Question House batteries

[lostinfla]

Currently have the 8 flooded batteries and was wondering, when it's time to replace, if I should go with lithium or just agm batteries. (No solar) We seldom boondock, but were stuck without power for a few days from the hurricane in SC, so I'm starting to think ahead. I have the magnum panel with SOC display but not sure it's compatible with lithium. Also, with lithium, I assume they are all 12v?

 

[AbdRahim]

Depends on how much power you want and how much you want to spend. I had 6 six volt agms. One bad one pulled down the rest. Coulld barely get through the night with nothing on. I went with 3 Li 330AH batteries. I now lose about 1/2 % per hour under the same conditions. That is about 4 days to reach 50%. Hopefully, next year I can get the bigger inverter and be able to run the A/C on batteries. Wish I had room for one more. It should survive the paint shoo without going dead.

If you get agms, I would load test each battery before you drive off. All mine looked good on the volt meter, but, when I finally bought a load tester, found one battery’s voltage went to dead zero under load.

 

[lostinfla]

What brand lithium did you end up with?

 

[Neal]

That is about 4 days to reach 50%

Keep in mind with LiFePO4 batteries the "50%" rule does not apply. You can take the batteries down closer to 10%, which is your bottom limit. Per SES you should cycle them monthly, I run mine down to about 20% the beginning of each month.

I am all in on Lithium (LiFePO4) both in RV and plane. Can't think of using anything else this day and beyond. Great batteries and prices have really come down. If you don't want to do the job yourself I highly recommend Solar Energy Systems in Nappanee. I'm not affiliated! Not only great work but great support as you learn the new system. It can be as simple as just batteries or you can get a more complete upgrade with components that work better with LiFePO4 batteries.

I'm a big fan of Victron but if doing it myself I'd consider the SOK brand. You have things to consider such as internal BMS vs. external, i.e. what is controlling the batteries for voltage and temp protections.

With your conversion @lostinfla from FLA you'll probably want to cleanup the mess those make but you'll also need (want) to seal up that compartment for Lithium's so there is more involved to consider.

 

[Neal]

One item to add for consideration. LiFePO4 batteries cost more but they last 2X as long if not more than lead batteries (FLA and/or AGM). You'll find warranties on batteries typically in the 10+ year realm. Victron is 5 years.

 

[lostinfla]

Anybody thinking of, or in the process of converting to lithium (without solar) please chime in.

 

[punkinhead]

I just started ordering stuff today to replace the 8 FLA batteries in my 2018 Ventana. I'm going to start with a single 460 aH Epoch battery. I think that will be plenty because we had 920aH in our class B and it never got below 50% when boondocking for 4 days, including making coffee each morning and running the microwave, air fryer, and/or induction stove to cook meals. My Magnum inverter doesn't have a lithium charge profile but I can program it for a custom profile. I'm on the fence about whether I'll swap out the BIM for a lithium version or just disconnect it because I don't think alternator charging will be necessary. I plan to add a disconnect switch on the positive side of the battery since Magnum calls for disconnecting positive first when removing batteries.

I've ordered bus bars for positive and negative terminals. I'm going to start without a shunt and see if I'm happy monitoring the battery state of charge via Bluetooth. It's easy enough to add a shunt with remote display later.

It'll be nice to remove over 400 lbs of weight and open up some additional basement storage.

 

[AbdRahim]

I run mine down to about 20% the beginning of each month

Really?I have never cycled mine. Tough to do with A/C running 24/7 and smaller inverter. Hopefully, I will be able to get the larger inverter next year in order to do this.

 

[AbdRahim]

Anybody thinking of, or in the process of converting to lithium (without solar) please chime in.

I have no solar.

 

[Kevin D Pem]

There is salesmanship (hype), and the truth! Here are some facts!

All batteries are rated in cycle life, not years! Years are based on estimated cycles that normal use present! Year estimates are hype!!!

A typical lead acid battery has a rating of less than 600 cycles. A cycle is considered 20% discharge. For a full timer without solar this equates to just about 2 years if they never plug in.

AGM batteries will typically last twice the cycles. So about 4 years if you don't equalize.

Lithium are typically rated between 2000, and 4000 cycles. This is where things can be confusing!!! A cycle on a Lithium is based on a different concept. Although discharging one shouldn't discharge more than 80% the cycle is based on using 100% of the capacity! To clarify, if you bring a fully charged battery down to 50% twice that would be a cycle! Put another way using a 100 ah battery as an example and a 2000 cycle life battery your battery in theory would supply 200000amp hours before it would need replacement. However when a Lithium battery's capacity reaches 80% it should be replaced! This is a safety issue!!!

Personally I am back to using my Northstar blue lead carbon AGM battery pack! Cycle life at 20% discharge is 7000 cycles 4000 at 50% discharge.

That should give you what you need for an informed decision! All batteries suffer greatly when abused , no matter the chemistry. That is the reason solar makes sense for most off grid full timers. For someone that is always plugged into the grid? The least investment in battery storage, is what I would do!

Hope this is helpful!