12V LED Power supply in a caravan as main power supply

[linbaato]

Hello, I am currently DIY upgrading a caravan with my girlfriend but need some advice.

The (very old) 230VAC to 13.8VDC power supply broke down and needs to be replaced. It is rated with 10A output but I would like to replace it with a 12V one with at least 15A. The old supply was intended to also charge a lead battery but we do not have one nor do we want one.

So searching for a replacement I noticed the special caravan power supplies being much more expensive than other 12V power supplies. E.g. the MeanWell XLG-200-12-A is intended for use with LEDs but I don't know the reason behind that. It has different kinds of protections included and provides enough power. I would love to buy that.
(I want to stay away from those cheap noname 20€ power supplies)

FYI: There is lighting, a refrigerator, a water pump and USB power ports to be driven by that 12V.

There are already two relays next to the other electrics in the caravan (for priority power) so I do not need those integrated priority relays.

So in the end I want to know if the MeanWell power supply would be fine or if there are reasons to take a specialized power supply. If you can make suggestions please do so

Thank you in advance!

 

[Lucien Nunes]

SMPSUs are made to a range of different specifications and those intended for LEDs are likely to have a slightly different feature mix compared to general purpose units. For example, they might have more ripple and noise on the output as they are not designed to feed sensitive electronics, but anything designed to work on vehicle power will cope with much worse. Often they will run with very high case temperature as they are not designed to be used domestically, nor built into a piece of equipment.

Looking at the specs and from general experience with SMPSUs, I would say that the parameters relevant in your application are the ability to withstand load current inrush (e.g. pump starting current) and the 12V output voltage.

So long as the unit is of ample rating for your load, including pump starting current, it should be OK. Many RV-type loads assume there will be a battery present to handle those load peaks, but in the absence of a battery you need to be sure that they won't trigger the overload protection. There's no 10% overload margin as there is on some units, but the unit goes into constant current mode between 8.4 and 12V once the output voltage is pulled down, before chirrup-mode protection begins. As LEDs don't impose an inrush load on the supply, the reservoir capacitors might be smaller for a given output current rating and less able to ride out the peaks.

RV / automotive products are designed to work in the 11-14V range and in some cases will give slightly more power / brighter light at the higher voltage. 12V will be fine, but with complete freedom of choice in the PSU department, 13-13.8V would be a more desirable voltage. This is because there will always be voltage drop in the wiring, and unless it is very short or the cables are very large, it could be up to 1V for the heavier loads. Launching at 12V means that a typical wiring drop of 0.5V puts the load voltage at 11.5, very close to the bottom end of the usable range, but launching at 13.8V gives the load a comfortable, perhaps optimum 13.3V

You didn't mention the type of refrigerator. I assume that it's compressor-based, because you wouldn't run a 3-way absorption unit (230V/12V/gas) on the 12V system when 230V is available. My experience of them is that the compressor starting current is very modest due to the very efficient inverter drive, but they are intolerant of voltage droop e.g. through undersize wiring. An absorption unit is a serious power guzzler on 12V with 8A constant load being typical, as that's only expected to be used under tow with the engine alternator running.

 

[littlespark]

Be best to source a unit designed for the job.
Any caravan spares website or marine shop.

 

[brianmoooore]

My first caravan came with a very heavy 50 Hz transformer based power supply with a limited output. I successfully replaced this with a PSU from a tower PC. As it came, the output was exactly 12 volts, but I upped this with a couple of silicon diodes added to the regulator circuit.
Worked perfectly for the decade + that I had that caravan, with or without a battery fitted.

 

[littlespark]

What a way to invalidate your warranty, or your insurance.

Caravan burns down due to electrical fault.

Loss adjuster: “hmmm. This part isn’t original or a specified replacement part…… no payout”

 

[linbaato]

Thank you all for your answers, they helped a lot (especially yours @Lucien Nunes , very educational!)

Also the insurance point is reasonable.

I decided to look for other solutions