Dc to dc charging tie into 3500 battery/alternator

[AH64ID]

One more stupid question. If I connect directly to the battery, for the negative would I put my ring terminal on top of the IBS? I don't see any other stud available.

Correct.

No extra ring terminals on the neg because they expect you to ground at the block or one the frame.

 

[niemoy]

Actually need to correct my explanation. According to Victron it's identified as "Smart Alternator" setting where voltage always fluctuates. Not sure if that's the same as the built in IBS System.

Eloctronut, Im about to install the same victron 12 12 30 unit in my 5th wheel and running anderson connectors at the rear of the truck. Was planning on using 6 awg wires and a 40 amp fuse at the positive side of the truck battery and the negative directly to the ibs. Do you have any install tips or advice that will save me from having to learn the hardway? Any pics of your victron settings? Did you leave smart alternator disabled? I wasn't planning on running an aux switch and was just going to use the truck not running autodetect feature.

 

[Electronut]

Eloctronut, Im about to install the same victron 12 12 30 unit in my 5th wheel and running anderson connectors at the rear of the truck. Was planning on using 6 awg wires and a 40 amp fuse at the positive side of the truck battery and the negative directly to the ibs. Do you have any install tips or advice that will save me from having to learn the hardway? Any pics of your victron settings? Did you leave smart alternator disabled? I wasn't planning on running an aux switch and was just going to use the truck not running autodetect feature.

Your on the proper track. Everything you said you are using for hardware is fine. I also used 6awg wire. I did use the fuseless switch style circuit breakers which also work well as shutoffs when necessary. I have one 50amp on the truck side and another on the DC to DC charger side.

T Tocas Hi-AMP T3 Circuit Breaker... https://www.amazon.com/dp/B01F76VJKQ?ref=ppx_pop_mob_ap_share

Set the Victron DC to DC charger in standard alternator mode. Your setting for battery type depends on the batteries your using in your RV. I'm running 500ah of Battleborn Batteries in my setup so I set voltage parameters on the Victron app for lithium accordingly. Battleborn provided me with the settings for input into the app. Pretty straight forward but has to be done correctly so you get the maximum performance out of the batteries. Same also goes with the solar controller.

 

[AH64ID]

Eloctronut, Im about to install the same victron 12 12 30 unit in my 5th wheel and running anderson connectors at the rear of the truck. Was planning on using 6 awg wires and a 40 amp fuse at the positive side of the truck battery and the negative directly to the ibs. Do you have any install tips or advice that will save me from having to learn the hardway? Any pics of your victron settings? Did you leave smart alternator disabled? I wasn't planning on running an aux switch and was just going to use the truck not running autodetect feature.

I would run 60A circuit breakers, that’s what Victron wants for the 30A charger.

The 30A is output, not input. There is some loss when you step the voltage back up to the proper level as well as the lower the input voltage the higher the amp draw for the same load.

 

[niemoy]

I would run 60A circuit breakers, that’s what Victron wants for the 30A charger.

The 30A is output, not input. There is some loss when you step the voltage back up to the proper level as well as the lower the input voltage the higher the amp draw for the same load.

I was going to run a 40amp fuse on the truck battery side and then a 60amp breaker between the charger and lithium battery bank on rv

 

[niemoy]

Your on the proper track. Everything you said you are using for hardware is fine. I also used 6awg wire. I did use the fuseless switch style circuit breakers which also work well as shutoffs when necessary. I have one 50amp on the truck side and another on the DC to DC charger side.

T Tocas Hi-AMP T3 Circuit Breaker... https://www.amazon.com/dp/B01F76VJKQ?ref=ppx_pop_mob_ap_share

Set the Victron DC to DC charger in standard alternator mode. Your setting for battery type depends on the batteries your using in your RV. I'm running 500ah of Battleborn Batteries in my setup so I set voltage parameters on the Victron app for lithium accordingly. Battleborn provided me with the settings for input into the app. Pretty straight forward but has to be done correctly so you get the maximum performance out of the batteries. Same also goes with the solar controller.

Thanks for the info! Yes I plan on monitoring the charging profile from my victron 100/50 mppt but I was more curious about the settings you used for the truck battery. Voltage to start charging and voltage to stop charging etc. Dis you wire a remote switch or just enable the feature that sense the truck running or not? Thanks !

 

[AH64ID]

I was going to run a 40amp fuse on the truck battery side and then a 60amp breaker between the charger and lithium battery bank on rv

Both sides should be fused the same.

 

[niemoy]

Both sides should be fused the same.

I was wrong in my previous statement. I had bought both 2 40-amp fuses and 2 50-amp circuit breakers. Going to use the circuit breakers and return the 40 amp fuses

 

[AH64ID]

I was wrong in my previous statement. I had bought both 2 40-amp fuses and 2 50-amp circuit breakers. Going to use the circuit breakers and return the 40 amp fuses

Victron does recommend 60A, the specs are 10V min at 360W with 87% efficiency. That’s a max draw of 41.4A, and applying the standard 70% rule for fusing that Ram recommends thats 59.1A. So you may not blow a 50A fuse with 6ga, but you can see where the 60A recommendation comes from.

With a 50A fuse and the 70% rule from Ram you should be fine as long as your input voltage remains above 11.8V at max charger output.

 

[downsc123]

Just read entire this tread - lots of great info - for those that are removing the 12V aux charging from the 7 way connector, are you just removing fuse F30? I have Lithium batteries in my RV with enough solar onboard so I don't need any help from the truck and just want to get rid of the connection to ensure no harm to the truck's electrical system. Thanks,

 

[Jeffmc306]

Just read entire this tread - lots of great info - for those that are removing the 12V aux charging from the 7 way connector, are you just removing fuse F30? I have Lithium batteries in my RV with enough solar onboard so I don't need any help from the truck and just want to get rid of the connection to ensure no harm to the truck's electrical system. Thanks,

Yep! You’ve got the right one. F30 is the 7 pin charging fuse.

 

[jsalbre]

Just read entire this tread - lots of great info - for those that are removing the 12V aux charging from the 7 way connector, are you just removing fuse F30? I have Lithium batteries in my RV with enough solar onboard so I don't need any help from the truck and just want to get rid of the connection to ensure no harm to the truck's electrical system. Thanks,

I'd actually suggest making the disconnect on the trailer side. The trailer is what you've modified the power system on.

 

[AH64ID]

I'd actually suggest making the disconnect on the trailer side. The trailer is what you've modified the power system on.

Agree, while removing F30 will work, it’s better to modify the trailer and allow any other trailer to be towed with the proper 12V connection.

 

[Jeffmc306]

The reason I pulled the fuse vs. disconnecting the trailer’s power so I can use it to power the trailer’s running lights at night when at a rally.

All you do is insert a blade fuse between the 12V positive and the running lights terminal on the trailer’s 7 pin plug.

I taped the fuse to the inside of the cover in case I ever need it.

Photo from last year’s Airstream International Rally in Rock Springs, WY (not my photo). 2500 Airstreams showed up.

 

[downsc123]

I'd actually suggest making the disconnect on the trailer side. The trailer is what you've modified the power system on.

That was my first thought but it could not find a wiring diagram from the trailer (2023 Grand Design Reflection 324MBS) - anyone know how to disable on the trailer end short of pulling out the pin on the 7 way connector?

 

[AH64ID]

That was my first thought but it could not find a wiring diagram from the trailer (2023 Grand Design Reflection 324MBS) - anyone know how to disable on the trailer end short of pulling out the pin on the 7 way connector?

The 12V + lead should be pretty obvious where is comes into the 12V distribution panel, just make sure the emergency brakes aren’t back fed on that same wire.