I'm glad it was helpful. We have been using it for a number of years now and it still works very well.

Hi, thanks for your question. The short answer to having a Smartpass is unfortunately "no". The Smartpass does not have a Solar Controller built into it. You would require one of the D250 ranges of controllers from CTEK. The purpose(s) of the Smartpass are to 1. Help boost charge from the Alternator to the Service Battery running fridges etc. 2. To assist the starter battery by using power from the service battery to start the car when the starter battery is too low. So, if you purchase one of the D250 ranges of DC to DC chargers (either D250, D250 S or D250SE) then you can also use a solar panel up to 300w that supplies a panel voltage of no more than 23 volts, also it can handle up to around 24/25 amps. Therefore, if you connect your two solar panels to your hopefully new D250, YOU WILL BLOW IT UP!!!!!!!! SO DO NOT DO THAT. If you genuinely want to utilize the solar capacity of your two solar panels, then you will need to purchase a solar controller with a capacity of around 40 to 50amps because a 250watt solar panel will provide around 20amps. Presently, CTEK do not produce such a controller, but if you do buy a solar controller, then I would make sure it is a MPPT version. The agent you buy from will know what that is....

Many thanks

No man, this is such a shame. A real legend has left us. Thank you for letting us know. Gerrit will be deeply missed by one and all.

Only found out today that he died, very sad, I use to live and work there years back, met my German wife there, living in Germany with her now. We are both very sad .

I know, it is so sad that such a lovely man has gone.

Thank you for the kind words and, yes, it was an amazing trip.

It got separated from the herd.

Hi Agustin, Thanks for the message. It's always good to hear a reply. Let me come at your questions reply for you from two angles: 1. Before I decided upon our DC to DC setup, I was in the fortunate position to be able to field test similar DC to DC setups in the bush in ambient temperatures of over 40 Deg c with equipment from Victron, Redarc, Ring, National Luna and of course as the CTEK D250sa and Smartpass 120. a. All tests were carried out utilizing the same alternator (360Amps output) with a full SOC (State of Charge) starter battery (Varta 100Ah AGM), the same set up for wiring and, two brand new 140 Ah AGM service batteries that were at the same SOC at the commencement of the test and were discharged to exactly the same 20% SOC before each DC to DC charging system was require to recharge the service batteries. This means that to complete the tests, I had 10x brand new 140Ah AGM service batteries at my disposal; b. The Charging process was carried out five times at three different times of the day over exactly the same route (with no traffic) on each DC to DC charging system. The tests commenced at 06:00 hrs when the ambient temperature around 18 Deg c; then at around 14:00hrs with an ambient temperature over 40 Deg c and then finally at around 19:00hrs when the ambient temperature was around 28 Deg c. Of course, these were the outside car temperatures, and inside the car recorded by the two service batteries were about 15 Deg c warmer; c. The course the vehicle drove was exactly the same route for a duration of 2hrs and 30 minutes to typically simulate a 2 to 3-hour overland drive a user might take each day having drained their service battery set up overnight and then require charging them the next day; d. At the end of these tests, very clear data emerged. Many of the DC to DC charging units could not generate their full stated charging quantity or amount during the higher ambient temperatures. By this, I mean that lets say a unit “could, according to the manufacturers recorded data” charge at 30Ah. The reality was, that in higher ambient temperatures, the unit would in fact only charge at around 18Ah. This would mean that over that 2hr 30-minute drive, the unit was down a total of 33amps on what it could or “should” have actually been able to provide to the service batteries. So, with a 280Ah service battery bank that had been depleted down to a 20% level I.e. the 56Amp left in the two battery’s (set in parallel). After the 2hr 30-minute drive, the unit that should have been able to put around 75Amps into the service batteries, but had in fact, only put in 42amps meaning the service batteries were charged up to around 98Amps SOC, way down on the require minimum of 80% SOC (224Amps). This information was concerning because it would mean that a user would not have sufficient power in their service battery bank to sustain the required demand the next night. e. Now even if the said units could have provided their full output to the service batteries of say 30Ah, then in reality, with a service battery bank of 280Ah (which is not a large service bank), from a starting SOC of 20% (56Amps), the unit could only have put in a maximum of 75Amps that could have brought the service batteries SOC up to 131Amps, again way down on a required or necessary 80% level nearly 100amps down on what would be required. This would have meant the user would have had to drive for at least another 3hrs 30-minutes to get the batteries up to the required 80%. This clearly would not be a practical option if the ‘overlander’ was only driving for a 2hr 30-minute duration. f. The other thing to consider is that batteries (other than lithium) are inherently not efficient when charging from the 80% level up to the 100% level SOC. The last 20% takes a very long time to charge. g. As indicated, at the end of the tests there was only one unit that was over the duration of the tests able to charge the service battery bank to a full 100% SOC, that was the CTEK system. Yes, the D250 and Smartpass 120 combined can utilize a mammoth 140Amps from the alternator and of course, this was way more charge per hour than any of the other units on test. But the interesting data was that regardless of the ambient temperature, the CTEK units provided their full outputs overt the duration of the tests. h. I decided to remove the Smartpass 120 to bring the test into a more level playing field. The D250 unit again provided its full 20Ah over the same duration. i. Other than the CTEK, all of the units on test were unable to provide their recorded manufacturers output. One unit in the higher ambient temperatures could in fact only provide a worrying 4Ah when the it had a stated 30Ah output. Another that had a stated 25Ah output could in fact only sustain 6Ah output. j. All of this data was very useful in allowing a decision to be made on which unit(s) would achieve what was required I.e. getting the service batteries back up to the minimum of 80% SOC. Only one set of units was able to full charge the service battery bank up to the full 100% SOC in the allotted time scale and that was the CTEK system; k. Interestingly, I was contacted by a manufacturer in Australia (not Red…..) that stated that their system would “out perform the CTEK system and that the CTEK could not possible do what it did and would have had to over-charge the batteries” (not actually possible, because the batteries govern how much charge they will absorb, not the unit). So, I put it to this Australian manufacturer that if they wanted to loan me their unit, I would test it back to back against the CTEK system, THEY DECLINED MY OFFER!!!!! 2. So, to the second angle: a. We have now been running the same 2x 140Ah AGM batteries for over 3 years now, they have never been off load during this period with, a two fridges and other accessories constantly loading the batteries overnight or when the car is switched off; b. In this time, yes of course the overall SOC of the two batteries have declined over this time, but the CTEK system has never overcharged the two batteries contrary to what a certain manufacturer erroneously suggested; c. I monitor the service batteries very closely and yes, now after three years the two batteries are coming up for renewal as they are now holding about 80Ah each; d. My plan like you is to utilize lithium batteries in our system but, I will be using the CTEK D250se and Smartpass 120S to charge my new service battery bank that will be increased to a huge 600Ah plus. To conclude, in my view given I am not sponsored, I do feel the CTEK system is without doubt the best currently available. It performs flawlessly and has never let us down. Yes, the installation is very important and yes, I oversized my wiring to ensure the least possible voltage drop to the units from the front of the car. I hope this helps……

@@overlandi5056 Wow, not only thankful for taking the time to answer so fast but also for being so generous! It is amazing the tests you did and how clear and straightforward you are about test conditions and performance. I really thank you for your reply.

Hi Augustin, Just wondering how you are getting on with your setup???

Tigers are more cowards

Not unusual at all, I saw many lions fleeing from buffaloes.

Are you an Indian?

It's a road through a game park in South Africa.

We will be uploading new content soon.

Hi Chris, Thanks for your question and, may I apologise for not replying sooner. Things have been somewhat hectic with three of us in our family going down with Covid all at the same time. To answer your question, I am going to assume you are also using a D250 (variant) charger in conjunction to the Smartpass. Equally, given CTEK’s advice to not install their units under the bonnet of the car, I am going to work on a 4 to 5-meter cable run much the same as our set up. With the DC-DC charger and Smartpass combined, the two units can draw up to 145amps to provide a charge to the service batteries up to a colossal 140amps (per hour) of charge, obviously dependent on the power the alternator can provide. I also worked on the basis of quite high temperatures in the car that could, at times be as high as 45 deg c. Potentially, at this amount of charge, the calculations for the cable would be a 95mm cable or 4/0 AWG. So, based upon this information, I used two 50mm cables on my supply run from the Starter Battery to the CTEK units because to try and route a single 95mm cable through the car was simply not going to work. In running such large cable, my voltage drop was very low and thus the current drawn did not go up significantly (ohms law - as voltage goes down so, current must go up). The key thing to remember as well is to use a thick negative cable from the CTEK units and ensure it is grounded really well. All my joints were soldered with a bridge in the solder joint to aid any vibration issues. I hope this helps answer your question.

@@overlandi5056 thank you really appreciate it

You are welcome..

Perhaps it helps to get the lions hyped up.....

I'm sorry the music upset you, the said music is from African artists and is part of African life.

Lions seem to like it....

Hi Micah, Thanks for the question. We have been running the CTEK D250SA and Smartpass 120 in combination for about 2 1/2 years now and I have to say, they have been absolutely faultless. They have kept our service batteries (2x Enertec Discoverer 140A/h AGM's) completely topped up and, the Smartpass keeps the Starter battery pulsed with power from the Service battery's, thus ensuring the Starter Battery (also an AGM) is always as full as it can be. To give you some specifics of what kind of current I am seeing, I will explain a little. We used to run a Land Rover (Densol) standard alternator and at Idle, if the service batteries were low, say around 50% (or less) SOC (state of charge), then I would see around 50-60 amps at idle, providing the Starter battery was full and, I was not loading the alternator with lots of lights, fans etc. But as soon as the RPM picked up to around 1,500 RMP, I would see over 100amps of charge. In time, I realized that if I wanted greater charge at idle or when running along normally, I would need to increase the output of the alternator. We now have installed, a monster 360amp alternator. When installing, I place a slightly smaller wheel/pulley on the alternator, so now, at idle, if the service battery's are as described above, then I now see around 90amps of charge and when at around 1,200RPM or above, I can now charge at a combined (D250SA and Smartpass) 143amps without affecting the alternator and, I can run all the lights and fans etc. or the car. In my view, the CTEK system is without doubt the best in car DC to DC charging system presently available. The key thing to the installation is your wiring. I use a 50mm cable set up and in doing so, my voltage drop is minimal. This is the important factor to ensuring the efficiency of the system. Soon, we will be upgrading our Service Battery's to 3x 200A/h Lithium battery's. We will not hesitate to change over to the D250SE and Smartpass 120S.

@@overlandi5056 Amazing! Really appreciate the info. I figured it was a robust well thought out device. I've not read any complaints from owners of them only skeptics thinking that type of charge rate wasn't realistic and would be potentially damaging. The actual numbers and hearing about your setup really put my mind at ease. Can't wait to set it up. I've got some heavy wire and my starter battery is under my seat so it is a short run to the service battery.

@Micah. I'm glad I was able to put your mind at ease. It is unfortunate but, there will always be people who are skeptical of such things. The reality is that CTEK clearly put alot of time and effort into their products and they last. The only time there is ever a problem with the units is when people do not follow the installation instructions. Primary one in this case is; DO NOT INSTALL THE D250 AND SMARTPASS UNITS UNDER THE BONNET. I hope your intended installation goes to plan and, if I can help any further, please do not hesitate to get in touch.

Hi, thanks for the question. Yes, this is quite normal. The CTEK is monitoring the load and resistance as well as temperature. It will regulate automatically. Mine does exactly the same and I run AGM service batteries as well.

Hi Serkan, Yes, the 20amps charge is rated at per hour. If I can be of any further help, please do not hesitate to contact me.

@@overlandi5056 thank you for reply.I sent an email to Ctec before asked you Answer is confusing me What is your comment please (Serkan Ask to ctec: I need information about this device.According to description when connected with solar panel technical info says ''charge up to 20A'' Does it mean 20 amper hour? 20 Ah) (Ctec answer:Hi It means that the out put from the D250 is 20A and it can charge a 300Ah battery) So without smartpass device, with only de250se is what can I do maximum for life batteries I am planing to set up 2 pcs. optima 75 amps underneath of 6nd and 7th seat.There is a empty spot. I t means 150amps/20AH=7,5 hours need to full charged Please correct me If I am wrong Thanks&Regards D3 2005 TDV6 Serkan

Hi Serkan, sorry, I did not see this question until now, so I'm really sorry for the very later response. To try and help, the D250 can provide 20Ah (amps per hour of charge) so that means it can charge the service battery at up to 20ah. At this charge current, it mans that the unit is capable of charging a service battery configuration of up to 300ah. So if you have a 100ah battery or three x 100ah batteries, it is more than capable of charging them.

Hi Steve, Thanks for your question. The Smartpass itself does not regulate the alternator voltage to the desired voltage of your service batteries (AGM, LITHIUM, DEEP CYCLE ETC.). In order to do that, you will need the D250 unit. If you decide to purchase a D250 unit, I would suggest the D250SE unit because, then you will be able to charge Lithium, AGM and Deep Cylce batteries. The D250S does not cater for Lithium batteries.