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Battery Drain
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offgrid View Drop Down
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Posts: 5290 		Post Options Post Options   Quote offgrid Quote  Post ReplyReply Direct Link To This Post Topic: Battery Drain
    Posted: 04 Dec 2022 at 12:58pm
For anyone thinking about converting to lithium batteries that is reasonably  handy electrically consider purchasing 4 standard 280 amphour  3.2V prismatic LiPO cells and a BMS and building your own. Those cells are down in the $170 range and an appropriate  BMS is about $40, giving you a 280 ah 12V battery for around $700. You don't have to order from on Alibaba either,  the materials are available from us stock on Amazon , Ebay  etc. If you do the math that's cheaper per usable  amp hour than lead acid. At that kind of cost  the only reason not to go with Li is the charging system conversion costs as others have mentioned. 
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Linda&Gino View Drop Down
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Posts: 32 		Post Options Post Options   Quote Linda&Gino Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 11:19am
It really comes down to what works for your use case and what your willing to spend. If flooded or AGM batteries work and you are willing to deal with venting, weight and only being able to use 50% of the available Ah, then more power to you(no pun intended). I can say that an 11 year old flooded DC battery is an outlier based on my experience with them and I am meticulous about battery maintenance. Most folks are lucky to get the 3-5 years our of them.

For me the lithium setup is the way to go and was our long term plan for our Rpod before we decided to upgrade to another RV. They charge faster, deliver almost 90% of their capacity without damage, are lighter and can be stored in the coach without venting. I was going to move my battery bank to the storage area under the bed in the 179, install a DC to DC converter, and replace the onboard converter/charger. Finally, install a plastic tool box on the tongue that would more than make up for the storage lost in the storage bay.
gpokluda
2017 Rpod R179 SOLD!
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2022 Ford F150 4X4 EB3.5
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Grinkle192 View Drop Down
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Posts: 18 		Post Options Post Options   Quote Grinkle192 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 10:53am
Another downside to Lithium is that in systems with multiple charging options, some of those charging options may not work easily with Lithium batteries.  A couple examples have been brought up in this thread already.  As an additional example, I have a 2nd alternator in my van for charging, it works well for lead-acid but since Lithium batteries (which I have in my van) hold voltage high very deep in the discharge, the regulator on that alternator won't charge until the battery is quite low already, I can't really idle the engine with a half full battery and top it off, the regulator still sees high voltage and won't charge.

Lithium does win vs lead acid on -

Weight per Ah
Usable Ah for a given total capacity as they can be more deeply discharged (one might club this with weight per amp hour and not think of it as a separate thing)
Installation flexibility since the don't out-gas and can be installed inside the cabin without venting concern (nice for keeping them warmer)
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jato View Drop Down
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Posts: 3227 		Post Options Post Options   Quote jato Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 10:29am
Originally posted by Linda&Gino

We're being told that the LifePO4 batteries in our new RV will last 10 years as long as the batteries stay between -20F and 115F.


That being said then it makes sense stay with the old technology (lead acid battery) if looking at it from a purely dollar and cents point of view.  My cost so far with an old 11+ year old Interstate (cost when new $ 80 divided by 11 years is $ 7.27/year and will continue to drop as battery ages.  My newer Trojan cost $ 220 back in August 2021 so IF it were to last only 10 years the cost is still only $ 22/year.

Do not know the cost of the lithium battery but I also know you need to change out the converter and that comes at a cost as well.  The cheapest LiPO4 battery I saw was a Dakota for $ 399.  The best price I could find for a converter for a lithium battery was made by Progressive Dynamics which is priced at $ 274.  So . . . . . . . battery + converter = $ 673 and IF it lasts 10 years the yearly cost is $ 67.30/year or over triple the cost of using lead acid and that is if you use the cheapest battery and converter that i found available. 
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Linda&Gino View Drop Down
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Posts: 32 		Post Options Post Options   Quote Linda&Gino Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 9:06am
We're being told that the LifePO4 batteries in our new RV will last 10 years as long as the batteries stay between -20F and 115F.
gpokluda
2017 Rpod R179 SOLD!
2022 Escape 5.0 TA
2022 Ford F150 4X4 EB3.5
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jato View Drop Down
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Posts: 3227 		Post Options Post Options   Quote jato Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 8:36am
Originally posted by StephenH


StephenH -

I am hoping that the projected much longer lifespan of the LiFePO4 battery will pay off in the long run.


What is the projected or expected lifespan of a LiFePO4 battery and will that vary due to where you are located; hot verses cold climates?
God's pod
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Jim and Diane by beautiful Torch Lake
"...and you will know the Truth and the Truth will set you free."
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Grinkle192 View Drop Down
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Posts: 18 		Post Options Post Options   Quote Grinkle192 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 7:34am
StephenH - I'm going through your mods list - its fantastic.  The things you have done are things I feel competent to attempt, and I really like the function-first approach you take.  The Great Stuff molding for the hitch box is genius.  I haven't gotten to the battery mod yet, and I'm not going to fast forward, its all great stuff.  Thanks for compiling it all and for referring me there!
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StephenH View Drop Down
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Posts: 6289 		Post Options Post Options   Quote StephenH Quote  Post ReplyReply Direct Link To This Post Posted: 03 Dec 2022 at 7:32am
Okay, the WF-8955-AD-MBA was not available when I did my LiFePO4 conversion. I guess the newer RVs will have the WF-8955-AD power center so that will mean that part of what I had to do would not be needed. The DC to DC charger would still be needed though if one wanted to charge an LiFePO4 battery while driving.
StephenH
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ouR escaPOD mods
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Colt View Drop Down
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Posts: 383 		Post Options Post Options   Quote Colt Quote  Post ReplyReply Direct Link To This Post Posted: 02 Dec 2022 at 11:53pm
Actually, if you match A-Hr capacity, two 6v and two 12v batteries will be very close to the same weight.  The plate area required to get 200 a-Hrs has to be the same.  12v batteries have more cell dividers, so there's a little more plastic in them. 

I had to replace my power center board because it was overcharging the battery and had a large voltage swing.  The replacement Main Boards are almost all WF-8955-AD-MBA that autodetects Li vs Pb batteries and charges accordingly.  It costs about $200 mail order. 

However, I run a LiFePO4 battery in my Miata.  I bought the dedicated charger for it, but the manufacturer states that a normal PbSO4 charger may be used as long as its voltage does not go too high.  Typical, simple brute force chargers must be watched to keep the voltage below spec (15.3V?). 
John
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StephenH View Drop Down
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Posts: 6289 		Post Options Post Options   Quote StephenH Quote  Post ReplyReply Direct Link To This Post Posted: 02 Dec 2022 at 8:56pm
Originally posted by Grinkle192

StephenH -

"when comparing the typical 12V battery with a pair of GC-2 batteries, the GC-2 batteries will be much heavier than a single 12V battery"

This makes sense to me.

I also see that the stock battery on my new 192 is a Marine battery, and I agree with your assessment that it is not true deep cycle.

If I replace it with a 100Ah Lithium (not sure I would, but if I did upgrade, that is likely what I would consider) would the A/C charger be able to charge it, do you know?
It depends. I don't know what power center you have. The WFCO 8955 does not properly charge LiFePO4 batteries. I swapped out the converter for a WFCO-8950L2-MBA, which is what works. I also installed a DC to DC charger because the Frontier was not charging the battery. Because the battery is a little higher in voltage, it was fooling the Frontier's alternator control into thinking the battery was charged, so if effect, the trailer's battery was supplying power to the truck and I would arrive with a battery that had much less charge than when I started.

Read my mods, and you will see what I did. I am hoping that the projected much longer lifespan of the LiFePO4 battery will pay off in the long run. Short term, the two 6V GC-2 batteries connected in series is much less outlay, but they do have a shorter lifespan. You would need to determine if you will be keeping your R-Pod long enough to recoup the investment in an LiFePO4 battery. I always thought that if I did change, I could revert the system to stock and move the battery and DC to DC charger to a new trailer.
StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS
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