We were gifted the CTEK D250SA and Smartpass120. All opinions are our own.
For the caravanning or camping enthusiast power is often one of the biggest issues we face. Or more correctly, the lack of power. So when we were offered a CTEK D250SA and Smartpass120 Battery Management System we jumped at the chance to install it into our BT50.
When we purchased our BT50, I had very little experience with DC to DC charging systems. All of my previous dual battery systems relied on a battery isolating solenoid that gave the rear batteries full alternator power as soon as the voltage was over about 13 volts (depending on isolator)
When we were initially setting up the BT50 I was talked out of a 40 AMP DC to DC charger as I was told the 20 AMP would be more than enough. Unfortunately it wasn’t. It didn’t handle our charging requirements well right from day one. 20 AMPS is just not enough to charge two big auxiliary batteries when they were being worked as hard as ours are.
The CTEK system handles charging all our RPA batteries with ease.
TIME FOR A CHANGE
I had been looking for a better charging system for about six months before we were offered the CTEK system. I did a bit of homework, read the specs and asked around. And WOW – it looked like the CTEK D250SA and Smartpass120 were exactly what we had been needing for about the last 3 years!
The D250SA and the Smartpass120 can be set up as stand alone units or linked together to take full advantage of their capabilities.
D250SA CAPABILITIES
The D250SA is CTEK’S latest 20 AMP DC to DC charging unit. It has a built-in solar MPPT (Maximum Power Point Tracker) regulator. It also has a battery rejuvenation cycle if the charger detects high sulphate concentration on the lead plates in the battery. This is the first step in a five-step charging process. The D250SA is smart alternator compatible and will charge your auxiliary batteries from either the alternator or solar panels or a combination of both if needed.
The CTEK Battery Management System can trickle charge the starter battery from a solar panel.
It will change the charge rate depending on battery temperature. It will also trickle charge the starter battery from solar panels if needed. You can also wire it up for an AGM (Absorbent Glass Mat) battery. It will comfortably look after a battery bank up to 300 amp/hours.
SMARTPASS120 CAPABILITIES
The Smartpass120 is an alternator charging system. It hooks the starter and auxiliary batteries together so the alternator charges both batteries. It has a 12 volt output for appliances that cuts out at 11.5 volts, for non-critical consumers. This prevents your auxiliary battery from deep discharge.
The Smartpass120 automatically connects the starter battery to the auxiliary battery for start assistance if the starter battery is low. It will also trickle charge the starter battery from the auxiliary battery. It will handle up to an 800 amp/hour battery bank.
COMBINING THE TWO
When the two units are linked together you have a great charging system. You get all the features of each stand alone unit. Together, the combination turns into a 140 AMP charging system. It will trickle charge the starter battery from a solar panel, auxiliary battery or a combination of both. A minimum of a 100 amp/hour battery bank is required but the system can handle up to an 800 amp/hour. It has full battery temperature monitoring for charge rate.
The Smartpass120 is capable of a 350 AMP, 10 second burst back to the starter battery. To fully utilise this function you need a minimum cable size of 0B&S (275AMP) between the starter battery and the Smartpass120 and between the Smartpass120 and the auxiliary batteries.
We linked the CTEK D250SA and Smartpass120 together.
SUMMARY
We now have both the D250SA and the Smartpass120 fitted into our BT50. They are maintaining a 220 amp/hour battery bank. We are still giving the batteries the same work as before the CTEK system was installed but now we have a system that:-
- Has it’s own solar MPPT regulator.
- 22+ volts straight from the solar panel (no regulator) to the D250SA minimising current loss.
- Will monitor battery state of charge from starter battery to auxiliary battery
- Will charge auxiliary batteries in a much reduced period of time.
- Start assistance.
- Temperature controlled charging.
- Up-rated AGM charge rate.
We are so impressed with this combination already. It is perfect for charging our RPA batteries, as well as phones, laptops and cameras. We would highly recommend this system for anybody who has serious power requirements when travelling.
You can check out our full power panel on You Tube……
Happy Travels……..Brenden
This post is written in accordance with our Disclosure Policy.
Hi I will have a 660ah battery bank for my caravan that I permanently live in, can I just use the smartpass 120. Thank you
Hi, yes the Smartpass will work by itself.
Cheers
Brenden
Hi thanks for the fast reply helps a lot.
Michelle
Hi Brendon
Planning to install the ctek d250se and smart pass 120s into a Prado120 v6.
Wanted to know what fuse/circuit breaker should I use at near battery side .going to use 0b&s cable running along the back or firewall or should I reroute it to the front of car.
Will be installing it in the engine bay.
Thanks
Hi Jason,
we have used a 300a fuse at the starter battery. It recommends this size in the install instructions. The large size ensures the current gets back to the starter battery if it goes flat or fails. You can still start your car from the second battery.
This has saved us once already.
Cheers
Brenden
Hi Brendon
I have 675amps of deep cycle lead acid and. Have a 200amp Lithium to add shortly. Will your system work to charhe both banks. We have separate alternators. To charge our other 400 amp start batts.
+800 amps of solar
I guess I may be dreaming😎
Hi Ian,
The short answer is no. Deep cycle and AGM batteries require different charging algorithms to charge fully and make the most of your battery(s). Lithiums accept charge at a much greater rate than lead acid batteries so charging time is much shorter. You will need a seperate charger for each battery bank but you could run both chargers of the same alternator.
Cheers
Hi Brendon, i have a camper with a d250sa that manages solar from camper roof and twin 100 ah batteries all from Anderson at rear of bt50 from primary starter battery atm. I’m looking to install a slimline 120ah agm behind seat in bt. My question is do i keep the ctek in trailer and add another in car ? Cheers john
Hi John, It would definitely be a more efficient system with the second D250SA. There is a D250SE now that is Lithium compatible if you are thinking about that upgrade in the future. Cheers Brenden
Hi Brendan, I have a D250Sa and a smart pass I will install as soon as I understand what in hell i am doing. I have Lead Acid Aux under the bonnet and a Lead Acid in the trailer
Questions are…:
– Can I charge the trailer batt from my Smartpass wiyth DCDC charger into another D250Sa which the Lead Acid in the trailer is connected to?
– Or should I have a seperate cable bypassing the trailers D250 for charging from car purposes (that D250sa is used for solar and the previous owner used t to charge from the car crank direct). Then link that to the in car DCDC and smartpass?
Thanks for considering all this!
Jeremy
Hi Jeremy,
The first option you talk about will work. The “Smartpass”in our BT50 feeds the DC-DC charger in our van and works perfectly.
Cheers
Brenden
Hi Brendan, Where did you pick up a + ignition source for the red “Smart” cable? I have a BT50 as well, and really dont want to run such a THIN wire all the way back from the tub to the “Ignition”
Hi Chris,
Our ignition source is from a “piggy back”fuse at the fuse box in the dash. This was fitted with some accessories by TJM when we purchased the vehicle. Don’t be to concerned about the size of the smart wire as this is only a “trigger” wire and carries very little current. It just switches the modes in the charger. If you are fitting this system to a current shape BT50, remember that the smart alternator wire doesn’t need to be connected as the alternator on a BT is not the variable(smart) type.
Cheers
Brenden
it mentions in the article that this can be ‘wired’ for an agm battery, I dont suppose someone could explain this as that is exactly what I am ordering, the d250sa and either one or two 105ah varta agm’s (also is it quite simple to have 2x batteries?)
Hi Nick, Wiring for an AGM battery changes the D250SA’s charging cycle to 14.7 volts instead of 14.4. A higher charging rate for AGM batteries is required to take full advantage of the batteries technology. It is as simple as hooking up the black wire from the D250SA to earth. When multiple batteries are linked up, you only need to connect the CTek to one of the batteries, and it will look after them all. It will charge up to a 500ah battery bank with ease.
Cheers
Brenden
Hi Brenden
In this exact article it is stated the units will charge upto 300AH for the 250sa and 800AH for the smartpass. This is quite a difference to your estimated 500Ah for the 250SA that you claim.
If both units are capable of a full system check, why is it implied it is necessary to get both units.
I am aiming towards a 600AH bank for my next build, and wonder why it is necessary to get the 250SA if the Smartpass will do the job.
In the words of a famous poet, Please Explain?
Glen
Hi Glen,
The reason for running both units is for the DC-DC charging ability of the D250SA/E. The DC to DC charging process of the D250SA will increase the life of your auxillary battery. The vehicle alternators charging cycle only is not beneficial to your aux batteries.
Cheers
Brenden