Lithium Battery ?

I am replacing the AGM batteries in my R pod camping trailer with lithium LifePO4 and am wondering if I need the remove the power wire in the 7 pin to not hurt the lithium batteries or my alternator? Is this something you guys have done or am I over thinking it? The R pod will charge the lithium to 80% and my solar should bring it up to 100%.

 

You’ll be fine charging off the 7 pin connection. Check what converter you have installed to see if it is lithium compatible. If not it’s a relatively cheap and extremely easy replacement.

 

With LiFePo you will want a DC-DC in the trailer. The fuse on the wire will pop before you damage the alternator but most LiFePo batteries will try to draw too much and do exactly that if not regulated.

 

The battery isn’t drawing anything, it’s accepting what is input. I have had zero problems charging lithium batteries off the trailer connection over two years, tens of thousands of miles and four different trucks.

 

There's a difference between older lithium and LiFePo batteries. The BMS on LiFePo will typically try to charge at whatever it is rated for and because there's no meaningful voltage drop for most of the battery's depletion, charging methods that rely on voltage thresholds don't work correctly.

You can't level between AGM or lead acid and LiFePo because they run a lower nominal voltage. You need an intermediary.

 

I don’t buy it based on my actual experience. My batteries are modern Renogy LiFePo batteries. They accept the charge given to them, they don’t draw a charge into themselves. They typically charge at about 8-10 amps from the trailer connection, 25+ amps from solar on good days and 35+ from the converter when plugged into 120v power.

 

Don't buy it if you don't want to makes no difference to me, but the correct way to mix conventional and LiFePo is with a DC-DC.

 

Better? Yes, it’s a more efficient charge but at the cost of money spent on parts and rewiring the connection. Using the stock trailer 7 pin connection as is has no downside other than a slower/less efficient charge. It won’t damage anything while providing a nominal level of charge to the trailer batteries while under tow.

 

Your Renogy (mine too) has a max charge spec of 14.4v and charging above that will damage your battery. Conventional batteries will charge as high as 14.7-14.8v and that will reduce the life of a LiFePo battery. The smart alternator is somewhat of a savior here and probably why your setup works but it's not a substitution for the correct way to do things.

I've said what needs to be said to answer OP. In the end it's your truck and trailer so I cannot possibly care less what you do.

 

Someone’s grumpy.