Aux Battery/Yandina wiring diagram

[singler3360]

After weeks of study, I'm finally willing to expose my underbelly and share a diagram of how I think I should wire in an aux. battery with a Yandina battery isolator. Bear in mind I am going from complete ignorance of 12v auto wiring to this, my first draft of a wiring scheme that hopefully won't ignite my van into a mushroom cloud. This is a distillation of many Samba posts. As a result, the following assumptions are made: I think I can learn something new after asking many dumb questions, a single aux. battery will be installed in the rear bench seat, and I'm still not sure how much all this is actually going to cost.

The overall idea is to wire inline a Xantrex Freedom HF 1000W Inverter/Charger that can auto-detect AC from shore power to the camper outlets or invert DC from the aux. battery in the absence of AC. The Yandina will further make wife, kid and absent-minded me-proof while allowing a TruckFridge or equivalent to run on a big ole honkin' deep cycle battery that is too big for the driver's side compartment. Note also, dash wiring is for late model Westy.

And finally, to the expert and newbie members that have contributed to my still increasing knowledge on this subject, PLEASE PROVIDE FEEDBACK ON THE SPECIFICS OF THIS DIAGRAM. (wire sizes and fuses?)

[GreenMachineVW]

If you are going to use a Xantrex Freedom HF 1000W Inverter/Charger, you might should have the outlets hooked up to it, preferably with the breaker between the Xantrex and the outlets. That way the outlets are always ready, whether with shore power or inverted power. Your diagram does not show any connection from the Xantrex to the outlets. In your diagram, move the Camper and Cabinet Outlets connection from the 15A Camper Fuse Panel (which I am hoping is the circuit breaker next to the rear seat), to the inverter.

[singler3360]

Thanks for the suggestion Green. One question of detail, in the stock configuration, is one outlet wired to the other in a series or do they do they both go back to the shore power plug separately? Since I don't have a Xantrex yet, I don't know if they can be wired out separately from the unit or done similar to the way home outlets are strung. I know, I know... consult Bentley, but I find it confusing (although I'm getting better).

The diagram above has been edited with this suggestion.

[madspaniard]

any of the wiring/power gurus here cares to share his opinion? This is really interesting, I'm also going through this process and need same advice.

[Dogpilot]

A couple of comments. I would leave the breaker before the inverter. It is to protect from faults from shore power, put another one for you inverter after that. Personally, I like to have shore power come into the van for power things when I'm at base for tools etc. You can split one of the outlets to be 50/50. The 70 to 80 amp fuses! Remember what fuses are for, to protect the wiring from flaming. 80 amps is well over what most of your wire will carry, be huge and expensive, if your thinking you can start off the AUX through the Yandina, your wrong. It will melt down completely at that load. So something like 30 amps would be just fine there. Most of your charging systems will have fuse recommendations, as will the fridge. The Norcold actually has its own fuses installed. Go online and look for fusing recommendations for wire sizes and match up the two.

So folks understand. The Yandina is just a switch to combine both batteries for charging. If you run down the starting battery, you can do two things. Switch the Yandina to combine manually, which allows the AUX to charge the starting battery. Or, you can put jumper cables to the stating battery from the AUX to start off. Do not have the Yandina in Combine mode then or it will die a smoky death. Realistically, you want complete isolation of both systems. Leave the starting system alone, except for charging. This way when camping, you will only kill the AUX system from poor management. Otherwise, brush up on hitchhiking or always park on a hill facing downhill.
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[Mr. Electric Wizard]

FYI, you don't need the Yandina in this configuration.
You could just use a regular old Isolator (ex. Shure Power).
I got mine for like $25 on eBay.
You only need to separate the battery banks.
_________________
"Saying what we think gives us a wider conversational range than saying what we know."
~ Cullen Hightower

(T)exas (C)oalition (B)uses
(H)eidenhammer (B)ully (B)oyz

--1966 De Luxe Camper

[singler3360]

Dog, thanks for the clarifications on how to spec out the remainder of this diagram. And I really appreciate your comment about how to jump the starter from the aux. battery with the Yandina installed (but not in combine mode). This question went unanswered elsewhere. As far as the 50/50 outlet wiring is concerned, the diagram assumes the Xantrex unit that contains an Iota-like switching device that can auto-detect the source to the outlets, so each plug in an outlet can be wired the same and will default to AC shorepower when plugged in at a campground, or auto-switch to the AC inverter power when sourced from the aux. battery. At least, that is the impression MadSpaniard and I were left with from posts here in Samba.

[Mr. Electric Wizard]

That is correct.
The interior outlets will be fed either from Xantrex inverter featur, or from shore power.
When shore power is connected the inverter is switched off and the automatic switch passes the power through the unit and feeds the outlets.
_________________
"Saying what we think gives us a wider conversational range than saying what we know."
~ Cullen Hightower

(T)exas (C)oalition (B)uses
(H)eidenhammer (B)ully (B)oyz

--1966 De Luxe Camper

[singler3360]

[Mr. Electric Wizard]

I'm sure it'll be fine.
_________________
"Saying what we think gives us a wider conversational range than saying what we know."
~ Cullen Hightower

(T)exas (C)oalition (B)uses
(H)eidenhammer (B)ully (B)oyz

--1966 De Luxe Camper

[Dogpilot]

If that where the case, then it should be just fine. I still would keep your breaker wired at inlet and a second one after, if one is not integrated into the shore power unit itself. Remember the breaker is there to protect everything inside from external issues cropping up inside, like your shore power unit turning into a miniature sun when it decides to melt down, taking the Westy with it. Again, fuses need to match the wire and the draw of the unit. The wire should also be selected to match the draw as well.
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[Mr. Electric Wizard]

Definitely!
Figuring wire size is about the most difficult part of the design.
_________________
"Saying what we think gives us a wider conversational range than saying what we know."
~ Cullen Hightower

(T)exas (C)oalition (B)uses
(H)eidenhammer (B)ully (B)oyz

--1966 De Luxe Camper

[singler3360]

From the external shore power plug to the breaker to the inverter, I was just going to rewire what is already there, but should the stock wiring here be replaced with different size? I assumed the load requirements on this leg are the same and I wouldn't alter the specifications any. A quick view of it behind the cabinets lends me to think it's romex,but I didn't spend a lot of time tracing.

Tonight once I get home I'll add the fuse back to between the shore power plug and the inverter.

[Mr. Electric Wizard]

Well most 110V receptacles (3 prong outlets) are rated at 15 amps.
The ones with the ear on one of the neutral (i think) are 20 amp.
So 12 awg romex ought to be fine.
Just make sure that you fuse between the shore plug and the Xantrex unit.
_________________
"Saying what we think gives us a wider conversational range than saying what we know."
~ Cullen Hightower

(T)exas (C)oalition (B)uses
(H)eidenhammer (B)ully (B)oyz

--1966 De Luxe Camper

[tencentlife]

Right, you definitely want a breaker on the shore power ac input line. Your inverter/charger will recommend a size, so stick with that.

The I/C's ac output may have built-in breakers already (many do), but depending on where you mount it they may be difficult to access. So if that is the case, install your own in an accessible location, the same or smaller than the ones on the unit. If it doesn't have its own, hard-wire to the inverter and install an ac breaker rated the same or smaller than your receptacles.

I would rewire everything ac with new 12ga. Romex, or if you want real heavy duty insulation and moisture protection (Romex is designed for installation inside walls of houses, where it will always be dry) use 12ga. UF wire (Underground Feeder). UF wire has an extruded jacket that completely encases the wires inside their own individual insulation. It is approved for direct burial (hence the name) so for locations where the wire will be inaccesible but there is the possibility of moisture (like in kitchens ) it offers the wire a lot of extra protection.

You will have large DC wires from your aux battery to the inverter, so that circuit needs to be protected with a fuse. Use the recommended DC input wire size, or larger, and protect it at the battery with an appropriately-sized fuse, preferably a Class T or R. The ac circuits present the danger of shock, but these DC wires present the danger of fire if shorted or there is an internal failure in the I/C. This is the most important fuse in the whole installation, in my opinion.

Whatever combiner you choose, it can be connected at the downstream side of the large battery-to-inverter fuse, as can the main positive feeder for your DC fuse panel. Essentially all current in and out of the aux battery passes thru this fuse.

The second fuse at the combiner's alternator or starter connection is optional; follow the manufacturer's recommendation here and consider your wire routing's exposure to possible physical damage.

If you chose a Yandina, the bidirectional charging would keep the starting battery charged as well when you connect to shore power, if that is desirable to you. I suppose it depends on how long you anticipate being on shore power without running the engine, and the condition of the starting battery.
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[singler3360]

[singler3360]

Here's version 2 of the diagram that has been edited with all suggestions to date:

Is there an advantage to paying the extra for an AC/DC fridge in this diagram? My thinking is to allow for recharging of the aux. battery without the draw of the fridge while on shore power. In this case, could the AC plug go to the Cabinet Outlet without damage, even if it is accidently switched to DC while on shore power? Or maybe it shouldn't be wired DC at all?

[1621]

[tencentlife]

That's a good analysis, but if the charger has enough amperage then leaving the fridge on DC could be fine, so long as the charger can exceed the fridge's load by a comfortable margin. A DC appliance is more efficient, generally, especially anything motor-driven like a compressor. But the ability to switch to ac could come in handy at times, you never know.

singler, I meant that you would attach the fuse for the big DC inverter feeders as close to the aux battery positive as practical, and then everything that attaches to that battery does so on the other side of the fuse from the battery.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[scottjk]

I just spoke with TF and the AC/DC model is back ordered for 30 days. Also they will be priced higher than before but at this point they couldn't give me a price other than "they will not be cheaper".

I'm planning on using a Battery Minder+ when hooked to AC power to maintain the yellow top Optima.

http://www.thebatteryminder.com/12v133abatteryminder-p-29.html

Do the gurus think that this will provide enough power to charge the battery as well as run the fridge?

Thanks

Scott