Electrical Setec cover removal.

[mikerezny]

Thanks Mike,

With the cable size, I was just going on advice posted here. I guess that's now two thumbs up for the 8B&S so I'll run with that and I know that will fit in the QC terminals.

I got the crayons out and put together a rough drawing of what I'm trying to achieve but would appreciate if you could skim over it and let me know if it checks out. The battery box is a portable one with Anderson plugs pre fitted so I can take it out and use it elsewhere. I can also get the box fitted with 8mm screw posts if you think that would be the better option to connect it to the setek.

Portable box to go underneath lounge - http://www.home12volt.com.au/bbox---std-model.html

My fold out solar panels have there own regulators.

Insulated QC terminals https://www.narva.com.au/products/56045BL

Am I on the right track?

Cheers

Hi,
this looks good. It follows the KISS principle.

I have a few comments.
1: Whether the run out to the draw bar needed to be 6B&S. 8B&S might sufice. Having said that, a run of 6B&S would let you run an air compressor etc that draw a lot of current.

2: It is good practice to mount the solar controller as close to the battery as possible. It is also then out of the weather and away from thieves. Consider getting a good quality MPPT controller. Good controllers sometimes have a temperature probe to measure the battery temp for better determining charge voltages.

3: Given that almost all loads inside a van will be less than 10A, 8B&S to these points is probably overkill. Standard lighter sockets cannot handle high currents.

4: Anderson plugs are available with a choice of terminals to take different wire sizes. They still all mate up correctly. If you do go 6B&S, check that the terminals will take that diameter cable.

take care
Mike

 

[Drover]

Sorry about that, all the specs sheets say 6 B&S though I usually use 8 B&S .............. The draw bar run I was thinking you would be going to a 3 way fridge hence the 6 B&S prefer over 8 B&S.........I hadn't viewed your photo until now as I was on my phone before............ I have also been howled down for suggesting 8 B&S...of course the smaller the number the larger the cable size makes sense to some but not me...

Normally Jayco with the Setek's the 12v from tug using a 12 pin would be about 10B&S and it would split into 2 with one line going to the Setek for battery charging and general 12v supply to van while the other line would go to the fridge, not an ideal set up as the loss could be large, a diode in the Setek would stop battery drain...............

In your case I think it would be better to run an dedicated line from battery in 8 B&S with an anderson on the end for your solar input and a run from the tug to the Setek so it can charge van battery this could be in 10B&S like the original as the draw wouldn't be that much but I may be wrong on that...in your pic you couldn't charge the battery and connecting it to the Setek would mean you couldn't run your solar panel........I would mount the Solar anderson half way down the side of the van this will then give you the ability to have your panel at front, side or rear of the van with shortest cable.
......... I think I would also wire the compressor fridge direct to battery less loss from cable/connections going thru the Setek.
Your outside CIG/USB socket I would just run from battery probably easier and in10 B&S.

and in anticipation of you adding to your power storage I would make sure the battery compartment has room for another and possibly fit a buss bar so just a single connection on battery and all the other connections come from the Buss, a way better type of set up with the battery leads having a fuse or circuit breaker instead of a great birds nest mess hanging off terminals...............not everything you may later fit can run thru the Setek so the buss bar keeps it simple.

Sorry if I've added to the confusion....

 

[mikerezny]

Hi,
since you are still only in the planning stage. It is easy to consider various options.

So, at the risk of adding complexity:

Van 12V systems can actually be more complex than one might initially think.
There are many facets to understand. batteries, charging from tug, 240V, and solar, roof top panels and portable panels.

The complexity also comes from changes in technology.
And another comes from a need to keep track of battery condition, power usage discharging batteries, power generation to charge batteries.

Further, off grid is much more common and that entails an increased reliance on the 12V systems. Use of 12V compressor fridges is becoming more popular and thus a camping trip then becomes completely reliant on the 12V system being up to the task.

Finally, I get to the point. Initially, the Setec was designed to be the central hub of the 12V system. It manages everything except for solar which is managed separately.
But a central hub can also be designed around a good solar controller with the 240V charging managed separately by the Setec.
I call these Setec-centric systems or Solar controller- centric systems.

There are advantages and disadvantages for each of them.

@Boots in Action has written extensively on this subject and makes some very good points on the superiority of a solar-controller centric approach.

Hopefully, he is able to add to this thread.

take care
Mike

 

[turbopsi]

Hey Guys thanks for the feedback.

I'll start with Mike.

1. If I was to go to effort if running it to the drawbar my thinking was to go to 6B&S to minimize voltage drop. The cabling run on the caravan alone would be 4.5m before you add the 5m-6m or so of cabling on the tow vehicle size. I'm changing my mind to whether I actually need to run this cable which I will comment on below.

2. My fold out solar panels have a regulator stuck on the rear of each panel so I have no choice there. They boxes are out of the rain as they sit on an angle underneath the panels and the boxes also look weather proof. In regards to thieves, I have always worried about free camping with things potentially getting knocked off. My version of camping / caravan parking is rock up > Set up > get out and see attractions / hikes and come back for lunch and dinner. Others however like to stay put and in that scenario you wouldn't have to worry about things getting knocked off unless it's while your sleeping.

3. Yes you are right about 8B&S being overkill for the inside sockets. I was trying to knuckle down the parts list so I get a move on with ordering them and I didn't know what I could safely go down to hence I stuck with what would definitely work but I agree. I'm good with instruction I knew nothing about seteks or 12v caravan / auto wiring before this. I've done a 3 day cram session with trying to get up to speed on 12v wiring and it's done my head in - So many variables and ways of doing things. Since I've lost this weekend and still being stuck on design I'll see if I can refer to the wiring amp table and maybe downgrade the internal cable running to cig and usb sockets.

4. Thanks for the top on Anderson plugs taking specific wire thickness. I was unaware.

Drover:

Hey mate, yeah a bit of confusion here I reckon I do have standard 3 way fridge which I didn't think to mention. I've updated the design sketch. Yes I finally figured out 6 is a larger cable than 8 The 12v compressor fridge mentioned is a 40l+ camping fridge. I'll be using a 12v distribution box as a hub to connect the fridge and a few other things on the awning side.

The current cabling is all stock standard Jayco stuff without any modifications to the caravan.

The caravan and tow vehicle have a 7 pin plug. In regards to the diode stopping drain. I don't know much about this and I've been disconnecting the 7 pin plug from the vehicle when we stop to prevent drain to the tow vehicle battery.

The next part gets a little muddy. The Conesus seems to be the thin aux cable running from the tow vehicle through the 7 pin and into the Setec Aux+ doesn't really to do much in regards to charging a large battery (120AH)? Or quickly? I see a heap of posts about others getting away from this method of charging and it doesn't really charge the battery to 100% and is more of a trickle? I don't have ANY experience with this.. just going on what I keep on seeing posted? However I would love for the factory system to work as it means less work for me! Maybe it will be a case of try it and see how the factory setup works...

With moving the anderson plug for solar closer the middle area of the van, I totally agree. It was my original plan to drop the cable around the middle somewhere, but I over planned for all scenarios and thought I would run it to the draw bar to future proof things incase I need a higher charge from the tow vehicle. I've now scratched that idea and updated the drawing to reflect the change.

I'm not keen on wiring anything direct to battery as I want the option of taking the portable battery box out of the van at times and still have all sockets work. Hence the use of the portable battery box with the anderson plugs. This way the Setek will power all 12v sockets and plugs when connected to 240v (caravan parks) even without a battery in the caravan.

Thanks for the tip on keeping room for another battery incase.

This all started from something that was supposed to be simple and temporary! We wont be able to go camping for my Wife's 40th because of Covid lock downs so I thought I would surprise her and camp at home on our property - away from the house as we live on small acreage. I thought I was just going to feed in a couple of wires from my battery pack into the setek for the overnight home camp and then be done with it. Things have since snowballed

I've attached the updated drawing.

Can anyone confirm whether the 50amp fuse between the setec and the battery Anderson connector is correct @ 50amp? or should it be lower ? 30A? 20A?

Thanks again!

 

[turbopsi]

Thanks Mike, I'll have a read of the (solar-controller centric) write up. For now I think I want to get this one over the line, understand things a bit better and see what we need to build on later. I've kept it quite modular and so it's no drama to change things if needed.

 

[turbopsi]

@Boots in Action has written extensively on this subject and makes some very good points on the superiority of a solar-controller centric approach.

Mike, would you happen to have a link to this? I've flicked through the Boots's posts and havn't managed to find it. Thx

 

[mikerezny]

Thanks Mike, I'll have a read of the (solar-controller centric) write up. For now I think I want to get this one over the line, understand things a bit better and see what we need to build on later. I've kept it quite modular and so it's no drama to change things if needed.

Hi,
in hindsight, I was quite fortunate. We knew nothing about caravans or towing them but I did have 50 odd years experience in electronics to fall back on.
We ordered a new Jayco Penguin and then had to wait 4 months before it was delivered.

So I had nothing to do in that time except read every manual I could get my hands on, join every forum and any other site related to camping.
Fortunately, I discovered this forum and I would have to say it has been by far the source of almost every bit of knowledge I have gained.
And it has been, again by far, the most friendly one as well.

Anyway, what I wanted to write was that as I gained knowledge in those months before delivery, my plans also changed. Most interesting was that my plans got simpler and simpler. That was unfortunate in one respect because as the plans got simplified, the thrill of doing all the great changes also became less. But it was a fun 4 months, waiting each day for a little eBay parcel from China containing yet another small part of the project. The odd trip down to Jaycar or Altronics for some cable. In that time I also wired the Falcon up with an electric brake controller, 12-pin wiring harness for the towbar, and a 8B&S run from the car battery to the 12-pin plug via a self resetting circuit breaker and ignition-controlled relay.

By the time we got the Penguin, the list of mods was relatively simple. In the end I added a led strip across the bed for a bed light (thanks @Boots in Action), a cable run from the battery to an Anderson plug near the external hatch. Couldn't decide on how to mount it on the outside of the van so left it coiled up inside the compartment where it has stayed and worked perfectly well for over 3 years.
Bought a 40W standard solar panel, controller, and power analyser.
A small LED voltmeter permanently mounted inside the lower external fridge vent to monitor the 12V input to the three-way fridge.
I was originally going to wire 12V lights in the external hatches and front boot. Then I discovered those little round battery operated led lights that run on 3 AAA batteries. $1 each, and run them with rechargeable batteries.
Fitted a single fridge fan to the top external fridge vent.
Also bought a home indoor/outdoor digital temperature and wired the outdoor sensor to inside the fridge and cable tied it to a shelf.
And that is the way it stayed for over two years. Despite me itching to find another "project" to make improvements, nothing obvious ever came to mind.

Earlier this year, I made a "major" improvement and added two 12v sockets on the benches. There was already one on the bench which is used for the plug that goes up the wall for the ceiling lights. I had made up a double adapter for that so we could charge batteries, phones, and eventually an iPad.

So, my suggestion is to take your time to enjoy the planning, enjoy weighing up all the options, enjoy pouring through the sites looking for exactly what you want, enjoy learning about all that is new, and enjoy putting it all together. And the best part, enjoy seeing it all working when you go camping, especially with the knowledge that you understand every part of the system and are capable of sorting out any issues that come up that are solved without having to spoil you time away by having to come back home early.

take care
Mike

 

[mikerezny]

Mike, would you happen to have a link to this? I've flicked through the Boots's posts and havn't managed to find it. Thx

The first place to look will be his posts on the huge solar panel thread.
https://www.expandasdownunder.com/threads/the-solar-panel-thread.1729/

Also do a search on "low voltage disconnect" posted by @bootsinaction

take care
Mike

 

[Drover]

So the fridge is a 3 way and the compressor fridge is the portable job.................okay rethink...........

This does change things, so I will throw an idea out, trying to KiSS the layout.... I am looking from an off grid point of view.

1....Your 3 way fridge will probably have its feed as detailed earlier, possibly sharing #2 pin on the 7 pin plug, it doesn't matter as I would run a dedicated cable from tug to fridge, nothing else off it just the fridge 8 B&S or 6B&S with a 40amp maxi fuse either end, this fat cable can terminate at the rear of the fridge, by replacing the terminal block with a bigger one so the new cable fits and you connect the fridge side of the 12v to it, the original 12v incoming cable just cut and block the end...............fitting a fridge switch on the smaller cable side of the junction box will mean the fridge won't suck your battery dry when you stop....

By disconnecting the fridge this circuit should be enough to supply enough power for the Setek to top up your battery, many go on about its limit for charging but I look at it from starting a trip with a full charged battery from 240v, while travelling its only getting a trickle charge to keep topped up, if you run your battery flat camping then its not the battery or seteks fault, its not enough storage power.... I never had a drama with the Setek ....

2..... Since you only have a portable panel and to keep it simple I'm going with the controllers you have on the panel, you will need a seperate cable run for it as it must run to the battery directly again 8B&S and fused at battery 40amp maxi fuse is plenty big enough, ignore the load terminal on the controller its not possible or practical with a portable, this battery connection could plug into a battery box via an anderson, trust me fitting the solar plug in at the side of van will save you grief later on, vans throw large shadows.

3....... Any wires going to or from the Setek I would just have as 10B&S, even lighter for lights, fuse between battery and Setek 35 amp would be enough, the biggest fuse on my rig is 40amp off the batteries, I cannot see naything higher needed and if things start to draw that much I want it to pop early, in fact my main van feed only has a 35 amp and they get lower further on.... the main feed from under the Jeeps bonnet to van plug for my fridge is only 35amp.... The cables maybe rated high but you never know about connections and junctions, they are the spots things can happen, join melts down but cable and fuse are happy as its rated higher, a lower rated fuse pops before the melt down.


4...... Since you may want to use the battery box outside, then setting up connections to it via a Buss Bar would make it easy to do as it would be plug and play, just unplugging an anderson plug and lifting it out, if you haven't got any spare terminal in the Setek for your Cig/USB run again I would just piggy back off another terminal that doesn't have much load or use....but if you take away your battery box having at least 2 andersons on it will allow you to plug something into it and also hook your portable panel up as well....

5..... If not going to get into off grid fully then I wouldn't bother with monitors, meters and other bits and pieces, only adds heaps of $$$ for little value when plugged into 240 mostly.................... a fridge switch or similar is a must either way and maybe fit a digital voltmeter if you want to see whats what, if you decide to do more off grid camping then you can add meters and the other gizmo's later on, they are not crucial for a functional system but for off grid you would add a better controller, more battery storage and panels...If you do the original layout thinking of the future then adding to it is no drama when the time comes.
Rule of thumb I work on is a 100ah battery needs 200w of panel and at present I have 200ah and 320w, I need more watts as while mine works well I don't want to juggle things.

PS: the diode I mentioned is internal in the Setek on the 12v in circuit, this is originally there as since the 3 way fridge shared the same feed line if the tug was disconnected the fridge wouldn't drain the vans battery when on 12v, running a dedicated 12v feed from tug to fridge means this cannot happen it also gives a good supply of power to the fridge where as before it would be ordinary and at times not worth the effort.


Thats about it from me, this is a sit down at a table with pencil and paper sort of job........... just stay basic until you get to know more, its a simple job but can be clouded with uneccessary details which just makes your eyes roll back.

 

[mikerezny]

Hi,
in case you don't have a copy, here is the Setec STII manual.

It is also worth getting hold of the manual for your fridges. That will give you some idea of the power usage of 24 hours and the maximum current draw for each of your fridges.

For off grid, there are three principles that have to be understood in the following order:
1: your average daily usage in Ah.
2: This then determines the battery capacity needed to supply this power over a number of days.
3: Solar energy supply required to recover the batteries each day.

Allowance must also be made for cloudy days, camping spots without good access to the sun.
There are spreadsheets around, even on this forum that can assist in designing a suitable solution for your requirements.

It might be worth explaining the AUX input to the Setec and the way it is meant to work.
Historically, vans did not often go off-grid and seldom contained a battery. Further, 12V was mainly used only for lighting.
So typically, van rocks up to caravan park, plugs into 240V, the Setec then supplies 12V to power lights.
However, on occasions, there might be a quick overnight stop on the way to the camp spot and 240V power is not available.
No problem, the 12V from the car feeds into the AUX input of the Setec which then provides 12V to power the lights. Easy Peasy.
Just have to be careful to not run the lights too long and flatten the car battery.
In this scenario, 12V from the vehicle is permanently supplied to the van so the van lights will work when the engine is switched off.

Then add the van battery, the tug will also now charge the van battery as long as the battery switch is left on.
Note that there is a diode in series with the AUX input. This has a very specific purpose. It is to prevent a massive flow of current from the van battery back into the car when you crank the engine. The Setec, plugs, sockets, and wiring between the van and the tug battery are not designed to handle that amount of current.

From memory, it is a Shottky diode so there will be a 0.3V drop across the diode. The first block diagram in the Setec manual clearly shows this diode.

Once you have a van battery there are then two choices about how 12V is supplied from the vehicle. Either a direct connection as in the case when no van battery is present or 12V from the vehicle via a VSR or an ignition-controlled relay, etc. Having a direct connection is now not essential. Having 12V only present when the engine is running has the advantage of isolating the tug battery from being discharged accidentally by usage in the van. This can easily happen with a direct connection to the tug battery if one forgets to turn the battery swirch on in the van. In which case power for the van will be happily taken from the car battery.

take care
Mike

 

[turbopsi]

Thanks Guys, I reckon I've got enough for now to wire in the basics. I'll start ordering some parts. Cheers.

 

[Boots in Action]

Hi,
since you are still only in the planning stage. It is easy to consider various options.

So, at the risk of adding complexity:

Van 12V systems can actually be more complex than one might initially think.
There are many facets to understand. batteries, charging from tug, 240V, and solar, roof top panels and portable panels.

The complexity also comes from changes in technology.
And another comes from a need to keep track of battery condition, power usage discharging batteries, power generation to charge batteries.

Further, off grid is much more common and that entails an increased reliance on the 12V systems. Use of 12V compressor fridges is becoming more popular and thus a camping trip then becomes completely reliant on the 12V system being up to the task.

Finally, I get to the point. Initially, the Setec was designed to be the central hub of the 12V system. It manages everything except for solar which is managed separately.
But a central hub can also be designed around a good solar controller with the 240V charging managed separately by the Setec.
I call these Setec-centric systems or Solar controller- centric systems.

There are advantages and disadvantages for each of them.

@Boots in Action has written extensively on this subject and makes some very good points on the superiority of a solar-controller centric approach.

Hopefully, he is able to add to this thread.

take care
Mike

@turbopsi , @mikerezny and @Drover have sure supplied LOTS of info for you to digest. Don't get frightened by all the suggestions, just take each issue one at a time. Some points have not been covered and I am going to detail these now.
1. The charge voltage from the Setec is listed as 14.0 volts. For a Gel battery, this barely reaches the optimum setting of 14.2 to 14.4 volts, but is a safe charge in all conditions. However, if using a AGM battery, it is far below optimum. AGMs require around a charging voltage of around 14.7 volts, and the Setec will never enable FULL storage capacity to be reached. Approx 10 to 15% not then available. Okay for short periods in caravan parks , so I connect up my van to my "smart charger" - 15A 7 stage type - when I get home for at least 48 hours to ensure MAX storage is retained.
2. It is true that people believe that tug only produces trickle charge to van battery. But not because design. The main cause is lack of high enough charging voltage caused by alternator charging output voltage in modern tugs, plus voltage losses in wiring from tug to van and the in-line power diode in the Setec. @mikerezny has already explained its purpose earlier. By my voltage tests, it is not a low loss Schotky diode and one can expect around 0.7 volt drop. See attached regarding alternator outputs for your tug. So, if you are lucky enough to have an alternator that puts out say 13.5 volts when hot, you end up with only 12.6 volts at Setec to charge van battery (13.5 minus 0.2 voltage drop, minus 0.7 diode drop). This is far below charging voltage for any battery and does not even reach "Float" voltage level no matter how far or how long you drive!! This can only be overcome with a DC to DC charger and quite a few members have invested in this system. Your solar panels usually have a charging voltage of approx 14.3 to 14.4 4 volts (some of the better PWM type controllers and most MPPT controllers have user adjustable settings to achieve optimum charge voltages) and so your panels when off grid do better than your tug's system.

It is not a good idea to have multiple solar controllers from solar panels connected to the same battery as each senses battery voltages and loads differently. Indeed, some may have different max charge voltages and different float voltage settings even the same brands. Much better to bypass controllers on back of panels and channel all inputs into the one controller inside, preferably a MPPT type. More info on this if needed. Also have links to various battery/solar companies to back up my statements. The following attachments may give you some ideas for your own setups. Good luck.

 

[turbopsi]

Thanks @Boots in Action

Ive checked my battery specs and your right in saying Setek charging wont be able to get my battery to 100% charge in either scenario (240v or via tow tug). I also have an M100 7A CTEK 240v charger which does the job when connected to 240v albeit a little slower than yours

I just measured my solar panels output at the end of the cable run (after the regulator) and it's outputting a solid 14.9v. I'm not registering any AMPS on my multi meter though so I'm thinking the internal 10A multi meter fuse is blown.

Tow tug is a 2011 Pajero DID and although I don't get a specific mention in the redarc chart of alternators, I'm leaning towards it being the same as the 2012 model that is mentioned. I'll chase this up.

Thanks for the pic of the Anderson plugs. I'm assuming they are yours? They seem to be located on the side of the van. I get why the Solar input connection would be on the side (for portable panels) but can you give me as little more detail on the one labelled "battery charger only? Is this for connecting to the tow tug ? and why have you located it on the side of the van? Also the one labelled solar only, I'm guessing it feeds into a DC-DC charger with onboard solar reg or a sperate solar reg > then direct to battery?

I still don't get how the DC-DC chargers can take a feed that's possibly mid 12v-13v and boost it to 14+ volts? I guess I just have to know that it does just do it's thing and not get off track for now and investigate how they work later on. Park that one for another day

Thanks to you all, I'm feeling a lot more confident and have learnt quite a lot in this 2-3 day cram session.

 

[Boots in Action]

Thanks @Boots in Action

Ive checked my battery specs and your right in saying Setek charging wont be able to get my battery to 100% charge in either scenario (240v or via tow tug). I also have an M100 7A CTEK 240v charger which does the job when connected to 240v albeit a little slower than yours

I just measured my solar panels output at the end of the cable run (after the regulator) and it's outputting a solid 14.9v. I'm not registering any AMPS on my multi meter though so I'm thinking the internal 10A multi meter fuse is blown.

Tow tug is a 2011 Pajero DID and although I don't get a specific mention in the redarc chart of alternators, I'm leaning towards it being the same as the 2012 model that is mentioned. I'll chase this up.

Thanks for the pic of the Anderson plugs. I'm assuming they are yours? They seem to be located on the side of the van. I get why the Solar input connection would be on the side (for portable panels) but can you give me as little more detail on the one labelled "battery charger only? Is this for connecting to the tow tug ? and why have you located it on the side of the van? Also the one labelled solar only, I'm guessing it feeds into a DC-DC charger with onboard solar reg or a sperate solar reg > then direct to battery?

I still don't get how the DC-DC chargers can take a feed that's possibly mid 12v-13v and boost it to 14+ volts? I guess I just have to know that it does just do it's thing and not get off track for now and investigate how they work later on. Park that one for another day

Thanks to you all, I'm feeling a lot more confident and have learnt quite a lot in this 2-3 day cram session.

I am glad you are starting to get your head around the electrics for your van @turbopsi . So to answer your questions in order:

Your CTEC 7A charger should do the job of a "smart charger" if you have the right settings. As you said just a little slower!

Your voltage reading after the controller is not the method. If you check the voltage before the controller with no load (ie open circuit), it should be around 22 volts. You can also check the Isc short circuit current by touching together the pos and neg terminals of input terminals and check amperage, but not an indication of output under load ie connected to battery.

The next check is to read the voltage across the output terminals when connected to a load ie battery. Depending on battery state of charge and condition, controller voltage will be just above or equal to battery voltage. You can then measure amperage into battery with load applied and depending on solar panel performance, it should show input current. If you advise wattage of solar panel, I can work out a rough output in amps you could possibly attain. Let me know how you go.

I tend to agree with you that you probably have a temperature controlled alternator, although you could always check that out with REDARC. My 2011 Colorado is the last of the standard alternators but still does not get over 14 volts.

Correct about the picture of Anderson plugs on side of my van (Penguin). But not quite as grandiose as you think. The socket marked Solar is for my solar input only. As I have 3 solar panels (in series), I have bypassed all the controllers on the back of the panels and the solar input plug goes directly to my MPPT controller inside van - a very short distance and the leads from controller to battery which is very close, are even shorter. See attached. Easy access to connect panel/s at any time and in any position.

The one marked "Battery charger only" allows me to connect my "smart charger" (I have an Anderson plug on the battery charger lead instead of alligator clips) which also makes for easy connection when at home. Fitted nicely there as close to battery! No lifting up seats or having to get inside van!! .It also has another purpose. Being directly connected to the battery (30A in line fuse), that connection provides not only charging access, but a 12 volt heavy duty outlet for other things. Recently was able to connect up a lead from that point to another vanner with a low battery caused by run down by compressor fridge and all the time was still charging my own battery - a single 120ah AGM. A very handy arrangement and simple to do.

A DC to DC charger can receive a lower voltage from the alternator at say 12.3 volts at 5A and can convert this to say 14.7 volts albeit at a lesser amperage of say 4A. A similar system works for a MPPT controller converting excess voltage to extra amps to charge your battery. Simply speaking, the dc voltage/current is changed to AC so the voltage can be changed up or down, then converted back to DC current at the required voltage. Modern systems have very little losses and that is why you get more out of your solar panels in all conditions with a MPPT controller - some say as much as 30%!!

Seeing you are keen to learn about this stuff, I have attached some links to give you more in depth information. Happy learning.

https://www.aussiebatteries.com.au/...?awt_a=78c7&awt_l=Mf5Wm&awt_m=42_PYeAAeNR61c7

 

[turbopsi]

I am glad you are starting to get your head around the electrics for your van @turbopsi . So to answer your questions in order:

Your CTEC 7A charger should do the job of a "smart charger" if you have the right settings. As you said just a little slower!

Your voltage reading after the controller is not the method. If you check the voltage before the controller with no load (ie open circuit), it should be around 22 volts. You can also check the Isc short circuit current by touching together the pos and neg terminals of input terminals and check amperage, but not an indication of output under load ie connected to battery.

The next check is to read the voltage across the output terminals when connected to a load ie battery. Depending on battery state of charge and condition, controller voltage will be just above or equal to battery voltage. You can then measure amperage into battery with load applied and depending on solar panel performance, it should show input current. If you advise wattage of solar panel, I can work out a rough output in amps you could possibly attain. Let me know how you go.

I tend to agree with you that you probably have a temperature controlled alternator, although you could always check that out with REDARC. My 2011 Colorado is the last of the standard alternators but still does not get over 14 volts.

Correct about the picture of Anderson plugs on side of my van (Penguin). But not quite as grandiose as you think. The socket marked Solar is for my solar input only. As I have 3 solar panels (in series), I have bypassed all the controllers on the back of the panels and the solar input plug goes directly to my MPPT controller inside van - a very short distance and the leads from controller to battery which is very close, are even shorter. See attached. Easy access to connect panel/s at any time and in any position.

The one marked "Battery charger only" allows me to connect my "smart charger" (I have an Anderson plug on the battery charger lead instead of alligator clips) which also makes for easy connection when at home. Fitted nicely there as close to battery! No lifting up seats or having to get inside van!! .It also has another purpose. Being directly connected to the battery (30A in line fuse), that connection provides not only charging access, but a 12 volt heavy duty outlet for other things. Recently was able to connect up a lead from that point to another vanner with a low battery caused by run down by compressor fridge and all the time was still charging my own battery - a single 120ah AGM. A very handy arrangement and simple to do.

A DC to DC charger can receive a lower voltage from the alternator at say 12.3 volts at 5A and can convert this to say 14.7 volts albeit at a lesser amperage of say 4A. A similar system works for a MPPT controller converting excess voltage to extra amps to charge your battery. Simply speaking, the dc voltage/current is changed to AC so the voltage can be changed up or down, then converted back to DC current at the required voltage. Modern systems have very little losses and that is why you get more out of your solar panels in all conditions with a MPPT controller - some say as much as 30%!!

Seeing you are keen to learn about this stuff, I have attached some links to give you more in depth information. Happy learning.

https://www.aussiebatteries.com.au/...?awt_a=78c7&awt_l=Mf5Wm&awt_m=42_PYeAAeNR61c7

Thanks for that. Not black magic as I originally thought. MPPT for the win! Thanks for the pics, looks simple but great. Kind of where I want to get to. Can I run something past you guys. I've also seen this refenced on this site - about the battery switch but I don't get it.

"Similarly, if you have 12V on your 7 pin plug, the switch, when in the on position will charge the battery from your car alternator, when in the off position it will only be trickle charged."

If I put the iso switch between the Setec Batt+ and the Battery Box and switch it to the off position, how can the battery then receive a trickle charge? when the positive feed is interrupted by the switch being on the off position?

 

[mikerezny]

By my voltage tests, it is not a low loss Schotky diode and one can expect around 0.7 volt drop.

Hi @Boots in Action,
my bad. Somehow in the dim dark past, I thought it was 0.3V, thus a Shottky diode.

Happy that you have measured it.

take care
Mike

 

[mikerezny]

I still don't get how the DC-DC chargers can take a feed that's possibly mid 12v-13v and boost it to 14+ volts? I guess I just have to know that it does just do it's thing and not get off track for now and investigate how they work later on. Park that one for another day

Hi,

There are various ways to increase a DC voltage. For low currents, do a Google on Buck convertors.
One other way is to feed the input voltage into a high frequency AC voltage via an oscillator. Then feed this into a transformer, lift it up to a higher AC voltage then rectify and smooth it to produce a DC supply. But this can be quite inefficient so there are many variants on this idea.

Similar principles are used to efficiently step down a DC voltage. This is basically how MPPT solar controllers work.

If you want a good suggestion for a birthday, Xmas for you ask them for a DC clampmeter.
They are a great bit of kit for measuring DC currents without breaking into the circuit.
A few of us on the forum have the UNI-T UT210E True RMS AC/DC Current Voltage Mini Digital Clamp Meter Auto Range Resistance Capacitance Tester. They can be bought on eBay for around $50.

take care
Mike

 

[mikerezny]

"Similarly, if you have 12V on your 7 pin plug, the switch, when in the on position will charge the battery from your car alternator, when in the off position it will only be trickle charged."

Hi,
I believe you might be reading the wrong Setec manual.
I f I am not mistaken you have a Setec ST20 series II. Can you confirm that? The model is on a sticker inside the fuse cover.
If in doubt, if you have 5 load fuses and one status LED it is a series II.
If you have 8 load fuses and three status LEDs it is a series III.
The sentence you are refering to is taken from the series III. In this version, the battery switch is integrated into the Setec and performs differently to a series II where the battery switch is external to the Setec and completely disconnects the battery. Switch off, no charge at all to the battery from the Setec.

take care
Mike

 

[Boots in Action]

Hi @Boots in Action,
my bad. Somehow in the dim dark past, I thought it was 0.3V, thus a Shottky diode.

Happy that you have measured it.

take care
Mike

You have a good memory Mike @mikerezny. Was it so far back it was in the dim past?? That was the time when I was intent on getting every bit of voltage through my solar panels by changing the standard silicon diodes in them (A101??? which had a voltage drop of 0.7 volts) to the Schottky type which had a voltage drop of only 0.3 volts. And they were so cheap too. The posts concerned bypass diodes and their operation when part of panel was shaded and how current diverted around the high (reverse biased) resistance of non producing solar cells. Great posts by you too.

 

[Boots in Action]

Hi,
I believe you might be reading the wrong Setec manual.
I f I am not mistaken you have a Setec ST20 series II. Can you confirm that? The model is on a sticker inside the fuse cover.
If in doubt, if you have 5 load fuses and one status LED it is a series II.
If you have 8 load fuses and three status LEDs it is a series III.
The sentence you are refering to is taken from the series III. In this version, the battery switch is integrated into the Setec and performs differently to a series II where the battery switch is external to the Setec and completely disconnects the battery. Switch off, no charge at all to the battery from the Setec.

take care
Mike

@mikerezny and @turbopsi , as per your original picture, it is a ST20 Series II. Only 5 fused outlets and only one LED warning light. No separate battery switch.