Lithium batteries: who’s got em?

[Deucenut]

I need to replace the (4) 6V batteries in my motorhome as they are now about 10 years old. I was contemplating purchasing lithium batteries but I’m having trouble deciding if they’re worth it. So who’s got them? Are they worth the extra dough?

[IggyTech]

How long has your present lead acid batteries lasted?
How well do you maintain and use them?
Do you park your rig for months and not use it?
Are you a millionaire and don't really care about $600 or more for batteries.
All these questions need be answered to help answer your question.


My thought
Lithium batteries are probably 3 times the cost of lead acids and no guarantee they will last any longer.
I use Walmart batteries and I live in the hot zone of Arizona.
I replace my batteries every 4 years. ( 2 -12volts)
I'm sure you have more than two for your motorhome

[computerguy]

Yep have them. Worth it to me.
Considerably less weight
Will last years longer than AGM or FLA
Can charge so much quicker
No maintenance
If all you do is go from fhu campground to fhu campground they probably aren't worth it though

[twinboat]

Ten years on the lead acid batteries ?

How much longer are you keeping that RV ?

[757driver]

Yes, I have lithium. For the weight savings, deeper DOD, and years of service they were worth it to me.

[JFNM]

I have 'em. 10,000 watt hours. I spend nearly all my time boondocking and live on solar. VERY worth the VERY significant cost.

[VoiceNinja]

Got 'em. Love 'em! :-)

A couple of things to think about.

- Most RVers don't really use their batteries for anything more than a 12V pass through because they're almost always plugged into shore power. If that's you, a cheap lead acid battery is all you really need.

- If you do use your batteries during travel or for boondocking, you can replace your lead acids with a LiFePO4 bank that is half the "official" capacity. A 200Ah LiFePO4 battery bank has the same *usable* capacity as a 400Ah lead acid or AGM bank (if not more, depending on the size of the current draw).

- If you invest in LiFePO4 batteries, make sure you learn how they like to be charged and that your charger can be programmed to accommodate them. If you charge them properly, they can last 5 to 10 times as long as a lead acid battery.

- Other than charging them properly, they're zero maintenance. Sweet!

- If you have solar, the LiFePO4 bank will be able to accept a much higher percentage of the power the solar panels generate (higher charging efficiency, no wasted capacity during an absorption current tapering phase, charge currents up to 1C). That means you can have a smaller solar array or you can maximize the energy capture from a larger array. Win!

- You can leave them sitting at 40% - 80% state of charge indefinitely without worrying about sulfation, topping charges, water levels, self-discharge, etc. They're actually happiest being stored in the long-term at about 50% state of charge and *don't like* being on a floating charge or being stored at 100%.

- Their performance is incredible. No voltage sag, no loss of bank capacity at high current draw, a flat voltage curve, charging current up to 1C, 99% charging efficiency . . .

- If you use your batteries (see the first bullet point...), the increase in longevity with LiFePO4 will yield an equal or even lower cost per usable Amp-hour over the life of the batteries compared to lead acid or AGM. It stings more on the front end, but can be much better in the long run.

We're thrilled with ours!

[Deucenut]

Originally Posted by twinboat

Ten years on the lead acid batteries ?

How much longer are you keeping that RV ?

We bought the motorhome last April so it's new to me, so to speak. I don't think the previous owner ever boondocked as they had a site on a lake that they parked the unit at for the summer plugged in and used it for 2-3 weeks like that per year, then stored it in a barn plugged in the rest of the year.

The coach is like new(only 10500 miles, excellent paint, interior etc). My plan is to keep the coach for 15 years, which is my planned retirement date, and then upgrade. Although when I talk about upgrading in 15 years, my wife gets very quiet!

Originally Posted by JFNM

I have 'em. 10,000 watt hours. I spend nearly all my time boondocking and live on solar. VERY worth the VERY significant cost.

10,000 Watt hours!?!? wow! how many batteries is that? Stupid question, but is "Watt hours" the same as "Amp Hours"?

Originally Posted by VoiceNinja

Got 'em. Love 'em! :-)

A couple of things to think about.

- Most RVers don't really use their batteries for anything more than a 12V pass through because they're almost always plugged into shore power. If that's you, a cheap lead acid battery is all you really need.

- If you do use your batteries during travel or for boondocking, you can replace your lead acids with a LiFePO4 bank that is half the "official" capacity. A 200Ah LiFePO4 battery bank has the same *usable* capacity as a 400Ah lead acid or AGM bank (if not more, depending on the size of the current draw).

- If you invest in LiFePO4 batteries, make sure you learn how they like to be charged and that your charger can be programmed to accommodate them. If you charge them properly, they can last 5 to 10 times as long as a lead acid battery.

- Other than charging them properly, they're zero maintenance. Sweet!

- If you have solar, the LiFePO4 bank will be able to accept a much higher percentage of the power the solar panels generate (higher charging efficiency, no wasted capacity during an absorption current tapering phase, charge currents up to 1C). That means you can have a smaller solar array or you can maximize the energy capture from a larger array. Win!

- You can leave them sitting at 40% - 80% state of charge indefinitely without worrying about sulfation, topping charges, water levels, self-discharge, etc. They're actually happiest being stored in the long-term at about 50% state of charge and *don't like* being on a floating charge or being stored at 100%.

- Their performance is incredible. No voltage sag, no loss of bank capacity at high current draw, a flat voltage curve, charging current up to 1C, 99% charging efficiency . . .

- If you use your batteries (see the first bullet point...), the increase in longevity with LiFePO4 will yield an equal or even lower cost per usable Amp-hour over the life of the batteries compared to lead acid or AGM. It stings more on the front end, but can be much better in the long run.

We're thrilled with ours!

You mention "charging the batteries properly" What do you mean buy this? I have the typical charger in my motorhome that does the float thing etc. If I switch to lithium batteries, do I need to also change my charger? Since I have (4) 6Volt golf cart batteries now, would I also have to do extensive rewiring?

[VoiceNinja]

Originally Posted by Deucenut

You mention "charging the batteries properly" What do you mean buy this? I have the typical charger in my motorhome that does the float thing etc. If I switch to lithium batteries, do I need to also change my charger? Since I have (4) 6Volt golf cart batteries now, would I also have to do extensive rewiring?

It all depends on your lithium battery manufacturer's guidance and the type of charger you have.

This may not apply to you, because, in our case, we have a Magnum ME2012 inverter/converter, ME-ARC-50 remote console, ME-BMK battery monitor, and 4 x 100Ah of LiFePO4 from a new, yet-to-be-announced manufacturer.

Generally, you want to charge your LiFePO4 batteries to 14.4 - 14.6V and NOT float or equalize them.

To do that, we have our system set so that:

- Absorption voltage is 14.4V. That means it will charge at a constant current ("bulk" charge mode) until the battery reaches 14.4V, then hold that voltage and taper the current.

- Absorption ends when the State of Charge reaches 100%

- After Absorption, the charger goes "silent", which means it does not float.

- Float voltage is set to 13.2V. It shouldn't ever go to float based on other settings, but if it does, this voltage won't cause any issues.

- Equalization voltage is set to 14.4V and equalization time is set to 0.1 hours. That essentially nullifies equalization and makes it the same as a standard charge cycle if it should be turned on. This lets us intentionally trigger the "equalization" charge at any time to fully top off the batteries.

We have some other settings that we've configured with our AGS, but that's the important stuff. Your charger manufacturer should be able to tell you how to configure the charger for lithium.

As for rewiring, you may be able to re-use your existing battery cables, depending on how, exactly, you're wired now and how many LiFePO4 batteries you get. There shouldn't be any rewiring on your actual coach, just between the batteries.

[luvlabs]

Battery prices seem to be in multiple of 4 for each change in technology. For example, 6V, lead acid, deep cycle golf cart batteries - $100. Same battery capacity in AGM - $400. Same capacity in Lithium - $2000 +/-. Unless something has changed, you are going to have to purchase a new charger and charge controller unless, as VoiceNinja wrote, a battery than can live with current coach electrical systems is available. Still going to be expensive.

[Itinerant1]

Deucenut by your questions and replies it would be easier on your pocket book to replace with what you have with similar cheap batteries before getting more expensive Lifepo4 batteries.
This will give more time to ask/research the basics. As mentioned already if your a fhu campground to campground camper what you have will do everything you want and still allow for breif periods of drycamping at a fraction of the cost/ learning curve.

[vettenuts]

If you have an IOTA Charger, they make different plug in charge controllers one of which is for Lithium.

[Deucenut]

Originally Posted by Itinerant1

Deucenut by your questions and replies it would be easier on your pocket book to replace with what you have with similar cheap batteries before getting more expensive Lifepo4 batteries.
This will give more time to ask/research the basics. As mentioned already if your a fhu campground to campground camper what you have will do everything you want and still allow for breif periods of drycamping at a fraction of the cost/ learning curve.

Yes I'm coming to that conclusion as well. I can buy a 225AH 6 volt battery for $165. I need 4 of them. So to get the same number of AH in Lithium (if I cut the AH by 50% of the lead acid) I need around 450AH. To get that, it will cost me close to $4000. It would be really nice to have the new lithium batteries but I am thinking the technology is just a bit too pricey right now. Reminds me of when Plasma Tv's came out...they were crazy expensive and 5 years later they were very reasonable.

[757driver]

Originally Posted by Deucenut

Yes I'm coming to that conclusion as well. I can buy a 225AH 6 volt battery for $165. I need 4 of them. So to get the same number of AH in Lithium (if I cut the AH by 50% of the lead acid) I need around 450AH. To get that, it will cost me close to $4000. It would be really nice to have the new lithium batteries but I am thinking the technology is just a bit too pricey right now. Reminds me of when Plasma Tv's came out...they were crazy expensive and 5 years later they were very reasonable.

Not quite. Four 6v 225AH batteries gives you 450 AH total. To keep the life cycles to a reasonable amount using 50% gives you 225 usable AH.

The same usable in lithium would be 1 300AH battery or 3 100AH batteries with 240 usable AH (80% DOD). Cost $2800.00 or less with free shipping.