Can 1981 Univolt system handle AGM or lithium batteries?

[ole81]

I have not had my rig out for several years and am now dusting it off and getting it roadworthy.
When I do an internet search for RV batteries, all I see are AGM and LiFePO4.
Will my old Univolt system handle either one? or do I have to stick with a wet cell?
Yes, I should upgrade the system, but that is not an option right now. I have reservations at a state park on the 26th.
Any advice is appreciated.

[CBWELL]

Stick with your wet cell and get rid of that antique asap! Get a Progressive Dynamics 9300 series converter and then you can use any type of battery you want! Univolts are best used for boat anchors! I have replaced many!

[ole81]

Thanks, CBWELL, Does that unit fit in the same space and what level of expertise is necessary for the swap?

[CBWELL]

The size is less than 1/4 of the Univolt, and it is a very easy instal.l It plugs into the wall 110 volt outlet, same as Univolt,, disconnect the wires going to the battery from the Univolt and connect to the PD unit. If your old converter is under the front couch, or behind the stove, you will spend more time getting to it than putting in the new converter!
If you are at all handy with tools, no big problem.

[PaulBristol]

Originally Posted by ole81

I have not had my rig out for several years and am now dusting it off and getting it roadworthy.
When I do an internet search for RV batteries, all I see are AGM and LiFePO4.
Will my old Univolt system handle either one? or do I have to stick with a wet cell?
Yes, I should upgrade the system, but that is not an option right now. I have reservations at a state park on the 26th.
Any advice is appreciated.

You can buy flooded cell deep draw batteries at most automotive stores, many hardware stores, Tractor Store, Walmart, etc.

[gator.bigfoot]

My second set of Lifeline AGMs are approaching 9 years now. Still going strong. Does what I need it to do. I've never run out of power yet. It lives off the grid with 300 watts of solar when the snow is gone. I did manage to clear the panels a few times this year, but a lot of the winter I spend in Europe. So I just leave it plugged in. One day I will upgrade it, but for now I don't need any more.

[uncle_bob]

Hi

Your Univolt is well past its "use by" date. If it actually is still working properly it's one of the few that are.

What you do next is up to you.

Lithium batteries (at least right now) are way cheaper than AGM's. In terms of usable capacity, they are competitive most of the flooded cells out there. They *should* last a lot longer.

Last can mean different things to different folks. To some "it hasn't exploded yet" means it's still ok. To others "it still holds near the rated capacity" is what they go with. By both definitions, the lithiums should do much better than the lead acid batteries.

Does that mean you *should* upgrade? Nope. It does mean you should give it some thought and work out the plusses and minuses before putting money into this project.

Bob

[sdavis2616]

I second the Progressive Dynamics 9300. I installed it last year in my Excella. It took longer to remove and reinstall the drawer under the couch than it did to install the PD9300.

[Motivation]

Originally Posted by CBWELL

The size is less than 1/4 of the Univolt, and it is a very easy instal.l It plugs into the wall 110 volt outlet, same as Univolt,, disconnect the wires going to the battery from the Univolt and connect to the PD unit. If your old converter is under the front couch, or behind the stove, you will spend more time getting to it than putting in the new converter!
If you are at all handy with tools, no big problem.

Are you saying there’s no need to increase wire size when switching to lithium?

[Wazbro]

Originally Posted by Motivation

Are you saying there’s no need to increase wire size when switching to lithium?

That depends on a few things.
If you go with a converter with the same amp rating and don't increase your power usage you do not need to change wire size.

With an older trailer, like the OPs which likely only had a 30 amp univolt if he went with a 50 amp or more converter, upgrading wires would be needed.

Also anyone who changes to a larger inverter or adds other heavy loads would need heavier wires.

[uncle_bob]

Hi

There are a *lot* of ways to convert to lithium.

Your stock flooded cells likely are labeled as 80AH each. The pair give you 80AH of usable capacity out of that 160AH labeled capacity.

A single 100AH lithium will give you *more* usable capacity than your pair of flooded cells. Lithium lets you use the entire labeled capacity.

Net result: The direct swap is to exchange two flooded cells for one 100AH lithium. In the past, they have gone on sale for just a bit over $100 (delivered price). What will the price be in the future? Who knows ....

Does anybody ever do a lithium swap out that way? So far I have not seen anybody post that they have gone that way.

Yes, the converter / charger does need to be lithium compatible. If you have a 40+ year old Univolt, swapping that out is already part of the plan.

Other than pulling the charge wire that goes to the 7 pin. That's all you would *need* to do for a basic lithium upgrade on an older AS. You have no solar so it's not part of the process.

Pretty much everybody does a bit more ....

Bob