power supply mode on Battery charger(s)

You can run your 2500 all the time as a charger and when you run appliances your pulling power out the battery and the charger is putting it back in....... think of it as a car charging system, you don't turn everything of to charge the battery back up whilst your driving....... your 2500 is no different to an alternator, just a bit smarter.

As for supply mode all your battery is doing is going along for a ride, in supply mode you could disconnect the battery and still 13.7v from the charger....... the only time it will not deliver voltage is if it is set on normal charge mode and the battery is removed.

We have a similar setup in our van. These are great chargers with the remote display and control panel which makes it very easy to switch settings. When in power supply mode the batteries are maintained in float mode @ 13.8 volts. I think the simple answer to your second question is NO. It's possible to leave the projector charger in charge mode, but you run the risk of over charging the battery because the "smarts" in the charger are not seeing the correct voltages during a charge sequence.

If you have your charger remote from inside the van, there is an extension cable available, which makes it easier to switch settings.

Cheers
Racey

I think your question was 'can I run the 12v fridge off a 12v power supply' yes you can, I have one out the farm to run the UHF on the local fire channel. It can be used as a battery charger as well but better off as a 12v power supply.

Sorry but lest get a few things straight.

If your battery is presented with a voltage higher than its resting terminal voltage, it will charge to some degree.

SO if a battery is connected to a charger set to a "supply voltage" of 13.7 volts, the battery will be charging as long as the charger has the capacity to supply the load connected pluss some to spare.

The purpose of this "supply voltage" setting is to make the charger operate without the smarts.....it will still be operating as an older style dumb charger......but it will not be as dumb as the crude old unregulated chargers......but if the voltage is correct it will charge the battery.

SOME may operate in this mode without a battery connected...mine wont.

How various smart chargers function with with a load connected in addition to the battery varies......some of these chargers are smart enough to work this out.....others may not.

Yes it is possible to get a charger.....or a a power supply that will operate without a battery connected.

This is a "regulated power supply", this is what we used to use as a high quality battery charge before these "smart chargers" came along, and what is still commonly used in a lot of stationary and standby battery installations.

They come in two forms.....fixed voltage supplies, like are commonly used to power, allarm systems, CCTV, auto accessories CB and amateur radio equipment, and variable voltage supplies that are commonly called laboratory supplies that have a variable voltage output.
The Fixed voltage supplies may have an internal voltage adjustment.

Any voltage between 13.5 and 13.8 will charge the battery quite well and can be left connected to the battery more or less indefinitely.

It can be argued that these old style regulated supplies are more reliable chargers than the all singing all dancing smart chargers under some circumstances.
After all they have been proven in this application for decades.

cheers

Daz,

I have a Ctek battery Charger which I use on supply mode to apply a "maintenance charge to my camper batteries.
The camper has a Ctek D250S Dual dc-dc charger which would normally operate from the vehicle alternator or solar panels if connected.
Occasionally, I use a 7 amp Ctek charger to apply and maintain the camper batteries when sitting in the shed, connected to the "alternator" charge cable.
This charger is "too smart" in normal mode of operation as it detects something else (the D250S) in the circuit and flashes a fault indicator.
When placed in supply mode however, the "smarts" are removed and it then happily applies a constant supply voltage which is then managed by the D250S dual to supply a multimode charging process to the camper batteries.

My thoughts are, in your case, when your charger is used in supply mode, you may run the risk of overcharging the batteries if left connected for a prolonged time, as the charger will supply a constant voltage and not utilize the smart charging logic it would normally apply.
Even though the fridge is drawing current from the batteries, it would not be using anything like the 25 amps being input by the charger.
As the batteries near full charge, the charger will not detect this change and lower the charging voltage. It would continue to pump in the 13.7 volts and therefore an overcharge could occur.

This is where a device such as the Ctek D250S Dual, or a dc-dc charger from Redarc, amongst others, gives added protection and a smarter charging regime.