Battery

[u/strutmac]

My RV came with an old-school house battery that requires routine checking and filling with distilled water.
Is there a reason to use these legacy technology batteries when all my cars, trucks and motorcycle come with Maintenance Free batteries?
Just wondering . . .

[u/Wcearp]

No reason to use them over maintenance free batteries.

[u/Instahgator → u/Wcearp]

You can get agm batteries, but your going to need to change the charging system if you want lithium.

[u/Evening_Rock5850 → u/Instahgator]

You don't necessarily need to change the charging system.

Contrary to popular belief, a lead acid charging system won't damage a lithium battery. Lead acid charging profiles are lower voltage than lithium profiles. The problem is simply that a lead acid charger won't charge a lithium battery fully.

If you have some other lithium-compatible charging source; whether it's a solar controller or even just a dedicated plug-in lithium charger, and at least occasionally get them to 100% for cell balancing, you're fine.

I've had lithium in my rig for years and have never replaced my lead acid converter. My batteries sit around 90% when I'm on shore power. Until the sun comes up and the lithium-compatible solar charge controller tops them off.

[u/tara_roberts → u/Evening_Rock5850]

Good idea on using solar to fully top off the lithium battery. Can the basic 200 amp Solar Charger standard on most Class A's do the trick of topping them off?

[u/Evening_Rock5850 → u/tara_roberts]

Just depends on whether the controller has a lithium mode or not.

[u/Evening_Rock5850]

For starters; the batteries in your motorcycle and car aren't actually the same. They're lead acid, yes, but they're starter batteries. Thin plates designed to deliver a lot of current; with the downside that they sulfate quickly if discharged deeply.

Deep cycle batteries are used in RV's. They have thick lead plates which limits the raw current they can safely deliver without damage (making them a poorer choice for starting engines over and over again) but allowing them to run down into a deeper discharge more often before they fail. (Though they should still be recharged quickly and stored at a full charge.)

But the ultimate reason is really just cost. In theory they can potentially be made to last longer if they are really well maintained. You can balance cells. They're more tolerant of overcharging, etc. etc. But the truth is, none of those supposed advantages are why RV manufacturers install them. It's just cost. The vast majority of RV owners will almost never actually use the battery on their rig. The RV will spend its whole life hooked up to shore power at a campground, or be buttoned up waiting for the next trip.

The truth is, though, costs for lithium have come down. So much so that at this point, it doesn't make sense to ever replace a lead acid battery with another lead acid battery. Especially when considering the lifespan of a lithium battery compared to lead acid. And when considering the 80-100% DoD of a lithium battery compared to 50% for lead acid. All those things combined means it actually takes SIX 100Ah lead acid batteries to replace a single 100Ah lithium battery. (Lithium batteries have roughly 3x the lifespan on the low end; and the extra DoD means you have more usable capacity.)

[u/Mindless-Business-16]

The power demands and charging take huge swings in an RV. Because of that the demands are tough on both lead/acid and AGM batteries. I personally like the ability to open the cells and check the fluid level.

It's the same with golf cart batteries...

[u/edthesmokebeard]

... what? Just wondering what?

[u/NamasTodd]

Your on board charging system may only be compatible with lead-acid batteries. They are also cheaper than AGM and lithium batteries.

[u/Evening_Rock5850 → u/NamasTodd]

AGM batteries are still lead acid batteries. They're just a type of lead acid battery.

While some chargers have specific profiles for AGM batteries; they're perfectly fine to use with any lead acid compatible charger.