CTEK250SE low voltage output on solar

[Zave]

On a recent camping trip I suspected my solar wasn't charging the leisure battery. Today I think I've sussed why.

Using a multimeter, I can see the input voltage from the solar panel is 20v. The output is from the CTEK is 12v and the battery is 13v. I deduce therefore that the CTEK output voltage is insufficient to charge the battery. I believe the CTEK output should be around 14v. The BMV also confirms a zero amps charge with all other loads switched off.

Is there any reason the CTEK output voltage is only 12v?

When being charged through the CTEK via the alternator I can see from the BMV it's getting a charge of 18 amps.

 

[Dellmassive]

First try to reset the ctek by disconnecting all the cables or supply fuses for 15mins.

Then retest.

Does the engine charge work ok?

 

[Zave]

Thanks Dell, I shall give that a try

Engine charge works perfect from the Ctek.

I've also raised a support ticket with Ctek website. We'll see if they suggest anything.

 

[Sim60]

What lights are showing on your CTEK?
What’s the spec of your solar panel? - the CTEK can only cope with a max I/p voltage of 23V on solar input.

Simon

 

[Zave]

There are no error lights on Ctek.

Panel has a 24v max output. Travelvolts told me it would be ok but perhaps I've fried it.

 

[Sim60]

Ok - so no error lights - but what other lights are on?

 

[Zave]

 

[Sim60]

Looks good
I don’t understand what you mean when you say the CTEK output is at 12V but the battery is at 13V- surely they’re connected directly together ( via a fuse maybe) - and at the same voltage.

 

[Zave]

That's the issue. The output should be 14.2v on the lithium profile.

 

[Sim60]

It may well be that there’s a problem with the CTEK , but the voltages you give either means there’s an issue with your system setup or how you’re measuring the voltages.
Are you measuring the CTEK output voltage and the Leisure battery voltage with the same meter in the same way? If you do that, then the voltages should essentially be the same - regardless of whether the CTEK is working or not assuming they are connected directly to each other. No point trying to figure anything else out until you get to the bottom of this 13V vs 12V measurement difference .

 

[Zave]

I took the voltages in and out of the Ctek using the same method and multimeter. The battery voltage is from the BMV.

I haven't heard back from Ctek after raising a customer service query.

I've got a bike racing/ camping event in July and need the solar to be topping up the battery so that I can use an inverter to charge an ebike.

So I've gone ahead and bought this in the picture and hope to get it fitted and all working next Friday.

 

[Zave]

With respect to the 12v and 13v. Yes, I appreciate they should read the same. I'm not sure why they don't. Let's help this new Victron does the trick and thanks for your help.

 

[Zave]

Actually, I've now got my suspicions that when I take the seat out I'm going to find a blown fuse somewhere. Hence the difference in voltage readings... watch this space.

 

[Zave]

All fuses ok. Except my multimeter which has just blown a fuse

I've not fitted my Victron solar controller yet as I've been busy fitting an inverter.

I did manage to do some experimentation on the CTEK though.

It charges fine from the alternator but does run very hot.

The CTEK shows a solar charge even when the panel is not connected.

 

[Sim60]

That solar light looks very wrong!
How are you CTEK and leisure battery grounds connected to the rest of the van and loads.

 

[Zave]

Everything is grounded to the chassis via a bus bar from the leisure battery negative terminal

 

[Zave]

The CTEK has worked perfectly for 3 years.

Any how, I've now gone and fitted the Victron MPPT solar controller.

I'm getting some decent volts and amps into the battery. I therefore diagnose a faulty Ctek

 

[Zave]

The Ctek works off the alternator but gets extremely hot.

I've gone ahead and ordered a Victron B2B charger and shall fit that next week and be gone of the Ctek completely.

I'm so glad my 3 year old solar panel is ok, wear and tear accepted.

 

[Moodz]

If you open up your CTEK you may find you have a blown fuse inside

 

[Zave]

Victron B2B now installed. If somebody needs a CTEK for parts let me know.