Utility passthrough with AC200Max

Apologies if this has been answered before, but I couldn’t find it from a search

In discussions with electricians on how to set up a transfer switch for my AC200Max, a couple have suggested running the emergency loads full time on the AC200, while it’s connected to AC input.

Then if the grid goes down, they will run on battery, which will be automatically recharged when the grid returns.

I’m not clear from the manual or reading discussions here, as to whether the unit does ‘utility pass through’ - so while the grid is available, it just passes AC through to the loads.

Or in this setup, would it actually run the inverter continuously, and run the load off the battery while recharging when it drops to some preset percentage ?

If the latter, I would instead have the AC200 off and manually switch it over when the grid goes down.

Another electrician suggested an automatic transfer switch, however my understanding is that the inverter/AC output on the AC200 would need to be continuously on (with an ongoing consumption even without load) for the switch to work…

It is my understanding that all AC loads go through the inverter so I would recommend an auto transfer switch.

Thanks Scott

When you say all loads go through the inverter, do you mean that it’s like this IC Series Inverter/Charger: AC POWER PASS-THROUGH MODE - Go Power! - powered by HappyFox with minimal standby consumption (as the inverter isn’t doing any work)

Given that my outages are relatively infrequent, if AC pass through mode is possible but actually uses a fair bit of power itself, I’d probably then go down the manual switch route (with the AC200 off until manually switched on)

It is my understanding that pass through refers only to allowing using the machine while charging and there is no relay that allows AC current input to flow through without going through the built in inverter / charging / battery system. But with that said, the LifePO4 battery chemistry should not be an issue with any minor charging or discharging that may occur

I think i understand what you mean. The AC power brick outputs DC to the charge controller. Does that go straight into the inverter or does it go to the batteries and then the inverter? If it were to go straight to the inverter (pass through) then that would be like how a UPS works. As soon as the AC to the brick goes away the battery seemlessly picks up the load. This is a great question. Im not sure but the power brick is only rated for 500 watts so it wouldnt work for loads greater than 500 watts.

I’ve just tested it out this morning.

It definitely doesn’t do passthrough.

I put a small (200W) load on it, and it initially didn’t draw from the grid (so all from battery).

It later started to pull 300-400W from the grid to charge the battery, and continued to do this

So as I suspected, not a great option for an ‘always on’ backup, as it will cumulatively use a fair bit of power running the inverter and charging the battery - more than the actual load while the grid is available

The AC input is not a straight pass through.