CTEK SMARTPASS 120S and 250SE DC to DC charger basic features and install information

[K1LL3M]

I have been away a few times with only a watt/current metre on solar panels and a votage metre on the second battery to determine battery health, which to be fair has worked well as I've never had a problem, but I wanted a more detailed way to monitor battery health status.

I installed a simarine unit including a quad shunt for accessories power use and a main shunt for battery monitoring.

When over drawing one night (due to overloading the fridge, turning it up, and forgeting I had) pulling the battery down to 38% I started the car to boost charging and saw over 100 amps being pushed back into the second battery from the 120/250 combo. (Other than the 250 being added, it is wired as Ineos did it) Clearly this system does work and can work well. Having used it for a bit, i am not disappointed.

I have wired my installed accessories to the second battery (usbs/cig sockets/anderson plugs) with the only draw on the main battery other than ineos stuff, being a uhf radio and an led camp light on a roof socket. I would like to move the 3 roof sockets over to the second battery but haven't yet.

It feels to me that the car's system does not like the batteries to be fully charged with 85% being the goldilocks number. Anecdotally I feel If you drop into the 70s it will crank up the charge current but after 85% it fights you on full charging by bleeding off charge somehow and only very slowly charging. But you can get 100% through long driving or constant solar input.

At this stage I have no reason or desire to change the system. I can see what it is doing and it appears to be working... for me.

 

[globalgregors]

I have been away a few times with only a watt/current metre on solar panels and a votage metre on the second battery to determine battery health, which to be fair has worked well as I've never had a problem, but I wanted a more detailed way to monitor battery health status.

I installed a simarine unit including a quad shunt for accessories power use and a main shunt for battery monitoring.

When over drawing one night (due to overloading the fridge, turning it up, and forgeting I had) pulling the battery down to 38% I started the car to boost charging and saw over 100 amps being pushed back into the second battery from the 120/250 combo. (Other than the 250 being added, it is wired as Ineos did it) Clearly this system does work and can work well. Having used it for a bit, i am not disappointed.

I have wired my installed accessories to the second battery (usbs/cig sockets/anderson plugs) with the only draw on the main battery other than ineos stuff, being a uhf radio and an led camp light on a roof socket. I would like to move the 3 roof sockets over to the second battery but haven't yet.

It feels to me that the car's system does not like the batteries to be fully charged with 85% being the goldilocks number. Anecdotally I feel If you drop into the 70s it will crank up the charge current but after 85% it fights you on full charging by bleeding off charge somehow and only very slowly charging. But you can get 100% through long driving or constant solar input.

At this stage I have no reason or desire to change the system. I can see what it is doing and it appears to be working... for me.

You will see the answer to this in the Smart Alternator documentation posted some months ago. I’ll attach a link below.

To paraphrase, and by our observation, the system stabilises guided by actual use. We do a lot of driving, and have a fridge running pretty much constantly, so ours maxes out at 88-89%. According to the documentation, this will decrease as the battery life advances.

Periodically, the BMS will run the battery all the way up to 100%. Ours has done that three times in our year of ownership which leads me to think that this is an isochronal not a conditional function. Unforunately I haven’t been precise on recording the date/engine hours of this event so I’m hypothesising. If it’s in the document I missed it!

The system runs at the ceiling mentioned (80% of max, see p.6) for reasons of emissions reduction (so that a percentage of power consumed by the system is generated by energy recuperation rather than burning fuel): a saving of up to 3%.

Apologies if you’ve read the below post from @NQ94 this already, but if not it’s a rather interesting system and worth a look in my view.

Post in thread 'battery charge limitation'
https://www.theineosforum.com/threads/battery-charge-limitation.12415425/post-1333276455

https://www.theineosforum.com/attachments/intelligent-alternator-control-igr-used-on-2007-models-and-onwards-pdf.7857329/