CTEK Charging Question

[JasonW]

With the van sat idle for a while I thought I would give the main starter battery a top up.

So I've connected a CTEK MXS 3.8 battery charger. Black clip to chassis, Red clip to Positive battery terminal.

With the Battery still connected to the van, Battery type - Varta AGM 7PO 915 105 A ; 12V 75Ah, powered up the CTEK battery charger...

But after 12 hours+ the CTEK display is still stuck on '3' - Bulk Charging and the CTEK Charger is really hot, like its trying to pump loads of current in...

'3' mentions it bulk charges the battery voltage to 14.4V but I have a voltage indicator that plugs into the cigarette lighter. This displays 12.4-12.5V,(ignition off) this hasn't changed since the charger was switched on

It says '4' is 'ready to use' and that it should get to '7' which is 'pulse' or trickle charge. Am I doing something wrong or is the charger defective..? The van has start /stop function.

 

[Pete C]

I would disconnect the Ctek. Leave it for 10 mins, then reconnect it and see what happens.
Do you have a good connection on the chassis, and do you have a way of measuring the voltage at the charger leads ?

Pete

 

[Ayjay]

I've got a CTek MXS5 and it came with a 12V 'lighter' plug which is much easier than using the clips - I don't know about your van but the two 12V sockets in mine are permanently live. I think you can buy the lead separately if your charger has the facility to use one.

 

[rover220]

Made up a lead for my ctek to charge through the 13 pin towbar socket for those that have a towbar. Nice neat solution.

 

[JasonW]

I would disconnect the Ctek. Leave it for 10 mins, then reconnect it and see what happens.
Do you have a good connection on the chassis, and do you have a way of measuring the voltage at the charger leads ?

Pete

Thanks for the reply

No change after disconnecting for 10 minutes and re-connecting

Trying a different earthing point overnight. Bolt head for battery bracket...

Not sure what voltage is at the charger leads... I'll need to check.

 

[JasonW]

I've got a CTek MXS5 and it came with a 12V 'lighter' plug which is much easier than using the clips - I don't know about your van but the two 12V sockets in mine are permanently live. I think you can buy the lead separately if your charger has the facility to use one.

Thanks, Do you know what voltage your battery charges up to..?

 

[Nigel W]

I've got a CTek MXS5 and it came with a 12V 'lighter' plug which is much easier than using the clips - I don't know about your van but the two 12V sockets in mine are permanently live. I think you can buy the lead separately if your charger has the facility to use one.

I am a complete numpty with electrics, is it really ok to charge through the cig lighter?

 

[rover220]

I am a complete numpty with electrics, is it really ok to charge through the cig lighter?

Yes if you keep output to around 5 amps, 10 at most.

 

[EdH]

Ctek 3.8 charging programs question.

According to the manual for my charger 3.8 it appears that car symbol (normal batt program) and a snowflake (cold weather prog) charging voltages are same. Car symbol charging is to be used for all batteries including many AGM, while snowflake setting is to be used at low temperature and for AGM like Optima and Odyssey batteries.

Bit confused with these two settings given that the charging voltages are exactly the same. So, does it matter which of these two settings are used to simply maintain the battery in my 6.1 van, which is not in use due to the current Welsh lockdown?

Van hooked up via EHU and starter battery charger internally through cig lighter (lower dash) so maintaining both batteries (leisure battery charging via inbuilt Victron 12/15 charger).

 

[JasonW]

I would use your snowflake setting as the settings are temperature dependent... and the current outside temperature is in the range of -20 to +5

If it warms up consistently above +5 then use the car symbol setting...

Assuming of course your battery is AGM.

 

[Phil_G]

Not sure what voltage is at the charger leads... I'll need to check.

On a smart charger thats no indication as its current controlled until the bulk charge ends, it doesnt switch to constant voltage until then. Some dont even show a voltage until a battery is connected. If you want to be certain the battery is charging then you need an ammeter or multimeter set to 5 or 10A in series with one of the charge leads, or a DC clamp meter if you have one. A cumulative Ah meter is even better. Bear in mind that the MXS3.8 is a maintenance charger, it will take time to complete a bulk charge from any significantly disharged state. Its also feasible that you have some drain happening in the background (maybe a camera etc) which subtracts from the 3.8A max charge current, so it takes even longer.
Cheers
Phil
PS yes its fine to connect the MXS3.8 via the cig lighter, its ground is via the ECU current monitor.

 

[EdH]

I would use your snowflake setting as the settings are temperature dependent... and the current outside temperature is in the range of -20 to +5

If it warms up consistently above +5 then use the car symbol setting...

Assuming of course your battery is AGM.

Thanks for this. I presume that it's AGM battery, it's brand new T6.1. The converter has installed a fuse box on top and I can't see the rest of the writing on top of the battery. The only thing that I can see it's brand Exide. Leisure one under the swivel factory fitted seat is AGM Varta 75amp.

Is it safe to leave the charger plugged for, say 2-3 weeks time as we can't go anywhere now anyway. It has been on level 6 (float) for last 3 days? So how long you can leave it plugged in really, does it harm leaving it on until time comes to go out and about?

In respect of the Snowflake symbol, manual states that charger on this setting is for cold weather program and for charging AGM battery. On my Mk5 (2008) Golf it's ordinary battery, can I use this setting as well? I am reading these two settings as ability to charge any type of battery including AGM which is in my van for different ambient temperatures then? There is no exclusive setting for AGM battery charging only. Am I reading/interpreting this correctly?

 

[Phil_G]

Is it safe to leave the charger plugged for, say 2-3 weeks time as we can't go anywhere now anyway. It has been on level 6 (float) for last 3 days? So how long you can leave it plugged in really, does it harm leaving it on until time comes to go out and about?

Thats precisely what a maintenance charger like the MXS3.8 is designed for - its a smart charger, it cant do smart stuff if you keep unplugging it

 

[EdH]

Thats precisely what a maintenance charger like the MXS3.8 is designed for - its a smart charger, it cant do smart stuff if you keep unplugging it

Sorry, English is my second language. Do you mean that it's safe/ok to keep it plugged in until day comes when we can go about? Sorry for all the questions, and thanks for your reply.

I just googled some of the numbers from my starter battery, and it appears that it's EFB+ Exide battery. Are they any good?

 

[JasonW]

Most people have an AGM starter battery....

I might be wrong but an EFB battery isn't really the preferred option for T6 start/stop technology, but perfectly fine for most leisure battery applications...

EFB's and generally cheaper than AGM's and your paying the extra with an AGM for the battery performance.

and yes, you can keep the MXS 3.8 plugged in and switched on indefinatley.

 

[CAB]

Mine is a factory (I presume) Exide EFB starter battery, Highline 102 panel van originally.

As Phil said, keep it plugged in unless it's in the way.

My MXS 5.0 took about 24hrs to get my battery up to full charge after sitting for two weeks.

 

[EdH]

Most people have an AGM starter battery....

I might be wrong but an EFB battery isn't really the preferred option for T6 start/stop technology, but perfectly fine for most leisure battery applications...

EFB's and generally cheaper than AGM's and your paying the extra with an AGM for the battery performance.

and yes, you can keep the MXS 3.8 plugged in and switched on indefinatley.

Thanks for this. Strange why the brand new van did come then with EFB+ starter battery instead of the AGM one, whilst leisure battery it's Varta AGM? Maybe another VW cost-cutting method.

 

[JasonW]

Yes, Possibly a cost saving option by VW.... it seems other people have EFB starter batteries so i'm sure it will be fine...

Keeping it charged and conditioned with the CTEK smart charger will prolong the life of it anyway and keep it maintained and looked after