Eliminating 7 pin charge voltage

**powerscol** · 03-02-2024, 12:01 AM

Originally Posted by IBEW Sparky

@powerscol

"The other issue is if you do disconnect the 12V charge line (black wire in 7 pin cable) you may inadvertently disconnect your emergency break away switch. In my king pin junction box the charge line is tied to the 12v feed line to the power buss bar and also to the break away switch wire."

Simple enough to only disconnect the wire in the kingpin junction box coming from the 7 pin plug and safe it off. Leaving everything else connected and he'll be fine.... and save the $25 on the diode

Sparky you are correct, but the bottom line is he does not even need to touch it. Install the DC-DC and go on with camping. Leave everything else as is. it wont draw power from the tow vesicle or even reverse. It's just not an issue.

Safe travels

**BeerBrewer** · 03-03-2024, 11:17 AM

Originally Posted by powerscol

Sparky you are correct, but the bottom line is he does not even need to touch it. Install the DC-DC and go on with camping. Leave everything else as is. it wont draw power from the tow vesicle or even reverse. It's just not an issue.

Safe travels

I've been following this thread for a while and I'm still a bit confused, maybe even a lot confused.

I too am the process of upgrading to lithium batteries and I was not overly concerned about small voltage mismatch between the lithium batteries in my trailer and that of my Ram truck. So I wasn't planning upon doing anything with the charge wire inside the 7 pin nor was I planning upon installing a dc-dc to charger. I know that the truck puts a small charge (aprox 10 amps) into the battery as we travel but it was basically all absorbed by the Furrion DC frig, so the battery didn't get anymore than the 165W solar panel could give it.

Is this voltage mismatch something that I now need to worry about?

**powerscol** · 03-03-2024, 11:49 AM

Originally Posted by BeerBrewer

I've been following this thread for a while and I'm still a bit confused, maybe even a lot confused.

I too am the process of upgrading to lithium batteries and I was not overly concerned about small voltage mismatch between the lithium batteries in my trailer and that of my Ram truck. So I wasn't planning upon doing anything with the charge wire inside the 7 pin nor was I planning upon installing a dc-dc to charger. I know that the truck puts a small charge (aprox 10 amps) into the battery as we travel but it was basically all absorbed by the Furrion DC frig, so the battery didn't get anymore than the 165W solar panel could give it.

Is this voltage mismatch something that I now need to worry about?

To put it simply NO. Most automotive charging systems are capable of 14.4 volts or higher and are protected against back flow or excessive voltage and amperage output. However it will not fully charge a lithium battery. For that you need solar and a good MPPT controller that is lithium compatible, a Converter when on shore power that is lithium compatible or a DC-DC charger. There are lots of folks that just changed out the battery and run everything else stock. You should be able to reach 80% charge that way.

**BeerBrewer** · 03-03-2024, 01:23 PM

Originally Posted by powerscol

To put it simply NO. Most automotive charging systems are capable of 14.4 volts or higher and are protected against back flow or excessive voltage and amperage output. However it will not fully charge a lithium battery. For that you need solar and a good MPPT controller that is lithium compatible, a Converter when on shore power that is lithium compatible or a DC-DC charger. There are lots of folks that just changed out the battery and run everything else stock. You should be able to reach 80% charge that way.

That is exactly what I thought...phew!

We have a 25 amp solar controller (lithium capable) and 165W solar panel (I'm planning upon replacing it with 2 150W solar panels) and I also had our WFCO 9855 AD converter upgraded with the latest software so it "should be" lithium battery capable. I also own a separate 10A lithium charger that I can also use in a pinch and I'll soon own a generator. So I should be able to get the lithium batteries charged to 100%.

Thanks-you so much for the quick answer!

**powerscol** · 03-03-2024, 01:53 PM

Originally Posted by BeerBrewer

That is exactly what I thought...phew!

We have a 25 amp solar controller (lithium capable) and 165W solar panel (I'm planning upon replacing it with 2 150W solar panels) and I also had our WFCO 9855 AD converter upgraded with the latest software so it "should be" lithium battery capable. I also own a separate 10A lithium charger that I can also use in a pinch and I'll soon own a generator. So I should be able to get the lithium batteries charged to 100%.

Thanks-you so much for the quick answer!

Just a suggestion. Leave you 165 watt as is and add two new panels (as big as will fit like 200w each) and a new solar controller. I like Victron equipment - you can check status on your phone.

As for batterys check out LI Time https://www.litime.com/?gad_source=1 They have deep sales, especially Black Friday. Will Prose likes them https://www.youtube.com/@WillProwse

I used to like SOK but they have been having BMS issues.