Upgrading UPS with 2 X 18ah battery

[jwpwhite]

This is an overview of an upgrade to my RCT 2000VA UPS with 2 x 18ah batteries.

*** Consult a qualified electrician to assist you with this sort of project due to shock and fire risks. Working with high voltages is EXTREMELY DANGEROUS. I accept no liability for anyone following these steps. ***

1. Tape the two 18ah batteries together with ducktape with the terminals on the outer four corners.
2. The two 18ah batteries need to be connected in series to create a 24v battery. Create a short jumper cable to link the positive terminal of the 1st 18ah battery to the negative terminal of the 2nd 18ah battery. A 50AMP fuse should also be added to this jumper cable.
3. Next you will be creating the connector cables. To avoid short circuits, create the jump cables first and only connect them to the batteries once finished.
4. First create the black and red jumper cables to connect the existing 24v battery (2 x 7ah 12v batteries) to the new 24v battery (2 x 18ah 12v batteries) in parallel. One end will have a lug and the other a crimp connector.
5. Next create the black and red jumper cables (each 50cm long) that connect the batteries to the UPS. The one end of the cable will have a connector lug and the other the Brad Harrison connector lug. Insert the Brad Harrison connector lugs into the plug making sure the red cable connects to the positive terminal and the black to the negative terminal.
6. Wire up the two sets of batteries with the jumper cables you created
7. Power down the UPS and unplug it from the mains.
8. Turn it onto its side and unscrew the 4 screws holding the top onto the UPS.
9. Carefully lift the top of the UPS off the base. There are cables connecting the top to the bottom so be careful doing this. DO NOT TOUCH ANY OF THE INTERNAL COMPONENTS as they batteries are still powering up the unit with 240V.
10. Unscrew the battery bay and lift out the two batteries carefully.
11. Unplug the two battery terminals. Leave the jumper cable connecting the positive of the one battery to the negative of the other battery.
12. CAUTION: There is capacitor in the unit which means there could still be power in the unit even though the batteries are disconnected and the unit is unplugged.
13. DO NOT LET THE DC BATTERY TERMINALS TOUCH AFTER YOU DISCONNECT THEM FROM THE BATTERY
14. Drill a 15mm hole in the side of the UPS and thread the cables through one by one being careful that the connectors do not touch. Cable tie both ends of the cable to prevent the cable moving and putting pressure on the internal components.
15. Close up the UPS unit leaving both sets of batteries outside the UPS
16. Cut off the crimp connector on the red (positive) cable and connect it to one of the Brad Harrison connector lugs. Then insert the lug into the positive terminal of the Brad Harrison plug.
17. Cut off the crimp connector on the black (negative) cable and connect it to one of the Brad Harrison connector lugs. Then insert the lug into the negative terminal of the Brad Harrison plug.
18. Connect the Brad Harrison plugs and then connect the UPS to the mains.
19. Say a prayer and power the UPS on

 

[quovadis]

Battery supplier at that price?

 

[RedViking]

And 2x105Ah batteries?

 

[quovadis]

And 2x105Ah batteries?

Safer to just purchase an inverter with a rated charger.

 

[jwpwhite]

And 2x105Ah batteries?

I used 2 x 18ah batteries. I would ideally like to use 2 x 100ah deep cycle batteries but they would cost about R2,000 each... May upgrade in the future hence the Brad Harrison connectors

 

[Gaz{M}]

I doubt that UPS can charge 2 x 100ah batteries. It's probably rated at 3A charging current, so they will never recharge between loadsheddings. Even 2 x 18ah are probably not going to get enough recharge.

 

[Pineapple Smurf]

I doubt that UPS can charge 2 x 100ah batteries. It's probably rated at 3A charging current, so they will never recharge between loadsheddings. Even 2 x 18ah are probably not going to get enough recharge.

my APC 1000VA recharges my 2x105aH no problem at all, I have installed a voltmeter inline so i see the batteries charging from 25.4v (when ESKOM comes back on again) to 27.4V before it comes to a rest. Takes 2 or 3 hrs.
My original batteries were 2x12aH

 

[Gaz{M}]

my APC 1000VA recharges my 2x105aH no problem at all, I have installed a voltmeter inline so i see the batteries charging from 25.4v (when ESKOM comes back on again) to 27.4V before it comes to a rest. Takes 2 or 3 hrs.
My original batteries were 2x12aH

You telling me the 105's are completely depleted? No ways that UPS is putting out 40 amps into your two batteries in 3 hours.

 

[Pineapple Smurf]

You telling me the 105's are completely depleted? No ways that UPS is putting out 40 amps into your two batteries in 3 hours.

25.4 Volts i said

 

[jwpwhite]

my APC 1000VA recharges my 2x105aH no problem at all, I have installed a voltmeter inline so i see the batteries charging from 25.4v (when ESKOM comes back on again) to 27.4V before it comes to a rest. Takes 2 or 3 hrs.
My original batteries were 2x12aH

And the fact that the batteries are going through smaller cycles means they will last a whole lot longer

 

[Pineapple Smurf]

This is an overview of an upgrade to my RCT 2000VA UPS with 2 x 18ah batteries.

*** Consult a qualified electrician to assist you with this sort of project due to shock and fire risks. Working with high voltages is EXTREMELY DANGEROUS. I accept no liability for anyone following these steps. ***


View attachment 637206

1. Tape the two 18ah batteries together with ducktape with the terminals on the outer four corners.
2. The two 18ah batteries need to be connected in series to create a 24v battery. Create a short jumper cable to link the positive terminal of the 1st 18ah battery to the negative terminal of the 2nd 18ah battery.
3. Next you will be creating the connector cables. To avoid short circuits, create the jump cables first and only connect them to the batteries once finished.
4. First create the black and red jumper cables to connect the existing 24v battery (2 x 7ah 12v batteries) to the new 24v battery (2 x 18ah 12v batteries) in parallel. One end will have a lug and the other a crimp connector.
5. Next create the black and red jumper cables (each 50cm long) that connect the batteries to the UPS. The one end of the cable will have a connector lug and the other the Brad Harrison connector lug. Insert the Brad Harrison connector lugs into the plug making sure the red cable connects to the positive terminal and the black to the negative terminal.
6. Wire up the two sets of batteries with the jumper cables you created
7. Power down the UPS and unplug it from the mains.
8. Turn it onto its side and unscrew the 4 screws holding the top onto the UPS.
9. Carefully lift the top of the UPS off the base. There are cables connecting the top to the bottom so be careful doing this. DO NOT TOUCH ANY OF THE INTERNAL COMPONENTS as they batteries are still powering up the unit with 240V.
10. Unscrew the battery bay and lift out the two batteries carefully.
11. Unplug the two battery terminals. Leave the jumper cable connecting the positive of the one battery to the negative of the other battery.
12. CAUTION: There is capacitor in the unit which means there could still be power in the unit even though the batteries are disconnected and the unit is unplugged.
13. DO NOT LET THE DC BATTERY TERMINALS TOUCH AFTER YOU DISCONNECT THEM FROM THE BATTERY
14. Drill a 15mm hole in the side of the UPS and thread the cables through one by one being careful that the connectors do not touch. Cable tie both ends of the cable to prevent the cable moving and putting pressure on the internal components.
15. Close up the UPS unit leaving both sets of batteries outside the UPS
16. Cut off the crimp connector on the red (positive) cable and connect it to one of the Brad Harrison connector lugs. Then insert the lug into the positive terminal of the Brad Harrison plug.
17. Cut off the crimp connector on the black (negative) cable and connect it to one of the Brad Harrison connector lugs. Then insert the lug into the negative terminal of the Brad Harrison plug.
18. Connect the Brad Harrison plugs and then connect the UPS to the mains.
19. Say a prayer and power the UPS on

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Very neat setup by the way
On my setup I used a 50AMP fuse in line instead of that 1 red cable you have there to bridge my batteries in series.
It was already there inline with the 12aH batteries when i opened it up for the first time.

 

[Pineapple Smurf]

And the fact that the batteries are going through smaller cycles means they will last a whole lot longer

Exactly why i have put big batteries in and i try and keep my load to 400 watts or less.
Quite often i dont even bother switching on my 55" tv, then the batteries are even happier.
For me it isn't about how long can i run a big load, i like protecting my batteries and a Volt meter is important

 

[DeTector]

my APC 1000VA recharges my 2x105aH no problem at all, I have installed a voltmeter inline so i see the batteries charging from 25.4v (when ESKOM comes back on again) to 27.4V before it comes to a rest. Takes 2 or 3 hrs.
My original batteries were 2x12aH

Exactly what I am going to build only with a 1.2kva ups. What type of batteries are you using if I may ask? Normal lead acid, deep cycle or gel? And with about the 400W load you mentioned further down how long does this setup last for you?

 

[Pineapple Smurf]

Exactly what I am going to build only with a 1.2kva ups. What type of batteries are you using if I may ask? Normal lead acid, deep cycle or gel? And with about the 400W load you mentioned further down how long does this setup last for you?

i am using standard lead acid 2x105aH truck batteries, they're second hand and work well for me.
In the worst case scenario my batteries go down to 25.4Volts from 27.4V
There might be a decimal or two place difference as I am using a cheap voltmeter from eBay i purchased a few years ago. So it is just a guideline as to where my batteries are sitting. Will use my Fluke meter to get a more accurate reading.

My UPS in kitchen running mini hifi and undercounter LED light has been blinged with 2x22aH lead crystals (also 2nd hand) and they have been running now in the UPS for about 6 years (maybe more). Also no problem at all

 

[mh348]

What load do you have on the UPS and whats the runtime?

runtime before and after the upgrade?

 

[jwpwhite]

Exactly why i have put big batteries in and i try and keep my load to 400 watts or less.
Quite often i dont even bother switching on my 55" tv, then the batteries are even happier.
For me it isn't about how long can i run a big load, i like protecting my batteries and a Volt meter is important

Thanks Chuckmyster
I need to get a fuse included in my setup. Could you send me more info on the fuse and voltmeter you are using?

 

[Pineapple Smurf]

Thanks Chuckmyster
I need to get a fuse included in my setup. Could you send me more info on the fuse and voltmeter you are using?

The fuse is similar to a blade fuse as used in cars but physically a bit bigger. It came with my UPS.
Otherwise car audio shops will have something similar or even camp shops as the bakkie drivers like installing these things with their camp fridges, external batteries etc.

Here is a photo i took moments before ESKOM came back on again after 2 and a half hrs loadshedding whilst i was running my 55" TV, Yamaha Amp, laptop, 24" external monitor, wifi and various small items.
You can pick up these voltmeters at Communica for just over R100 I hear, just make sure you ask for the <30 Volts one and not the std 12v one as you are also in series.

 

[RVZ]

I'm thinking of doing something similar. I have 2 RCT 650va UPS's, with dead batteries. Can I connect a 105ah battery to each? Will they be able to charge the batteries? The one will power a NAS, IP camera and router, and the other one will power a router, POE switch with 2 POE cameras and a pc which will shut down when the power goes off. How much uptime can I expect from these?

 

[quovadis]

I'm thinking of doing something similar. I have 2 RCT 650va UPS's, with dead batteries. Can I connect a 105ah battery to each? Will they be able to charge the batteries? The one will power a NAS, IP camera and router, and the other one will power a router, POE switch with 2 POE cameras and a pc which will shut down when the power goes off. How much uptime can I expect from these?

You really should only do this if you understand what you're doing. It depends on the UPS and its technical specifications.

 

[jwpwhite]

The fuse is similar to a blade fuse as used in cars but physically a bit bigger. It came with my UPS.
Otherwise car audio shops will have something similar or even camp shops as the bakkie drivers like installing these things with their camp fridges, external batteries etc.

Here is a photo i took moments before ESKOM came back on again after 2 and a half hrs loadshedding whilst i was running my 55" TV, Yamaha Amp, laptop, 24" external monitor, wifi and various small items.
You can pick up these voltmeters at Communica for just over R100 I hear, just make sure you ask for the <30 Volts one and not the std 12v one as you are also in series.

View attachment 637344

Great, thanks Chuckmyster