AC to DC 12 volt Power supply for RV without batteries

[Andonso]

I have a RV that's connected to shore power 24/7 and thinking of removing it's two house batteries and installing a regular PSU without charger to supply 12 volts for the RV.

I use to have a PD9280 installed that stopped working and also have a PowerMax PM4-75LK 75 Amp PSU that I'm thinking installing into another rv.

The RV has a 4000 watt generator.

One problem is the 4000 watt genny requires 12 volts in order to start. So if I remove all the batteries I would need to temporally connect some sort of battery in order to start the genny. I do keep some extra batteries on AC/DC chargers so it would be likely a 12 volt lead acid battery would be available to connect to the RV if ever needed to start the genny.

Questions arises what type of power supply to look for and how many amps are actually needed.

The RV has 9 12 volt lights of which some have LED bulbs. The absorption frig requires 12 volts to operate (I've been thinking of replacing the absorption frig with an electric sometime inf the future)

There are also some control switches in the stove hood that have some controls but aren't ever use except perhaps once in the while a remote generator starter switch.

I don't ever use the RV gas furnace as it's broken and installed in it's place an electric heater and also have an indoor gas catalytic heater with safety features.

So most of the RV relies on AC and very little on DC. I do sometimes use the RV 12 volt cig. receptacles to plug in 12 volt cig adapters and electronics.

After a little searching I'm finding psu's from around 10 to over 25 amps. some of which are switching power supplies.

e.g. I found this one MW Mean Well PDF-320-12 DC Output 12V 25A Power Supply

also many others however I'm not certain if I should be looking for a particular type or just any 12 vdc ac/dc psu that I can be connected to a Progressive Dynamics AC / DC distribution panel.

I thought I would post this question to determine if there's something I'm overlooking as most people install RV converters with battery charger in RVs to supply 12 volts and charge the house batteries.

I think ~10 to ~25 amps should be enough power for a 23 foot motorhome that's kept in one spot all the time?

[Ralph_Cramden]

Do you have slides? You might want to check the amp draw when running the slide motors. Some manufacturers, BAL for one, state not to operate theirs without a connected battery. I know the Lippert POS above floor slide on our Rockwood does not like it when a battery is not connected, the small motors on our Schwintek ward slide seem to be ok without one. Running without battery may be a good way to fry a motor.

[Andonso]

landyacht318 wrote:
I think your issue will be trying to start the generator on a power supply, but I do not really know how much amperage their starter's consume.

I've been using the Meanwell Rsp-500-15 since September 2014 as a manual converter/charger. Capable of 40 amps.

After I posted I remember the genny which I've only started a couple of time the past 10 years. I did use it while camping a few times years ago however the RV now stays in one spot all the time.

I thought if ever needed for traveling it would be easy enough to install some house batteries with a spare converter / charger.

I re-edited the post to reflect the problem with starting the genny without a battery and AC.

I'm wondering if the Mean Well PDF-320-12 12V 25A Power Supply would suffice as a PSU for the RV? This one is used. For a similar price or a little less with shipping I'm finding new Mean Well 8 - 8.5 to 12 - 12.5 amps psus.

I'm wondering if 8 to 12 amps is enough for an RV's AC/DC psu?

Also because of voltage drop issues I'm wondering if a 13.5 VDC psu would be a better option?

[landyacht318]

I think your issue will be trying to start the generator on a power supply, but I do not really know how much amperage their starter's consume.

I've been using the Meanwell Rsp-500-15 since September 2014 as a manual converter/charger. Capable of 40 amps.