Batterymanagement and Smartpass 120S with 250SE

I ordered my INEOS 6 month ago and I searched a lot in this forum about the battery system and had a lot of questions.
I tried to understand how the Batteries are connected to each other and did some tests and now I want to share my experience with you to help each other

I'm not a native speaker, I hope I will describe everything well enough.


Here some of my questions:

1. How are the batteries connected to the power sockets
2. How does the Smartpass 120S works
3. Why does INEOS say “Don’t use the consumer output”
4. How and where can I Install a smart shunt, to monitor the AUX battery in combination with solar.
5. Where can I install a fuse box for my extra loads
6. How can I route cables to connect a solar panel to the 250SE



1. Simple answer, they are all connected to the primary battery. I don’t know why, I think it was cheaper, because of the AUX batt is just an extra feature and when you order the 2nd battery, they just need to connect the smartpass 120S batt out with the AUX batt and don’t need to completely overthink the cable management.
- >That’s the reason, why you will run out of Energy on both batteries, when you have your consumer running


2. So but why does the Aux Battery is running low, too, when the consumers are attached to the primary/starter battery?
The Manual of the 120S tell you the answer. It’s a little bit confused, but I tested it already and confirmed my guess:
It’s because of the trickle charge! The trickle charge does not just work in combination with Solar. It's always triggered, when the starter battery is between11.5V–12.6V! (SOC 0%-90%)
So, when your starter battery is discharging and running below 12,6V (which is around 90% State of charge), the AUX Battery will start the trickle charge function. Both batteries will discharge to 11,5V, which is not enough to start your engine again…. Then the smartpass will cut the AUX Batt, from the Starter battery, but the consumer will still drain the starter battery until it’s completely deep discharged without protection! When you look at the smartpass you can see, the LED is showing up the trickle charge routine every few seconds:



To get rid of this issue I want to use the battery guarded consumer output to keep my primary battery at 100%, even when the AUX battery is empty.

Battery guard:
SMARTPASS 120S disconnects consumers when the service battery voltage is low in order to avoid deep discharge, which would damage the battery. The consumers are reconnected after the service battery voltage has increased (AUX Batt above 12V).”


3. Still don’t know why, I have no problems with my consumers attached on the consumer connector and I don’t care.

4. There are 2 screws and they have exact tthe same size like t he 2 holes in the smart shunt. Just need to drill them from M4 to M6, to fit on the screws.
And you can see my wrench fittet on the negative cable coming from thr AUX Batt. In my case I unplugged the connected cable there and attached a 2nd cable on it running to a negative Busbar.


There we go, battery cable screwed and insulated and connected to the shunt. The shunt is connected to the busbar and the busbar connected to the original negative screw. One cable is running to the CTEK 250SE, I forgot to mark the line in the image.


5. You can see, there is still enough space for more and I decided to cut a 0,75mm aluminum plate and screwed it just at one side so far:

Explained: The 6 port fuse box is connected to the consumer output at the CTEK 120S. So all consumers attached to this fuse box will use the power of the AUX Battery. In this picture there are 6mm² cables but I replaced the + cable with a 25mm² (see next pictures).
The negative is still 6mm² because of I use short ways for the negative lines and use the car ground spots in the car on each location. (also see later in the pictures for example)

The 30A circuit braker will be used for the solar input, so I am able to cut off the solar power. Nice to have I think. The black cable in the picture with the DEUTSCH Plug is my solar cable coming from the roof, but I removed the DEUTSCH plug now. See in the next pictures.

6. Solar:


looking like an idiot in this picture hehe. You can see, there are enough holes behind this cover:

From the inside: (DEUTSCH Plug on both sides, already unplugged in this picture:

From the side with the rubber seal.



My favour was to replace the seal and use the existing hole for the 2nd cable, too, but I couldn't find one and decided to use a ugly method:

Not very happy with this solution and I think need to seal it additionally with silicone and there is way less space in this fuse boxes than you expect.
The cable endet up there in a DEUTSCH Plug will connected directly to the 250SE.

I won't give up on the already installed DEUTSCH plug, because of I have other plans for it. See here:



You can see the black cable through the new hole to install my solar and I rewirered the default DEUTSCH Plug to my AUX Fuse Box. So in this case I have on tthis connector permanently 12V from my AUX battery. You may ask why?
Because of my roof tent. I wan't to use this Plug to attach my DIY DEUTSCH to car cigarette lighter, that I can use my gadgets like LED or charge my phone etc in my tent. The Cable there is with 6mm² a bit oversized, but I had the cables at home and want to finish this before it starts to rain.


I'm still not finish with this project and will update my post later this week when I have my milestones reached. Feel free to ask if you have some questions

Thank you for your excellent work and the useful pictures. I would also like to connect a solar panel "quickly" before my holiday, in case I do end up spending a few days in one place. However, I have a solar charge controller from Victron.
Based on your comments, I'm wondering whether I should connect the controller directly to the starter battery? Connecting the auxiliary battery makes no sense at all. But is there anything in favour of connecting the Victron to the 120S?

For what it’s worth, if I remember correctly the idea of no longer allowing use of the consumer output post of the smartpass was because people were apparently overloading the post exceeding its maximum draw.

internal said:

Thank you for your excellent work and the useful pictures. I would also like to connect a solar panel "quickly" before my holiday, in case I do end up spending a few days in one place. However, I have a solar charge controller from Victron.
Based on your comments, I'm wondering whether I should connect the controller directly to the starter battery? Connecting the auxiliary battery makes no sense at all. But is there anything in favour of connecting the Victron to the 120S?

Click to expand...

I was connecting to the auxiliary and relying on the Smartpass to top the primary. Worked well.

Past tense as I now have a D250SE installed and acting as the solar input and controller.

globalgregors said:

I was connecting to the auxiliary and relying on the Smartpass to top the primary. Worked well.

Past tense as I now have a D250SE installed and acting as the solar input and controller.

Click to expand...

But wouldn't it be gentler to charge the starter battery and not the auxiliary battery via solar power, as it mainly discharges the starter battery for the refrigerator and otherwise has to be recharged via the second battery?

I would also connect the Victron solar charge controller (BlueSolar MPPT 100/30) to the CTEK 120, but I'm not sure whether this would work well and whether the specifications would fit. Has anyone here in the forum connected a solar charge controller other than the CTEK 250SE directly to the CTEK 120s?

UPDATE 1:

I finished the wires, here a Picture with my new cablemanagement:




and here a view of my roof:



and here a picture from my smart shunt, where you can see the trickle charge.

nuclearmonkey said:

For what it’s worth, if I remember correctly the idea of no longer allowing use of the consumer output post of the smartpass was because people were apparently overloading the post exceeding its maximum draw.

Click to expand...

When you connect the DC- DC charger to the primary Battery, the CTEK 120s will charge the AUX Batt, too. If this is what you want, than this would be the best way. The CTEK 120S will connect both batterys when the Input ( A + ) will reach 13,1V.
When you connect it only to the AUX battery, you will first charge the AUX batt to 100% and then the trickle charge will start, but the trickle charge is not a classicel charging mode für the primary battery, it's just to run against the self discharge of your primary battery

internal said:

But wouldn't it be gentler to charge the starter battery and not the auxiliary battery via solar power, as it mainly discharges the starter battery for the refrigerator and otherwise has to be recharged via the second battery?

I would also connect the Victron solar charge controller (BlueSolar MPPT 100/30) to the CTEK 120, but I'm not sure whether this would work well and whether the specifications would fit. Has anyone here in the forum connected a solar charge controller other than the CTEK 250SE directly to the CTEK 120s?

Click to expand...

Where did you connect your refridgerator? On the 12V rear socket? Then you are right, you will discharge the primary and the AUX battery at the same time WITHOUT protection on the primary Battery. Thats the case, why I rewired everything and connected my consumers on the consumer output. My wiring will only discharge the AUX battery and cut the output, when the batteery will reach 11,5V

So when solar output is connected to the d250, it charges the main directly, and then the 120 opens to connect both?

Snow678 said:

***
Where did you connect your refridgerator? On the 12V rear socket? Then you are right, you will discharge the primary and the AUX battery at the same time WITHOUT protection on the primary Battery. Thats the case, why I rewired everything and connected my consumers on the consumer output. My wiring will only discharge the AUX battery and cut the output, when the batteery will reach 11,5V

Click to expand...

Yes, sorry, I hadn't mentioned that: the fridge is connected to the 12-volt socket in the boot.

Your setup is what I actually want. But for the holiday I would go directly to the starter battery with the solar charge controller for the time being due to time constraints.

internal said:

I would also connect the Victron solar charge controller (BlueSolar MPPT 100/30) to the CTEK 120, but I'm not sure whether this would work well and whether the specifications would fit. Has anyone here in the forum connected a solar charge controller other than the CTEK 250SE directly to the CTEK 120s?

Click to expand...

That’s a question I be interested in knowing the answer to as well. I have a victron 75/15 solar controller which I am currently attaching to the jump start posts in the engine bay. But if I mount it permanently would like to know whether connecting to the smartpass or direct to the starter battery is better

Cheers
Steve

internal said:

But wouldn't it be gentler to charge the starter battery and not the auxiliary battery via solar power, as it mainly discharges the starter battery for the refrigerator and otherwise has to be recharged via the second battery?

I would also connect the Victron solar charge controller (BlueSolar MPPT 100/30) to the CTEK 120, but I'm not sure whether this would work well and whether the specifications would fit. Has anyone here in the forum connected a solar charge controller other than the CTEK 250SE directly to the CTEK 120s?

Click to expand...

Totally reasonable. Three reasons:

• I preferred to ensure both batteries are topped;
• Ease of access to the aux battery terminals; and
• This arrangement allowed me to lock the vehicle, trapping the solar blanket.

At the time I was running through a Redarc MPPT controller. No problems.

nuclearmonkey said:

So when solar output is connected to the d250, it charges the main directly, and then the 120 opens to connect both?

Click to expand...

Nope, the Solar is connected primary to the AUX battery and the trickelcharge will help to keep the primary battery full. When you use the consumer output, only the AUX battery will be discharged and the primary battery is untouched and you are safe to start your car again every time. But don't forget, INEOS connected all default AUX connectors to the primary battery, thats why I build this setup, to have all "real consumers" like a refridgerator wired to the consumer output. Just my external LED on my roof will drain the battery but they don't need as much power.

internal said:

Yes, sorry, I hadn't mentioned that: the fridge is connected to the 12-volt socket in the boot.

Your setup is what I actually want. But for the holiday I would go directly to the starter battery with the solar charge controller for the time being due to time constraints.

Click to expand...

Yes the connector in the boot is connected to the primary battery, too. And then you will end up in my case explained, that even the AUX battery will drain because of the trickle charge. So its like a balancer to keep the primary battery in best conditions to start the engine, but INEOS didn't connected it like CTEK offered the smartpass

Your solution sounds nice, so go for it

Rok_Dr said:

That’s a question I be interested in knowing the answer to as well. I have a victron 75/15 solar controller which I am currently attaching to the jump start posts in the engine bay. But if I mount it permanently would like to know whether connecting to the smartpass or direct to the starter battery is better

Cheers
Steve

Click to expand...

it depends on where you want to connect it at the smartpass. When you connect it on the left side ( A+) you are also connected to the primary battery. The right side, the battery icon labeled as "out" is connected to the AUX battery. The smartpass is watching on the left side, if there is more than 13,1V and then it will close the circuit between the batterys and will charge the AUX battery with up to 100A throughput.

I hope I explained it well enough, my english could be better for this technical parts