RG Colorado - Ctek 250s Dual Charger

Submitted: Monday, Feb 16, 2015 at 20:46
ThreadID: 111139 Views:6693 Replies:5 FollowUps:7
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Hi All,

I am fitting a Ctek 250s Dual Charger into my recently purchased 2005 Jayco Dove. Because the Colorado has a smart charge alternator I have to run a wire from the relay to the "ignition". Could someone please advise me of a good/easy place to tap into the ignition??
Thanks in advance for any and all advice.
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Reply By: Athol W1 - Monday, Feb 16, 2015 at 22:10

Monday, Feb 16, 2015 at 22:10
There is absolutely NO reason to fit any form of switch between the Ctec D 250s and your vehicle battery, as they are a one way only current flow and they also sense the alternator charge before they start to provide battery charge function, they also cease to provide any current flow to the van a short time after shutting the engine down so they will not discharge your starting battery. They are very similar to having a voltage sensitive relay but without the mechanical/electric system in the way they protect your starting battery.

I have used them in several caravans behind a LC 200TTD without any adverse effects over the past 4 years and over 70,000km of towing, only better charged van batteries.

Just run a good (6mm or better) supply from your starting battery, suitably protected by a 40amp fuse, to an Anderson Plug system, then similar cables to your Ctec D250s (located close to the battery) and then to the van battery.

Enjoy your travels
AnswerID: 546057

Reply By: Honky - Monday, Feb 16, 2015 at 22:41

Monday, Feb 16, 2015 at 22:41
Some of the other 12 volt to 12 volt chargers need a trigger wire but not the Ctek.
There is only a wire from the alternator andsolar panel and the negative wires goes to the - pole. the only other wire is the heat sensor.

AnswerID: 546059

Follow Up By: Member - Crocles - Tuesday, Feb 17, 2015 at 00:46

Tuesday, Feb 17, 2015 at 00:46

Thanks for your replies guy's, lots of info recomends a relay connected to ignition for the correct operation of this unit in a vehicle with a smart alternator including Ctek themselves. The above image is of a wiring diagram from their site and the same as the one in the instructions I recieved with the unit.
FollowupID: 833744

Follow Up By: MactrolPod - Tuesday, Feb 17, 2015 at 06:16

Tuesday, Feb 17, 2015 at 06:16
Because you have a smart alternator the supply from the alternator is connected to the solar input via a changeover relay, so you are heading down the correct path.
I can not see your diagram but have installed one in a Colorado with a smart alternator that had a changeover relay controlled by a input from the ignition.
The "other" side of the relay is for your solar panels.
There fore only one source at a time works to charge the auxiliary battery bank.
I am sorry but can not remember where we picked up a ignition "on" supply for the relay.
FollowupID: 833745

Follow Up By: MactrolPod - Tuesday, Feb 17, 2015 at 06:24

Follow Up By: Member - Crocles - Tuesday, Feb 17, 2015 at 18:59

Tuesday, Feb 17, 2015 at 18:59

Thanks for the info and the link mate!
FollowupID: 833795

Reply By: gbc - Tuesday, Feb 17, 2015 at 06:50

Tuesday, Feb 17, 2015 at 06:50
With advise like above no wonder why people get confused. The ctec web site has the ignition switching relay diagram for you to follow. It only needs to be a low current control wire like windscreen wiper circuit which is easy to get to.
I'd hope you've worked out that the solar panels get connected directly to the ctec and not the relay by now?
lc200 has a smart alternator and also benefits from ignition switching. They will work without it, just not very efficiently.
AnswerID: 546066

Follow Up By: gbc - Tuesday, Feb 17, 2015 at 06:52

Tuesday, Feb 17, 2015 at 06:52
Oh, and they aren't only one way current flow either. They will back charge and condition a start battery off a panel or other source automatically too.
FollowupID: 833747

Follow Up By: Member - Cuppa - Tuesday, Feb 17, 2015 at 17:11

Tuesday, Feb 17, 2015 at 17:11
I’m a little unclear as to what you consider to be wrong about what MactrolPod has posted. As I read it he has simply shared the same diagram (that he couldn’t see) as the OP (which apparently is from Ctek’s own site). The way I read it it is that because the Ctek is an MPPT solar regulator, using the changeover relay to switch the alternator input to feed through the solar side of the Ctek whilst driving allows the ctek to ‘boost’ the voltage (as it would if charging batteries from solar in low light conditions) making better use of the lower alternator voltage to charge the aux battery. When ignition is turned off solar charging resumes (if solar panels are connected). Or have I missed something?
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FollowupID: 833790

Follow Up By: Member - Crocles - Tuesday, Feb 17, 2015 at 19:04

Tuesday, Feb 17, 2015 at 19:04

I appreciate your input, I was going to follow the diagram included with the unit. I really was just wanting to know a good source to tap into the ignition, which you have given me.

FollowupID: 833796

Reply By: MactrolPod - Wednesday, Feb 18, 2015 at 19:31

Wednesday, Feb 18, 2015 at 19:31
Have you got it sorted crocles?

And where did you finally pick up an ignition on source?
AnswerID: 546137

Reply By: SuperGrover - Thursday, Feb 19, 2015 at 10:31

Thursday, Feb 19, 2015 at 10:31
I have an LC 200 and a ctek 250 s fitted to my caravan. The simple answer is the wire for your ignition is the charge wire from your car which you would normally have coming through an Anderson plug. I also have the relay installed as per the standard ctek site drawing. The relay is used to select either power from the charge source automatically being the car or the solar panels. The car being the first choice. The selected input feeds into the solar input on the ctek rather than the car input terminal. My understanding is that the ctek has inbuilt protection to prevent the flattening of the car battery. In modern cars the voltage does not increase enough under load such as when you are trying to run your fridge and ctek to charge your van battery. Due to the to your ctek from the length of cable, load from your fridge, wire size etc... the ctek thinks your charge battery ( car ) is flat and will not charge your caravan battery to protect your car battery. By connecting to the solar input using a relay this input does not have the same low voltage battery protection and will charge your van battery.
AnswerID: 546166

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