DC to DC charger install - does this work?

[krusovice]

That helps me to understand (I think) but isn't really what I'm trying to accomplish.

My issue is that since installing a DC/DC Charger, my house electrics are running off of the starter battery. If I disconnect that, I have no power to the DC items in the camper.

I don't sure that Magnatec, so I want to remove it for now.

From the write-ups you linked, I think I can just remove the Magnatec completely, and if I create a buss bar that connects all the circuit breakers, I'll be able to use all the DC functions from the house battery.

Am I on the right track?
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1984 Vanagon 1.9/4 speed
2001 Eurovan Camper

[xEVC]

Please let us know what works with only the house battery connected:

1 Interior Lamps above bed
2 Fridge
3 Furnace
4 monitor panel (and 12v sockets)
5 Propane Alarm.

As it turns out, 1-4 are on the same busbar, and #5 is on a separate one - these correspond to the dirty/clean circuits we are discussing.

* If none of these work, then its likely you simply mis-wired things
* If 1-4 work but #5 doesn't (or vice-versa) then you need to combine the bus bar.
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[xEVC]

More ideas:

1. Twice you've included a diagram (which is very helpful!) but it does not show any wire from the + side of the house battery back to the Eurovan. Did you simply forget that one? this would be the wire from House Battery + to the "Isolated Stud" (which you have at the connection of Orange and Pink in your highlighted factory wiring diagram). The + side of the house battery should have 3 connections: Solar Charge Controller, Battery Charger, and Isolated Stud.

2. LFP batteries can enter a protection mode, either due to high voltage, low voltage, or high amp draw. What is the voltage across the + and - terminals of the house battery? Perhaps you have things wired up correctly, but the battery has shut off.

3. Double check all the fuses - battery chargers sometimes have a capacitor that needs to charge up, and can pop a fuse the first time you plug them in.
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[krusovice]

I think the charger/Magnatec discussion is confusing things a bit. The main issue I have is that the DC/DC charger is preventing the house battery from powering anything. If I disconnect the starter battery, everything goes dead. I hook it up, and everything works.

No lithium batteries in the system.

Piecing things together, I think I have the DC/DC Charger on the "wrong side" of the isolation stud. Basically, power can flow TO the DC/DC charger, but it can't flow OUT OF it into the system.

I disconnected both power wires from the Magnatec (1J and K), and bridged the bus at the fuses, and get the same results (power from the main battery, nothing when I disconnect it and try and used the house battery).

If I bypass the DC/DC it works as it should.

SO, am I right that I need to move the DC/DC charger to the other side of the isolation stud? And if so, is there a good way to do it while leaving the physical device on the passenger side?

Thanks again, all.
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1984 Vanagon 1.9/4 speed
2001 Eurovan Camper

[xEVC]

Conceptually you have these issues:

1. The DC DC charger needs to have its input connected ONLY to the starting battery circuit - NOT to the isolated stud which serves as a bus for all the house-battery side devices. You've essentially wired the INPUT of the DC DC charger to the house battery side. That's never going to work (unless you believe in perpetual motion).

2. Negative after the Shunt needs to go to the van chassis body (you don't show one, but it needs to be there). In my van (2000) that's the wire that goes from house battery to a bolt on the body in the wheel well.

3. I suspect you will also need to create a new aluminum bus bar for the 5 fuses, but that can be done later after you figure out #1 and #2.


You want the wiring to be like this:

See changes in RED and BLACK

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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[kourt]

The other way to view this:

The isolated stud should only have two wires serving it.

One comes from the start battery and carries + current.

One goes to the DCDC charger + input.

Nothing else should be on that stud.

I realize the stud is there as an OEM fixture, and it is a great wiring convenience. But you've got to get the loads off of the stud.

The load panel positive lead should connect to the positive terminal of the house battery, not the stud. Ensuring this positive connection from the load panel to the positive terminal of the house battery will ensure your loads draw from the house battery exclusively.

Think of the DCDC charger as a firewall for your house battery. Everything related to loads should be behind that firewall.

kourt

[krusovice]

Sorry, yes, there is a black negative to the stud on the wheel well.

In the meantime I took the power line from the starter battery and wired that to the DC/DC in.

However, I wired the OUT back to the isolation stud, and utlized the original wire from the stud to the positive terminal on the battery.

I also re-attached the wires to the converter rather than making a bus bar.

Everything works now.

Is there a reason not to do this? My thought is the wire from the battery to the stud can provide power to the system AND if the DC/DC charger allows it, the same wire can charge the battery. Am I mistaken? Or do I need to run an extra wire?

If I DO need an additional wire from the DC/DC to the battery what is a good way to run it?

I assume the reason to remove the converter is to not charge a battery that can't handle it. I've unplugged the converter so it can't be used inadvertently (and my battery can still use it). is this OK until I decide if I need a new converter (AC Charger)?
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1984 Vanagon 1.9/4 speed
2001 Eurovan Camper

[kourt]

It would be nice if you drew a picture of how it is wired now.

My advice: eliminate the converter.

I can't remember if you said your house battery was lithium or not. The converter is inappropriate for any lithium battery system.

kourt

[xEVC]

[krusovice]

Thanks kourt and xEVC.

Here is a diagram for the sake of it. The only change to install the DC/DC was to "break" the circuit between the fuse and the isolation stud.

To be complete, I included the solar and smart shunt wiring.

I am still using lead acid batteries (for now). Once I have a better idea of my consumption I will look into upgrading and at that point I'll remove the Magnatec. (Or maybe when I'm cleaning up the wiring...I have no plans to use it. I've just had enough issues with what I'm doing that I figured it's better to not mess with anything I don't need to mess with.)

The yellow boxes are things I've changed. The rest is how it was delivered (except for the fuse replacing the OEM solenoid).
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1984 Vanagon 1.9/4 speed
2001 Eurovan Camper

[kourt]

Thank you -- this looks good. Everything is firewalled behind the DCDC, as it should be.

kourt

[krusovice]

[kourt]

It becomes even more obvious when you change battery chemistry to lithium, because you have to put all of that behind a special charger, and any chargers within the firewalled space must also be lithium programmable.

The Victron brand is convenient because there are so many published examples of how to config their chargers.

kourt

[xEVC]

Glad to hear, and I think that revised diagram is perfect.

Next step would be to remove the Magnatek and expand the bus-bar on the breaker panel.

Then you have to decide what to do with all the leftover space
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[wavefarer]

This is a very timely discussion as I am in the process of upgrading the house battery and charging system on my 1999 EVC. I have followed this and other Samba threads. The updates to this thread have come in at opportune times and have helped me move forward. Thanks for everyone's input -- truly invaluable!

I upgraded to 100Ah LiFePo4 battery and Victron IP22 AC/DC charger with merged filtered and unfiltered outputs to a single bus bar several weeks ago. I made sure the shore power charger was charging the battery and house loads worked with charger on and off.

Now, I am attempting to button up the upgrade to the passenger side with the Victron Orion Tr 12/12 30 Amp charger, Victron BMV-712 monitor, and battery on-off switch. I dry fitted everything today. I am having a similar problem to krusovice.

When I start the vehicle the house loads work, i.e. rear water sprayer and lights. When I shut off the vehicle the house loads do not work. I did the same test with sprayer and interior lights and also domestic fridge - all dead. I have verified battery switch is working and BMV-712 works on house battery.

Where is the isolator stud physically located in the van? I took the wire that came into the rear passenger battery area, removed it from the single post connector on the side of the battery box, connected the wire to a 40 Amp Breaker that goes to the the Orion Tr 12/12 30 charger input (+). This sounds similar to what krusovice did initially?

[kourt]

The stud is usually bolted to the black sheet metal frame that supports the rear propane heater. It should be somewhere near the forward end of that frame, near the water tank. Have a look around there.

kourt

[krusovice]

The isolater stud is on the driver’s side. Shortcut: you can see it by removing the larger black vent in the plastic shroud.

And it sounds like your problem is exactly what mine was. You have to put the DC/DC charger up-stream of the isolated stud.

What’s happening now is your DC/DC charger is preventing the power from going out of the house battery and into the system.

I located which wire arrives at the stud from the starter battery. I connected that to the DC/DC. Then a wire from the DC/DC to the isolated stud. The existing wire from the stud to the battery allows the battery to power the dc features, and also allows the DC/DC charger to charge the battery.

Once mine is tidied up the DCDC will be on the driver’s side.

I’m glad it helped more than just me!
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1984 Vanagon 1.9/4 speed
2001 Eurovan Camper

[wavefarer]

Another thought I had is that it looks like I incorrectly wired one of the 40 Amp Breakers. The breakers I am using has a BAT post and an AUX post. I assumed they were bidirectional but the labeling would tend to indicate otherwise.

I correctly wired the input breaker with alternator/starting battery wire to BAT post and wire to Victron battery charger from breaker AUX post to Input (+).

I incorrectly wired the Victron Output (+) to AUX instead of BAT. I will fix this tomorrow.

Not sure if this is my issue, but certainly I need to correct this.

[wavefarer]

Thanks guys! I appreciate the quick response.

I was reluctant to admit the problem to myself yesterday because I wanted to mount the dc/dc charger in the passenger side battery compartment.

I guess the people that have mounted the dc charger in the house battery area have run a new wire from the engine bay or from the driver side area. Neither of which is something I want to tackle for this season.

I will open up the driver side and mount the charger there.

Thanks again for the help.

[wavefarer]

Is this the isolation post that I need to connect the DC charger before?

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1999 VW Winnebago Campervan