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1L243

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Posted: 10/09/21 06:17pm Link  |  Quote  |  Print  |  Notify Moderator

When I installed my 500 watt panel, 2000 watt inverter, 340ah solar system it was a learning process. I have a 35 foot bumper pull Toy Hauler. My four 12 volt deep cycle batteries are on the trailer A frame which was designed as a generator rack. My inverter, charge controller fuses and switches are installed in the pass through storage just behind the battery bank.

I ran 4.0 wire from the inverter to the the batteries. My plan at initial install was to install positive and negative Buss bars in the battery box. along with the battery monitor shunt. After I installed all the wires reality set in that I did not have room for the buss bars, so I elected not to put them in. This meant that the the main pos/neg battery terminals and load side of the shunt got very crowded.

I used the system this way this season when dry camping for two weeks all worked as it should.

But when I got home I decided to rip all the wiring out of the battery box and rewire with the pos/neg buss bars and shunt moved into the storage area with the inverter and charge controller. It also allowed me to install a breaker protected fuse block for all the peripheral add on I have installed.

Now after a very long update my question.

My 4.0 inverter cable runs from the inverter to the battery through the buss bars BUT my chassis ground which runs from the frame of the trailer to the neg buss bar is only 2AWG. Should the chassis ground be 4.0 wire ?

[image]

* This post was edited 10/09/21 06:28pm by 1L243 *


2017 Coleman 300tq by Dutchman Toy Hauler. 34.5 feet long and under 10k Gross. 500 watt Solar 2000 watt Inverter, 1999 Ford F250 2WD 7.3 4R100 DP Tuner, S&B Cold Air Intake, Gauges, 6.0 Trans Cooler, Air Bags.


RickLight

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Posted: 10/09/21 08:16pm Link  |  Quote  |  Print  |  Notify Moderator

Yes!
A circuit is a circle and the neg is as much a part as the pos. The 2awg may handle the current but it's close to the edge.


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time2roll

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Posted: 10/09/21 08:31pm Link  |  Quote  |  Print  |  Notify Moderator

If the inverter positive and negative connect direct to the battery or bus, the existing ground is fine.
If the inverter negative uses the chassis frame to get power, yes the bus to chassis needs to be 4/0.


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1L243

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Posted: 10/09/21 09:56pm Link  |  Quote  |  Print  |  Notify Moderator

The inverter pos and neg is connected to the batteries via the Buss. The chassis neg is connected to the Buss.

time2roll

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Posted: 10/09/21 10:06pm Link  |  Quote  |  Print  |  Notify Moderator

1L243 wrote:

The inverter pos and neg is connected to the batteries via the Buss. The chassis neg is connected to the Buss.
#2 is fine. Maybe some overkill.

Bobbo

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Posted: 10/10/21 07:41am Link  |  Quote  |  Print  |  Notify Moderator

I agree with RickLight. The circuit is a circle. If ANY part requires 4/0 cable, the battery negative NEEDS to also be 4/0 cable.

If the inverter requires 4/0 cable, then the complete pathway back to the battery terminals need to be 4/0 cable. Either that, or wire the inverter directly to the battery rather than to the buss.

My Airstream got around having to use large cable for the trailer by wiring my inverter directly to the battery. (That meant I had to install a separate disconnect relay just for the inverter.)


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BFL13

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Posted: 10/10/21 07:54am Link  |  Quote  |  Print  |  Notify Moderator

The chassis ground goes to the neg bus and then to the load side of the shunt. #2 is likely plenty for that since the usual RV loads use the frame for part of their neg paths, and the higher amp items you have don't.

You need the fatter wire to go from the shunt to the battery bank since that side of the shunt carries the total of all the amps coming to the load side of the shunt which can be from a number of different size wires.

Also the wire from the neg buss to the load side of the shunt would be fatter since it could also be carrying the total amps. Might still be some loads going to the load side of the shunt but not via the bus, don't know.

The subject of this thread is solar wiring, which was not mentioned.


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RickLight

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Posted: 10/10/21 09:29am Link  |  Quote  |  Print  |  Notify Moderator

I agree that if wires go in parallel (same start and end) then they work together. But this might be a case for drawing it out on paper.

Solar just means there's a charger in there somewhere.

1L243

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Posted: 10/10/21 09:58am Link  |  Quote  |  Print  |  Notify Moderator

the Neg 4.0 wire goes from the Inverter to the Neg Buss then from the Neg Buss to the load side of the shunt. Then it goes from the battery side of the shunt to the Neg number four battery in the battery bank. The entire length is about 5 1/2 feet. The Chassis 2AWG ground goes from the trailer frame to the Neg battery Buss a distance of about four feet.

3 tons

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Posted: 10/10/21 10:47am Link  |  Quote  |  Print  |  Notify Moderator

Congrats for using 0004 to satisfy the inverter… 2 AWG is good for the inverter ground..

3 tons

* This post was last edited 10/10/21 11:16am by 3 tons *   View edit history

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