D250SE & SMARTPASS 120S: Which one is right for you

[@luc6217]

Very good !!!

[@martinambodensee8428]

The D250SE appears to be the perfect solution for integration in my VW bus. There is one remaining question: is the device ECE approved and is there a E.... number (e.g. E5 for Sweden) on the device

[@CTEKBatteryChargers]

Hi. All CTEK chargers fulfill all the regulations and needed approvals for all the countries it is sold in. So it got all that is needed. You can read more about this here: www.ctek.com/uk/quality. I hope you will be happy with the D250SE. Best regards CTEK Support

[@markwilliams2327]

I have just installed this setup, but the smartpass 120s stops charging as soon as the smart alternator voltage drops below 12.8v, leaving just the D250SE to provide 20A. Given starter battery will charge quickly after startup, and be trickle charged by Smartpass, I get little bulk charging benefit from the Smartpass 120s. Is my unit a dud, or working as per design? I have had two suppliers state they believe its as per design. I have a 230Ah Lithium to charge, and get couple minutes of 60+Amps then smartpass turns off and I only get 20.

[@CTEKBatteryChargers]

Hi. Thank you for this description. For me, it sounds like you have not connected the red cable on the SMARTPASS120S to Ignition signal, +15 clamp (DIN 72552). Please check manual on side 7 to see more information. Best regards CTEK Support

[@markwilliams2327]

@@CTEKBatteryChargers Thanks, this cable is connected to the ignition source, as is the D250SE, this was my first thought, so I have double and triple checked this, but still same issue. I have a ticket open with CTEK, so will add further details there. Thanks for coming back to me.

[@CTEKBatteryChargers]

HI, There can be nothing wrong with the Smart Pass as it provides the charging current that the generator is capable of delivering. Maximum charging current is delivered when the voltage from the generator is above 14 volts. You get 60A for a while. Most often it is the vehicle's generator that is not able to deliver high currents for a long time. Or it could be the battery's BMS that limits the charge of the cells for some reason. Can be the temperature, that the battery already has a high charge level, etc. Everything seems to be in order with the CTEK system according to your description. You can try to connect a powerful workshop charger to the starter battery to run a bit of exclusion method and it is probably stated that it is the generator that does not have the strength to keep the charging current.. I hope this will help. Best regards CTEK Support

[@sirjolly81]

i just ran my own switch to enable the alternator to charge at 14.4 volts. i was seeing my charge drop to 12.2 while driving. now i can keep it factory and override the smart alternator when required.

[@markwilliams2327]

@@CTEKBatteryChargers your second response here seems to contradict your initial response. What is the point of the smart alternator cable if you say that maximum charge is only available when above 14V, or in other words with a conventional alternator. I am not disputing any comments on temperature/charge level etc, but they do not relate to the fact as stated clearly here that my Smartpass 120S cuts out at exactly 12.8 volts. which is its published cutout for a conventional alternator. Again the published cutout for a smart alternator is 11.4 volts. So even if my alternator/battery could only handle 25Amps charge I would expect to see 25Amps charge rate at battery whilst alternator is above 12.8 volts and ALSO 25Amps charge rate at battery when the alternator is below 12.8A. With the units I have installed, in the above example I get 25A whilst above 12.8V and below 12.8V I get 20A. So if this is the correct operation of the Smartpass, then it does not adhere to the sales documentation or the user manual. Asking me to locate a powerful workshop charger does not help for multiple reasons. 1. I don't have access to any. 2. How would I simulate the operation of a smart alternator? and 3. you are missing the point clearly stated my original question. ie the cutout at 12.8V

[@davidshaw9324]

Hi CTEK, Quick question on the D250se The literature states that the limit for battery capacity is 300Ah. How strict is this limit as I'm about to build a battery using 4 X 3.2 volt 302Ah CATL lifepo4 cells. There is a chance that the cells might be slightly higher than the stated 302Ah or may be slightly lower but will be around the 302Ah mark. Will this be an issue?? Thanks in advance Dave

[@CTEKBatteryChargers]

Hi, the 300Ah is more of a recommendation. It will take longer time to charge the bigger the batteries are and at some point it will not get fully charged within an acceptable time, If you add the SMARTPASS120S to the system the time will be shortened a lot. Best regards CTEK Support

[@andytawa1114]

i have the flashing alternator light flashing on the ctekD250se but when starting the engine it goes solid .when i turn engine off again it starts flashing again .is that suppose to happen i also have solar thxs andy

[@CTEKBatteryChargers]

Hi, Thank you for your message! 😊 Please contact us at support.ctek.com/ and we will help you further. Have a great day! ☺

[@chriselv3182]

hiya, currently ctek 250se but im now and then turning on and running a 2000w invertor for a microwave and a kettle... this is normally after a day of the van being sat with a cooler fridge on ... so on old school split charge (t5) i could start up and be fine... now we need smart chargers and decent batteries...question.... will the smartpass cheer my system up... will it only draw the amps that it needs at that time...or is it force feeding 140amps? and so long as i put a decent battery in the rear for it (160agm) etc... (t6 under seat) will i be ok? i need to be able to come back , start up...and know that if required and i turned heavy duty items on... that i'll be charging up to be self sufficient off grid. (ps any help appreciated as your official support phone line was no help at all...and left me feeling a little bit negative about ctek) best regards chris

[@CTEKBatteryChargers]

Hi Chris. We will do our best to help you out. It would be great if you could send us some more information to [e-mail]. We like to know what type of system you have. Is it in a boat? Or a RV? or?? Do you take power from an alternator? or from the sun? How big are your batteries? Starter battery and service battery. With the relevant information available we can see how the system works - or not work.. Looking forward to hear from you. Best regards CTEK Support

[@IMEKNiGhT]

he fails to add that the D250SE only handles 400 watt solar so if you have more solar than this its pointless . the smart pass looks good tho!

[@CTEKBatteryChargers]

Hi, The D250SE can maximum charge with 20A, so you have a point. Best regards CTEK Support

[@aw5911]

Hi does the smartpass and d250 provide 140a continuously or just momentarily? If so, would that not destroy batteries at such high charging power?

[@CTEKBatteryChargers]

Hi. They will give UP TO 140A, but it is the amount of consumers as well as the battery that decides how much power that is needed. It is safe for the battery and for the electronic components connected to it. Best regards CTEK Support

[@antonblijlevens2997]

I am looking to build a portable power station (LiFeP04 100AH) to charge mainly from Solar and mains power. Occasionally from an alternator or another 12v battery. Am i correct that I don't need the smartpass and can use the SE and the Lithium 56-990 AC mains charger in parallel over the battery ? every diagram I see with the SE and the 56-990 mains charger shows the smart pass also hence asking. thank you

[@CTEKBatteryChargers]

HI, You do not need the Smartpass 120S. If you don't need more charge than 20A/hour, the D250SE will work just fine. Best regards CTEK Support

[@mange2]

Im really struggling to get information regarding what amps the 120 actually charges at. Every piece of literature just seems to mention the 120 amps. But 120 amps is far too high for most batteries to charge at safely. e.g. I have 2 x 130ah Leoch agm leisure batteries and the company has told me not to charge them at more than 30 amps. The general rule of thumb seems to be dont charge at more than 10% of the battery ah capacity. Does anyone know the actual amps the unit will charge at from a running vehicle with a non smart alternator. Thanks.

[@CTEKBatteryChargers]

Hi. The PRO120 charges with UP TO 120A but will adapt to what the battery can accept. This makes it possible to charge lead acid batteries sized from 10Ah up to 3 600Ah and lithium (LiFePO4) from 15A up to 1200Ah. You can also easy choose to charge current from 5A up to 120A. You can also use the PRO120 as a power supply with choosable current and voltage. I hope this helps. Best regards CTEK Support

[@chillybilly87]

yes the 120A thing is very vague. Is the SmartPass an actual 4 switch buck boost DC DC charger - or just relay / fets? If the latter, then it is not providing protection on to the service battery / inverters that may be exposed to spiking alternator voltages. The C250 shall provide that protection but is being bypassed by the SmartPass 120. I guess the SmartPass 120 allows huge current flows when your battery is flat / running large loads. Then the C250 does the last little bit to charge the battery up fully at the end. However, doesn't offer current / voltage limiting. Please answer.

[@bennymilne9290]

Hi there,I have bought the ctek D250se and smartpass 120, I am converting my 06 toyota coaster into a motorhome with solar and 2 service batteries..the coaster starter battery is x2 to make 24v start..my question is- will this work hooking the smart pass up to the 24v starter system for the alternator use.??

[@CTEKBatteryChargers]

Hi, Thank you for choosing CTEK. The D250SE and the Smartpass120 are 12V products so it will not work if your batteries are connected in series. If there is a 12V output from the batteries you can connect it there - but I guess you need to talk to the vehicle workshop to get correct information about that. Good luck. Best regards CTEK Support

[@paidoluca]

I've bought three AGM leisure batteries with 115ah each - can I still use the CTEK 250SE? It will be more than 300ah.

[@CTEKBatteryChargers]

Hi, you can use the D250SE, but it will take long time to fully charge. i recommend you to add the Smartpass120S to the system to increase charge speed. Best regards CTEK Support

[@stephenhowarth4916]

Your manual states D250SE 'Starter battery is only available as lead-acid battery' - my starter battery is AGM so is the D250SE compatible or not?

[@CTEKBatteryChargers]

Hi. No problem at all! An AGM battery is a type or lead acid battery so the D250SE works perfect. Best regards CTEK Support

[@stephenhowarth4916]

@@CTEKBatteryChargers Many thanks for the clarification - time to purchase :-)

[@chillybilly87]

hello, if the alternator spikes at 16/17V due to the Euro 6 feature on Iveco vans (for example) how does the Smart Pass 120 stop that 17V going onto the service / output batteries? Does it take the 17V and drop it to 14.4V?

[@CTEKBatteryChargers]

Hi. If you uses the SmartPass 120 as a stand alone product - the voltage will pass through. If you uses it together with the D250SA/E then the D250 will decrease the voltage down to 14,4. Best regards CTEK Support

[@chillybilly87]

@@CTEKBatteryChargers hello, if the SmartPass is in parallel with the D250SA how would the D250SA provide any assistance - at high voltage the current bypasses the 250SA and goes via the SmartPass at high voltage? Surely?

[@chillybilly87]

Hello, any responses to this, please. I think the product has been missold. It doesn't regulate voltage or current. It appears to let unregulated power through it

[@CTEKBatteryChargers]

@@chillybilly87 Hi. Sorry for a late response. If the alternator send out high voltage, this will be transfered to the battery. Best regards CTEK Support

[@Wildearthcampers]

Love these products! I’ve bought the SE and the CTX for monitoring. Check out my Chanel for the install videos, just installed solar into the SE and the MPPT works incredibly well. May use the 120s for future proofing the van too, let me know if you have any deals coming up 👍