C Tek D250S Dual Solar Pulsing

I have just connected mt 2 Lorentz solar panels up to the C Tek 250S solar input. I noticed the solar indicator was cycling on and off every 2 seconds. My clamp meter confirmed 8 amps going in, then off then 8 amps again. I thought it must be pulsing because of the almost fully charged batteries. however I hooked the 240 volt CTEK charger up to it and it was putting in a steady 12 amps.

The C Tek 25OS dual has MPPT solar regulator built in. Going away Saturday so I thought someone with one might know if its normal operation or what the cause may be. On the positive side the unit is not displaying any faults.

Perhaps it will deliver a steady voltage when the battery is a bit more discharged but I have yet to test this. Anyone able to tell me why it is pulsing
Cheers Peter
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Reply By: Member - Corrugate75 - Friday, Aug 10, 2012 at 06:48

Friday, Aug 10, 2012 at 06:48
G'day,
I don't own a CTEK D250S so can't comment on normal running. The reason I don't own one is because I was advised they were not suitable for handling more than an 80W solar panel, and I wanted to feed 120W through it. I'm just wondering, when you said you had 2 panels connected, what is the combined wattage?
Cheers
Corrugate
AnswerID: 492628

Follow Up By: Member - Rod N (QLD) - Friday, Aug 10, 2012 at 08:03

Friday, Aug 10, 2012 at 08:03
I am waiting for mine to arrive so can't comment on actual operation.
I have read that they have a bit of trouble with panels UNDER about 100 watts if flat mounted, but if tilted to track the sun can handle lower watts.
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Follow Up By: CSeaJay - Friday, Aug 10, 2012 at 09:43

Friday, Aug 10, 2012 at 09:43
Nope - it is the other way round

It struggles with anything LESS than 80-100W

CJ
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Follow Up By: CSeaJay - Friday, Aug 10, 2012 at 09:49

Friday, Aug 10, 2012 at 09:49
Sorry - that was Nope to Corrugate which means I agree with Rod N
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Follow Up By: Member - kwk56pt - Friday, Aug 10, 2012 at 22:36

Friday, Aug 10, 2012 at 22:36
Hi corrugate 75 my panels were 180 watts combined
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Follow Up By: Member - kwk56pt - Friday, Aug 10, 2012 at 22:38

Friday, Aug 10, 2012 at 22:38
Meant to mention I tried it with 1 panel 90 watts and it was the same
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Reply By: Sand Man (SA) - Friday, Aug 10, 2012 at 09:22

Friday, Aug 10, 2012 at 09:22
So that is two completely opposite statements on "what people have heard"?

Peter,

I have a bi-fold 80 watt panel and connect this to the solar input port on my D250S Dual controller by bypassing the panel's onboard controller, which aren't all that smart.
My suggestion is that you ensure you don't also have an onboard solar regulator on your panels. You need "raw" unregulated solar input voltage going into the Ctek, allowing it's built-in MPPT logic to control voltage and current output to the battery bank.

I haven't needed to test the input going into the battery bank. I know it is working by the fact that over longish periods of stationary camping with the Camper's Waeco upright fridge operating continually, the battery bank is not running low, so the panel has to inputting sufficient current via the Ctek D250S Dual controller.

Cycling would be normal as the batteries reach a fully charged condition as the Controller would be in "maintenance" (pulse) mode, so cycling on and off would be the normal expectation.

No idea why the 240v charger wouldn't be also cycling but perhaps it takes a bit longer for it's logic to "kick in".

Bill


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AnswerID: 492640

Follow Up By: Member - kwk56pt - Friday, Aug 10, 2012 at 22:34

Friday, Aug 10, 2012 at 22:34
Thanks for the reply. my panesl dont have a regulator. When you are on solar does the alternator light come on or just the solar and battery lights ? My alternator light was comming on with the solar when the motor was not running. I decided to disconnect the alternator input, must have touch something with the wire as the D250S is now lifeless.
Have you connected your solar directly to the 250S dual or via a fuse ? Did you run your earth directly to the battery or to the earth on the 250S dual ?
Thanks Peter
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Follow Up By: Sand Man (SA) - Saturday, Aug 11, 2012 at 09:27

Saturday, Aug 11, 2012 at 09:27
Hi Peter,

The solar panels plug directly into the solar port on the D250S, then via a 30A fuse to the batteries. I have an Anderson connector mounted on the camper and wired to the Ctek controller. I made up a second lead from the solar panel, bypassing the onboard regulator, which also has an Anderson connector on the end to connect to the camper's connector.
I have left the original lead on the solar panel which has a Merit plug which I can use to connect to my Thumper portable battery pack when I'm using that with a tent.

The D250S can accept input from both the alternator and solar panels (if they are permanently mounted) and the controller will determine the best input for it to use.
However, the alternator light should only coome on when there is voltage from the vehicle alternator, so it sounds like you have a wiring problem if it is illuminated when only solar panel input is applied.
If you disconnected the alternator input and it was live, something is very amiss.
I assume the engine wasn't running at the time?

It is also good practise to have fuse protection between the alternator circuit and the input to the Ctek to protect against shorts such as you experienced.

It kind of sounds to me as if your alternator feed may be via the primary battery without a dual battery controller in the circuit. This would result in full battery voltage being present all the time, rather than only when the engine is running and the battery controller has detected a full primary batttery voltage and thus energised the secondary circuit to your camper.

Bill


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Follow Up By: Sand Man (SA) - Saturday, Aug 11, 2012 at 10:46

Saturday, Aug 11, 2012 at 10:46
The negative (earth) wire connected to the D250S runs back to the negative terminal on the vehicle's auxiliary battery via heavy duty twin core cable and also to the negative terminal on the camper batteries. An isolator between the primary (starting) battery and the auxiliary battery keeps the two batteries electrically isolated from each other while allowing the alternator to charge both.

Never rely on body or chassis earthing only. A full earth circuit should run from the source battery (be it the starter, or auxiliary) to any remote ones and include any dc-dc charger in the circuit.

Derek Bester from Sidewinder has some excellent advice on remote batteries, etc.
These are available on his web site and also under the Articles heading on the top of the ExplorOz page.

Battery Article Link
Caravan Battery Charging

Good luck!

Bill


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Reply By: CSeaJay - Friday, Aug 10, 2012 at 09:47

Friday, Aug 10, 2012 at 09:47
Peter

The solar indicator should stay lit. It is going off because not enough power is coming in from your solar, it 'cuts out' when it reaches a certain minimum.

Had the same on mine. Had it tested by my supplier. At the time it had a 60W panel connected. Once we added my portable 80W, the problem went away, the light stayed on and the unit worked continuously

CJ
AnswerID: 492644

Follow Up By: arjay - Friday, Aug 10, 2012 at 23:33

Friday, Aug 10, 2012 at 23:33
My D250S experience FWIW.

I have a D250S Dual charger which is normally connected to the (main battery) alternator and a 90 watt panel. When I have the vehicle parked at home in the driveway I switch the solar input across to the output of a 13.8 volt 25amp DC power supply (built into the vehicle).

As I have Victron Battery monitor installed I can observe the amount of current flow to & from the battery and have noticed the same 'pulsing' effect (that has been described above) when 1st connected to the 23amp power supply.

After a short time (approx 3 min) the current flow settles down to a more continuous (non-pulsing) flow.
I'm guessing that initially the charger applies some charge to the battery and then does some checking. This goes on for a short time while it monitors the battery's progress before applying a continuous charge. I've watched the battery monitor display as the charge drops down to under an amp.

My panel can easily supply well over 5 amps (in good sun) and the wattmeter I have connected in series with panel advises a 'healthy' input to the ctek when the sun is plentiful.
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Follow Up By: Member - kwk56pt - Saturday, Aug 11, 2012 at 01:01

Saturday, Aug 11, 2012 at 01:01
Hi Arjay, thanks for your response. When you are on solar without the car engine running does the alternator light come on with the solar and battery light or do you just have thge solar and battery lights on, that is the alternator light never glows when you are on solar alone.
Mine was cycling solar alternator solar alternator and battery and then cut out and repeat the cycle.
Cheers Peter
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Follow Up By: arjay - Saturday, Aug 11, 2012 at 14:40

Saturday, Aug 11, 2012 at 14:40
Peter,

Alternator Light (while using only solar charging):

My alternator light will come on but only after the 2nd battery is fully charged. This indicates that the Main battery (engine starter) is now being charged by the solar panel, i.e. you now have 3 lights ON, [1Green & 2 Amber lights, Solar panel & Alternator].
The indicator lights explanation is shown on page 4 of the manual.


Alternator feed to Ctek:

FWIW my ctek 'alternator' connection is via the +ve terminal of the starter battery, without any voltage-sensing disconnect hardware in between.
The ctek charger has the 'smarts' to manage this.........from page 12 of the manual-> "CHARGING PROGRAM D250S DUAL
The charger starts charging the target battery when the supply voltage exceeds 13.1V for 5 sec (engine on).
The charger stops charging the target battery when the supply voltage drops below 12.8V for 10 sec (engine off)."


Pulsing O/P from ctek:

The picture (see below) found on page 12 of the ctek manual and shows the various charging phases and may help to explain the pulsing behaviour that is often mentioned.
(The 1st charging step is desulphation with pulsing voltage & current.)



The manual may downloaded from:
http://ctek.com/Archive/ProductManualPdf/D250S%20DUAL_EN.pdf

regards,
Rob
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