Modifying a RCT2000VA UPS with an External charger

[thehuman]

OK, this is how I ran a similar setup at work for a couple of years without any problems. The extra battery pack (12V or 24V depending on your UPS) is connected in parallel to the UPS internal pack via the normally open contacts of a 220 Volt relay. The relay is fed from the mains supply, thus as long as there is mains the extra batteries are disconnected from the UPS internal battery pack. The ups chargers its own battery pack and the external pack is connected to a separate charger. When the mains fails the relay drops out and connects the external pack to the internal pack and Bob's your Auntie.

Show that to your electrician
Take old bateries with

 

[BigEars]

 

[thehuman]

View attachment 218222

Alot safer if a electrician do the mods .

 

[KOPITE]

Show that to your electrician
Take old bateries with

I can do that myself, very easy to put a relay switch on.

 

[KOPITE]

Alot safer if a electrician do the mods .

Is my explanation correct @thehuman

 

[thehuman]

Is my explanation correct @thehuman

Will make a drawing sometime tomorrow

 

[AfricanTech]

This is scary...

 

[BigEars]

This is scary...

Not really. Just have to know what you are looking for.
Chargers can be disconnected...without damaging things. Very hard over the Net though.

In front of me = sorted. Difficult on Forums or away from a hands on approach.

Gotta see the circuitry in front of me.....

 

[KOPITE]

So what kinda of a relay switch is needed to go that route to pull all that current.

 

[spiff]

guys here is how to connect a 220vac / 12vdc relay so that it DISCONNECTS the 100Ah battery from the UPS when the MAINS comes back ON. allowing your normal battery charger to charge the 100Ah battery.

the UPS battery charger will still charge the UPS's battery.

 

[KOPITE]

guys here is how to connect a 220vac / 12vdc relay so that it DISCONNECTS the 100Ah battery from the UPS when the MAINS comes back ON. allowing your normal battery charger to charge the 100Ah battery.

the UPS battery charger will still charge the UPS's battery.

View attachment 218280

Your graph just says to put the relay on the 2 cables between the ups and the batteries

 

[spiff]

Your graph just says to put the relay on the 2 cables between the ups and the batteries

yes. since I just bought my UPS I'm not going to mess with it, nothing wrong with your method - this is another way around the problem of charging larger capacity batteries while still utilising the larger capacity battery via the UPS


you connect your 100Ah battery to your UPS battery for extra capacity - with relay in between - mains power keeps the relay OPEN

without mains the relay closes supplying extra capacity to your UPS

when mains is restored the relay opens - allowing your UPS to charge it's own batteries and your other charger to charge the 100Ah

 

[KOPITE]

yes. since I just bought my UPS I'm not going to mess with it, nothing wrong with your method - this is another way around the problem of charging larger capacity batteries while still utilising the larger capacity battery via the UPS


you connect your 100Ah battery to your UPS battery for extra capacity - with relay in between - mains power keeps the relay OPEN

without mains the relay closes supplying extra capacity to your UPS

when mains is restored the relay opens - allowing your UPS to charge it's own batteries and your other charger to charge the 100Ah

Is it really necessary to have the 2 small batteries connected. Can I just not add the relay switch on the cables that connects the batteries to the ups.

 

[mister]

Is it really necessary to have the 2 small batteries connected. Can I just not add the relay switch on the cables that connects the batteries to the ups.

The UPS will show a battery fault/alarm and might not power your equipment when the power is still on

 

[spiff]

Is it really necessary to have the 2 small batteries connected. Can I just not add the relay switch on the cables that connects the batteries to the ups.

sure no reason why not - don't think it will damage anything internally.

when mains is restored the relay disconnects the 100Ah battery to the UPS.

just remember I'm using my UPS to power my CRT tv / dstv PVR & a 14w LED light - so that I don't have to reboot dstv or unplug anything when the mains goes off. the relay will just give the UPS an extra 3hrs of use instead of the 40min via it's internal batteries

 

[thehuman]

Internal bateries is there to make ups happy when external battery disconected via relay
Remember relay takes a few mili seconds to engage and internal bateries will cary ups for this time

 

[spiff]

The UPS will show a battery fault/alarm and might not power your equipment when the power is still on

Internal bateries is there to make ups happy when external battery disconected via relay
Remember relay takes a few mili seconds to engage and internal bateries will cary ups for this time

this is true.

 

[Gnome]

OP try what I suggested. I do not believe it will **** anything up. One of 2 scenarios..

1. UPS is dead and won't work. Simply connect R14 again.
2. Charger only has stopped working. Everything else fine.

This can very likely work. Given what I posted above.

R14 is used to specify charging current. If you remove it and leave it in a high-z state the charger will probably just stop working.

Have you actually tried it?

guys here is how to connect a 220vac / 12vdc relay so that it DISCONNECTS the 100Ah battery from the UPS when the MAINS comes back ON. allowing your normal battery charger to charge the 100Ah battery.

the UPS battery charger will still charge the UPS's battery.

<snip picture>

That looks like a 12-15 amp relay?

1000 watt Inverter @ 24v requires approx 80-100amps.

Overall just bad idea imo.

 

[spiff]

This can very likely work. Given what I posted above.

R14 is used to specify charging current. If you remove it and leave it in a high-z state the charger will probably just stop working.

Have you actually tried it?



That looks like a 12-15 amp relay?

1000 watt Inverter @ 24v requires approx 80-100amps.

Overall just bad idea imo.

12vdc

 

[thehuman]

Remember you can signal a bigger relay with a smaller 220v relay