How do batteries charge with a change over switch.

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Rohan1981

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Hi All,

I am looking for some assistance, I recently installed a 3Kw inverter , directly to the DB, and i have 2 x 200AH DC batteries (with fuses), The Inverter has a built in change over , in that if the mains goes off, the inverter powers the house via the batteries. Note this is only for load shedding, (geyser not connected to the inverter - bypassed and works on the main only) - for now everything works fine, however since there is no change over switch - I can not do maintenance, or worse case replace the inverter should something go wrong i have no power until the bypass is done on the BD.

My question is, if i install the change over switch, how will the batteries charge , as i assume when i am on mains there is no power going to the inverter to charge the batteries ?
 
Rohan1981 said:
Hi All,

I am looking for some assistance, I recently installed a 3Kw inverter , directly to the DB, and i have 2 x 200AH DC batteries (with fuses), The Inverter has a built in change over , in that if the mains goes off, the inverter powers the house via the batteries. Note this is only for load shedding, (geyser not connected to the inverter - bypassed and works on the main only) - for now everything works fine, however since there is no change over switch - I can not do maintenance, or worse case replace the inverter should something go wrong i have no power until the bypass is done on the BD.

My question is, if i install the change over switch, how will the batteries charge , as i assume when i am on mains there is no power going to the inverter to charge the batteries ?
Click to expand...
The changeover switch is connected to the output of the inverter not the input, so you will still have power to the inverter and the inverter will still be able to charge the batteries.

The changeover just gives you the option to get power from the inverter or mains.
 
Disconnect the output of the inverter and connect it to input 1 on the changeover switch, connect input 2 on the changeover switch to the mains then connect the output from the changeover switch back to the circuits on your DB

Recommend getting an electrician to do this so you can ensure compliance.
 
Sorry, I thought a re-read would have worked. The way Im reading it, he wants a change over BEFORE the inverter so that when the inverter fails he can still run mains while fixing what needs fixing. ?

Im in the same sort of boat ... all the lights and 1x plug runs via the inverter and therefor stays on during loadshedding, but if the inverter had to fail, I have NO lights until said inverter is replaced ... there is no option to go back to mains in this case.
 
Rohan1981 said:
Hi All,

I am looking for some assistance, I recently installed a 3Kw inverter , directly to the DB, and i have 2 x 200AH DC batteries (with fuses), The Inverter has a built in change over , in that if the mains goes off, the inverter powers the house via the batteries. Note this is only for load shedding, (geyser not connected to the inverter - bypassed and works on the main only) - for now everything works fine, however since there is no change over switch - I can not do maintenance, or worse case replace the inverter should something go wrong i have no power until the bypass is done on the BD.

My question is, if i install the change over switch, how will the batteries charge , as i assume when i am on mains there is no power going to the inverter to charge the batteries ?
Click to expand...

Heh? It's an inverter, what maintenance do you want to do?

It's not going to fail and be stuck in backup mode, it'll switch back to mains pass through.

You don't need to complicate things with a change over switch.
 
Short answer ,

Connect the output of inverter to changeover supplying loads .

Connect input of inverter to mains ( before changeover ) via an circuit breaker.
 
Dimpie (COMPUTEK) said:
Sorry, I thought a re-read would have worked. The way Im reading it, he wants a change over BEFORE the inverter so that when the inverter fails he can still run mains while fixing what needs fixing. ?

Im in the same sort of boat ... all the lights and 1x plug runs via the inverter and therefor stays on during loadshedding, but if the inverter had to fail, I have NO lights until said inverter is replaced ... there is no option to go back to mains in this case.
Click to expand...
Maybe you are as confused as he is about the whole thing, and I don't mean this in a nasty way, a changeover switch is meant to select between two sources, now if you connect it before the inverter it will be the mains source on one side and what will be on the other side?

You connect it on the output so that you select between the output of the inverter and the mains, if the inverter fails you switch it to mains and go on with your life.

Looks to me like he needs a way to isolate the inverter if he needs to do whatever maintenance he needs to do, in that case he needs to put an isolator before the inverter, ie on the AC input to the inverter.
 
TheChamp said:
Maybe you are as confused as he is about the whole thing, and I don't mean this in a nasty way, a changeover switch is meant to select between two sources, now if you connect it before the inverter it will be the mains source on one side and what will be on the other side?

You connect it on the output so that you select between the output of the inverter and the mains, if the inverter fails you switch it to mains and go on with your life.

Looks to me like he needs a way to isolate the inverter if he needs to do whatever maintenance he needs to do, in that case he needs to put an isolator before the inverter, ie on the AC input to the inverter.
Click to expand...

Yes that makes sense and I suppose that is what he (and I suppose me) needs to isolate the inverter for maintenance.

... and yes, when my inverter fails the mains will just pass-through like is does when there is no loadshedding, but I need to isolate it to be able to remove it and connect a new unit.

All Good ... Im sure he also understands now :thumbsup:

Come to think about it, the electrician did install a cut-off switch (isolater) for the inverter ... sorry, my bad :p
 
Rohan1981 said:
Hi All,

I am looking for some assistance, I recently installed a 3Kw inverter , directly to the DB, and i have 2 x 200AH DC batteries (with fuses), The Inverter has a built in change over , in that if the mains goes off, the inverter powers the house via the batteries. Note this is only for load shedding, (geyser not connected to the inverter - bypassed and works on the main only) - for now everything works fine, however since there is no change over switch - I can not do maintenance, or worse case replace the inverter should something go wrong i have no power until the bypass is done on the BD.

My question is, if i install the change over switch, how will the batteries charge , as i assume when i am on mains there is no power going to the inverter to charge the batteries ?
Click to expand...
the change over switch is installed if you want to bypass the inverter.

as long as the inverter is powered up controlling your appliances, it will always charge the battery.

that’s the way the system must be set up instead of manually changing over when your power cuts.
 
Thank you all for the responses ,

i can see where there might be some confusion,

Firstly - with my current setup - if the inverter fails/ breaks - this means i have no power until i can bypass it. (example i have switched the inverter off and i lose all power to the house even if the mains in on)

This is why i was thinking of adding the change over, as when the inverter fails there is no bypass on it currently.

So if i get this right, if the change over is connected to the output of the inverter and mains to the input of the change over, i can toggle between the two when needed.

this will also allow for the inverter to be on and charge the batteries while i am on mains ?
 
Rohan1981 said:
Thank you all for the responses ,

i can see where there might be some confusion,

Firstly - with my current setup - if the inverter fails/ breaks - this means i have no power until i can bypass it. (example i have switched the inverter off and i lose all power to the house even if the mains in on)

This is why i was thinking of adding the change over, as when the inverter fails there is no bypass on it currently.

So if i get this right, if the change over is connected to the output of the inverter and mains to the input of the change over, i can toggle between the two when needed.

this will also allow for the inverter to be on and charge the batteries while i am on mains ?
Click to expand...
Yes, here's a nice diagram, just replace generator with inverter output. The only difference is that the generator does not have an AC input like the inverter.

9c82477acc513f5353c4b69cf641edb9.png
 
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