Help me assess the value of lithium

[scottfelt]

Hi folks. Very new to all of this and don't even have a unit picked out and have never owned one. I have done some reading to educate myself. So, thinking long term value and flexibility, I can clearly see the argument for a lithium system. I do know they cost more up front. However, in the articles I've read, they are comparing the cost of a lithium battery (say, $1300) vs the cost of an AGM batter (say, $250). My problem is that when I look at new class B rv's, I see a $20-$25k premium to have these systems. Can somebody help me understand what else drives this cost? And, knowing how RV dealers and manufacturers inflate the cost of everything, what is a fair mark-up? Like, if I negotiate the cost of the coach without lithium and get it to price $x and then say, ok, I want that but add lithium, can I expect to get it for less than the $20-$25k? Thanks for all the help. I'm sure I will have more questions as I go down this process of deciding what to get.

[wny-pat]

Can't help you a lot, but looking at a new Class B, when you add lithium batteries, you have to also add the cost of a special battery charger.

[JonK]

Your question is unfortunately unanswerable as stated since there are many variables in the transition from lead to lithium. It is unlikely that the usable battery capacities are identical between the two systems. In all likelihood the lithium system has a much higher capacity.

The question you need to answer is how you will use the van and then what usable battery capacity is appropriate for that use. This question has nothing to do with lead versus lithium, that question becomes relevant once you know the needed capacity and usage pattern.

Given how you framed the question suggests to me that you would benefit from a lot more study of this site and the Sprinter forum site to learn the differences between lead and lithium systems as a total system. The vendor is offering you systems with very different capabilities for the $25,000 price difference. And, no, they will not drop the price the way you hope. You're hoping they will sell you a Tesla for the price of a Ford, I can't see that happening.

[mkguitar]

determine first what your energy needs will be


in our older RV propane serves cooking, fridge, hot water, heating- the larger energy uses


DC power is used for fridge control, tv, lighting and detectors


genny is used for AC and microwave ( never used it camping)


our low DC needs mean we get by about 5 or 6 days with an old style battery with help from a briefcase sized solar cell which supplies a max 1amp/hr


newer units go all electric and have different needs...converting DC to AC through an inverter involves waste. lithium is expensive in many ways
I don't completely trust lithium- fire




mike

[booster]

Lithium systems from the manufacturers are hugely different from drop in lithium batteries, IF they are done well with good controls, heat, charging, etc. Some manufacturer systems and not really much better than drop ins with shortcomings. They all cost big time from the OEM RV manufacturer, though. Some are probably worth it, some probably not.


As was mentioned, figure out how you are going to use the van first and foremost. How much shore power, driving, off grid etc. Then try to figure out how much power you will actually need to use and if you are willing to have propane or van fuel heat, hot water, and cooking (not using electricity for those items is a big deal). Do you have pets that need AC when not on shore power for some amount of time (huge power use).


Do as much reading here, as there is lots of good information, and everywhere else, but don't believe anything the RV sales types tell you

[coss370]

When you buy a new car, you negotiate off the entire price. Its not like you can take 30% off the car and 45% off the battery. I mean you could, but who does it that?

[Davydd]

Is this your first Class B you are considering? If so, get the cheapest set up which would be AGMs and learn what you like or don't like about RVing and talk to others in campgrounds and rallies to see what they think and you can get a demonstration of what they are telling you. You can't get that in a show room. I have had an 800ah lithium battery bank for 6 years now and was one of the first. I've had two other Class Bs with lead-acid wet batteries and AGMs. I have my experience and preferences and would not go back to AGMs but I also think if your battery power considered is less than about 400ah battery capacity you might be better off with AGMs.

[coss370]

The issue with AGM is that whatever they are rated, you really only get 30-40% of it. If it is 100ah, you should plan to have 40ah before the battery gets damaged. WIth lithium, at least you only lose about 10%. 100ah you know you have at least 90ah (if not more)

[booster]

Originally Posted by coss370

The issue with AGM is that whatever they are rated, you really only get 30-40% of it. If it is 100ah, you should plan to have 40ah before the battery gets damaged. WIth lithium, at least you only lose about 10%. 100ah you know you have at least 90ah (if not more)

Not true, and probably comes from the lithium seller propaganda "comparisons" although 30-40% is even lower than they claim.


The rated life of AGM, in cycles, is normally at 50% discharge, so you for sure have that much. If you look at it as energy stored and reused, which is the best way to rate lifespan, and go to 80% discharge in an AGM, you shorten life somewhere around 15%. You don't cut it in half, you don't destroy it instantly, etc like the various claims are pushing.


This has been extensively discussed here on the forum and includes all the necessary reference materials and calculations to back it up. All you really need is the lifeline cycle life vs depth of discharge graph to do it yourself if you care to.


So you really should be comparing 80% to your 90% for your capacity calculations.


Lithium has some advantages to be sure, like low weight and high sometimes high discharge and recharge rates, but usable capacity is not one of them.

[avanti]

Originally Posted by booster

you don't destroy it instantly

Correct.
OTOH, with lithium, you just MIGHT destroy it instantly under various cold-weather scenarios.

[coss370]

I wasn't talking about life cycle, I was purely talking about energy stored. I can run my AGM down to 10% daily and I am sure it will last 1-2 years. I do the same thing to my lithium and I know it will shorten its life too. I will get what 6-8 years instead of 10? That's why I was throwing some conservatives figures to factor in losses over time. All batteries lose capacity as they age, that's a fact and there is no way around it.

Assuming the manufacture isn't lying (which many of them do), the rated power on the batteries (AGM especially) are nearly impossible to get to. Everything they show is under the most perfect optimistic condition (low C rate, 90F, etc). When I do my calculation, I figure I have 90% of what the manufacture says on the AGM and 95% of what lithium says. From there you can decide what you want to stretch yours down to. If you want to take it down to 5%, go for it. The capacity is the same, how you want to treat your battery is your call. I am just saying in general on how you can make it last 4-5 years.

I have both types batteries, I don't care what I use as long as it works. I do know lithium last longer under most condition and I don't have the same constrain as I do with the AGM.

Originally Posted by booster

Not true, and probably comes from the lithium seller propaganda "comparisons" although 30-40% is even lower than they claim.


The rated life of AGM, in cycles, is normally at 50% discharge, so you for sure have that much. If you look at it as energy stored and reused, which is the best way to rate lifespan, and go to 80% discharge in an AGM, you shorten life somewhere around 15%. You don't cut it in half, you don't destroy it instantly, etc like the various claims are pushing.


This has been extensively discussed here on the forum and includes all the necessary reference materials and calculations to back it up. All you really need is the lifeline cycle life vs depth of discharge graph to do it yourself if you care to.


So you really should be comparing 80% to your 90% for your capacity calculations.


Lithium has some advantages to be sure, like low weight and high sometimes high discharge and recharge rates, but usable capacity is not one of them.

[booster]

Originally Posted by coss370

I wasn't talking about life cycle, I was purely talking about energy stored. I can run my AGM down to 10% daily and I am sure it will last 1-2 years. I do the same thing to my lithium and I know it will shorten its life too. I will get what 6-8 years instead of 10? That's why I was throwing some conservatives figures to factor in losses over time. All batteries lose capacity as they age, that's a fact and there is no way around it.

Assuming the manufacture isn't lying (which many of them do), the rated power on the batteries (AGM especially) are nearly impossible to get to. Everything they show is under the most perfect optimistic condition (low C rate, 90F, etc). When I do my calculation, I figure I have 90% of what the manufacture says on the AGM and 95% of what lithium says. From there you can decide what you want to stretch yours down to. If you want to take it down to 5%, go for it. The capacity is the same, how you want to treat your battery is your call. I am just saying in general on how you can make it last 4-5 years.

I have both types batteries, I don't care what I use as long as it works. I do know lithium last longer under most condition and I don't have the same constrain as I do with the AGM.

The ratings for the AGMs is normally the point they get to 80% capacity so nowhere near only having 30-40% capacity.


I think you can come close to the rated life in AGM batteries if you have very good charging equipment, maybe not all the way, but close. Our Lifelines are about 5 years old and still test as new for capacity and voltage.


From the data given on the life charts, when going by energy in/out, the lifespan deteriorates fairly quickly when you get below 20% state of charge, so using the 20% normally stated by the manufacturers for deep discharge looks to be a good point to go to. At least with AGM, and probably lithium also, the cycles of various discharge depths average out in terms of battery degradation, so an 80% discharge and a 20% discharge cycle are basically equivalent to two 50% discharges.


The energy stored in a 100ah AGM at 20% SOC is nearly the same as in a 100ah lithium with a bit of difference due to voltage.


The big deal right now is that nobody really knows how long the lithium will last in RV use yet and based on the wide range of life ratings we see in them, it is anyone's guess which is even close to actual.


Glad you are happy with what you have, but your original statements did not reflect the actual characteristics or capabilities of the AGM batteries, IMO.

[@Michael]

Originally Posted by Davydd

Is this your first Class B you are considering? If so, get the cheapest set up which would be AGMs and learn what you like or don't like about RVing and talk to others in campgrounds and rallies to see what they think and you can get a demonstration of what they are telling you.

I'll second this.

For example, if you buy an RV with a propane refrigerator, propane stove, and don't ever need to run your A/C from battery or run an electric coffee pot or instapot while on battery, then the value that lithium adds is low.

If you always camp in campgrounds & pay extra for electric sites, then the added value of lithium is low.

On the other hand, if you have a large compressor refrigerator, induction stove, and/or expect to run the A/C without being plugged in, lithium is the way to go.

[SteveJ]

We owned a 2000 200 Versatile for about 6-7 years. For five of those years we got along just fine on one battery(eventually a group 29). Solo, I was good for an easy three nights on it unless it was really cold(lows in the 25 to 45 range) without solar. We could go perpetually on 150 watts of portable assuming no long string of cloudy days.

LP did all of the heavy lifting, cooking, heat, hot water, fridge.

Most of our camping is extended boondocking/dry camping. Water was our time constraint. Solo, good for two weeks, dual 6-7 days, as long as we stayed away from humid areas in the summer.

FWIW, the battery wasn't even an AGM but a sealed "maintenance free" group 29DC Maxx from Walmart for less than $100. At 2.5 years old when I sold the RT it was still performing well with about 4-5 months use per year on the road. Decent(not the best) on board and solar charging likely helped.

Normally the portable solar did not get deployed unless planning on more than two nights at a location, very cold weather excepted.

We virtually never had to run the generator for battery charging, occasionally for an hour or two for the A/C or microwave. Running the genny all night for sleeping was extremely rare, we/I would find a place to plug in if it came to that.

If you choose to use induction cooking and otherwise choose not have LP on board, things get real spendy, real fast.

I do lean toward the old school on RV tech. We replaced the 2000 RT with a '98 Safari Trek.

[MsNomer]

Another concern is drawdown voltage. We added a second 100Ah AGM not because we needed the extra Ah, but to mitigate the drawdown voltage when we use the microwave. My understanding is that this is not an issue with lithium.

[Bud]

Originally Posted by MsNomer

Another concern is drawdown voltage. We added a second 100Ah AGM not because we needed the extra Ah, but to mitigate the drawdown voltage when we use the microwave. My understanding is that this is not an issue with lithium.

Just might be, e.g.

Ask yourself this: If the 100ah battery had been lithium and you had wanted to run the a/c, not microwave, would you have added the second 100ah battery?

It appears that you're pretty much right though. There really do not seem to be many applications where 'draw-down' is an issue with lithium vs agm.

[booster]

Originally Posted by MsNomer

Another concern is drawdown voltage. We added a second 100Ah AGM not because we needed the extra Ah, but to mitigate the drawdown voltage when we use the microwave. My understanding is that this is not an issue with lithium.

I think this is a valid concern for those that use sporadic high amp loads. We have a big bank at 440ah of AGM, but I did test is on our Dometic microwave and the Dometic AC (12,000 btu) in our 07 C190P on the batteries. We are good on the micro down to about 40% SOC with low voltage cutoff at 11.2v, AC down to about 50% SOC. We could probably go lower if we dropped the cutoff off to 10 or 10.5v.
When we had 260ah of Trojan deep cycle wet cells, which don't give up current very easily compared to AGM, we needed to keep the cutoff at about 10v to use the micro without running the engine if the SOC was down below 70% or so.
We have seen varying recommendations, particularly on Battleborn, about charge and discharge rates, with some documentation saying 40 amps per 100 ah battery but others have called Battleborn and been told that their previous 100 amps is OK, so who knows what is OK. Lithium still seems to be the wild west of specifications and claims by various manufacturers and their paid "influencers".

[NAZCamperVan]

Original poster Scottfelt,
You've stimulated ALOT of good discussion about battery systems here. I hope you can gleen practical advice, that the amount you want to invest in the electrical system in your campervan, is dependent on how you plan to camp, including what your electrical needs are (running aircond, plugging in appliances, etc) Many of us consider solar an essential part of our electrical system, and have evaluated the amount of electric power we need. From: 2-AGM batteries+ DIY200w solar+battery monitor, no inverter.

[jrobe]

We quickly found that we don’t need lithium batteries. We don’t stay in the same place very long. We also rarely stay in campgrounds with electricity. With our second alternator we only have to drive 30-60 min daily to fully recharge our AGM batteries which we almost always do anyway traveling. Our AGM battery capacity is plenty for us to use all our devices, coffee maker, TV, refrigerator, satellite dish, etc.. We are probably even fairly high electricity users compared to a lot of RVers.

Living in the north, I am also glad I don’t have to deal with the cold weather requirements of lithium batteries. I just keep a battery maintainer on our batteries all winter and forget about the weather.

I would do a very careful energy use analysis and then decide if you really need lithium batteries. We don’t. We also don’t need solar panels as long as we have our second alternator.

[booster]

Originally Posted by jrobe

We quickly found that we don’t need lithium batteries. We don’t stay in the same place very long. We also rarely stay in campgrounds with electricity. With our second alternator we only have to drive 30-60 min daily to fully recharge our AGM batteries which we almost always do anyway traveling. Our AGM battery capacity is plenty for us to use all our devices, coffee maker, TV, refrigerator, satellite dish, etc.. We are probably even fairly high electricity users compared to a lot of RVers.

Living in the north, I am also glad I don’t have to deal with the cold weather requirements of lithium batteries. I just keep a battery maintainer on our batteries all winter and forget about the weather.

I would do a very careful energy use analysis and then decide if you really need lithium batteries. We don’t. We also don’t need solar panels as long as we have our second alternator.

I think to anyone who hasn't been around here for a while, it is important to mention that with a big alternator you can recover a day's use in 30-60 minutes without question. But, that is only if you are relatively low on charge when you start the recharge. The upper 20-30% takes much longer to do, so getting to totally full will not happen that fast.
In much of the real world this doesn't matter, as solar will finish off the charge if you have solar, or you will be on shore power in the future to top off and preserve battery life. But, you need to understand you will be starting your next discharge cycle at 80% full instead of 100% full. If you have a big battery bank, no big deal, but it you are on a single battery or two, it might be. Recharge time does not really change much with bank size when you are in the top 20% of SOC.