24 Volt Inverter with a 12 Volt RV System

chiz33 wrote:
Hi everyone

I recently acquired a 24v inverter along with 2 12v batteries for free. They are from a computer backup system (UPS) consisting of the 24v input inverter along with 2x12v batteries in series (24v). I know this isn't the best option for an RV with a 12v system (alternator, fridge, lights, radio, etc.) My question is, is there any way to wire this inverter to my RV so that when I'm driving, the alternator charges the batteries and the batteries power the 12v appliances AND the inverter?

Thanks

Quick answer, no.

Long answer, not in the present form you have.

The 2 12V UPS batteries would need reconfigured to parallel for 12V.

Then the 12V from the vehicle could charge them.

Then to get 24V DC for the inverter you will need to 12 to 24V DC-DC BOOSTER (a switching power supply which takes 12V in and outputs 24V DC).

To get one large enough to run the UPS inverter is going to cost you much more than simply buying a 12V inverter. Typically UPS units of 600W and larger operate at 24V DC so your UPS must be at least 600W..

UPS inverters are also not known for being energy efficient and adding a additional DC to DC power supply into the chain will waste a lot more energy. This is going to add a lot of needless load to your vehicles charging system..

Then to add insult to injury, many UPS units will not "cold start", in other words they NEED 120V AC in order to turn them on.. This is done so they can sync to the AC line.

Some APC units can indeed be started without 120V AC but only on select models.

Wasted money and time.

My suggestion is use it as a UPS when on shore power and when not on shore power use a plain old inverter..