Adding inverter with existing battery charger

[SVRealityCheck]

I plan to add an inverter. My a/c panel has a switch to toggle between shore power and the generator. My inverter will become a third source of a/c for this panel.

Problem - I have a battery charger that plugs into one of the a/c outlets being powered by this panel. If I switch the panel's a/c source to the inverter, it will create a loop.

i.e., battery goes to inverter - inverter powers a/c panel - a/c panel powers charger - charger goes back to battery - repeat

Anyone have experience wiring a solution to this? My guess is I’ll need to separate out the power source for the charger and have it come directly from either the generator or shore, but not the inverter. Just don’t know how to go about that, exactly.

[rslifkin]

Use an inverter with a transfer switch in it. Feed it from the panel main, then make a sub-panel with just the loads you want the inverter to power (so the rest of the loads are only powered from shore / gen).

[starcruiser]

Is your battery charger hard wired to the AC panel outlet or does it plug in? If it is hard wired, you should put an inline on/off switch on the charger. If it plugs in...simply unplug or switch off the plug while the inverter is on.

[smac999]

The normal way is to split the panel into inverter and non inverter loads. And the inverter will have its own transfer switch. Normally built in. Because other loads like hot water tank etc are also not inverted. .

[CruiseN]

On left is a physical isolation relay.
Only one power source can be physically used at any one moment.
Switching faster than modern electronic devices recognition. No glitch.
That can be wired to give mains priority.

On other left is a timer. Isn't needed but smooth sailing.
It can be tuned to allow delay of relay. Incase mains blackout, it doesn't switch on and surge with everyother man and dog.

The charger can feed from mains.

[Peterix]

A Switch like this?
Position 1 : connect battery charger to battery and inverter disconnected
Position 2 : connect inverter from battery and battery charger disconnected

[Carole ann]

Magnum makes an inverter with a 50 amp charger built in and when shore power is on it cuts out. Great gadjet.

[wingssail]

A number of inverter/chargers are produced and sold for marine use which are connected directly to the shorepower. In your case to the output of the "shore/genset" switch between the switch and the AC panel. The charger is not plugged into any outlet.

When AC is present these devices use it for the charger. When not (if the inverter function is enabled) the inverter cuts in and supplies AC to the AC panel.

[Stu Jackson]

Originally Posted by SVRealityCheck

I plan to add an inverter. My a/c panel has a switch to toggle between shore power and the generator. My inverter will become a third source of a/c for this panel.

Problem - I have a battery charger that plugs into one of the a/c outlets being powered by this panel. If I switch the panel's a/c source to the inverter, it will create a loop.

i.e., battery goes to inverter - inverter powers a/c panel - a/c panel powers charger - charger goes back to battery - repeat

Anyone have experience wiring a solution to this? My guess is I’ll need to separate out the power source for the charger and have it come directly from either the generator or shore, but not the inverter. Just don’t know how to go about that, exactly.

Yes, and any quality inverter installation manual should have a series of wiring diagram OPTIONS.


Good for you for recognizing the potential issue.


What you need to do is separate the charger input from the inverter output. Conceptually, we're all in agreement there. But without a wiring diagram of what you have, no one in the universe can tell you "Move wire A to position Z."


And you can ignore all the well intentioned discussions that mention I/Cs and built-in transfer switches, doesn't apply to your situation at all. You do need to assure that "I" power and either shorepower and/or generator are never on at the same time, but you seem to know that already.



Good luck, you're on the right path.


Perhaps with a wiring diagram, we could help you out. Show us what you have and what you plan to change and we can help a lot more than these generalities.

[waterman46]

Smac999 and Wingssail have it right. Read online info about transfer switches. Buy an inverter with a built-in transfer switch and read the manual. A wiring diagram from the manual will make it clear but if you need more explanation then post the diagram here.

[smac999]

Originally Posted by Stu Jackson

And you can ignore all the well intentioned discussions that mention I/Cs and built-in transfer switches, doesn't apply to your situation at all. You do need to assure that "I" power and either shorepower and/or generator are never on at the same time, but you seem to know that already.
.

lots of inverter only have transfer switches. like the current xantrax freedom x. xantrax also used to make an automatic external one any inverters without one built in. not sure if they still do.

edit : still do https://www.xantrex.com/power-produc...fer-relay.aspx

these transfer swtiches go after the shore / gen swtich and have nothing to do with each other.

see diagram on page 17

https://www.xantrex.com/documents/Po...Rev-F)_ENG.pdf

[waterman46]

Originally Posted by smac999

lots of inverter only have transfer switches. like the current xantrax freedom x. xantrax also used to make an automatic external one any inverters without one built in. not sure if they still do.

edit : still do https://www.xantrex.com/power-produc...fer-relay.aspx

these transfer swtiches go after the shore / gen swtich and have nothing to do with each other.

see diagram on page 17

https://www.xantrex.com/documents/Po...Rev-F)_ENG.pdf

Yes this is a good example. His battery charger, not shown in that diagram, should get its AC from the panel at far lower left which in turn is supplied from the shore-generator switch. Battery charger DC output can connect to same terminal on isolator as the alternator.

[CruiseN]

Originally Posted by Carole ann

Magnum makes an inverter with a 50 amp charger built in and when shore power is on it cuts out. Great gadjet.

Yes..
That..

But ensure circuits are always isolated. Eg during throw of switch it is physically impossible to bridge circuits.

Some caravan switches use big handles but they are slow and can spike electronic equipment. Glitches in switches. Stuff risking replacement of electronics..
Switch above same thing.
Physical isolation. But switch rate faster than electronic power supplies. They don't see a beat.

[CruiseN]

Originally Posted by Peterix

A Switch like this?
Position 1 : connect battery charger to battery and inverter disconnected
Position 2 : connect inverter from battery and battery charger disconnected

Quoted wrongly..
I meant. Yes. That..
I don't know what other quote is

[CruiseN]

If don't know.
Maybe ask electrician about a physical lock out switch. It'd take a decent electrician about 15 minutes to terminate IMO.