AUX Battery Diagram - AM I WORTHY?

[WESTG]

Before you throw me under your van and run me over for posting another house battery thread... I built my own diagram and plan and want someone to check my work so i dont burn down my van or build a useless system.

Heres where Im putting it:
Battery/Solar Controller/Inverter -- cabinet next to water tank
DCDC/Shore/FusePanel -- Under Drivers Seat

Questions (numbered circles on diagram):
(1)Can I run two wires off the house battery? The solar/inverter and DCDC/Shore will be on opposite ends of the van. If yes, can I connect both positive wires to the same 250A fuse?
(2) Is 5feet in wire length between the battery and DCDC/Shore too long?
(3) Do I need all these individual circuit breakers for each line? Or is there a simpler, cleaner setup?

let me know what info i didn't include. Im a newb, but i have no feelings... please tell me the honest truth.

thank you all in advance!
-G

[/img]

[Abscate]

This isn’t for beginners. It’s not the wiring diagram that will get you into the trouble, it’s the implementation.

Making crimps, routing for Chafe, vibration, and strain relief make this a craft , not a hobby.
_________________
.ssS!

[revolution337]

From the looks of your diagram, neither the house battery, nor the shore charger are connected to chassis ground. If that is the case, none of your consumers will work when powered off your house battery when isolated from the start battery (they have no path to ground)

This diagram is taken directly from the Renogy manual. Note how both the start battery, and house battery both have their own ground cable.

_________________
1982 Westfalia AEB 1.8t
2017 VW Golf Sportwagen
2001 Audi A4 4.2 V8 swapped
2000 BMW Z3 roadster
-Mark

[DuncanS]

Without further information is is not possible to advise. For example how are you controlling the charge rate for the house battery when on shore power?

[Ronzo_volvo_guy]

G;

I'm all for hands-on, but you are dealing with high levels of electrical stored energy...high enough to easily light things up (just as an example, may I point out that the squadron of engineers who were undoubtedly involved in designing the battery storage system on the Boeing 787, didn't get it right the first time either...! Ref: https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems)

So here are some general notes...Fusing should be sized taking (at the very least, but no less than) two things into account:

1. Wire gauge, considering the entire current path...so this includes DC Return or Neg, or chassis path), as well as the power buss, or Pos path, so that before a current high enough to overheat wiring flows, the fuse blows and interrupts the overcurrent, preventing a wiring fire.

...and 2. Fuse can also be added as a safety device to limit energy into a device or user, OR out of a source, to prevent damage to the devices.

Of course , when a fuse does blow, a part or even much of the system becomes unavailable and unusable...this is, in the case of a valid blowing of the fuse, a good thing, but in case some unforeseen unusual condition blowing it, which was not carefully considered during the system design, a nuisance at least, so failure (or even just "unusual") modes (like a single failed cell in one of the batteries) must also be carefully considered.

It is also advisable to include monitoring provisions in a system, which alert an operator to high (charge or discharge) currents, or circulating currents within the system (since there are multiple sources, some of which can be at different levels of charge or output) so that preventative measures can be undertaken BEFORE a fuse needs to blow to safe the day!

I don't know what you based that 250A fuse on...if it was some arbitrary criteria, but you figured you should have it in the circuit just in case, with a value like that, chances are that it will stand, happily-by as damage occurs,

Speaking as a heavy hands-on electrical engineer, and long-time radio amateur who has been home-building, and (admittedly!) occasionally blowing up circuits (but also learning from those events!), it is no small engineering task to design a usable, efficient, safe, and reliable high power electrical system, consisting of multiple storage sources, and with house and starting batteries, prioritized users. I don't wish to rain on anyone's parade, but your box diagram is only a start!...I suggest you present your diagram along with the specification of each of the boxes, not only here, but also to a qualified, experienced, and hands-on electrical engineer for a critical evaluation and consideration...then listen to their advice for wire gauge, and fusing. It might also be advisable to base your system on a previously designed and installed system with some field experience behind it...

German saying: Lange Rede... kurzer Sinn:...
Long speech...short point...: Keep it as simple as possible, but no simpler, and be safe!

Cheers

[dobryan]

When I develop my house battery and charging systems I do it component by component.

Start with the house battery and fuse block for accessories. Diagram it fully. Fuses or breakers if you are using them.

Now add a solar panel and charger to the diagram.

Now the DC/DC charging system, etc.

It is difficult to visualize the whole system at one time at the start.

Remember that a fuse/breaker just disconnects that current path at the fuse. Both ends of the wire are still live if they are connected to power sources (i.e. a battery on one end and a charger on the other). The fuse does not prevent a fire in the case of a short unless both ends are fused and very close to the power sources.
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[space]

250 amp fuse is adequate for the 2/0
THHN 2/0 CU is capable of handling 285 amps according to the NEC
All other fuse/wiring seems fine (except for the aforementioned missing grounds)
The only question I have: Is the total loads from the distribution panel less than
40 amps?
While one could certainly assume that all loads wont be used at the same time, I think I would err on the side of caution (if in fact the total loads are above 40a)

T

[DuncanS]

Agree with all of the commentators. There are tons of good posts and diagrams. Read a huge number of these before you start. And then get crits on individual components. For example, just start with the house battery alone, its isolation, charge control and fuses first. When all the choices of the best components are made and the wiring resolved......................THEN start to think about other options in terms of wiring. The additional loads will require changes to your original house design. Good. Don't try to outguess yourself right at the beginning. Reconfigure the components, fuses and wire sizes and then move onto the next addition. Add the next, reconfigure and adapt and so on. I doubt the Mars rover project was done all at one time on a single piece of paper. If this were the case, why didn't the Wright brothers just start with a 747?

Sneak up on it and remember the rule of the 6 P's.

Duncan

[jocoman]

The Renogy needs a separate 12v ignition signal to turn it on. I wired in a switch to mine. Also, you can put in another switch so that the output to the charge battery is 50%.
I wired that in as well.
_________________
'86 Westfalia 2.0L Zetec
'97 Volvo 850 AWD Turbo
" The fun never stops"

[Vanuber]