Ctek D250S DUAL

[TrueDink]

I will be getting a Ctek D250S Dual in the near future and I can't get my head around the fridge wiring.

All of those who have one can I as some advice. Do you still wire the 12v part of the fridge to pins 6 and 7 of the 12S plug (or pins 10 and 11 in my case) or do you just wire it straight to the leisure battery in the camper.

Thanks.

[rubberrat]

My understanding is that it is wired to 12s so it works on the move and shuts down when on site (240v or gas then) but take better advice than my shaky knowledge.

[keeflester]

I've studied the manufacturers data and the charger can supply twenty amps if it has a suitable input. Your absorption fridge will typically draw eight amps, however it's neccesary to ensure that the input supply is not interrupted for any length of time or the fridge will discharge your leisure battery in a few hours, and definitely overnight. If you are using a compressor fridge, these limitations do not apply. Similarly if you have a very large capacity of leisure battery, you may go overnight without serious problems if you are relying on a large solar array. If you tell us what kind of fridge you have and what source/sources you are charging from we can give specific advice. Kind regards, K33F

[sabconsulting]

The answer really depends if you are using a 3-way or compressor fridge. You certainly don't want to keep the 3-way fridge running on 12v when the engine isn't running - it will burn through your camper battery pretty quickly. So I guess you could consider keeping it wired to the pin that supplies power only when the engine is running, since if camping without hookup you'll be using propane for the fridge.

With a compressor fridge you don't have the option of running of propane, but it will use less electricity anyway, so I recommend doing what I did - wire it to the camper battery via a switch and fuse.

The D250S can then take an input from the truck battery and another input from solar if you have it and the output will be wired to the camper battery.

You can remove the charging relay in the truck because the D250S does that for you and also reverses the current flow to charge the truck battery from solar when the camper battery is full.

Steve.

[TrueDink]

The way I have it wired now is using a voltage sensing relay on the truck which is connected to a 13 pin socket on the tow bar. When the engine is running power is fed to pin 10 for powering the fridge and there is also permanent power to pin 9. When the engine is switched off the vsr disconnects pin 10 so the fridge doesn't drain the truck battery. There is no way to power the fridge using the leisure battery in this traditional wiring system.

I have a Dometic MES 3 way fridge btw.
On this camper I only have the trucks alternator and hook-up as power sources. I will be getting 2 solar panels in the near future though. I left my panel on the Northstar I sold.

This is all straight forward. The problem comes when I introduce the dc to dc charger to the mix. Do I do away with pin 10 and the vsr altogether and take the power for the fridge from the leisure battery? I would prefer to keep the vsr so there is no way to flatten the truck battery so I'm left stranded. Would I then connect the dc to dc charger to pin 9 (permanent power) and the fridge to the leisure battery? This seems like a backward step to me as I run the risk of flattening the leisure battery if I forget to switch over to gas. Also mine isn't but an AES fridge would always automatically select 12v if there was supply and no hook-up.

Or is it safe to connect the fridge to the vsr via pin 10 and the dc to dc charger to pin 9?

I'm not worried about the earth paths. I have them sorted in my brain.

[sabconsulting]

In your situation I would connect the D250S to permanent live on the truck battery - it will not drain that battery if the alternator is not running because it has a voltage sensor of its own. Plus when you add solar it will be able to charge the truck battery from that after it has fully charged the camper battery.

Then keep the VSR running the other pin on the socket and run the 12v of the 3-way fridge off that. That way the 3-way fridge only gets 12v power when the engine is running and there is no risk of it flattening either battery.

Steve.