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OBIWAN_CANOLI

From standard to Lithium Batteries

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My current battery system is this:

4 - 6V batteries, 115 min @ 75 Amps, 450Ah total available (225 Ah @ 20Hr); Assume batteries are 4 years old (3 years since I purchased the MH, could have sat on the lot a while, so...). I have 480W of roof-mounted solar (3-160W panels @ 8.7A peak output per panel, a 30A Zamp controller, plus a 120W single, portable panel. I have room for 3-5 additional panels on the roof. It's mounted on a 2017 Newmar Ventana LE 

Because my plans include a fair amount of boondocking, the move to Lithium seemed prudent, and, over time, more cost effective. What I've found is that most Li batteries for RV's tend to be rated at 100Ah, so I would need a minimum of 2 Li batteries. I'm thinking 3 LI batteries woud be wise, as the reserve gives me peace of mind should the need arise, and circumstances require. Could even consider adding another Li to the bank, since I'd have room for 4... Cost is always an issue, of course, but I'm willing to invest for the long-term here, be it personal use or eventual sale, but for now, I'm most interested in the practicality of the Li option

I'm pretty much a novice on the electrical side of things, and usually have to read things 3-4 times before it starts to sink in. Still, have tried to read and learn as much as I can, complimented by the astute advice and observations I read here... thanks for your input!

 

Edited by OBIWAN_CANOLI

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When I went to lithiums I installed 4 100 amp lithiums in place of 6 AGMs.  The thinking is that because lithiums useful range is down to about 90% discharge versus 50% for AGMs, the about of run time is more than what I had.  I have 800 watts of solar, 3K Xantrex inverter, and a residential refrigerator.;

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4- 6 volt batteries about $400.00. for about 5 years of service. That would be $800.00 for 10 years of service. Do you need more that 200 amp hours at 20 minutes? LI is more than double the cost.
I still don't see the economics of LI batteries.

Richard

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18 hours ago, RLS7201 said:

4- 6 volt batteries about $400.00. for about 5 years of service. That would be $800.00 for 10 years of service. Do you need more that 200 amp hours at 20 minutes? LI is more than double the cost.
I still don't see the economics of LI batteries.

Richard

I'm thinking there's a peace-of-mind aspect to this as well... True, Li's are more expensive on the front side. But they're worry free, need no maintenance, weigh in about 1/3 of typical lead-acid batteries, and can be drained up to 90%, perhaps more, without damaging or impacting lifespan. Further, they recharge in only a few hours, and for most I've read about, are drop-in ready. As for lifespan, Li appears to have a longer potential. 

 

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20 hours ago, RLS7201 said:

4- 6 volt batteries about $400.00. for about 5 years of service. That would be $800.00 for 10 years of service. Do you need more that 200 amp hours at 20 minutes? LI is more than double the cost.
I still don't see the economics of LI batteries.

Richard

Not all economics is about money. There are a few reasons we're considering lithium  batteries for our next go around...

  • Faster recharge time
  • Ability to charge at higher rates when solar is performing at peak
  • Much more capacity per pound
  • Constant voltage level from fully charged to lowest usable point in SOC

For some these things don't matter as much. For some the money aspect is the primary one. Since we tend to do quite a bit of dry camping/boondocking, having the ability to fully charge during a few hours on the road or with a few hours of peak solar is important. The lower weight is also important, as it will be the key to allowing us to carry the necessary solar to keep things recharged. (Yes, I can use the generator to recharge the batteries, but I truly hate having the listen to the generator when we're camping in an isolated lake front site.)

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Include the cost of a new LI battery charger if you desire the maximum life from the LI batteries.

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11 hours ago, RayIN said:

Include the cost of a new LI battery charger if you desire the maximum life from the LI batteries.

A cost, for sure. But, in the scope of this project not by any means the largest cost.

Some of the newer batteries are designed to charge with the same charging parameters as flooded cell batteries and can use existing chargers. Not sure how well that works, but it's an option for the short term. We have a stand-alone battery charger, and the lithium-specific model to replace it is only about $250. Not free, but a relatively small piece of this puzzle.

However, if you are using a combination inverter/charger and yours won't work with lithium batteries, then you're going to have to figure out a new plan.

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I have long been a proponent of wet cell batteries if buying them as a premium unit. Crown 260s may last ten years if cared for at $ 165 per. My biggest argument in favor of them is the price/life span.. The Lithium craze will play out over time and I do not advocate buying on the early stages of new technologies and the claims are often exaggerated or extrapolated from engineering "should be" information. The argument for Lithium holds many good points if the expectation of use and then actual use occurs. The biggest concern for many these days in convenience. Is it easy to spend 3 or 4 thousand to avoid watering or cleaning upkeep. But then the rate of charge, the weight, the depth of discharge does make them more attractive for the long haul. It should make selling the coach easier to those younger and into the tech scene. I'm not sure the value is there for me at 74.  One thing I failed to mention so the edit, is charging. Lithiums do not like cold which in northern climates could, will add another dimension. I am told that there are some manufacturer adding heating elements to the batteries. This would certainly be a plus for some, me included.

Edited by RSBILLEDWARDS

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As noted, I too do not like to buy new technology....or a new make/model vehicle for that matter.  Another question re charging.  It has been noted the Li batteries need a special charger....will that charger charge the AGM/gel/lead acid chassis batteries or must they be Li as well?

Edited by FIVE

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Every-time I hear about Ion Lith, I have vision of the "Dream Liner." by Boeing!  

FIVE, RS. Ditto!

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On 8/16/2020 at 6:23 PM, richard5933 said:

Not all economics is about money. There are a few reasons we're considering lithium  batteries for our next go around...

  • Faster recharge time
  • Ability to charge at higher rates when solar is performing at peak
  • Much more capacity per pound
  • Constant voltage level from fully charged to lowest usable point in SOC

For some these things don't matter as much. For some the money aspect is the primary one. Since we tend to do quite a bit of dry camping/boondocking, having the ability to fully charge during a few hours on the road or with a few hours of peak solar is important. The lower weight is also important, as it will be the key to allowing us to carry the necessary solar to keep things recharged. (Yes, I can use the generator to recharge the batteries, but I truly hate having the listen to the generator when we're camping in an isolated lake front site.)

We spend 3-4 months in the winter off grid with our 4 wet cells and 505 watts of solar. Our batteries do achieve over 90% charge on sunny days, even when the furnace is running on those cold desert nights. We average 30 minutes a day of generator time to microwave and give the batteries a slight kick in the lead @ 15.5 volts and 125 amps of converter. You can give those wet cells a huge kick in the lead on those cool mornings, just as long as you don't overheat them. We can travel in below 0º weather with batteries stored outside. Laptop and satellite TV is on most of the day. We have all the electrical conveniences we need and wet cell weight is not an issue in our old Bounder. I'm sure your buss doesn't have a battery weight issue.

 

Richard

Edited by RLS7201

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I switched to LiFePO4 batteries 3 years ago.  If your inverter/charger has a profile that will support charging LiePO4, no extra charger is needed.  My reasons for changing are all stated above.

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I've run into a dilemma...

I was planning to change out my four 6V flooded batteries for Lithium's, and found a low temperature option from LiFeBlue Batteries - they offer 100 Ah, 200 Ah, and 300 Ah, and I was considering two 200 Ah Li's... 

Measuring the tray (10.5" X 30"), it would seem I do not have room for any version of this battery. It would appear some modification of the tray would be necessary to accommodate the batteries by extending the tray another 8-10".

Has anyone done this kind of modification? 

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After further review, decided to remove the tray to make room for 4 Battle Born 100Ah to replace the current flooded bank. My service guy says doing so results in enough room for 8-10 total of these, and he can easily place these in a secured way. New Li's arriving at service center tomorrow, excited to complete the process (install of Victron 712 Voltmeter w/Bluetooth, and Victron 100/50 Controller). 

Once completed, will review adding 2 more solar panels (current 480W / 3), though it seems I have enough capacity to leave well enough alone. Figure 30A/day for power needs, have a 2K Inverter/charger, Li capable. 

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I was heading for AGM’s to replace my four 14 year old original Interstate flooded 6v U2200 (GC2’s).  But then I read how heavy they are.  And 2 new maintenance-free group 31 chassis, and 4 AGM GC2’s would run around $1500 at Batteries Plus Bulbs.  I had read, last year, articles in Motorhome and the FMC magazine about lithiums, and 31 lbs. @ sounded better than the 160 lbs. I’d heard AGM GC2’s weigh.  But Battle Borns 100ah are $950@, and that’s $2300 more than AGM’s plus the cost of the two maintenance-free chassis bats.  The deal breaker was having to change inverter and solar setups.  Nope, won’t do that.

But then a couple months back I read someone said you don’t necessarily need to change anything if your setup can charge AGM’s, because you just need to not use equalizing charge on lithiums.  Just set your dipswitches and/or inverter remote panel for AGM mode.  Okay, bad back, 31 lbs we can handle... not 160.  And I’m not sure the battery tray, built for 360 lbs., would like the extra 400 lbs the AGM house ones would add.  Regarding that tray, the Battle Borns are 2 inches longer than GC2’s, but when I looked, the tray has only a 1” angle iron backstop, with 3” or 4” more to the very back of the tray;  all I have to do is drill new bolt holes and move the angle iron backstop a couple inches back.

So then I check into different brands of lithiums.  Be forewarned that there are cheaper brands out there, including some that others touted a great Costco deal.  But that brand, though some $200 @ less on sale... well you get what you pay for.  Made in China, it’s lighter weight is due to a less stout structure.  That means it may not hold up well to the vibrations it’s case and internal mountings and connections will encounter on highways;  they are made for use in non-mobile mass assemblies in backcountry and off-grid home solar setups.  Battle Borns are built differently than that, perhaps of some Chinese components, but designed and assembled here with highway use in mind.

Yes, the 100aH vs ~220aH notion seems troubling, but as others here note, taking a flooded or AGM lower than 50% is more than what’s commonly advised, if not plain abusive.  Lithiums are not harmed if drained to nearly 0%. And they’ll supply full voltage the whole way, behaving much like any lithium cordless tools you may own... it just keeps going until it suddenly stops.  Battle Borns and some others have monitors to check on their status.  And consider also that in the field you won’t need to run your genset as long because they charge back up faster.  Does it come down to longevity and weight?  My Interstates went 12 years before giving me serious charge-holding issues.  Those that only get 3-4 years must be regularly dumping theirs below 50% (at 12 volts it’s half discharged).

The cold weather thing is bothersome, but we’ve rarely found ourselves boondocking in subzero conditions, so that is a factor that members who do  may want to explore.  I understand there are devices or mats that some use to gently heat the lithium bank.  Where the energy comes from for that is your guess.  200 or greater aH models may be available, but their power comes from being larger.  Those of us with the more common class A diesels that have trays designed for four GC2 house batteries can find that there are, like in my case, very minimal tray modifications to make 100 aH Battle Borns fit.

This probably sounds like I’m a Battle Born salesman, but I’m still edgy about the value factor.  Will it add to the coach resale?  Maybe, but you and I know it won’t be as much as we’d hope.  Sure, there’s a brand that offers an FMCA discount, but the numbers I saw still doesn’t make them competitive.   I merely came here to glean more opinions and see what others have done and experienced, and ended up posting this long-winded expose.  My apologies.  I just know that although I have no great issue with having to occasionally add water to wet cell golf cart batteries, I’m sure as heck tired of the corrosion on the metal tray parts and having to replace “melted“ hold-down strap buckles every couple months.  The older a wet cell gets the more charging effort it requires, the hotter it gets, and the more gassing it emits, resulting in more frequent water replenishment and acid gas metal erosion.    

Decisions, decisions.

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