Solar Panel through 7-pin plug

Submitted: Sunday, Sep 08, 2013 at 16:56
ThreadID: 104240 Views:3743 Replies:3 FollowUps:9
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Hi,
I just bought 150W folding Solar Panels and want to connect them through my 7-pin plug directly to my slide-on camper which has a house battery and a Ctek multi xs 15000. The Solar Panels have a MPPT controller attached to them. Can I keep the MPPT attached to the Solar Panels or should I bypass it before connecting through the 7-pin plug? This is the plug where the power from the alternator comes through when driving (which of course will be disconnected when parked and before connecting it to the Solar Panels. I understand the MPPT controller is just a basic one. Also will my Ctek correctly charge the battery from the Solar Panels or would it be better to use the crocodile clamps which came with the Solar Panels and connect them directly to the battery?
Thanks
Evie
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Reply By: Member - Frank P (NSW) - Sunday, Sep 08, 2013 at 17:20

Sunday, Sep 08, 2013 at 17:20
Hi Evie,

Your Ctek Multi XS 15000 is not suitable as a solar charger, so you cannot bypass the controller on the panels and connect to the 7 pin plug to feed the Ctek. It won't work and you will probably damage the Ctek.

Also, you cannot connect the output from the MPPT controller to the 7 pin plug to feed the Ctek to in turn feed the battery. That won't work either.

You have two options:

1 Connect the crocodile clips that came with the panels and the regulator directly to the battery.

2 Buy a better MPPT controller, install it in your van then bypass the controller on the panels and feed your panels directly into the new controller.

Cheers
FrankP

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Reply By: Sand Man (SA) - Sunday, Sep 08, 2013 at 17:44

Sunday, Sep 08, 2013 at 17:44
Evie,

Your Ctek xs 1500 would be connected directly to the battery bank and only be operational from 240v input.

The best option available to you is to install a ctek D250S Dual dc-dc charger.
Not only will this boost the voltage from your alternator to ensure an effective multi-stage charging regime while driving, but the D250S has a solar panel input port which will provide a similar charging regime as the alternator input.
Both sources can be connected at the same time and the D250S will determine the best input source and use it.

My Camper trailer has a multi-stage 240v charger which can be used at home, or at a caravan park on a powered site, but I rarely use caravan parks, preferring bush camping.

I installed a D250S dc-dc charger and moved the alternator input cable connections from the battery bank to the alternator input port on the Ctek.
I also installed another dual core cable fitted with an Anderson connector to the solar input port and mounted the connector inside the camper, in a convenient spot.
As the Ctek has a very good inbuilt MPPT controller I needed to bypass the cheaper and less functional regulator on my folding panels. (You cannot have two in the circuit)
To do this is a simple matter to pick up the output terminals in the junction box (before the regulator input) and install a short dual core cable to another Anderson connector I mounted on the box cover. The original cable was left in place so I can use the solar panel to connect to another portable battery system I also have, or use the cable with the Anderson connector to connect to the D250S solar input.

Have I confused you?

Any competent electrician could perform this fairly simple addition for you to give you the best multi-stage charging function for your camper/caravan batteries whether they are charged from the alternator (while driving), or the solar panel array (while stationary).



Bill


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Follow Up By: Evie - Sunday, Sep 08, 2013 at 19:41

Sunday, Sep 08, 2013 at 19:41
Hi Bill,

thank you very much for your reply. I am a bit confused regarding the charging of the house battery. I thought that the Ctek does actually regulate the input from the alternator? So why would it not also regulate input from solar panels? I also asked the manufacturer of the slide-on if I could use the 7-pin plug as input from the solar panels (I would need to have the correct plug wired to the solar panels of course) and they advised me that this is possible.
Thanks
Evie
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Follow Up By: Member - Frank P (NSW) - Sunday, Sep 08, 2013 at 20:16

Sunday, Sep 08, 2013 at 20:16
Evie,
I'm afraid the advice you have been given by the slide-on manufacturer is incorrect. The Multi XS 15000, now labelled MXS15, is a mains-only smart charger. It will not accept input from the alternator, nor from solar.

Bill's advice is very good.

Chances are that with your present setup you are not properly charging your batteries while driving - though you could be. To make a proper judgement we need more information about the output of your alternator and the cabling that has been installed .

Installing a D250S Dual with proper cabling will guarantee proper charging of your house battery while driving and it will accept solar for camping. Leave your MXS15 in place for mains charging because the D250S doesn't do mains.

Cheers
FrankP

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Follow Up By: Sand Man (SA) - Sunday, Sep 08, 2013 at 20:20

Sunday, Sep 08, 2013 at 20:20
Evie,

The Slide-On manufacturer is maybe confusing you.

The Ctek Multi XS 15000 only has a 240vac input source. A very good charger all the same but it would be wired to a 240vac source.
The Slide-On camper would have a 240v caravan style external 15 amp weather proof "plug" and probably wired inside to the input of the charger. There would also be one or more 240v power outlets with an RCD safety device in the circuit for protection against shock.

This 240v circuit would only be able to be connected up via a 15 amp lead, or a 10 amp to 15 amp converter such as the "Ampfibian", or similar device.

No Ctek charger to my knowledge has a 12 volt input, other than the D250S dc-dc charger.

Perhaps what they were intimating is that they could provide an alternative circuit allowing the alternator circuit to be connected direct to the battery bank. This is certainly possible without the Ctek D250S dual, providing heavy duty cable was used to limit voltage drop.
The success of this connection would be largely dependent on the output characteristics of your alternator. Some late model vehicles have a restricted output.
With this circuit, a solar panel could be connected to the cable via an Anderson connector or similar and rely on the smarts of the solar controller on the panel.

The advantage of the D250S dual controller is that any lower level voltage will be boosted to an optimum level for efficient and effective charging, with a current of 20 amps, regardless of whether the input is from the alternator or the solar panel.

Bill


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Follow Up By: Evie - Sunday, Sep 08, 2013 at 21:55

Sunday, Sep 08, 2013 at 21:55
I think I'm going to write to the slide-on manufacturer for some clarification regarding the connections and cabling. In the meantime I will stick to the crocodile clamps until I know how it is all connected.
Thanks again for the advise.
Evie
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Follow Up By: Nomadic Navara - Monday, Sep 09, 2013 at 00:17

Monday, Sep 09, 2013 at 00:17
The solar panel with its regulator can be connected to the 7 pin connector. The battery lead from the connector will feed directly to the battery. The panel will work OK, even though it would not be quite as effective as it would be if the controller was mounted close to the battery. The manufacturer was not misleading you (I did not see anywhere where you were advised by the manufacturer that the battery feed was routed through the Ctek so I can not see where this "I'm afraid the advice you have been given by the slide-on manufacturer is incorrect." came from.)

If you mounted the controller in the line between the battery you would not get the little voltage drop between the controller and the battery. However if you do mount the controller there the direct charging from the alternator may not work (MPPT controllers require a little more voltage than the alternator will produce.)

However if you do want to improve he efficiency a little from your panel then you can go the extra expense and fit the Ctek D250S. This will also improve the efficiency of the alternator charging as well.

Discussing the XS 15000 is a bit of a red herring. the only connection between the circuit from the 7 pin plug and the charger is they are both connected to the battery. The line from the 7 pin plug only operates from the alternator or your proposed panel. The Ctek only operates when the mains is switched on.
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Follow Up By: Sand Man (SA) - Monday, Sep 09, 2013 at 07:22

Monday, Sep 09, 2013 at 07:22
Peter,

I suggest you go back and re-read Evie's original post.

Part of her query was "will my Ctek correctly charge the battery from the Solar Panels", so the assumption was that she was under the impression that her battery charger was in the circuit.

That is why I have responded in the way that I did.

I agree that the solar panel could be connected to the 7 pin plug, but I also believe this is poor practice and therefore I wouldn't recommend it, even for a low current draw from the solar panels.
7 pin plugs and sockets are notorious for bad connections that cause problems.

I did suggest an alternative circuit to charge the slide-on's battery and even connect the solar panel to but this would utilise Anderson connectors rather than the silly little trailer plug/socket that too many people employ, then wonder why they experience problems.

Evie,

May I suggest you read through Power and Electrics to get a fuller understanding of good practices that will get the best results without inherited problems down the track.

Bill


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Follow Up By: Member - Frank P (NSW) - Monday, Sep 09, 2013 at 10:28

Monday, Sep 09, 2013 at 10:28
Evie,

I mis-interpreted your post about what the slide-on manufacturer said, so humble apologies for that and the incorrect advice that followed.

In Follow-up 797579, Nomadic Navara is correct - if the alternator line to the 7 pin is wired directly to the house battery then you CAN connect the output from the regulator on the panels to the appropriate pin.

However, depending on cable sizes and total length, it would be probably be poor practice. The total cable length from the regulator to the battery would likely be long and likely pretty thin - two factors which will work against getting the best from the regulator. Ideally the regulator should be mounted as close as possible to the battery and long cabling confined to between the panels and the regulator.

I would go with the crocodile clips direct to the battery purely for efficiency reasons (and not because via the 7 pin won't work at all - it will to a degree) until you decide about something like the D250S Dual.

Nomadic Novara - thanks for highlighting my error, which gives an opportunity to correct it.

Cheers
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Follow Up By: Member - Frank P (NSW) - Monday, Sep 09, 2013 at 22:10

Monday, Sep 09, 2013 at 22:10
Evie,

There's one more thing you should be aware of before you outlay your hard-earned on a DC-DC charger such as the Ctek D250S mentioned in this thread.

The charging system on many vehicles nowadays outputs a much lower voltage than was common not so long ago. Many people think the old rule of thumb is 14-odd volts and that it continues universally today. That is no longer reliably so. Many vehicles output in the low 13's once the crank battery is charged and/or the system has warmed up. My Prado settles at 13.1 to 13.2 volts on an average day.

This low voltage is lower under load at the end of a cable from the engine compartment to the house battery - around 12 volts under a 30 amp load. 12 volts will not charge a lead-acid battery. You need a DC to DC charger that will reliably boost this low voltage to what the house battery needs to charge it, around 14.4 volts.

Some members of the club I am in have experienced issues with the D250S when the input voltage to the Ctek falls below 13.8 volts.

To avoid disappointment you need to find out what your vehicle's charging system does, that is, is it like my Prado (and others) which have a much lower than traditional output?

As an alternative to the Ctek, Redarc make a product that will accept both solar AND the low voltage produced by many new vehicle charging systems. You can see it here. There may be others.

Shop carefully.

Cheers

PS As usual, no affiliation or axe to grind with any of the products mentioned. They are all good in the application for which they are designed.
FrankP

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Follow Up By: Member - Frank P (NSW) - Monday, Sep 09, 2013 at 22:22

Monday, Sep 09, 2013 at 22:22
From the D250S Dual 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).

It is easy for the supply voltage to be below 13.1 volts at the end of a long cable run from the alternator, in which case the unit will not charge the house battery.
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Reply By: Sapper D - Sunday, Sep 08, 2013 at 20:14

Sunday, Sep 08, 2013 at 20:14
Hello Evie
I've done exactly as you described, and it works fine.....Cheers.Sapper D
AnswerID: 517840

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