Truck Bed Battery Box Brain Storming

[JimmyD714]

I’ve disagreed with 2/3 of what I’ve read in this thread if that tells you anything.

I know you're the forum auto expert so you should probably be the one advising how to handle this.

My chiming in was mainly to make sure proper fusing is used. I've seen this done wrong so many times in auto applications where people just add wires without fusing or tap into an existing circuit downstream of a fuse with wire way too small to handle the current rating of the upstream fuse.

[KRT]

I know you're the forum auto expert so you should probably be the one advising how to handle this.

My chiming in was mainly to make sure proper fusing is used. I've seen this done wrong so many times in auto applications where people just add wires without fusing or tap into an existing circuit downstream of a fuse with wire way too small to handle the current rating of the upstream fuse.

I’m no expert. I’d have a different way of doing some of it is all.

[Rubberhead*]

I am not recommending this but if it were me, I would test the following system before installing anything using the exact battery, relay and cable lengths below and measure both the voltage drops and current to make sure all the assumptions were correct and adjust as necessary.

The M-ACR relay I suggested would not let the rear battery get charged if it is drained below 9.5V. With an internal impedance of the rear battery of 0.1 ohms and a 18 foot run of 6 gauge wire, there'd be a maximum current draw of 39.3 amps. Suffice to say, your bed battery would have to be very, very sick and/or discharged to get below 9.5V. A more normal situation would be your house battery would be at 12.0V meaning your current draw would be around 17.5A.

The big variable (unknown) is the internal impedance of the extra battery. I could not find any good data on the internet.

[ADP]

Easiest solution yet... Just buy a Chevrolet or GMC as they come from the factory with a outlet already installed.

[FEETDOWN]

Easiest solution yet... Just buy a Chevrolet or GMC as they come from the factory with a outlet already installed.

You never met BB huh?

[Tater]

Easiest solution yet... Just buy a Chevrolet or GMC as they come from the factory with a outlet already installed.

He drives a Tundra. Hell, my 2013 Tacoma has a factory outlet in the bed.

[Rubberhead*]

Easiest solution yet... Just buy a Chevrolet or GMC as they come from the factory with a outlet already installed.

That's not what he's looking for but you did make me remember that there might be a battery charging circuit on a 7-pin trailer connector...have you thought of that BB?

[ADP]

You never met BB huh?

He drives a Tundra. Hell, my 2013 Tacoma has a factory outlet in the bed.

I'm sensing a common denominator in this thread... BB

Carry on..

[KRT]

I am not recommending this but if it were me, I would test the following system before installing anything using the exact battery, relay and cable lengths below and measure both the voltage drops and current to make sure all the assumptions were correct and adjust as necessary.

The M-ACR relay I suggested would not let the rear battery get charged if it is drained below 9.5V. With an internal impedance of the rear battery of 0.1 ohms and a 18 foot run of 6 gauge wire, there'd be a maximum current draw of 39.3 amps. Suffice to say, your bed battery would have to be very, very sick and/or discharged to get below 9.5V. A more normal situation would be your house battery would be at 12.0V meaning your current draw would be around 17.5A.

The big variable (unknown) is the internal impedance of the extra battery. I could not find any good data on the internet.

Did you copy and paste this bullshit off Google? Vehicles have ran dual batteries for years. It’s callled parallel. It’s no golf cart wired in series to up voltage. It’s done to in parallel for amperage.

Run it in parallel and tap into the back battery for 12 volt DC.

No different than the winch tied into my single battery.

Ho lee fuck the nonsense in this thread.

[KRT]

Reminds me of BMW overthinking electrical and running fiber optic.

[Tater]

Someone got a case of the sassy today….lol

[Rubberhead*]

Did you copy and paste this bullshit off Google? Vehicles have ran dual batteries for years. It’s callled parallel. It’s no golf cart wired in series to up voltage. It’s done to in parallel for amperage.

Run it in parallel and tap into the back battery for 12 volt DC.

No different than the winch tied into my single battery.

Ho lee fuck the nonsense in this thread.

Bless your heart.

[KRT]

Bless your heart.

The first response about a relay about did it, then the last one I couldn’t stand it.

Wiring a relay in line before another battery. You can’t make this shit up.

[mello_collins]

That's not what he's looking for but you did make me remember that there might be a battery charging circuit on a 7-pin trailer connector...have you thought of that BB?

Power to most 7pin connections is a 30 amp fused circuit.

[KRT]

I disagree with 2/3 of this thread like stated before. I was actually impressed with some knowledge of it was on the controls side.

Yes the 7 pin is fused… after the main battery.

Yes you want a relay for anything that is hot to the switch then switched to ground to power up a component (light bar) Again this is an accessory “after the battery”.

Just to put a battery in the back and charge it… no you don’t put in a fuse or a relay. You fuse or relay the control side of the component after the battery

DC (direct current is not rocket science.

Run 4 awg wire in parallel to the rear battery. Come off the rear battery with fuses and relays for whatever you plan on doing back there.

[Tha Dick]

LOL, I thought the same thing KRT.

I'm just too lazy to type a response to all the nonsense...

Like texting. You get 1-2 texts Maybe 3 if I'm not busy, after that pick up the dang phone and call!!

[Rubberhead*]

I disagree with 2/3 of this thread like stated before. I was actually impressed with some knowledge of it was on the controls side.

Yes the 7 pin is fused… after the main battery.

Yes you want a relay for anything that is hot to the switch then switched to ground to power up a component (light bar) Again this is an accessory “after the battery”.

Just to put a battery in the back and charge it… no you don’t put in a fuse or a relay. You fuse or relay the control side of the component after the battery

DC (direct current is not rocket science.

Run 4 awg wire in parallel to the rear battery. Come off the rear battery with fuses and relays for whatever you plan on doing back there.

I would bother to try to explain to you why everything you suggested is wrong. But, at this point, I know 100% that you would not understand it.

Big Brother,
Do not do what is recommended in the quote above. Your hand tools will run less than twice as long and then your truck won't start. Give me a shout if you want more information. I'll have to be done with this tread now because, for some reason, it triggers KRT.

[KRT]

Ignorance is a lack of knowledge. No trigger here. I tried so hard to not say anything. Stick to taking pictures of hummingbirds.

[KRT]

LOL, I thought the same thing KRT.

I'm just too lazy to type a response to all the nonsense...

Like texting. You get 1-2 texts Maybe 3 if I'm not busy, after that pick up the dang phone and call!!

The shit in this tread will be used as a learning class in my next shop meeting. It’s all going to be printed minus my response. My techs will then explain to me how to do this.

[Tater]

I repeat. Battery. Solar panel. Chill.