An electrical Question

[Mderou]

Hi All,

I purchased an Attwood Female receptacle for the truck and notice it has 10 Gauge wire affixed to it. I was planning on running 8 gauge wire to the truck battery, but would that be nullified by the 10 gauge wire? In other words should I just run 10 Gauge to the battery?

Also I've read about Automatic Charging Relays and Thermal Breakers. Does anyone have any links or info of which to get for these? I have been prepping this FWC all summer long and this is the last thing I need to address before loading the camper. A lot of work, but most of it enjoyable. Electrical stuff is my weak point so if you want to explain it to me like I'm 5, that would be cool .

 

[BFH4N]

A little 10-ga won't negate the lower resistance of the 8-ga. Just make the 10-ga part as short as possible. It's the total resistance that matters.

The more important question is how you will make the splices. Poorly-done splices could add a lot of resistance and cancel out the benefit of large wire. It's a question for another thread!

 

[Mderou]

A little 10-ga won't negate the lower resistance of the 8-ga. Just make the 10-ga part as short as possible. It's the total resistance that matters.

The more important question is how you will make the splices. Poorly-done splices could add a lot of resistance and cancel out the benefit of large wire. It's a question for another thread!

So perhaps I should get 8 Gauge. I planned on soldering at the receptacle and then butt connectors elsewhere

 

[Vic Harder]

I got a lot of my electrical gear from PKYS.com - Marine gear is a whole lot better than RV gear.

The Blue sea ML series of ACR’s are great, and their surface mount circuit breakers are good too, and double as switches so you can isolate circuits during maintenance.

 

[Mderou]

I got a lot of my electrical gear from PKYS.com - Marine gear is a whole lot better than RV gear.

The Blue sea ML series of ACR’s are great, and their surface mount circuit breakers are good too, and double as switches so you can isolate circuits during maintenance.

Curious Do you know if the ACR is compatible with AGM batteries? I have 2 Optima Yellow Top and I've read it's not a good mix? I searched ACR for AGMs with nothing.

 

[craig333]

I can't see why an ACR would care what kind of batteries you have.

 

[PaulT]

As an inanimate object, the ACR doesn't "care" about anything.

I have had a Blue Sea ACR on my boat with AGM starting battery and AGM house battery since 2008. My first AGM batteries lasted for 7+ years and the second set of AGM batteries have lasted since mid 2015 without issues.

Paul

 

[Mderou]

Okay thank you, I read something here about AGM's and ACR's I must have misunderstood it.

So, Blue Seas 7611 with (1) 30AMP Thermal Breaker supplied usng 8 Gauge CCA wire to Female Receptacle, tied into AUX batteries. Am I missing anything?

 

[bajaphile]

My only comment would be to ensure there is a similar breaker (I just use regular reset-able circuit breakers) at the Aux battery side if there isn't one already. You want the breaker as close to the battery as possible on both the truck battery and camper battery.

 

[K7MDL]

The 7611 ACR will work fine. It will sense either side so it will close when either side voltage rises above the setpoint. If you have solar this will keep your stating battery topped off. My truck battery is drained after 2 weeks so now it is topped off daily while it is parked outside.

In my case I had the 7611 installed under my truck bed before my camper to isolate and charge my ham radio gear and aux battery. In the past I have bypassed the camper's stock relay in favor of my dual sensing ACRs but with my new Hawk with solar, the internal camper relay is always on when needed so I left them in series, been working fine.

The ACR when located near the truck bed power connection Attwood connector) can act as a terminal strip making for easy transition between 6GA wire for the truck battery/breaker and the 10GA wire on the Attwood connector. The short bit of 10GA won't affect much.

Mike
K7MDL

 

[Mderou]

My only comment would be to ensure there is a similar breaker (I just use regular reset-able circuit breakers) at the Aux battery side if there isn't one already. You want the breaker as close to the battery as possible on both the truck battery and camper battery.

Would a 30 amp inline fuse suffice? I have half a dozen of those laying around.

 

[Mderou]

The 7611 ACR will work fine. It will sense either side so it will close when either side voltage rises above the setpoint. If you have solar this will keep your stating battery topped off. My truck battery is drained after 2 weeks so now it is topped off daily while it is parked outside.

In my case I had the 7611 installed under my truck bed before my camper to isolate and charge my ham radio gear and aux battery. In the past I have bypassed the camper's stock relay in favor of my dual sensing ACRs but with my new Hawk with solar, the internal camper relay is always on when needed so I left them in series, been working fine.

The ACR when located near the truck bed power connection Attwood connector) can act as a terminal strip making for easy transition between 6GA wire for the truck battery/breaker and the 10GA wire on the Attwood connector. The short bit of 10GA won't affect much.

Mike
K7MDL

Thank you for the input. I don't have solar yet unfortunately, that is next summers plan. I planned to solder that joint at the attwood connector with the 8Gauge-to-10G.

 

[Mderou]

I don't have Clearance/Marker lights in my Grandby, as such the third prong of the attwood plug can remain dead. Should I run a hot wire there anyway just in case I may need to use it in the future for other things? I read somewhere about someone using that power source for their dc-to-dc charger. Sorry for the obscure conceptualizing, but electric stuff always serves challenging.

 

[K7MDL]

I don't have Clearance/Marker lights in my Grandby, as such the third prong of the attwood plug can remain dead. Should I run a hot wire there anyway just in case I may need to use it in the future for other things? I read somewhere about someone using that power source for their dc-to-dc charger. Sorry for the obscure conceptualizing, but electric stuff always serves challenging.

I would not run any wire until you know the final usage. There is a good chance the wire size needed then is not what you might run now causing rework. You could run a new signal wire into the camper through that connection for turning on stuff like rear flood lights from the cab.

 

[Mderou]

I would not run any wire until you know the final usage. There is a good chance the wire size needed then is not what you might run now causing rework. You could run a new signal wire into the camper through that connection for turning on stuff like rear flood lights from the cab.

Good point, Floods are on my to-do list. Would 12 Gauge suffice here? I bought a spool recently. Perhaps I'll finally use an upfitter switch for that.

 

[K7MDL]

For LED floods 12GA would more than enough though its large size diameter may make routing through your camper and walls difficult. I would imagine you would run the floods off your camper battery via the 12GA wire, a fuse, and a relay in parallel with a switch, both in the camper. Then can run a small 16GA wire between the cab and camper to the relay.

For determining wire size you can use an internet calculator that considers wire length, load current and allowable/tolerable voltage drop. Go one size up if in doubt. A relay is very low current to the voltage drop is minimal. Lights can be 10%. Bigger wire is less voltage drop. Lots of online calculator and charts but this link is a good start. Select your desired lights, look up their max current draw. Figure your wire length between the battery source and the lights.

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

 

[Mderou]

For LED floods 12GA would more than enough though its large size diameter may make routing through your camper and walls difficult. I would imagine you would run the floods off your camper battery via the 12GA wire, a fuse, and a relay in parallel with a switch, both in the camper. Then can run a small 16GA wire between the cab and camper to the relay.

For determining wire size you can use an internet calculator that considers wire length, load current and allowable/tolerable voltage drop. Go one size up if in doubt. A relay is very low current to the voltage drop is minimal. Lights can be 10%. Bigger wire is less voltage drop. Lots of online calculator and charts but this link is a good start. Select your desired lights, look up their max current draw. Figure your wire length between the battery source and the lights.

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Thanks for the great information and link.

 

[mobilelists]

I am in the process of changing some of the wiring in my camper. Does anyone know if it matters if the Blue Sea 285-Series Circuit Breaker - Surface Mount is mounted sideways? It would make it easier to route some wires if I can mount the breaker sideways instead up up/down.

Stay healthy,
Pat

 

[craig333]

I've never seen a breaker that matters how its oriented. Might be confusing to someone else down the road but I think you'd be okay.

 

[mobilelists]

I can see a potential issue if a standard breaker was upside down. In that case...off would be up.