DC/DC CTEK D250S Dual in D4

[Javii_V7_I]

Hi;

I wanted to ask you that you think the DC / DC Dual CTEK D250S for connecting an auxiliary battery in the D4.
Do you think it will work with the new charging system of D4?. From what I read is important to connect the negative ground terminal and the negative terminal of the main battery, but they are still operating according to the main battery voltage, so my question


(Sorry for my english)

[Wilbur]

Hi;

I wanted to ask you that you think the DC / DC Dual CTEK D250S for connecting an auxiliary battery in the D4.
Do you think it will work with the new charging system of D4?. From what I read is important to connect the negative ground terminal and the negative terminal of the main battery, but they are still operating according to the main battery voltage, so my question


(Sorry for my english)

Hi Javi,

Welcome to the forum.

In general, DC to DC type dual battery systems seem ideal for the D4. There are a lot of different views on this forum and this is my view. I prefer the DC to DC converters because they give the correct multi-stage charging that helps the auxiliary battery to charge more completely and to last longer.

However, the specs on the D250S do not specify that the starter battery is automatically disconnected when the car engine is stopped. It seems that you also need to fit the Ctek SmartPass to isolate and protect the starter battery. With the complex electronics in the D4, draining the starter battery can mean trouble.

The SmartPass is expensive. You can do a similar thing with a cheap automotive relay that only connects the D250S to the starter battery when the D4 ignition is switched on.

Most important though see this post from Drivesafe - he shows you where to connect the negative lead. http://www.aulro.com/afvb/d3-d4-rrs/131065-some-timely-warnings.html

Cheers,

Paul

[CaverD3]

DC/DC chargers are fine for the D4 just more expensive than other options.

[drivesafe]

Hi Javii and welcome to AULRO.

What sort of battery are you going to use as your auxiliary and where are you mounting it?

[Javii_V7_I]

Hi, and thanks for the responses.

On the issue of the CTEK not disconnect when the car is stopped, thought about putting a relay fix. But I'm not sure that a system DC / DC which is based on the voltage of the starter battery to function properly in these new D4. Is that it worked properly RoverLander (with redarc) after connecting the negative terminal to ground and the negative terminal of the main battery, but I still have clear because this meant the improvement.

Regarding the battery had thought to put an Optima Yellow Top 4.2 (55 Ah) in the engine box, if I can change the ECU and wiring in place.

Cheers,

[drivesafe]

Hi again Javii, there is a link below to the VERANDAH section on this site and this will give you an idea of how you can set up your D4.

The kit is for a D3 but if you move the ECU, the kit is exactly the same for a D4.

Because you are going to use an Optima Battery ( the Optima D34 is the correct battery for the D4 ) you are far better off not using a DC-DC device because the Optima Yellow Top can take full inrush currents when charging and combine this with the way the D4 charges, you nearly fully charge an Optima battery from a low state in about an hours driving.

I’ve measured up to 64 amps going into a low Optima and a D3 owner in the UK has measured up to 97 amps going into his Optima when the battery was near flat.

DC-DC devices just can’t handle these sorts of load and again, the way both a D4 charges and the way an Optima can be charged, just mating the two, via a decent isolator will give you the best set up.

Again, the kit in this link will give you an idea of the way to set up your D4 and I supply these kit world wide.


http://www.aulro.com/afvb/verandah/62580-traxide-full-power-cable-kit-d3.html

[Wilbur]

Hi, and thanks for the responses.

On the issue of the CTEK not disconnect when the car is stopped, thought about putting a relay fix. But I'm not sure that a system DC / DC which is based on the voltage of the starter battery to function properly in these new D4. Is that it worked properly RoverLander (with redarc) after connecting the negative terminal to ground and the negative terminal of the main battery, but I still have clear because this meant the improvement.

Regarding the battery had thought to put an Optima Yellow Top 4.2 (55 Ah) in the engine box, if I can change the ECU and wiring in place.

Cheers,

Hi Javi,

The DC - DC system will work properly regardless of the starter battery voltage. That is the best reason to go for the DC-DC - they charge properly whatever the starting battery voltage.

Also, in my experience alternators can be damaged by excessive current draw - with both the starter battery and the auxiliary battery drawing high current it puts a big load on the alternator. In my experience this reduces alternator life, maybe as little as five years.

The relay fix and the D250S should work very well for you.

Cheers,

Paul

[drivesafe]

So what your saying Wilbur, is by adding a DC-DC device to the set up you now have a better system.

Well your math does not add up.

To add a DC-DC device to a D4 set up means the Optima battery if low will actually far take longer to fully charge than when using nothing more than a standard isolator.

Next, with your suggested set, you need to spend far more to get less available battery capacity.

Your set up give 44Ah of usable battery capacity while an SC80-LR gives at least 85Ah for a lower set up cost and this 85 Ah will be replaced far quicker than your DC-DC device can do it.

As to alternator use, with the 180 amp alternators in a D4, are suggesting that even if a battery pulled 90 amps while charging then the alternator is going to be damaged.

Tell me then why the same alleged damage has not happened in D3s with their smaller 140 amp alternators.

You do like to make up mythical problems, don’t you Wilbur?

[Wilbur]

So what your saying Wilbur, is by adding a DC-DC device to the set up you now have a better system.

Well your math does not add up.

To add a DC-DC device to a D4 set up means the Optima battery if low will actually far take longer to fully charge than when using nothing more than a standard isolator.

Next, with your suggested set, you need to spend far more to get less available battery capacity.

Your set up give 44Ah of usable battery capacity while an SC80-LR gives at least 85Ah for a lower set up cost and this 85 Ah will be replaced far quicker than your DC-DC device can do it.

As to alternator use, with the 180 amp alternators in a D4, are suggesting that even if a battery pulled 90 amps while charging then the alternator is going to be damaged.

Tell me then why the same alleged damage has not happened in D3s with their smaller 140 amp alternators.

You do like to make up mythical problems, don’t you Wilbur?

Hi Drivesafe,

No, I don't think I am making up mythical problems. You see, if the auxiliary battery takes 90 amps the starter battery will also be taking current, and this could be getting close to the maximum alternator rating. ~Rich~ had to replace his alternator at 5 years - see http://www.aulro.com/afvb/d3-d4-rrs/129316-leaking-voltage.html Maybe if he had been using a DC - DC system that put less load on the alternator than the Traxide this would not have happened.

Yes, I do understand that the Traxide system gives more usable power for the auxiliary loads than any other system because it also drains the starter battery into the auxiliary loads. For those not worried by this, the Traxide is great, and has been proven over the years.

However, for those who don't want to drain their starting battery, I believe the DC - DC system is the best and well worth the extra money.

Cheers,

Paul

[drivesafe]

As far as high current draw goes, with all these set ups including Rich’s, because they are not pulling high currents every time they get into their D3 or D4 or any other vehicle for that matter, the loads are irrelevant.

These high current draws are only likely to be periodical at best or are you saying any high current draw will damage an alternator.

If so then why is yet another one of your unsubstantiated theories not happening. If you were correct, then there would be all forms of vehicles lining up at auto electricians to get their alternators repaired/replaced.

The fact is that there are few alternator failures, whether the vehicle has a dual battery system or not, and means that this is just another one of your unsubstantiated scare mongering attempts to make out you know something about a field you quite obviously know nothing about.

This is also valid as per your claim about it not being safe to discharge a cranking battery down to 50%. This is based on nothing more than your ignorance, not on any factual evidence.

[Wilbur]

This is getting personal again, so I will leave it at that. At least I have shown Javi that there are other opinions and other risks and benefits.

[drivesafe]

This is getting personal again, so I will leave it at that. At least I have shown Javi that there are other opinions and other risks and benefits.

WHAT RISKS?

It’s only getting personal because you keep posting up deliberately misleading info.

If your unsubstantiated claims had any validity, you should be able to post up relevant info to back your claims. You never do.

I’ve leant my trade from hands on experience and from HONEST info posted on the net.

On the other hand, you have a thoughty or read some grossly exaggerated advertising hype and then you’re hell bent on making out it’s fact, because you posted it.

Don’t complain when your misinformation comes back to bite you, it’s your doing.

[roamer]

Hi Javi,
Those c-tek d250s are they not dual, as in one connection for alternater, and one for solar input, are you going to also charge from solar panels.?
If so I think you will need some thing to regulate it and those C-Tek dual are the best way to go for that.
Re your question about negative connections, it seems as though all extra negative connections should go to stud,( body)
(i.e. nothing extra connected to neg terminal on cranking battery)


Cheers Ken

[101RRS]

Drivesafe - Wilbur

Can you sort your issues.

I appreciate you both have your own points of view and have a lot to contribute but ...........

Thanks

Garry

[CaverD3]

Stop arguing guys. :mad:

Both work but look at the cost and what you want to do with it.

[drivesafe]

So what your saying is just let Wilbur post up his rubbish, let others think that it’s factual and then when they spend big bucks on gear they never needed, then they might come and buy the right gear off me.

I pay to advertise on this site and when people post up about other brands, I don’t comment unless they have the info wrong, and on a number of occasions, I have helped a number of people with other brands, sort out problems with their gear.

This is not the case here ( and on a number of other threads ), Wilbur has repeatedly posted up erroneous info and continually implies that using my gear could cause problems, without having a single shred of evidence to justify such claims.

Now if there was a potential for problems, I wouldn’t mind someone posting up info about such problems. This is not the case with Wilbur’s posts, he is simply slandering my gear for his own sick gratification.

If this is not the case then maybe the rest of you can answer why someone would go out of their way to mislead other AULRO members like he is doing?

[101RRS]

For my part, I do not know who is right or wrong - I suspect there are aspects of both views that are relevant but the point is that when either of you post something on these charger related topics the other responds and the thread just ands up as a shouting match - devaluing the information coming out in the thread.

In know you both have provided valuable information in a range of areas on AULRO and you are to be congratulated on this - but where threads deal with dual battery systems, chargers etc then maybe there needs to be a self imposed moratorium from both of you in responding. Others can provide suitable responses and a poster can always PM either of you for your view.

Clearly if you have vendor rights then by all means use the appropriate sections but clearly if either of you respond to these electrical posts it starts again.

Garry

[Wilbur]

For my part, I do not know who is right or wrong - I suspect there are aspects of both views that are relevant but the point is that when either of you post something on these charger related topics the other responds and the thread just ands up as a shouting match - devaluing the information coming out in the thread.

In know you both have provided valuable information in a range of areas on AULRO and you are to be congratulated on this - but where threads deal with dual battery systems, chargers etc then maybe there needs to be a self imposed moratorium from both of you in responding. Others can provide suitable responses and a poster can always PM either of you for your view.

Clearly if you have vendor rights then by all means use the appropriate sections but clearly if either of you respond to these electrical posts it starts again.

Garry

Okay Gary, what you say makes sense, and I will comply and in future will not answer any posts relating to dual battery systems or chargers.

However, I do feel entitled to defend myself to this extent-

When I first innocently advised someone to use a DC-DC convertor I was so visciously attacked by Drivesafe and Blknight that I read a few previous posts on the subject to find out why the attack was made. At the time I knew nothing of the Traxide unit.

I soon realised that the Traxide was made and sold by Drivesafe.

Since then all I have done is POLITELY put across an alternative point of view when it seemed useful, and repeatedly said that I have no fight with the Traxide unit.

I do though unreservedly apologise to having been a party to ill will on what is otherwise such a friendly site.

Cheers all,

Paul

[KOOS BEST]

landy guys dont get personal dont turn this thread into a salgging match.

I have taken this quote below form a South African forum about something like what's happening here, which are also related to you down under

Fellow Land Rover owners I have always regarded us as people from gentry stock, after all we have green and gold blood in our veins as is our National sporting teams. We have tradition, heritage and proud of the brand. We greet each other, we rush out and help each other in need. Don't throw that away by responding in a nasty manner to bored unrelated people trawling the thread and trying to stirr. Just ignore it and accept it from where it came from.

[Wilbur]

landy guys dont get personal dont turn this thread into a salgging match.

I have taken this quote below form a South African forum about something like what's happening here, which are also related to you down under

Fellow Land Rover owners I have always regarded us as people from gentry stock, after all we have green and gold blood in our veins as is our National sporting teams. We have tradition, heritage and proud of the brand. We greet each other, we rush out and help each other in need. Don't throw that away by responding in a nasty manner to bored unrelated people trawling the thread and trying to stirr. Just ignore it and accept it from where it came from.

Yeah, well, you could practice what you preach. I am NOT a "bored unrelated people trawling the the thread and trying to stir."

[RoverLander]

So glad I'm not saying anything on this... just sitting back enjoying a cold beer from my 12V fridge, running on my two extra batteries that are charged by my expensive and effective DC / DC charger. :)

[clubagreenie]

And I can only refer to two heads of elec eng science in two separate universities that I questioned the last time this discussion arose and wondered why anyone would want a DC/DC when you want to regain available charge asap not withstanding the costs. Not one app where I'm studying uses a DC/DC source for anything (quoted from Professor of Elec Eng and Digital Sciences).

Thats why I use Tim's products. That and his outstanding service.

[Javii_V7_I]

Well, what a mess!!! :o:o:o :rocket:

First of all, I thank the responses of some and others. When I win the lottery, I will travel to Austraia and I have a few beers with you, do not argue over that life is short and expensive gasoline (at least in Spain)

Drivesafe know the system and is one of the options I have in mind, provides quick loading, installing plug and play, and many users that support its operation. But I also wanted to consider other options such as DC / DC. Who have incomveniente loading slower, true, but also offer greater control of the load can be beneficial .... another option to consider. I wanted to know if the latter option works in the D4 and new electronics, so simple. I understand that plug negative ground and the negative terminal of the main battery, yes, work (not going to break anything).

Drivesafe: Regarding the D34 optimal battery is no longer sold in Spain, now sells the yellow top 4.2 (I know several users that have mounted D3 through a projectaDBC100k and everything is correct).

Roverlander: Enjoy beer. And a question: To change the negative connection, will the main battery voltage (the boot) will reach higher levels of stress or low values ​​still? And now the auxiliary battery charge when you go to higher gear (accelerating)?

roamer: CTEK D250S it is dual. Yes lets you connect two different sources, alternator and solar bale without an additional unit, although you can add SmartPass. ... I understand that watching your manual.


Cheers to all!!!!

[drivesafe]

So glad I'm not saying anything on this... just sitting back enjoying a cold beer from my 12V fridge, running on my two extra batteries that are charged by my expensive and effective DC / DC charger. :)

It’s this sort of comment that has me amused when ever there is anything mentioned about DC-DC devices.

So you say it’s effective, and is this based on you testing your set up with and without using the DC-DC device?

On another forum I got into an argument with a guy who had just bought a DC-DC device and reckoned it was the ants pants and it did a better job of charging his two house batteries than his alternator could ever do by itself.

A couple of months later and to the guy’s credit, he came back from a trip, where curiosity had got the best of him and he tested his set up with and without the DC-DC device.

What he found when ever he had used a fair bit of house battery capacity at one camp site and then charged by either system while moving to the next camp site was, that even when he drove for a good few hours between sites, he still never managed to fully charge his house batteries by either set up, but they always seemed to be in a higher state of charge when letting his alternator do the job.

He still uses his DC-DC device but just for topping up his batteries.

His comments are that while he got a decent charge when using a DC-DC device, he would never waste his money on another one because, IN HIS CASE ( and it won’t be the same for everybody ) his alternator did just as well or better.

[harlie]

I can only report on what I own and have tested.

Install #1. Installed by myself last year; Car (L322) and camper with the house batteries located in the camper controlled by a basic solenoid switch by ignition. (Solenoid was used so a small winch could operate from the same Andersen plug). The camper also has a Ctec MSX10 batter charger with the same multistage charging as the DC-DC device listed above. I have solar to charge while at camp. Journey home is always in the morning, so the house batteries are usually only down by one nights running of fridge, water pump and lights. When I get home the trailer is connected to the grid, enabling the Ctec to do its thing – according to the doco it charges to 14.4V then goes to an “Analyse” stage (when the battery is fully charged) for 3 min and then “Float” stage. This has always happened in less than 2 minutes of being connected, most times less. At this point the little indicator lamp claiming 100% charge is also on.
So the Ctec device is happy that the battery is fully charged after a 2-3 hours on the Alternator.

Install #2. Installed by factory in 2005 on a Boat; 520ah of house batteries charged by a 2 BEP VSR (simple voltage sensitive relays that connect at 13.8v and disconnect at 12.8v) between house bank and the 2 small start batteries (one for each engine). Engines (pair of Volvo MD2040 40hp diesels) have 60amp alternators on each, there is 3 x 130w of solar and a grid connect 40amp smart charger (Xantrex). House batteries are drained by elec toilets, water pump, fridge/freezer, TV for the footy / F1 / kids movies, lights, auto pilot and nav ect instruments – so they get some use.
If we are out for an extended time and the weather is fine / sunny then the solar can cover everything, and the solar regulator will drop out most days, so engine input is relatively minor if they are started. Again most outings we choose to return home in the morning of the last day and the house bank is well used, if the wind is favourable engines are not used except for berthing and on these occasions the grid charger can take up to 2 - 3 hrs to reach its float stage, up to 7 - 10 if we sailed and haven’t had much sun for a few days. It there the wind gods are unkind, an engine will be run for 1-3 hours plus, on these occasions the charger will start to float with in 5-30 mins depending on how far the engine was run and if 1 or 2 engines were used for that time. The 60amp alternators are original. We have never had a charging issue with standard alternators and experience the same result as the newer camper installation, according to the smart charger the batteries are well charged.

I have nothing to do with Drivesafe, and would not install his product in a boat because of the lower cutout voltage (generally boats have much bigger house banks than the start batt), however I would use for a duel batt in the car for this same feature (and smaller house batt than start batt). As noted I have purchased and use CTec products. Personally I think the DC-DC converters are definitely not needed – I’m not saying they don’t work.

[OffTrack]

He still uses his DC-DC device but just for topping up his batteries.



Reading the D250S Dual/Smartpass documentation it appears that when using the two units in combination the D250S is used for primarily charging from Solar panels or other external sources and top up charging from the alternator.

The Smartpass charges at up to 100A and appears to be directly connecting the alternator to the service battery to achieve this. CTEK indicate that the Smartpass can be used standalone, which would suggest CTEK don't see any issues with direct alternator to battery charging.

[drivesafe]

Hi OffTrack, I actually experimented with this type of operation some 3 or 4 years ago.

One of my suppliers is an importer of high end battery chargers and high current DC-DC converters.

One of the units they have is a USA made 40 DC-DC converters, but even using this unit and having the hand over from direct alternator - battery charging to alternator-DC-DC converters-battery charging, take place at a much higher current available than is available from the toys they sell here, there was just no justification for the high set-up costs when far cheaper and better set ups were/are available. Note, the 40 amp unit is not much dearer than the 20 amp units sold here.

There is a single controlling factor when ever you charge auxiliary/house batteries while on the move, and this just how long you are actually on the move for!

As I have stated repeatedly and as Harlie commented, no one has posted that these things don’t work, the problem is the misleading way they are marketed, leads unsuspecting people to think these devices will out perform alternators when ever you fit one these devices.

This is just not the case and a perfect example of how deliberately misleading advertising hype can be used to make these devices look like the are the end all for battery charging is an article that appeared in the Wanderer magazine a few months back.

This was an article ( actually it was nothing more than an infomercial discussed as an article ), written by one of Wilbur’s hero’s, Collyn Rivers.

The article was out to heap greatness of these devices and listed all manor of wonderful things about them.

One of the treasurers that Collyn Rivers used to imply these devices were better than alternators was some data from Ranox, where they had a graph showing how their 25 amp DC-DC converters could charge two 100Ah batteries from 75% SoC quicker than an alternator could.

The graph shows how the two batteries are charged is 150 minutes using their DC-DC device, while the alternator took 180 minutes.

I have no argument with the data in the graph and would say it was probably spot on the money.

The problem is that most people would be lead to believe these devices will charge their two 100Ah batteries quicker than an alternator could and in reality, as long as they never discharged their two 100Ah batteries below 75% this would be the case.

But if someone had all the facts presented, the first thing that should jump at you from their data is WHY THE HELL WOULD YOU HAVE TWO 100Ah BATTERIES IN THE FIRST PLACE.

If you never discharged your two 110Ah batteries below 75% then a single 100Ah battery will easily meet your needs and you still won’t need to cycle it below 50% SoC and this is a safe discharge level for ANY battery.

The reason the graph started at 75% SoC is because if it went just 5% lower, to 70% SoC, you could literally flip a coin to determine which would set up charge the two batteries quick.

If you discharged the same batteries down to 60% you would have at least a 20 minute advantage when using your alternator, at 50% SoC, you would be at least 1 hour better off when using just your alternator.

At 40% you would be getting close to 2 hours better off, at 30% the gain is better than 3 hours and at 20%, the lowest level you can safely take deep cycle batteries, you would be 4 to 5 hours better off using your alternator than using their 25 amp DC-DC converter.

But what the hell, why let something as trivial as the truth get in the way of potential sales!

BTW, if you re-read Harlie’s thread, he is confirming this very point and based on actual use.

[nelpd96]

Sorry for the thread dig here team. I understand many of the points raised here and for the most part I have adhered to them in terms of never having bothered to run a DC-DC charger. However, I was due to replace the solar controller in my Jayco van as it was playing up. One Ebay PREWINTER sale later and I have a C-Tek D250SA for $280 which not only does solar as well as DC-DC but has a second set of wires that are used to change the trigger point input voltage at which the DC-DC section starts working due to the lower operating voltage that the D4 can experience when running low loads with a fully charged start battery. Read smart alternator function.

I have not run a second battery in the vehicle but have run heavy guage cable to the rear of the vehicle with a 100A Anderson plug. At the moment that it connected to the battery and the earth mounting point on the vehicle as mentioned in one of the stickies. I trust that this is acceptable or should I be running it directly from the alternator? From the manual I understand that the requirement is for the trigger wire to be connected to an ignition power supply from the vehicle such that it uses a wider input voltage to charge as well as isolates the start battery when the ignition is turned off. I have not had much luck in confirming this from the C-Tek manual or website so any input would be greatly appreciated.

Kind Regards
Paul Nelson

[iannicki]

And here's a different question.

I already have the CTEK D250S in my D4 (it was just what the installer used, and a few years before reading this thread). It can act as a MPPT controller for, as I understand it, unregulated solar panels.

I have just bought a 160w folding solar panel kit by Rich Solar. The PWM controller is hard wired and would be difficult to bypass.

So, which way should I go:

1. connect the solar panel to the CTEK unit (meaning Solar Panel, PWM Controller, MPPT Controller, Dual Batteries (noting the CTEK will charge the auxiliary battery first, then the starter battery))

2. connect the solar panel to the auxiliary battery (meaning Solar Panel, PWM Controller, Auxiliary Battery (only))

3. bite the bullet, cut the wires between the solar panel and PWM controller and then conenct the (now unregulated) solar panel to the CTEK unit (meaning (unregulated) Solar Panel, MPPT Controller, Dual Batteries)

Option 1 seems preferable, but only if having a PWM controller and then a MPPT controller in series would actually work.

Grateful for the replies of anyone who knows whether having two different types of controller in series is a good or bad idea.

[RoverLander]

And here's a different question.

I already have the CTEK D250S in my D4 (it was just what the installer used, and a few years before reading this thread). It can act as a MPPT controller for, as I understand it, unregulated solar panels.

I have just bought a 160w folding solar panel kit by Rich Solar. The PWM controller is hard wired and would be difficult to bypass.

So, which way should I go:

1. connect the solar panel to the CTEK unit (meaning Solar Panel, PWM Controller, MPPT Controller, Dual Batteries (noting the CTEK will charge the auxiliary battery first, then the starter battery))

2. connect the solar panel to the auxiliary battery (meaning Solar Panel, PWM Controller, Auxiliary Battery (only))

3. bite the bullet, cut the wires between the solar panel and PWM controller and then conenct the (now unregulated) solar panel to the CTEK unit (meaning (unregulated) Solar Panel, MPPT Controller, Dual Batteries)

Option 1 seems preferable, but only if having a PWM controller and then a MPPT controller in series would actually work.

Grateful for the replies of anyone who knows whether having two different types of controller in series is a good or bad idea.

Go option 3. This is what works for me with a 150w panel and a redarc dc/dc MPPT unit. The MPPT in you CTEK will do a better job than the controller on your solar panel.

I am not sure but I would think it would not work having the two controllers between the panel and batteries.

[matti4556]

Iannicki. I tried feeding a regulated solar supply into my setup like yours and it went all cock-a-hoop. Fortunately I could bypass the solar regulator on the panels. So I say go option 3 as well. Matti

[Redback]

We have a DC/DC in our camper run from the car and while it does work, it doesn't charge the camper battery fully, we charge the battery before we leave home from our 240 charger and the DC/DC charge keeps it topped up while on the move.

Now this is good for the first couple of nights, but if we move to another camp, the DC/DC doesn't seem to re-charge the camper battery fully to the next camp, this was very noticeable after our first camp was 3 days of rain and cloudy weather and what we had to do was break out the inverter and 240 charger to charge the camper battery off the auxiliary battery in the car overnight even after a full days drive, the water pump barely worked we had to use the hand pump on the first night.

So now we just have the USI160 that charges the other two batteries in the car, it now charges the camper battery while on the move, the USI160 allows you to hook up a solar panel if needed also, to be honest I didn't think it would make that much difference, but I was surprised at how much better it is now.

Anyway no need to top up the camper battery now when we get to camp, all good now.

Baz.

[DiscoMick]

Solar regulators often limit the charge to 10 amps. What does the CTek do - 20 amps?
I wouldn't connect a panel with a regulator to a DC-DC. One or the other.
I just have the solar panels with regulators connected directly to the battery on both the camper and Defender. Put the regulator close to the battery if possible.
I do have a DC-DC on the camper, but the solar doesn't go through it, it just compensates for voltage drop from the vehicle.

[donh54]

PWM controller on the solar panel, 3-way Anderson plug, one to car (aux battery and via Traxide controller to start battery) and one to trailer battery. Decent sized cables from aux to trailer = little or no voltage drop. All batteries fully charged within a few hours of leaving camp. (Standard Disco 1 alternator)