Lithium batteries

[WheelingIt]

Lots of negative comments here which I find interesting. Lithium is the leading edge and definitely not for everyone. For those who don't bonndock a lot they're useless, and for those who aren't tech-minded they don't make sense. Most folks should stick to lead acid...cheaper and easier.

But if you're a techie and boondock a lot, lithium has some major advantages.

And the pricing has come down. You can get 1000 amp hour battery for $1,200. And it can be less if you build your own batteries (from cells). Weight is less than lead acid (by allot, per amp hour), charging is quicker, usability is more. That 1000 amp hour battery provides 800 usable, safely. To get the equivalent in lead acid you would need 1600 amp hours of lead acid (~50% usable)...even more in colder temps (since lead acid capacity drops massively in colder temps).

During our last mountain boondocking trip (last week) our 440 amp hour lead acid bank dropped to about half capacity because of the temps...meaning we only had 220 total or 110 usable during the night!! That was tight and we had to conserve quite a bit. Our lithium neighbors had close to their full 400 (80% of 500) amp hour capacity.

There are certainly also negatives...this is leading edge, you need to have strict safety stops, you need to get the batteries above freezing batteries for charging (most folks keep them inside the coach). But wow...we are blown away by the positives. For us, specifically.

Here's some Balqon prices:
http://www.balqon.com/balqon-battery-cells/

Again, lithium makes NO sense for those who don't boondock a lot and/or don't see the benefits in more amp hours, faster charging, more capacity etc.

[Smitty77]

On this thread I went a bit soft on my post, with not too much detail.

But let me repeat my positive thoughts about Lithium batteries for RV in general. You can, and many are, do it today - and for a price that has dropped by a good 30-40% over the last few years. As I noted, I expect we will see Lithium battery prices really come down, once the volume of production from Musk's new mega battery factory come on line. (Not just great for RV'ers, but should really expand the number of On Grid homes that also add battery banks for night time usage at the same time they add Solar Panels to their homes.)

For those with existing rigs, it's also the added costs of having to be sure your charger, and or SP Controllers, are able to support the Lithium charging cycles. As Nina mentioned, newer inverters (and SP Controllers) are able to set custom programs for charging. But, I suspect the bulk of existing RV's do not have chargers capable of supporting them - so that is also an added cost.

The key here is how you use your coach, heavy Boondocking - is where Lithium really comes into it's play.

The RV industry will shift to more and more coaches that have Lithium, with supporting equipment, as OEM over the next five to ten years.

Think about how many coaches of the say the 80's and into the 90's - did not have robust inverters as stock. Today not on are inverters 'trickled down' into the entry level coaches, but more and more coaches are also coming OEM stock with Pure Sine Wave, and more sophisticated chargers combo's.

When I did my analysis three years ago on a new battery bank and solar panel system, I future proofed my design with equipment that will cover Lithium batteries in the future. At that time, the difference between X's 4 L16 Lifeline's (800AH) compare to 500AH Lithium (I never run down below 70% SOC on my AGM bank, so 500AH of Lithium is more usable AH power then 800AH of AGM's, and I'm conservative on how I use my battery bank.) was about $5K more. So I decided to run with Lifeline's, and be prepared for Lithium in the future.

Fun technologie, and as with so many things I see in RV'ing, one answer does not fit all owners. Many will be very happily and economically supported with 2 or 4 Golf Car 6V batteries forever. Park to Park owners, or very limited State or National Park (without hook ups) owners, also fit into this mix.

I do see a trend by many that feel that those of us who spend all that money on AGM's, or even Lithiums - have a problem in their thinking! But, I also know that many of us see the virtues of both of these battery types, and don't get too concerned with being thought of as having a thinking problem. Not to pick on the comment about bragging rights - but that is a classic example of what I'm saying. I got the same comment by a few, when I added excess SP capacity.

Each owner can make their own decision, and the majority of the RV'ing community is open and friendly enough to respect other's decisions. Very small population that beats the drum so strongly that we are loose in our thinking between the ears!

Best to all, and go have fun - in however you use your coach!
Smitty

[ecurb74]

I read the below listed blog about a couple that built their own lithium ion battery bank for their motorhome. It's quite interesting and might answer a lot of your questions about lithium batteries for your coach. They do give a one year follow up on their endeavor.

http://www.technomadia.com/lithium/


Bruce & Teresa
40' 2000 Foretravel U320
Cummins M11 450hp
Allison HD4060R 6 Spd W/Retarder

[nothermark]

FWIW It strikes me that another place for Lithiums might be the high end small coaches that are coming through with compressor based refrigerators but not enough battery and no room to add more.

[Tony Lee]

One problem with comparing different batteries is that the proponents of one type will skew things their way for their batteries and skew it the other way for the ones they don't favour.

For instance - AGM batteries being limited to 50% DOD. Since when! Battery lifecycles vs DOD is a matter of compromise. Take AGMs to 70% DOD and cycles will drop but this assumes that all cycles go down to that level. Even then, it will likely still be quite economical on a dollars per whole of life kWh and likely be ahead of lithium. Lithium's supposed weight advantage may not be as great if the calculations are done fairly, and anyway, since when has the average class A been too worried about a few extra pounds. Lithium promise (????) 20 year life or something equally silly while AGMs "only" get x years. Who is going to keep score over a 20 year span. Why aren't opportunity costs ever included in these cost comparisons?

Lithium proponents are their own worst enemy in many cases because they can't get their facts straight. Once it gets out of the realm of DIY first adopters and becomes a mainstream product, then, and only then will the average RVer get interested.

BTW - also need to get realistic as far as figuring out how to get the charge back into super-batteries once they become discharged. Seems to me that for the serious boondocker and full-timer, their dollar will go a lot further by spending a little bit on as much solar as can be fitted on the roof, rather than wasting it on expensive batteries with no (quiet) way of recharging them.

[WheelingIt]

Originally Posted by Tony Lee

BTW - also need to get realistic as far as figuring out how to get the charge back into super-batteries once they become discharged. Seems to me that for the serious boondocker and full-timer, their dollar will go a lot further by spending a little bit on as much solar as can be fitted on the roof, rather than wasting it on expensive batteries with no (quiet) way of recharging them.

Yes and no. Solar is fabulous for boondocking (we have 600 watts and we want more), but batteries are equally important. You need the batteries for overnight and you need batteries for those cloudy days (which you will have) and those short days (all winter) and those partially shaded days. Last week we barely made it through the night on our 440 amp hour lead-acid bank because temps had dropped (which had halved the capacity), we needed to run our furnace overnight (thanks to the chill) and sun was rising later & setting earlier thanks to the 10,000 foot mountains we had all around us. Of course we could run the generator, but where's the tech fun in that? So, we most definitely want more batteries.

But yeah...if you're not a boondocker, or you don't mind running the generator, or your not a techie none of this makes sense!!

[WheelingIt]

Originally Posted by Tony Lee

For instance - AGM batteries being limited to 50% DOD. Since when! Battery lifecycles vs DOD is a matter of compromise. Take AGMs to 70% DOD and cycles will drop but this assumes that all cycles go down to that level. Even then, it will likely still be quite economical on a dollars per whole of life kWh and likely be ahead of lithium. Lithium's supposed weight advantage may not be as great if the calculations are done fairly, and anyway, since when has the average class A been too worried about a few extra pounds. Lithium promise (????) 20 year life or something equally silly while AGMs "only" get x years. Who is going to keep score over a 20 year span. Why aren't opportunity costs ever included in these cost comparisons?

Well, we're talking more than a few pounds. Let's say I want 800 usable amp hours (which happens to be our goal right now).

-> Taking AGM's to 70%, I would need ~1,100-1,200 amp hours of AGM. If I go with my current batteries I'd need 10 of them, which would weigh around 660 pounds. If I upgrade to the honking 16L size I'd need 6 of them, just over 700 pounds. I can't physically fit that many in my rig, but let's ignore that for now.

-> Taking the Balqon to 80%, The 1,000 amp hour battery weighs 92 lbs. And I can fit it in my existing puny space, or slip it into our bedroom closet.

Again, none of this makes sense if you're not a serious boondocker since most folks never need that kind of battery capacity. But we're boondockers and we love to have the extra capacity...

[WheelingIt]

Oh and let me reiterate. For most folks Lithium doesn't make any sense at all. They're too techie, too expensive & most folks just don't need that much capacity. For the vast majority of RVers basic lead acid is cheap and easy. In fact a few basic golf cart batteries work perfectly fine and is all most people need.

For us, being avid boondockers...well it's different. We want 'em, oh yes we do.

[WheelingIt]

Originally Posted by WheelingIt

Well, we're talking more than a few pounds. Let's say I want 800 usable amp hours (which happens to be our goal right now).

-> Taking AGM's to 70%, I would need ~1,100-1,200 amp hours of AGM. If I go with my current batteries I'd need 10 of them, which would weigh around 660 pounds. If I upgrade to the honking 16L size I'd need 6 of them, just over 700 pounds. I can't physically fit that many in my rig, but let's ignore that for now.

-> Taking the Balqon to 80%, The 1,000 amp hour battery weighs 92 lbs. And I can fit it in my existing puny space, or slip it into our bedroom closet.

Again, none of this makes sense if you're not a serious boondocker since most folks never need that kind of battery capacity. But we're boondockers and we love to have the extra capacity...

Whoooops....sorry slight miss-calculation here (= major brain fart). You need 4 Lithium for the right voltage (12V system) so we're talking 368 lbs of Lithium compared to 660-700 lbs of lead acid (using the 70% model for the lead acid batteries). Not quite as dramatic, but you get the idea. At 50% draw-down on the lead acid you're looking at 950 lbs of battery....a bit more dramatic.

The cost of the Lithium for this usage level (800 amp hours usable) around $4800 compared to ~$3,500 for 6 of the L16 AGM's (assuming you take the L16's down to 70%). At 50% for the lead-acid I'd need 8 of the L16's at ~$4,600....getting close.

Space is a different matter. No way I could fit that many AGM's into our space.

[Luv2go]

Here's my experience with batteries in the Canyon Star:

I originally installed 1000AH of AGM lead acid, and despite babying the pack it lasted less than 3 years before it had only 20% capacity (200AH). It cost me $1000. About 3 1/2 years ago in the spring of 2011 I installed a 400AH lithium ion pack (composed of eight 200AH LiFePO4 cells from Thundersky). It cost $2100. In a capacity test I ran a few months ago they had 120% (480AH) capacity. Yes, there's a difference in AH capacity, read on...

With the lead acid pack, I kept most discharges to 15% (150AH) and once discharged to 40% (400AH). The new lithium ion pack is routinely discharged to 50% (200AH), several times to 80% (320AH) and once to 120% (480AH, the discharge mentioned above). It's on track for lasting more than 8 years and now has lasted longer than the lead acid pack it replaced. It has not lost significant capacity (seems to have gained instead) and will cost less per cycle than the lead acid battery pack it replaced at the end of 6 years.

The lead acid pack weighed over 1000lb, the lithium ion pack weighs 180lb. The coach was borderline overweight with the lead acid's and now is comfortably underweight.

To get equivalent AH capacity of lithium as I had with lead acid I would have spent $5250, but I had designed in enough lead acid to be able to discharge an average of 20% to maximize cycle life (theoretically), with lithium I was able to size the capacity of the battery much more closely to our actual use without excessive worry about shortening the life. Thus the difference in AH capacity.

This does not seem to be a typical experience with lead acid, most people see 5 years plus, I just must have been unlucky. Or maybe I bought a bad batch of AGM batteries. I could have bought Lifelines, but would have spent about $2500 for them. They undoubtedly would have lasted longer.

I would also agree with other posters that lithium ion batteries are not for everyone:

• When I did that capacity check (where I found the batteries had 120% capacity) I carefully monitored cell voltage and stopped the discharge before any cell got less than 2.9V. If I had gone too much lower I would have caused capacity loss or lost a cell.

• My pack needs periodic rebalancing using a separate power supply to bring up the low cells to the level of the high cells. Balancing is normally done automatically by a BMS, which I don't have (long story short, the battery supplier never sent me one I had ordered so I went without it). I do have a Cell Log 8S display in the coach which tells me each cell voltage and alerts me if they become too imbalanced. I'm investigating the latest BMS systems to see if there is a better one available than there was in 2011, as the one I ordered really didn't work the way I wanted it to.

• Charge and discharge parameters must be carefully chosen and a lot of chargers are not configurable enough to use with lithium ion batteries. The inverter/charger I use is a Trace SW2512 built in 2001, it has every feature I wanted including being fully programmable and includes an AGS. For example, I can shorten the absorption cycle to 0. The newest hybrid sine wave Magnums I've seen have a similar feature set if equipped with the AGS option. IIRC they have a setting (or documentation on settings) for LiFePO4 batteries.

• I usually store my coach with shore power connected, and for the year I didn't have shore power I relied on my solar panels to keep the batteries charged,so haven't had to worry about completely disconnecting the lithium pack. I would have to if I did not have solar or shore power. It's much more critical with lithium ion batteries because one gross overdischarge (under around 2.5V per cell) will permanently ruin the cell. Lead acid can be charged from 0V and will usually recover.

We do not full time, however we like to enjoy nature in the state and federal campgrounds we frequent with no generator noise. We have solar to charge our batteries even though it cost a lot more than if we just ran our generator when we needed a charge. But in our case as mentioned above the lithium ion batteries look like they will cost less per cycle than the lead acid batteries they replaced. Looking at Technomadia's cost analysis lithium ion batteries with the same useful capacity will cost less per cycle than Lifeline batteries, given the same AH discharge per cycle (i.e. comparing apples with apples).

The Technomadia posts had not been made in early 2011 when I designed my system, but they would have been a great help if they were.

Another interesting site with lots of lithium battery information can be found at evtv.me run by Jack Rickard. The site is geared towards electric vehicle converters, but he has done a lot of work with lithium ion batteries. He's disproved a lot of the myths along the way, and generated controversy as well (he, for example, does not believe BMS systems are necessary, almost everybody else says they are a requirement). My own experience leads me to believe there's a place for BMS's, but he gives a great counterargument for them, he has pointed out the the Cell Log 8S monitor that I use caused imbalances in his packs (search for Cell Log, it's in the comments).

Lithium ion coach batteries are not for everyone, but I for one have enjoyed designing, building and using our coach electrical system with them.

BTW, here's a link from this topic discussed last year, and yes, we're still in the early adopter/tinkerer stage!

[WheelingIt]

Originally Posted by Luv2go

Here's my experience with batteries in the Canyon Star:

I originally installed 1000AH of AGM lead acid, and despite babying the pack it lasted less than 3 years before it had only 20% capacity (200AH). It cost me $1000. About 3 1/2 years ago in the spring of 2011 I installed a 400AH lithium ion pack (composed of eight 200AH LiFePO4 cells from Thundersky). It cost $2100. In a capacity test I ran a few months ago they had 120% (480AH) capacity. Yes, there's a difference in AH capacity, read on...

With the lead acid pack, I kept most discharges to 15% (150AH) and once discharged to 40% (400AH). The new lithium ion pack is routinely discharged to 50% (200AH), several times to 80% (320AH) and once to 120% (480AH, the discharge mentioned above). It's on track for lasting more than 8 years and now has lasted longer than the lead acid pack it replaced. It has not lost significant capacity (seems to have gained instead) and will cost less per cycle than the lead acid battery pack it replaced at the end of 6 years.

The lead acid pack weighed over 1000lb, the lithium ion pack weighs 180lb. The coach was borderline overweight with the lead acid's and now is comfortably underweight.

To get equivalent AH capacity of lithium as I had with lead acid I would have spent $5250, but I had designed in enough lead acid to be able to discharge an average of 20% to maximize cycle life (theoretically), with lithium I was able to size the capacity of the battery much more closely to our actual use without excessive worry about shortening the life. Thus the difference in AH capacity.

This does not seem to be a typical experience with lead acid, most people see 5 years plus, I just must have been unlucky. Or maybe I bought a bad batch of AGM batteries. I could have bought Lifelines, but would have spent about $2500 for them. They undoubtedly would have lasted longer.

I would also agree with other posters that lithium ion batteries are not for everyone:

• When I did that capacity check (where I found the batteries had 120% capacity) I carefully monitored cell voltage and stopped the discharge before any cell got less than 2.9V. If I had gone too much lower I would have caused capacity loss or lost a cell.

• My pack needs periodic rebalancing using a separate power supply to bring up the low cells to the level of the high cells. Balancing is normally done automatically by a BMS, which I don't have (long story short, the battery supplier never sent me one I had ordered so I went without it). I do have a Cell Log 8S display in the coach which tells me each cell voltage and alerts me if they become too imbalanced. I'm investigating the latest BMS systems to see if there is a better one available than there was in 2011, as the one I ordered really didn't work the way I wanted it to.

• Charge and discharge parameters must be carefully chosen and a lot of chargers are not configurable enough to use with lithium ion batteries. The inverter/charger I use is a Trace SW2512 built in 2001, it has every feature I wanted including being fully programmable and includes an AGS. For example, I can shorten the absorption cycle to 0. The newest hybrid sine wave Magnums I've seen have a similar feature set if equipped with the AGS option. IIRC they have a setting (or documentation on settings) for LiFePO4 batteries.

• I usually store my coach with shore power connected, and for the year I didn't have shore power I relied on my solar panels to keep the batteries charged,so haven't had to worry about completely disconnecting the lithium pack. I would have to if I did not have solar or shore power. It's much more critical with lithium ion batteries because one gross overdischarge (under around 2.5V per cell) will permanently ruin the cell. Lead acid can be charged from 0V and will usually recover.

We do not full time, however we like to enjoy nature in the state and federal campgrounds we frequent with no generator noise. We have solar to charge our batteries even though it cost a lot more than if we just ran our generator when we needed a charge. But in our case as mentioned above the lithium ion batteries look like they will cost less per cycle than the lead acid batteries they replaced. Looking at Technomadia's cost analysis lithium ion batteries with the same useful capacity will cost less per cycle than Lifeline batteries, given the same AH discharge per cycle (i.e. comparing apples with apples).

The Technomadia posts had not been made in early 2011 when I designed my system, but they would have been a great help if they were.

Another interesting site with lots of lithium battery information can be found at evtv.me run by Jack Rickard. The site is geared towards electric vehicle converters, but he has done a lot of work with lithium ion batteries. He's disproved a lot of the myths along the way, and generated controversy as well (he, for example, does not believe BMS systems are necessary, almost everybody else says they are a requirement). My own experience leads me to believe there's a place for BMS's, but he gives a great counterargument for them, he has pointed out the the Cell Log 8S monitor that I use caused imbalances in his packs (search for Cell Log, it's in the comments).

Lithium ion coach batteries are not for everyone, but I for one have enjoyed designing, building and using our coach electrical system with them.

BTW, here's a link from this topic discussed last year, and yes, we're still in the early adopter/tinkerer stage!

Cool write-up. Cheers for sharing. Cell balancing is the one area we're still trying to properly understand before we make the jump. I'll read through the evtv.me link.

[joes2901]

I looked at the referral to a Lithium Ion battery mfgr. (in So. Calif's Harbor City) attached to one of the posts and noted that the 2.6K AH battery pack was $1,650 but one of the specs. that has not been mentioned is that it is limited to a max. discharge rate of 150 Amps. to 50% and 100 at 70%. That would be a problem if you have a 2.8 KW inverter and leave it on all the time so you have power like you are always connected to the grid. For example, you wake up and the battery bank is 70% and you turn on the coffee maker, then run the convection microwave for 10 minutes to bake breakfast, while watching Direct TV. The inverter will be pulling 233 to 350 Amps. from the battery bank which exceeds the Lithium capability. I do this a couple times a week and the 800 AH Lifeline bank handles it just fine.

My 2012 Newmar Bay Star 2901 has 4 Lifeline L-16s laying across the Ford chassis frame rails (480 pounds) and I have a Magnum 2.8 KW Inverter/Charger with the BMK and AGS plus 765 Watts of solar panels connected to an Outback controller. I expect 10 to 12 years of trouble free AGM use because the AGS starts the generator when the batteries drop below 65%. During the 14 hour daylight days of Summer I see up to 400 AH from the solar panels on a bright cloudless day. It is 8:00 AM when the generator starts if I have had 2 days of clouds, and on a bright sunny morning I am seeing 40 Amps from solar and 125 Amps from the generator so the AGMs are accepting 165 Amps and the run time to 90% is only an hour to an hour and a half. The discharge rate limits of the Lithium Ion battery bank could not improve on that even though it would be lighter in weight and less costly than the $2,500 for 4 Lifeline L-16s.

What is the deal with the Canyon Star that caused such a short life for your AGMs?

[Luv2go]

Originally Posted by joes2901

I looked at the referral to a Lithium Ion battery mfgr. (in So. Calif's Harbor City) attached to one of the posts and noted that the 2.6K AH battery pack was $1,650 but one of the specs. that has not been mentioned is that it is limited to a max. discharge rate of 150 Amps. to 50% and 100 at 70%. That would be a problem if you have a 2.8 KW inverter and leave it on all the time so you have power like you are always connected to the grid....

Yes, that is one of the things to be careful of. The LiFePO4 batteries I have are rated at 3C continuous (1C = 200A). Since I use two in parallel that makes continuous a discharge rating of 1200A, no issues here.

The battery pack you are referring to is really about 200AH (they rate at at 2.6KWH, divide by 12 to get amp hour rating) the cells look like the same ones I use, so they are derating it for some reason, most likely the copper buss bars between the cells.

I doubled up on the ones the manufacturer provided, my calculations showed that doubling enough gave the equivalent of 4/0 wire, which is recommended by my inverter manufacturer for battery wiring.

Originally Posted by joes2901

...What is the deal with the Canyon Star that caused such a short life for your AGMs?

I suspect the batteries were defective. One was for sure, soon after I disconnected it the voltage read 8V. The others are still sitting in my basement, last time I checked they were about half charged.

[wanderso]

One wonders if there are higher fire risks with Lithium. Witness the Boeing 787 battery fire issue (recently fixed) along with both Dell and Apple's challenge in the past.

I would love to get the weight reduction. With more and more cars also utilizing engine start/stop methods, the tech is bound to become more unimportant.