changing rv battery to lithium..alternator question and dc to dc charger

Jerry Davis

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I have a new 2024 Silverado HD 2500 diesel crew cab and when the battery goes in the GD 303 wanting to go to 100amp lithium battery. The Rv has a 360 w solar panel and I do not plan on any boon docking.

I have read diffrent veiw points on the truck alternator being damaged when towing Rv and it is charging the Rv lithium battery. People say you need to install a dc to dc charger.

Has anyone made the change to a lithium battery and did you install a dc to dc charger. Is it necessary to make the change or just leave it along?

Thanks for inputs
 
I have a new 2024 Silverado HD 2500 diesel crew cab and when the battery goes in the GD 303 wanting to go to 100amp lithium battery. The Rv has a 360 w solar panel and I do not plan on any boon docking.

I have read diffrent veiw points on the truck alternator being damaged when towing Rv and it is charging the Rv lithium battery. People say you need to install a dc to dc charger.

Has anyone made the change to a lithium battery and did you install a dc to dc charger. Is it necessary to make the change or just leave it along?

Thanks for inputs

If you are just using the 7 pin you will NOT damage the truck alternator. If you want to use the truck as a real charging source then you will need a DC/DC charger. ( More than the 7 to 10 amps +/- an hour the stock truck system gives you)
 
If you are just using the 7 pin you will NOT damage the truck alternator. If you want to use the truck as a real charging source then you will need a DC/DC charger. ( More than the 7 to 10 amps +/- an hour the stock truck system gives you)

Thanks ...that was my thought, using the 7 pin connector. The wire size would not let the alternator draw too much
 
Thanks ...that was my thought, using the 7 pin connector. The wire size would not let the alternator draw too much

So much mis information out there in regards to lithium. It makes it way more complicated than it needs to be.
 
I did a series of videos on the electrical upgrades I did to my Reflection 303RLS. Below is a link to the DC-DC charger install video.

While I did disconnect the 12v charging source on my seven way connector, it is not necessary. Some will say that the LiFePo4 will pull too much from your alternator but that is simply not correct. Your solar charge controller will ultimately do more to keep your coach battery charged than your alternator ever will.

I installed the DC-DC charger so that I can get a relatively quick charge while traveling if/when we use Harvest Host sites. Since I have a 460ah battery bank, the alternator alone on my truck (through the seven way connector) would make very little difference on a typical travel day. I also have dual high output alternators that are more than capable of running the 60 amp charger.


https://youtu.be/ThQP5A9a6y0?si=60Ymu-WK1E8QeKzo
 
I have a new 2024 Silverado HD 2500 diesel crew cab and when the battery goes in the GD 303 wanting to go to 100amp lithium battery. The Rv has a 360 w solar panel and I do not plan on any boon docking.

I have read diffrent veiw points on the truck alternator being damaged when towing Rv and it is charging the Rv lithium battery. People say you need to install a dc to dc charger.

Has anyone made the change to a lithium battery and did you install a dc to dc charger. Is it necessary to make the change or just leave it along?

Thanks for inputs

If you are just using the 7 pin you will NOT damage the truck alternator. If you want to use the truck as a real charging source then you will need a DC/DC charger. ( More than the 7 to 10 amps +/- an hour the stock truck system gives you)

I'd agree 100% with JKellerJr. One can just use what is available from the truck to charge batteries.

I do tend to go in the opposite direction of most tho when it comes to whether a DC-DC charger is needed. I have one; complete with heavy gauge wire, Anderson connectors, controlled via up fitter switches, circuit breaker, etc. But - I almost never use it. Since we almost always camp with an electric hook up, and since we almost never travel more than 6 hours at a time, I let my battery do what it is suppose to do - provide electricity to the rig when not on shore power.

We don't have solar (so a lot less confusion in our 23v system); we have a residential refrigerator; we have a 200ah Li battery; after a 4 or 5 hour drive it's SOC is in the mid 70%s.

Best reason for DC-DC --> correct and constant voltage (and current?) provided to the Li battery(s) when using it.

Only reason to go Li - weight, ability to use more of the charge.
 
I did a series of videos on the electrical upgrades I did to my Reflection 303RLS. Below is a link to the DC-DC charger install video.

While I did disconnect the 12v charging source on my seven way connector, it is not necessary. Some will say that the LiFePo4 will pull too much from your alternator but that is simply not correct. Your solar charge controller will ultimately do more to keep your coach battery charged than your alternator ever will.

I installed the DC-DC charger so that I can get a relatively quick charge while traveling if/when we use Harvest Host sites. Since I have a 460ah battery bank, the alternator alone on my truck (through the seven way connector) would make very little difference on a typical travel day. I also have dual high output alternators that are more than capable of running the 60 amp charger.


https://youtu.be/ThQP5A9a6y0?si=60Ymu-WK1E8QeKzo

This is a perfect example of when a DC to DC charger is a good idea. Its just not a requirement on a basic system

I'd agree 100% with JKellerJr. One can just use what is available from the truck to charge batteries.

I do tend to go in the opposite direction of most tho when it comes to whether a DC-DC charger is needed. I have one; complete with heavy gauge wire, Anderson connectors, controlled via up fitter switches, circuit breaker, etc. But - I almost never use it. Since we almost always camp with an electric hook up, and since we almost never travel more than 6 hours at a time, I let my battery do what it is suppose to do - provide electricity to the rig when not on shore power.

We don't have solar (so a lot less confusion in our 23v system); we have a residential refrigerator; we have a 200ah Li battery; after a 4 or 5 hour drive it's SOC is in the mid 70%s.

I had 200 in our old unit and 400 in our current one. Our previous truck would put out about 7 amps trough the 7 pin, I would lose about 3 to 4 amps per hour. We also have a residential fridge. The new truck seems to put out about 10 amps. It pretty much keeps up with the loss. Though I think I have a slight discrepancy with the monitor and in and out power so I need to figure that out to be sure.

If I do end up leaving somewhere with a depleted battery (which is rare) I just fire the generator for a couple of hours (love the onboard geney). Our Multiplus inverter/charger charges at 95 to 100 amps per hour. It doesn't take long to bring it back to 100%

Only reason to go Li - weight, ability to use more of the charge.

And recharging speed!
 
So much mis information out there in regards to lithium. It makes it way more complicated than it needs to be.

Totally agree. We dont have a DC-DC charger and still dont see the need with solar panels. No harm to the last two trucks including the current 2022 GMC. Last trip we left our campsite with the batteries at 75% SoC and by the time we finished our 90 min trip home.....solar had them to 100% SoC.
 
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