Help with House Electrical Design and Components

[SternWake]

A thick copper ground cable from Load/charge side of shunt to alternator mounting bolt is much better than grounding to frame, and no additional beefing of original grounds is then necessary for house battery.

The PD converter casing is supposed to be grounded. I've skipped that part, but I can't tell you to skip it. Do note that if you do do it, that when you insert the (+) wire to the PD dc output, and use an Allen key with the angle, then this might be able to short out (+) and (-) if you touch the allen key to the PD's metal casing.

If you decide to skip it, and if you notice that you lose radio stations or TV stations when The PD9245 is charging, then the ground 'might' help reduce that, or possible eliminate it, or perhaps do nothing at all.

 

[sassypickins]

Sternwake,

Good tip about the allen wrench.

Sassy

 

[Mobilesport]

Would this work?
It's partially what Stern said then a little from Falcons drawing and then I changed out the positive bus bar and added just the fuse block instead.

 

[SternWake]

That works MS, I could nitpick a few things though.

In Following the instructions on the Fridge, I would run a separate inline fuse right to the battery(+) terminal and not use the common fuse block. I would also run the fridge (-) to the load side of the shunt and not to the (-)Buss bar.

The Deltec shunt is brass, and is susceptible to battery fume corrosion. I would not put it right on the (-) battery terminal, as the shunt is a precision resistor, and corrosion when it sets in will reduce that precision in time.

The Shunt also has two smaller screw terminals for the battery monitor. This is supposed to be twisted pair wire to negate RFI, and these wires are not shown in that diagram. They run to the battery monitor, and it is better if they are not really in close contact with other wires/cables, and cross other AC or DC wires at 90 degrees, as induction could throw off the accuracy. This is very hard to achieve in a clean manner so Keep it in mind, and if the amperages look off, or bounce around when you think they should be steady, perhaps consider shielding these twisted pair wire.

I've not had issues with RFI, until the wires loosened up in the back of my monitor and all of a sudden it started reading hundreds of amps. I wrapped my twisted pair with that aluminum tape over the 5 foot run from monitor display to shunt and tried the 90 degree thing and no parallel runs, where possible.

Twisted pair wire need not be thick wire as it carries no significant current. One could use cat 5 ethernet cable. Use two of the wires for each side of the shunt.

The twisted pair wire which attaches to the shunt's two sides should be a ring terminal, rather than just stranded wire wrapped around the screw. crimped and soldered would be better than just crimped.

When assembling all of these wires, if the connections are new and clean, consider wiping them/ spraying applying this on and over the mating surfaces. Use gloves and do not breath the aerosol if the spray is used:

http://store.caig.com/s.nl/sc.2/category.192/.f

These Kits are wonderful to have:
https://www.amazon.com/dp/B004GE15JG/ref=twister_B00WIXZPH0?_encoding=UTF8&psc=1

Magic electrical juice. try it on your phones USB connections. They will seat with a click, and perhaps charge the battery faster, and reduce wear on the contacts.

The Fuse on the battery to solenoid to alternator should technically be within 7 inches of the battery(+) and inbetween solenoid and battery, Not in between Solenoid and alternator. The OEM wiring from alternator to engine battery will be already fused by the vehicle manufacturer.

It would also be better to have the Inverter (-) ring terminal right on the load/source side of the Shunt rather than to the buss bar. The Inverter can present the biggest load so it is best if it is right on the Shunt. rather than having the circuit path longer and having to flow through the length of the Bussbar as wel.l

The 200+ watt Inverter fuse should also not be run through the fuse block for the same reason, but have its own cable with ring terminal right on the battery (+), fused or a Circuit breaker on this cable, the rating to protect the wire size, but the inverter instructions might list a fuse size to use and that overrides what the wire size should be fused at.

 

[Surly Biker]

Mobilesport,

I'm no electrician, but it looks like you are connecting your inverter to the 12v blue sea fuse box. I'd be very concerned about that. I haven't read the whole thread to see what wattage inverter you're running, but if its over 200W or so that is way too much amperage for that DC panel. Connect the positive and negative leads to the inverter directly to the battery posts (or more conventionally) to separate positive and negative bus bars.

The amperage drawn by a 1000W inverter overwhelms every other load in the system. I probably haven't explained this very well, but it's a big deal.

 

[Mobilesport]

@ Stern
How far away from the battery should the shunt be positioned? 
Thanks

I agree with you about not having the inverter and fridge running through the negative buss bar
But would the positive side be OK running the fridge and inverters positive wires through the fuse block as long as I kept the wires thick and the runs short?

 

[SternWake]

Just outside the battery fume radius. If the Deoxit shield and perhaps some Dielectric grease smeared over terminals, then it can be closer. Mine is about 4 feet from battery, as that location is most convenient.

No circuit should be any longer than it has to be. BUT everything is a compromise.

Plenty have put the shunt right on the battery (-), and this eliminates 2 ring terminals.

The twisted pair wire length from shunt to battery monitor, well ideally that would not be a mile long and running parallel to a bunch of other wires unless completely shielded.

 

[Mobilesport]

@Stern
Also notice the red wire that goes from house battery to the fuse block then to solar controller , I'm thinking it would be possible to have this be just one wire and it would run along side the fuse block with a t  connection that mounts it to the fuse block for one less connection , what do you think?

 

[Optimistic Paranoid]

Mobilesport,

I'm no electrician, but it looks like you are connecting your inverter to the 12v blue sea fuse box.  I'd be very concerned about that. I haven't read the whole thread to see what wattage inverter you're running, but if its over 200W or so that is way too much amperage for that DC panel.  Connect the positive and negative leads to the inverter directly to the battery posts (or more conventionally) to separate positive and negative bus bars.

The amperage drawn by a 1000W inverter overwhelms every other load in the system.  I probably haven't explained this very well, but it's a big deal.

+1

The manual for the inverter will tell you what size fuse it needs, and that is often bigger than any fuse that will fit in a standard fuse box.  You usually end up running a single specialty fuse to the inverter direct from the battery or the positive bus bar.

The exception to this MIGHT be a small inverter "designed" to plug into a cigarette lighter, in which case you can probably get away with wiring it directly to the fuse block with 10 gauge wire.

 

[Mobilesport]

Mobilesport,

I'm no electrician, but it looks like you are connecting your inverter to the 12v blue sea fuse box.  I'd be very concerned about that. I haven't read the whole thread to see what wattage inverter you're running, but if its over 200W or so that is way too much amperage for that DC panel.  Connect the positive and negative leads to the inverter directly to the battery posts (or more conventionally) to separate positive and negative bus bars.

The amperage drawn by a 1000W inverter overwhelms every other load in the system.  I probably haven't explained this very well, but it's a big deal.

Right now I have my inverter running straight to my battery but in the diagram I drew I was thinking that I could get a fuse block that would handle the inverter etc.
H92 many amps does a 750 watt inverter draw.
My fridge is only 3.5 amps.

 

[Optimistic Paranoid]

Right now I have my inverter running straight to my battery but in the diagram I drew I was thinking that I could get a fuse block that would handle the inverter etc.
H92 many amps does a 750 watt inverter draw.
My fridge is only 3.5 amps.

750 watts / 12 volts = 62.5 amps

 

[SternWake]

The Solar charge controller should go to battery (+) through its own fuse/circuit breaker, not through the fuse block. Loads on the other circuits on the fuse block would change the battery voltage the solar controller sees. The FUSE block is for DC loads. The solar controller is a charging SOURCE, not a load.

Your way will work, it is just not as good as a direct circuit so that the solar controller sees as close as possible to actual battery voltage, instead of voltage at the fuse block.

Also the fuse blocks have a 30 amp maximum rating through any one circuit. The 1000 watt inverter at a 1000 watt load, is ~82 amps at 12.2v. DO not run a big inverter through a blue seas fuse block.

So BOth Fridge and Solar controller should not go through the main DC fuse block. Technically the fridge 'could' but all Danfoss ansd sawafuji compressor models say to NOT share a fuse block or Buss bar with other devices and to fuse right at battery (+). With the Shunt there is no option but to run it to the shunt, or the bussbar connected to shunt's load/charge side.

Power supply (Fig. 1)
DC: The electronic unit must always be connected
directly to the battery poles (2). Connect the plus to
+ and the minus to -, otherwise the electronic unit
will not work. The electronic unit is protected against
reverse battery connection.
For protection of the installation, a fuse (3) must
be mounted in the + cable as close to the battery
as possible. It is recommended to use 15A fuses for
12V and 7.5A fuses for 24V circuits. If a main switch
(4) is used, it should be rated to a current of min. 20A.
The wire dimensions in Fig. 2 must be observed.
Avoid extra junctions in the power supply system
to prevent voltage drop from affecting the battery
protection setting.

source:
http://files.danfoss.com/TechnicalInfo/Dila/06/bd35-50f_electronic_unit_ac-dc_04-2009_ei100g402.pdf

This refrigerator operates on 12/24 volts DC current from a battery.
CAUTION: Only connect the refrigerator directly to the battery. Because they
often generate high voltage pulses and cause transistor defects in the inverter, no
other switches, lead wires, or electrical equipment should share the wiring between
the refrigerator and battery.
When using either a converter or a battery charger, make sure that they are connected in
parallel between the battery and the refrigerator. Do not use a converter or battery charger
to supply the DC power directly to the refrigerator because these two devices do not
supply filtered DC power

source:
http://www.thetford.com/wp-content/uploads/2015/04/825/Installation-Owners-Manual.pdf

That is two fridge makers saying not to share busses or fuse blocks with other devices but to hook the power leads directly to battery. Obviously with the shunt the (-) wire cannot go right to battery (-), but right to the shunt itself is better than to the bussbarr which is sharing loads with other devices which then goes to shunt.

Any yes, one can argue they have been not following these recommendations and using an undersized underwired Ciggy plug and receptacle and has worked 'just fine' for X amount of time and the direct connection is completely unnecessary. Go argue with the Manuals of the manufacturers.

Looking at the specs of this fuse block it says 100 amps total and only 30 amps on any individual circuit.
https://www.bluesea.com/products/5026/ST_Blade_Fuse_Block_-_12_Circuits_with_Negative_Bus_and_Cover

I have a 30 amp circuit breaker on my solar controller to battery on 4awg. It is a POS. I will be eventually upgrading to this for less voltage drop:

https://www.bluesea.com/products/5006100/MAXI_Fuse_Block

 

[Mobilesport]

OK , I revised my drawing

 

[SternWake]

After vewing revised drawing
Move Solar controller (+) to battery (+) using its own fuse/ circuit breaker

Place fuse on other side of solenoid.

Also on the solar controller. From solar panel (-) to solar controller PV- input, this wire cannot be shared with the common ground as you have it drawn with the voltage sense(-). Charge controller will have 2 inputs + and - and 2 outputs + and -. The OUtput (-) can goto the (-) buss bar, or right to Shunt. The INput (-) from solar panel can only goto solar controller (-) input. It will not work properly/at all, as you have drawn it.

 

[Mobilesport]

Final drawing
There's 6 positive wires going to the house batteries positive terminal , what's the 
best way to manage those connections ?
Could someone run one huge thick positive cable to a positive bus bar and then make all the connections at the bus?
Or all 6 wires with ring terminals right on the battery post stacked like in the drawing?

 

[highdesertranger]

this is the type of bus bar I am talking about, https://www.amazon.com/Blue-Sea-Sys...d=1482881996&sr=8-4&keywords=blue+sea+bus+bar . I would run all your Positives to that and run one big fat wire to the battery. highdesertranger

 

[Gary68]

this is the type of bus bar I am talking about,  https://www.amazon.com/Blue-Sea-Sys...d=1482881996&sr=8-4&keywords=blue+sea+bus+bar .  I would run all your Positives to that and run one big fat wire to the battery.  highdesertranger

$62.57 :s i suddenly feel the need to go to the bathroom

 

[Surly Biker]

Wouldn't a 250A bus bar be adequate for this installation? That's 3000W which seems well over the loads the OP is planning. I'm asking because I'm in a similar situation planning a system with1200W (100A) inverter. Im planning a 250A busbar with 2/0 AWG cable to battery. Don't mean to derail the thread, but appreciate your thoughts.

 

[highdesertranger]

sure use whatever you think will work. I just wanted to show a top of the line bus bar. Blue Seas makes higher and lower amp ones. highdesertranger

 

[Surly Biker]

Well, just like the OP, I'm trying to design and build a system that won't start a fire in my van! I agree that Blue Sea components are top of the line, but like all marine gear they are expensive. The OP seems price sensitive so maybe a 150A Blue Sea Dualbus for about $20 would be a good choice.