CTEK CT5

[Thenextchapter]

I have to leave my very much loved Grenadier in the garage for extended periods (sometimes), and looking to maintain the battery while away. Given the EFB and start-stop optimization of our INEOS batteries, looking at the CTEK CT5 as an option. Anyone got any experience with this specific maintenance charger? In a related question, would it be best to connect the charger to a) the auxiliary battery which will charge the starter battery via the CTEK 120S pulse charge feature, b) to the starter battery(see note 1) or c) both starter and auxiliary. This second question maybe for CTEK support, but asking here in case someone already knows the answer. I will ask CTEK as well. Thanks

Note (1). To allow the battery management system (BMS) to correctly determine the State of Charge (SoC) for the starter battery, option b) would have the wiring connected to the jumpstart post in the engine bay.

Note (2). Old reference of CTEK D120 corrected to CTEK 120S.

 

[Quartermaster]

What is CTEK D120? Isn't it 120 S from factory?
My factory CTEK lets the auxillary battery only charge the starter batterie when this is under ~ 12,3 V, otherwise it is disconnected. So a) wouldn't work (.... to keep the starter full at all times)

 

[Korg]

I use the Victron charger connected to the starter battery along with a Victron battery monitor on each battery. One app for all devices. Works well.

 

[Thenextchapter]

What is CTEK D120? Isn't it 120 S from factory?
My factory CTEK lets the auxillary battery only charge the starter batterie when this is under ~ 12,3 V, otherwise it is disconnected. So a) wouldn't work (.... to keep the starter full at all times)

Ooops, I meant the factory CTEK 120S. Fixed that in the original post.

I think most people will choose option a) as it will definitely charge the starter battery, but let’s see.

 

[Thenextchapter]

I use the Victron charger connected to the starter battery along with a Victron battery monitor on each battery. One app for all devices. Works well.

I have a Victron smart monitor in my other truck. So, not sure why I did not think of this. Nice idea to install one on the auxiliary battery given the dash does not display voltage of SoC for the auxiliary.

Will look into the Victron charger. Thanks

 

[Quartermaster]

Ooops, I meant the factory CTEK 120S. Fixed that in the original post.

I think most people will choose option a) as it will definitely charge the starter battery, but let’s see.

Manual says: trickle charge between 11.5 - 12.6 V of starter batterie, my own observation is 12,3 V . But you will see

 

[Thenextchapter]

Manual says: trickle charge between 11.5 - 12.6 V of starter batterie, my own observation is 12,3 V . But you will see

You must have a better manual than me. I did not find this in my manual. But thanks for the advice.

 

[Thenextchapter]

Ok, a bit of an update based on some further research.

1) Wrote to CTEK support. Will see what they say. But on their website they have a document giving advice when the charger connected to the service battery (here) and a different document with advice when connecting to the starter battery (here). Picture below as an example. It is a little hard to determine if the connection to the starter or service battery is preferred, but looks like they are recommending the starter battery. Their exact words are:

• Connecting it to the starter battery is preferred for storage reasons or when you have loads applied to both starter and service battery.
• Connecting it to the service battery is preferred when only the service battery is in use.

2) Based on another post in the forum by (Lollo050968), it is recommended not to trickle charge the battery. I looked at the MOLL website, and found a data-sheet for a battery that is very similar to the one in the Grenadier. The data-sheet is (here). A couple of useful things in the data-sheet. Recommended charge voltage is 14.4volts and recommended charge current is 11 Amps, but this would be 10.5 Amps for our batteries (as they at 105 Ahr). But I am less worried about charging, and more about maintaining. So, maybe this is less important to me.

3) The Victron Smart charger has a storage mode which according to their manual states; "The battery voltage is maintained at the configured storage voltage, which is slightly reduced compared to the float voltage to minimise gassing and extend battery life whilst the battery is unused and on continuous charge". While the CTEK MXS10 also has a maintenance mode based but is based on a pulse function. And from their manual; "Maintaining the battery at 95–100% capacity. The charger monitors the battery voltage and gives a pulse when necessary to keep the battery fully charged".