. And they are both 3W low Ohm resistors. That tells me they are handling the actual current going from internal charger to internal battery/s. Design probably has a transistor base emitter junction waiting for 0.6V to switch on...and then current limits. Gut feeling.
Click to expand...

Do you actually do these electronical components work as a day job?
 
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