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Lithium Ion Batteries
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Jon,
That chart is from MIT (my alma mater) and is very accurate. The iron phosphates are the least efficient type of Li batteries. Now that chart is comparing apples to apples, not apples to say oranges which seems to happen frequently in this discussion; perhaps one can get away with far less in terms of output with an Li iron phosphate battery, I just do not know….still trying to find out.
Yes I will agree that there are benefits to this newer and ever evolving technology, personally I think it is way too early in the game for a winner to be called. I have yet to be able to locate one supplier of any type of Li battery that compares directly to the 8d in terms of output. Yes it can be done by wiring a group together but does that really make any sense?
Let me return to Tesla for a moment, a powerful electric car with a price to match, no iron phosphate here but rather cooled Li cobalt batteries with I am certain, the most advanced battery control system available, after all his second business is the missle company now making routine deliveries to the international space station. Bottom line is that if you want the bang for the buck you have to be willing accept the risk of a bang. And that’s the truth!
A good discussion on the costs of Li can be found here:
http://www.technomadia.com/2011/11/lithium-update-3-lithium-battery-cost
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A 190 to 220 amp hour iron phosphate 24 volt battery is the equivalent performance of 2 8D batteries with a listed 255 amp hours.
What makes the seemingly lower capacity an equal is a conventional battery starts off at its fully charged voltage and then drops off, so as the volts fall, and the load in watts remains a constant the amps are actually increasing so the draw in amps at the end of the charge cycle is higher than at the beginning. On a lithium battery the voltage delivered is a constant right up until it shuts down.
So any 24 volt lithium ion battery in that 190 to 220 amp hour size range is roughly equivalent or greater in performance to an 8D conventional battery. Each battery is capable of replacing 2 12 volt 8D batteries and the battery will have a weight of 125 pounds compared to 2 at 168 pounds for a weight saving of 211 pounds. If you have 8 8D batteries your coach would be 844 pounds lighter. I have no clue how that weight data was developed because I am citing data from the battery specification sheets.
In a previous post you made and that of Gil you guys were all over the risk of lithium batteries. I, like both of you, would not be prone to accept risk on my coach. The reward is just not great enough to accept any risk. But while I strongly believe there will come a time in the near future when converters are all using lithium batteries for those of us with conventional batteries that time is unlikely to be now. But lithium batteries are clearly are where we are headed.
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How many Li batteries is Liberty putting in their new coaches? Also an AGM can only go down to 50% of charge, what is the depth of charge can an Li battery go down to?
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I don’t know how many batteries except to say the available battery power is equal to or greater than the conventional batteries they replaced. My guess is 2 but someone that really knows needs to answer that part of the question.
With respect to how deep a battery can be drawn down AGM and lithium batteries cannot be compared because of how each functions. An AGM gradually loses voltage as power is drawn from the battery. Some autostarts turn on the generator when the batteries have gotten as low as 11.9 volts or lower. That is well below the 50% charge.
A lithium battery maintains full voltage as its power is depleted until it reaches a certain percent of charge, at which point it shuts down. That sounds scary except a properly designed lithium ion system will actuate the generator prior to that point. A lithium battery has controls to protect it from a total loss of charge, but it also has protection on the other end to prevent an overcharge.
http://www.mastervolt.com/marine/products/li-ion/mli-ultra-24-5000/
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You can draw them down below 12.2, 50%, but it reduces the expected life cycle. Some autostarts are in the low 11’s.
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All of my discussions have revolved around direct replacements, certainly not complete system changes. You are probably spot on with regard to a 24 volt Li battery but that most certainly is not a simple direct replacement. Aside from various controls for the new battery banks, now we are dealing with 24V vice 12V so the task at hand becomes much more involved.
You mention the fact that Li batteries remain constant in output until controls shut them down, a very nice feature but also the same, and a much cheaper alternative, would be the NiCad which, although I have never seen them in 8D sizes, are available in 4d 12V. Look to be about 20% lighter than a Lead Acid and an easy direct replacement which would no doubt far less cumbersome in anything other than a new coach which has been developed from the onset for Li batteries.
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When I started this thread it was as John points out with the understanding lithium could be a drop in replacement. This idea was based on a conversation with a lithium battery manufacturer that led me to believe that was possible.
I understood a DC to DC converter was needed for 12 volt needs but was led to understand the inverters would work and the generator “Watchdog” used for autostart on my Liberty would be acceptable because it was set for a low voltage generator start.
Further investigation revealed however it isn’t so easy. To do a lithium installation correctly it is much more involved and as the needed devices and systems are understood it became apparent to me I can retrofit my coach with Lithium but the cost to do so is just prohibitive. There are definite benefits, such as lighter weight and a constant DC voltage power supply, but the bottom line is my coach does not exceed any weight limits and my normal 5 year life from house batteries is not a hardship looking for a cure.
If I were to purchase a new coach however I would expect lithium batteries unless I was assured conventional batteries such as AGM would not be the cause of an overweight condition once I loaded my stuff in the coach. I just wonder how many new coach buyers include weight limits (not only axle weight but side to side) in their requirements when specifying a new coach.
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Jon,
We have both probably spent a good deal of time researching these batteries and I do believe our conclusions are about the same. While by far the Li Cobalt is the best of this group it does have substantial downside risks. The iron phosphate seems to have eliminated much of the risk but that has come at some loss in battery performance, although still with substantial benefits over lead acid, especially in the long term.
All of these Li systems apparently have to be designed from the ground up for optimum performance and reliability; while replacing the lead acid batteries is certainly possible the fact remains that the ends will probably not justify the means. The lions share of these units that I have seen described are installed in older converted passenger busses with a basic house electrical system, mind you these are the same guys that pull into McDonalds for their second hand grease for their bio-diesel set up’s. I am quite certain that solar panels may also be involved as well as discussion about living off the grid; this is a far cry from the sophisticated electrical systems and components found on most of our conversions.
My reading also shown me that virtually all of these Li iron phosphate batteries are manufactured in China although “assembled” in the USA. This leads me to the conclusion that the manufacturer of these batteries may have some somewhat toxic side effects that has caused EPA and others to become involved, not that this matters to the end user it does introduce at least some question about quality control. I realize that Apple has most of their devices made in Chima, to me its another minor underlying concern. Finally I do not see any established organizations involved in this process of developing, manufacturing and marketing; they are all rather new entities, some with virtually no track record. Alas, is the rarely mentioned patent/trade mark wars that are apparently underway behind the scenes.
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I would agress that Lithium Ion are not a great drop-in replacement battery. They can be ideal when the entire charging/inverting system are designed around them.
I noticed that Marathon has used them in at least one coach:
http://www.marathoncoachtexas.com/gallery/index.cfm?coach=1199&tech
Also, I believe Liberty uses two in each of their coaches.
I will be installing 700 amp hours @ 24V in my vintage bus project… but I had to make sure the entire bus was designed to make sure it was an ideal implimentation. So, if you’re converting a bus instead of working on one that is already converted, then I’d consider this technology. But you have to be quite committed to learning a lot to adapt them to an existing coach.
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Ben, I would like to hear more details on your plans for the lithium house battery installation. Which inverter are you going to use? Which supplier of batteries and battery monitor? I met Chris and Cherie last summer and saw the technomaida approach. (Victron and GBS batteries).
I have been to the converter in Coburg and toured your coach. They do nice work.
I am in the process of converting a H3-41 tour bus and I will be buying an inverter and batteries this summer. I am still on the fence with the decision to go with lithium.
Thanks, Milo
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Tom, according to Inverter Service the (2) Magnum Energy MS2812 that I purchased recently are fully programmable and will work with Li-ion batteries. There is a good article in the February 2016 issue of MotorHome magazine where they integrate solar, Li-ion (LiFePO4) and a Magnum Inverter. They used a “hybrid” inverter but the inverter/charger portion is the same as my unit. The hybrid means it can work in tandem with a smaller rated shore power source or smaller generator.It may not work with the existing auto start but from what I have read the stock unit is set too low for it work properly anyway. Magnum has their own auto start and that may work but if it does not it is not a deal breaker.
Jon, I’m not sure when you did your research but things have gotten to the point where they are plug and play. They are the same size and terminal orientation as the 8D Lifelines with the battery mangement system integrated into the battery itself. See websites for the following companies RELiON or Smart Battery. I don’t know how to include links on this site or would have. There are less expensive choices but would require a bit more work i.e. external bms boards. If I go with Li-ion I am not sure which route I would take.
Andre, thanks for the Technomadia link and I had already read through that information a few times and watched the video. One thing to keep in mind, that they make clear, is that they were on the bleeding edge of that technology (2011) and they freely admit that much has changed since then including such things as a more conservative AH rating, the quality of construction and a better bms.
I plan on buying Technomadia’s mobile internet handbook and signing up for their forum regarding mobile internet communications system so I can ask questions regarding incorporating a network attached storage device (NAS) in the mobile internet system which is how I store my high resolution music and photographs.
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My info was 3 or 4 years old, and mine might be a problem because I have a 12/24 volt house which requires additional equipment.
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Let us know how that LI works out for you using your current equipment.
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You won’t find any L I that will work with your current inverters, auto-start, charging, etc.
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The below link shows how a younger bus nut, added Li to a much older bus. He has a lot of info including 3.5 years of data on Li use. It may answer some questions about Li retrofit installs.
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