Ctek chargers

Definitely don't want to char it! lol

Thanks for your input, I might use both seeing I have them, cheers.

Well researched Allan - that first para would be a great contender for 'Friday Funnies' - well spotted :O))

Cheers - Phil

As they say - one missed typo, and your whole day is urined!

Cheers, Ron.

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Classic Ron.

Thanks Bill.

Yes, thanks Bill.

That answered an obvious immediate question I had to the OP (why not just charge vehicle aux via VSR at 70amps / 80 amps etc ?).

This is how I've had the Ranger aux setup for about 5 - 6 years now, and it works well, no other camper needs as yet for more power.

I also put both batteries on the smart charger / desulphater every few months, so far one AGM in 4 years, but think with most aux batteries that is about the life with pretty rough driving conditions, and never have it go lower than about 80% SOC.

Hi Allan, yes, this is the main reason I am doing a major upgrade, our recent trip with no sun the 3 way was sucking the life out of the batteries, major headache.

What is your suggestion?

Thanks Wayne.

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Hang on, I'll draw it up.

Is there any reason that you cannot use gas to power your 3 way fridge , it is common knowledge that they are very high users of 12v batteries because of the heater element system of cooling...they or ours runs quite well when traveling on 12v connected to the cars system , but as soon as we get to camp we switch it gas..cheers

Hi Rooster.

I do flick it to gas on parking up, its towing thats causing all the grief.

I think I have an issue on 12volt as my last car/van combination was fine.

Cheers.

Nothing like an expert , but is does seem like a lack of charging from the alternator, our fridge runs of the "ütilities" line in the car to van plug.

Yeah I'm not sure whats going on, anderson was showing 14.5v with the truck running.

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OK Wayne, here is what I suggest. All you require additional is a relay or solenoid.

The setup in the vehicle is standard. It charges the aux battery via the Ctek, allows for solar charging, and tops up the crank battery from solar. The addition to this is simply a 60Amp relay
(Jaycar SY-4074, $8.95)

This relay supplies power to the caravan only when the engine is running and ensures that the fridge can only draw from the alternator. This arrangement thus protects all batteries from the fridge when stationary and requires only one cable via Anderson plugs from the vehicle to the caravan.

Nutta
If the previous setup worked the fridge ok then something now must be different.
Nice to have 2 DCDC units to use but I am curious as to how the anderson plug will be reading 14.5v. Even IF the alternator was producing 14.5v at the alternator terminal, the cable and anderson plug whilst under load of the fridge isn't going to read 14.5 v, it should be less if running the fridge 12v element. If it is very close to, or at, the alt voltage then it would seem the fridge isn't using current or very little. Either way not much cooling will happen.

So, even if you add the relay Allan suggests and supply the trailer DCDC and the fridge from that line, I would think you will still have the same problem.

Have you isolated the fridge supply and directly fed the fridge with power to see what happens, as a test? Perhaps testing the fridge current draw amp flow while delivering a constant 14v to it may show what is happening. ie testing by eliminating all the cables, anderson plugs etc. Unless you know the fridge is working as it should, ie, do basics first, your refurbishement may not be aimed in the best directions.

Nutta
Have you isolated and tested the fridge to see if it performs properly, ie, amp flow and voltage correct while being delivered with minimum cabling lengths???
Unless you know it is working properly before anything else, all the cabling and DCDC chargers aren't going to improve your troubles.

I cannot see how you can have 14.5v, at the anderson plug of the van if the fridge is running. The cables would have to be quite large in cross section AND the alternator would have to be producing in excess of 14.5v for that voltage level to be present at the anderson under load.

If you have a cable supply problem, the direct to trailer through the relay, Allan suggested will be trying to run the DC DC unit AND run the fridge, ie, two electircal loads on the anderson plug line. The fridge which is having troubles at present may not improve unless the basic problem is found. Adding expensive electronic chargers may not solve the problem.

Nutta,

When you measured 14.5V at the Anderson, was there anything plugged in to it?

It is the voltage at the Anderson when a decent load is plugged in that matters.

Try plugging in your van with the fridge set on 12V, then probe the back of the terminals on the Anderson and report what the voltage is.

Cheers

Thanks guys, I'll pass this thread onto my mate so he can have a read o it as I'm not the best with electrics.

I do know all the cabling is heavy duty, I saw it the other day when I checked the fuse which I think was 50amp.

The anderson plug was showing 14.5 volt with no load.

I will get back to everyone when I get to the bottom of it.

Sorry I can't answer all questions, (not much knowledge) thanks again.

Hi Allan B - If I understand it correctly, your approach/diagram would prohibit the Fridge and Van Aux battery from getting any charge from the Solar when stationary. Is that right?

Not sure what the solar arrangement is, but if simple to switch the solar over, then I assume no reason why you cannot ustilise the solar input on the Van CTEK250S if you wanted to (ie. a second solar input on your diagram).

Given it sounds like the 3-way is 12V hungry and better served on gas when stationary - and given the need to provide 12V to a fridge in the car also, your solution seems like a good one in this circumstance.

If someone was wanting to run both the car and van fridges on 12V you'd probably want a different arrangement to allow all batteries to be charged via a single solar input simultaneously?

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Hi Tim,

The proposal I offered to Wayne was based on minimal change to his existing system, merely using the Ctek chargers he already had and adding only a relay. in his description of his existing system Wayne said that he wanted to add a battery into "the rear of his truck" which had a "200w solar panel on the roof". There was no mention of solar on the caravan.

So yes, the proposed circuit wold not allow the "Van Aux battery from getting any charge from the truck Solar when stationary." His existing 200W solar panel would be inadequate to contribute to both the truck aux battery, the van aux battery and the needs of the 3-way fridge.

Certainly, it would be easy to have a solar panel on the caravan servicing the van battery via the Ctek D250S. It was not shown on the diagram because no van solar was mentioned. But such a panel would not be sufficient to support the needs of the 3-way fridge.

Re your final paragraph.... the 3-way van fridge can only be satisfactorily run on 12V when that is available from the alternator. No "different arrangement" would serve.

Hi Allan, I got your pic which I will print out and show my friend, thank you.

The van at each stop was always flat like nothing was getting to it, my truck was almost as bad with its 2nd battery as I have a fridge in the back seat as well, but it seemed to be worse than normal too.

The anderson plug on the truck is off the crank/alternator.

Cheers.

Nutty
Do you have two 3 way fridges running while travelling? An accurate description of what you have would be of assistance to anyone replying.
It is impossible for the batteries to be flat, partially discharged maybe, while the alternator is running.
Either you have a disconnect while travelling, ie, no power to either battery system and fridges OR the alternator is not charging sufficient amp output.
Perhaps the alt has a blown diode and has lost 2/3 of it’s output. That might keep the engine running but nothing extra for fridges or batteries. Until you get a surety of the systems performance it seems pointless to alter things in an attempt to charge batteries and run fridges.
My alt runs at 14.4v and through a decent connection and Anderson plug, it charges and runs a 3 way fridge at around 12.7v while travelling. Fridge runs off at least 12.7v. Van battery will be less than fully charged when that is happening. The solar and DcDc unit replaces that when stopped and fridge OFF.

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Nutta,
By the way, that circuit I proposed is not just speculative. I have installed it a couple of times and they have worked perfectly. A simple concept yet eliminating the common problems of a 3-way fridge in a caravan,

Thanks Allan.

Hi Rmd,

Only 1 x 3 way fridge in the van and the 12v waeco in the back seat of the truck.

There must be something breaking down in the system somewhere, I'm hoping to have it looked at this weekend.

Cheers

The dc’s will get in the road of your bulk charge until you get your other issues sorted. I’d work out what is going wrong first. 3 way’s can flatten a battery pretty quick, how long do you leave it run on 12v with the engine off?

I turn it off as soon as we pull up.

Thanks Von.

The solar on the truck has no reg but the van does, I'm not sure how ill get around that yet. jayco has its own setec, no doubt a cheap clone of ctek.