CTEK 250SE & strange behaviour

[widu13]

This is more of an observational post that anything. I got a CTEK 250SE in mid 2020 and it has been problematic since installation. It very often does not charge and it happened one time when I was close to @travelvolts (who supplied it) and he very helpfully took a look at it but could not fault the unit and of course on him looking it was actually charging despite not charging for the previous 36 hrs. His suggestion was that the piggy back fuse may be questionable or loose. On conclusion of the trip I changed out the piggy back and ensured all connections were good. The intermittent charging issue has continued.

I installed a solar panel and as I do not trust the CTEK, I actually purchased a Victron solar charger. I haven't used the van for a while, but via the BM2 I could see that the panel is doing it's job. I took a 3 hr drive and used the camper from the battery and the following day observed that it was not charging again. There was no green light or other lights. I checked all of the connections (continuity and connection were good) and on a hunch removed the positive feed from CTEK to the batt. On reconnecting it, the CTEK started working. What I have noticed however is that it no longer jumps straight in to charge at 14.8v + as it should but started charging at 13.5v and then started gradually increasing. Today was the 3hr return trip and I observed that it was charging but that the charge was "erratic" and inconsistent. All connections are good and tight and have continuity. I can only think that something is switching in the unit, but I think the cards are on the table for the CTEK. I've seen lots of issues posted about the units and there seems to be zero interest in resolving them from the company. I'll contact CTEK but don't have much hope.

If I were installing again, I would personally avoid the CTEK 250SE.

Erratic charging 30/4 & 1/5



More detailed view of 1/5

 

[Sim60]

You write “What I have noticed however is that it no longer jumps straight in to charge at 14.8v + as it should but started charging at 13.5v and then started gradually increasing.”

starting Charging at 13.5 V and gradually increasing is the correct behaviour in Bulk charging mode. ( Constant current, increasing voltage) .It then moves to absorption mode - holding the voltage at 14.8V with decreasing current.

The erratic charge could possibly be that the CTEK smart alternator cable has become disconnected . in this case, the CTEK will only charge when the Starter battery is at a high enough voltage - ie when the alternator is charging the starter battery.

Simon

 

[widu13]

You write “What I have noticed however is that it no longer jumps straight in to charge at 14.8v + as it should but started charging at 13.5v and then started gradually increasing.”

starting Charging at 13.5 V and gradually increasing is the correct behaviour in Bulk charging mode. ( Constant current, increasing voltage) .It then moves to absorption mode - holding the voltage at 14.8V with decreasing current.

The erratic charge could possibly be that the CTEK smart alternator cable has become disconnected . in this case, the CTEK will only charge when the Starter battery is at a high enough voltage - ie when the alternator is charging the starter battery.

Simon

Cheers Simon, ALL connections are sound. I would say over the last year or so most of my focus has been on the the pos feed from ignition and starter. It never occurred to me that manually "resetting" the charger would force a change in the unit, but the erratic charging is surely a sign that something is just not right.

 

[Sim60]

Do you have a BM2 on the starter as well to compare - your trace from 1/5 looks very like alternator charge of starter battery which is why I suggested ign connection fault - where do you have this connected ? In the fuse box?

 

[widu13]

LOL, that's because it was the starter data, it must have switched when I was checking the history . Correct leisure data added and starter below.

 

[Sim60]

Charging from 10.00 to 10.15 looks fine - CTEK in bulk mode and leisure battery slowly rising. ( CTEK thinks leisure battery less that 80% charged)
No solar generation during the day.
Bulk charging from 4.45 to 5.00 ok.

Looks like a large load kicks in at that point and CTEK doesn’t sustain the voltage at this point - I don’t think this is a problem- the spikes look like the load switches off and on,and the CTEK continues in bulk mode - you can see each subsequent spike has a higher voltage as bulk charging continues .

I don’t think there is a problem ( unless there is no leisure battery load at 5.00 onwards)

Simon

 

[widu13]

That's good to know, but there was no large load bet 1645 and 1900... It was exactly the same load as bet 0001 and 0900.

Perhaps you might know? When I first installed the unit it would charge at 15.1/15.2v, but after the first no charge episode it has never reached that voltage again. Does that sound odd?

 

[Sim60]

looking back at your original trace, it looks like you’re continuously loading the battery from 29/4 . Is this a fridge or something which is switching off and on?
Also - where exactly is the BM2 connected? Are you measuring some voltage drop through some cabling?

The ctek is temperature compensated , so nominally 14.7 v in AGM mode, but it adds Something like 25mv for every degree C below 25 C - so if you fitted it in winter, the voltage would have been higher then if it was a cold day.

Simon

 

[Pauly]

You dont actually say how its wired
do you have any pictures ?
is the black fly lead grounded ?
is the red fly lead connected to an ignition live ?

think i would be contacting the manufacturer for advice/replacement

 

[widu13]

It is a fridge that was running. Both BM2s are directly fitted to each battery... No cabling. The CTEK was fitted in a June IIRC, but it has never operated at that voltage since the first charging drop out.

Any theories on why charging drops out but is reinitialised by disconnecting and reconnecting it...I know that's the IT go to resolution, but it doesn't give me any ideas and there has to be an underlying issue surely?

 

[Pauly]

I had a faulty D250, worked fine for several months then one of the inputs died and wouldnt respond its possible you just have an iffy unit

 

[widu13]

I had a faulty D250, worked fine for several months then one of the inputs died and wouldnt respond its possible you just have an iffy unit

Cheers, TBH the grief the missus gives me when it packs up might just justify writing it off and using another brand. I've seen plenty of threads about poorly performing CTEKS.

 

[Pauly]

For the length of time you been messing with it i would have given it the special hammer fix long ago !!!

I returned my unit no problem and swapped it for another 250 that im still using now with no issues, dont think they are a bad unit just do get the odd faulty one

 

[widu13]

You dont actually say how its wired
do you have any pictures ?
is the black fly lead grounded ?
is the red fly lead connected to an ignition live ?

think i would be contacting the manufacturer for advice/replacement

Sorry missed this in the crossover, yes grounded to common earth, switched live. All connections are sound and continuity proved. I will contact CTEK directly.