Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4)

Discussion in 'The Garage' started by _cy_, Jan 20, 2012.

  1. _cy_

    _cy_ Long timer

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    Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4)

    Let's examine the most popular battery types, how to charge, advantages, disadvantages, etc.
    In particular the new Lithium Iron Phosphate (LiFePO4) batteries. being fairly new not a lot of long term feedback exist yet.

    Have been experimenting with li-ion cells for many years and was part of the original group on Candlepower Forums to adopt use of Li-ion cells. We were among world first users of individual li-ion cells. Several fires and explosions back then. A123 was barely getting started.

    If you are in the market for a Li-ion motorcycle like I am... lots of questions to be answered. Are LiFePO4 motorcycle batteries with 18 Amp Hour rating and weigh 2lbs possible?

    Are Lithium Iron Phosphate (LiFePO4) motorcycle batteries ready for prime time?
    should I spend my hard earned $$$ for AGM, Gel, or std Wet Lead acid?

    Hopefully we will answer these questions and more in this thread...

    Note: this thread will constantly change as new information surfaces, errors corrected, etc. Apologies in advance for the technical mumbo jumbo that's unavoidable. Will do my best to simplify when possible.

    My Electronics lab
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    A few tools we will be using

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    Snap-on Carbon pile variable load tester added, to replicate a motorcycle starter motor typical load of 75amp.

    [​IMG]
    #1
  2. _cy_

    _cy_ Long timer

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    This thread has become voluminous to point of putting most eyeballs to sleep reading it all. so here's a quick review of conclusions so far ...

    -------------------------------------------------

    have posted this several times, but here goes again:

    provided you actually need a new battery ...

    for most folks, my advice is go with AGM. unless weight is totally critical. AGM has one of the main advantages of LiFePO4 which is very low self discharge. unless one has a large parasitic current drain. trickle charger will not be needed for LiFePO4 or AGM over the winter.

    some bikes normally have a small self discharge. for those bikes a trickle charger will be needed regardless of what type battery is used. Your lead/acid battery charger may or may not properly charge LiFePO4 batteries.

    if you've got a modern adventure bike and decide that it's worth $$$ to save 10 lb or so over AGM or Gel. forget the marketing hype mfg use to calculate which battery to use.

    use actual amp hour rating less 25%. note this is for modern Adventure bikes, which has one of the highest battery demands of any bike. example, if factory ratings is 12 amp hour x .75 = 9 amp hour actual LiFePO4 amp hour rating.

    some bikes that only are used in fair weather can get by with much lower LiFePO4 amp hour ratings. one advantage of LiFePO4 batteries is ability to deliver larger amps for size, while maintaining a very flat discharge cycle.

    learning how to start your bike with LiFePO4 in cold weather is mandatory. yes procedures are different.

    take mfg amp hour ratings with a bucket of salt... use real amp hour ratings to size your LiFePO4 needs. LiFePO4 batteries when sized properly are robust, super lightweight batteries.

    ----------------------

    use caution when replacing any battery substantially smaller than OEM. mount battery equally secure as OEM. taking extra care to make sure positive side cannot ground out.

    Lithium batteries discharge at HUGE rates. Dead shorts are suspected in bike fires resulting in total loss.

    LiFePO4 batteries that use cables to attach instead of fixed posts require special caution. positive connections need enough insulation, to where grounding out is not possible. including in the event battery gets lose. dead shorts can result in temperatures hot enough to weld with.

    -----------------------------

    one of the advantages of Lithium batteries is it's ability to deliver HUGE amps.

    but drawback is extra costs as compared in equal amp hour energy delivered. more amp hour capacity = more $$$

    this is why LiFePO4 batteries found it's first non-electric vehicle acceptance in the marketplace in Motorcycles and not in applications like starting diesels or cars. to create a battery with enough amp hours to support those applications. costs would exceed benefit.

    what's it worth to you to save say 10lbs.... for the weight wienie paying $$$ for carbon parts for his race bike and/or wanna be race bike. those are some of the cheapest lbs one can unload.

    but for most folks ... best replacement battery still remains AGM. unless of course it's worth all the $$$ to save those 5-10 lbs.

    yes ... one can successfully use LiFePO4 batteries in the most demanding applications. but the amp hour capacity has to be there. my recommendation is actual lead acid amp hour ... less 25%.

    if you follow most lithium battery mfg suggestions. you'll end up with a battery that supports your bike in the summer. NOT for the winter.

    R1200GS has some pretty demanding requirements. including needing reserve amp hour capacity to crank bike over repeatedly if your bike should go down from contaminated fuels, etc. there will be times pounding on fuel pump while cranking and cranking will get your bike back up again.

    for cold weather, one needs to understand warm up cycles consumes amp hours. starting procedures has to be learned to start your motorcycle in cold conditions.

    your heated gear doesn't understand all those fancy PB/EQ ratings battery mfg use. heated gear draws real amps... if your lithium battery say has only 4.6 amp hours. then your heated suit uses a chunk of that reserve just before you put bike away.... guess what happens next morning?

    above is why for most folks ... my recommendation is to stick with AGM. but some of us are willing to pay the toll to save 10lbs. not likely someone trying to sell you a lithium battery will inform you... probably because they don't know better.

    here's a chart listing voltages with corresponding battery charge state
    [​IMG]

    --------------------------------

    Amp Hour capacity in LiFePO4 batteries and how important it is to properly size a lithium battery.

    PB/EQ is most lithium battery mfg's attempt to capitalize on Lithium battery's ability to discharge at huge rates. without diving into all the technical reasons why this is so and putting most eyeballs to sleep in the process. :lol3

    this video by Joel Wiseman, one of the most knowledgeable BMW tech's on Adv.

    shows what happens when a LiFePO4 battery is undersized as compared to AGM batteries that are correctly sized.

    <iframe src="http://www.youtube.com/embed/ySNbSZTgplA" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

    -------------------

    a common question .... will a standard lead acid battery charger properly charge my LiFePO4 battery?

    answer is it depends on the charger. for not all lead acid battery chargers work the same. it's best to use a charger designed specifically to charge LiFePO4 batteries. But one can improvise and use a charger designed to charge lead acid by carefully monitoring charge. then remove when charge gets close to full. being careful not to exceed max voltage of 14.4v for LiFePO4 batteries.

    Cellpro Powerlab 8 is what I'm using. A favorite of the RC world. considered the most powerful/versatile of all hobby chargers with software to track charge cycle and generate graphs.

    here's my charge station with a full electronics lab
    [​IMG]

    --------------------------

    Using Heated Gear with LiFePO4 batteries

    heated gear don't understand PB/EQ. they draw real amps. Almost all LiFePO4 battery mfg like to use amp equivalents to lead acid batteries. that may be valid for starting requirements. but heated gear don't care... they draw regular amps.

    listed amp/watts for Gerbings micro wire. even if you don't have Gerbings, amp draw will be real close. amp x volt = watts

    1. Jacket 6.4 amp/77watts
    2. Vest 4.5 amp/54watts
    3. Pants 3.6 amp/44watts
    4. Gloves 2.2 amp/27watts
    5. Grips 3.0 amp/36watts

    let's say you've got a heated jacket, heated gloves and heated grips = 11.6amp draw

    let's say your LiFePO4 battery has an actual Amp Hour capacity of 6 amp hour. this means your battery will support your heated gear for about 1/2 hour before going dead.

    then let's factor in alternator output and amp draw from rest of bike. on short rides using heated gear, it's quite possible to use more amps from your battery than Alternator has a chance to replenish.

    when you put your bike away for the night after that short cold ride. your 6 amp hour battery may not be fully charged.

    next morning it's say 30f degrees ... you go to start your bike with a half dead battery.... fail ... one automatically blames the battery. when the fault is putting bike away with a half charged battery.

    this is where LiFePO4 batteries with BIG reserve capacities shine. Lithium batteries internal resistance goes way up with battery gets cold. this means substantially less amps will be delivered. cold start procedures calls for a load to be placed on LiFePO4 battery. this heats up battery reducing internal resistance, allowing more amps to be delivered.

    ahhhh... but there is a catch... heating a cold LiFePO4 battery takes amps... battery must have enough reserve capacity to heat battery up and start your motorcycle.

    clear as mud... nah.. it's not that hard to understand. Adventure bikes must have some of the hardest demands on a battery. if you've got a R1200GS and you are planing on climbing the Andes mountains and camping out.

    go with an AGM or if saving 10lb+ is worth the trouble... go with largest LiFePO4 motorcycle battery available.
    #2
  3. nulluser

    nulluser Been here awhile

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    I am looking forward to what you come up with, specifically in regards to Peukert and temperature effects.

    AGM batteries were chosen for my electric bike because of price considerations. I picked up the batteries for around $20 each and decided to design a bike around them: http://evalbum.com/3500

    The plan is to experiment with the Thunder Sky lithium iron yttrium phosphate batteries in a Geo Tracker next summer.
    #3
  4. _cy_

    _cy_ Long timer

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    hmmmm ... was not planning on getting Peukert law, but was going to experiment with effects of temperature on lithium iron phosphate battery once I get them in. it's well known li-ion cells can drop dramatically under cold temps. the same with AGM which could loose about 45% of rated capacity at 4f degrees.

    what Peukert law basically states is high amp draws will use up more capacity than slower amp draws. efficiency loss could be 15% to %40+ vs lower current drain rates will achieve close to full rated capacity.

    which leads us up the some of the mumbo jumbo used by some folks trying to sell these new li-ion batteries. we get to hear about effective amp hour rates. vs actual AH rates. marketing strikes.... 6 AH becomes 18AH for an effective increase of 3x.

    let's cover one important aspect of li-ion cells... which is it's ability to discharge at an extremely high rate. this is why CCA (cold crank amps) rating for li-ion batteries means very little. Li-ion cells will deliver full power, then fall flat. little to no warning battery is running low.

    different li-ion chemistry deliver different voltages and capacities. some are more stable then others. lithium iron phosphate is the most stable of all the li-ion chemistry so far. li-ion cells is a dynamic field with improvements being discovered constantly.

    for instance...Aleees claims new double-layer nano-carbon coating technology enhances battery cycle life 2.7 times ... if this claim pans out... implications could be HUGE for electric auto mfg.
    #4
  5. Anorak

    Anorak Woolf Barnato

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    What is there to experiment with? The Thundersky is well proven in regular electric vehicles. A friend built an electric R1 using them years ago. He also does a plug in Prius conversion with a 50 mile pure electric range. They aren't too good for high performance due to the max discharge rate of 3C.

    This is one of his projects.
    #5
  6. nulluser

    nulluser Been here awhile

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    I don't want to cause a negative association to the brand name, but from what I have read the batteries are hit and miss. There are some problems with expansion and the need to make a metal frame to keep the cells compressed, and capacities that do not meet the claimed numbers.

    Again, I do not have any first hand experience, but I would like to see real test data.
    #6
  7. nulluser

    nulluser Been here awhile

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    A big problem I had was estimating the 45 minute rate from the usual two hour advertised rate. In particular, my batteries are rated at 55 amp-hour (2 hour), and that ends up being about 25 amp-hour for 45 minutes. Combined with keeping the pack above 50 percent depth of discharge, I was left with around 13 amp-hour at 72 v, (6 batteries) which was around 1000 watt-hours. Well bellow the 4000 watt-hours I imagined from the raw numbers.

    At a 50 percent depth of discharge, the AGM batteries were good for around 500 charge-discharge cycles, which I consider poor. My pack would have cost around 1200 full retail when I bought it, and a two year lifespan is not good enough in my opinion.

    Now, consider modem lithium cells for a 4000 watt-hour pack. 14 of the 3.2v 90 Ah cells would run around $2000. I wonder if the run-time would be longer because of different internal resistance due to the battery chemistry.

    It was hard for me to make an apples to apples comparison because of the lack of manufacture data. What wold be very useful is a graph of capacity vs discharge rate, and a graph of capacity vs cycles for a modern cell chemistry.
    #7
  8. Anorak

    Anorak Woolf Barnato

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    He doesn't use Thundersky in the motorcycle. And, the Prius batteries are compressed in a metal frame. The advantages of Thundersky, they're pretty safe and they're pretty cheap with better energy density than lead acid, nicad or nimh. For high performance, check out Enerdel. Enerdel batteries are made in the USA.
    #8
  9. anotherguy

    anotherguy Long timer

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    Anyone have experience with lithium iron phosphate batteries in their bike? They seem to offer some advantages,well other than cost.
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  10. _cy_

    _cy_ Long timer

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    that seems to be the basic problem ... aside from custom packs made from 4x A123 cells bundled together to make up 12v... there's very little information available.

    what we need feedback on is the newer lithium iron phosphate batteries made from prismatic cells. which are just started to be marketed to motorcycles. for the electric scooter crowd lithium iron phosphate has a decent track record.

    note... anyone that's used a new generation li-ion battery powered drill from Dewalt, Milwaukee, etc has used lithium iron phosphate batteries.

    here's what's en route to me. a true 20AH lithium iron phosphate battery that happens to be the correct dimension for my R80G/S. note this 20ah battery weight 6lbs vs Shorai 18ah (claimed) weight 2lb .. conclusion so far ... not possible for a battery that weight 2lb to deliver a true 20ah capacity. note the balancer listed is for overcharge protection.

    http://www.electricmotorsport.com/store/ems_ev_parts_batteries_lpf_gbs_20ah.php

    [​IMG]

    Shorai 18ah (pb eq)
    http://www.batterystuff.com/powersports-batteries/LFX18A1-BS12.html

    [​IMG]
    #10
  11. Anorak

    Anorak Woolf Barnato

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    I've got a Lightning Nano on my K1200R. It uses eight A123 cells with battery management circuitry. I've posted a video here previously of it starting my 420SEL Mercedes. So far it works fine. Lightning doesn't make any spurious capacity claims.
    #11
  12. _cy_

    _cy_ Long timer

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    great feedback! you video demonstrates why CCA ratings mean little with li-ion cells. li-ion cells will discharge at high rates, then fall flat suddenly when empty.

    some don't need much reserve capacity, some do... since I'm running electric Gerbing jacket/pant/gloves/socks. depending on what's used. I'd like to have at least stock AH reserves on hand. in case bike is doing short runs.

    what's the weight of your pack?

    do these spec's match your battery?
    http://racetech.com/html_files/LightningBattery.html

    Specifications:

    • Cranking Amps: 240
    • Capacity: 4.6 Amp-Hours
    • Nominal Voltage: 13.2 Volts
    • Max Charging Voltage: 15.0 Volts
    • Weight: 1.8 lbs. (817 grams)
    • Dimensions: 115mm wide x 75 deep x 65 tall (4.5" x 3 x 2.6)
    [​IMG]
    #12
  13. Watercat

    Watercat . . . gravity sucks

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    :lurk

    There's gotta be at least a few inmates out there with real-world ADV-riding experience, who've used the Shorai ? ? ?

    Please chime in.

    Awaiting cy's test results, too . . . . . . :ear

    Thanks.
    #13
  14. Anorak

    Anorak Woolf Barnato

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    Yes, that's the one.
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  15. nulluser

    nulluser Been here awhile

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    Heh, I was thinking about electric vehicles when I read the thread.

    For a regular motorcycle, the most important thing to me is the self discharge rate. I would love to be able to park the bikes over the winter and never have to worry about starting them in the spring.
    #15
  16. _cy_

    _cy_ Long timer

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    if self discharge is your most important criteria ... then a sealed battery like AGM will do the job. provided there is no ghost discharge (disconnect battery for long term) a new AGM battery will discharge at 1-2% .. so let's call it 3% self discharge per month. no battery tender needed.

    lithium iron phosphate cells discharges at 2-3% per month (5-10% per month with smart circuits). note a gel cell battery is best at deep discharge applications. NO battery should discharged to completely dead. permanent damage typically occurs.

    AGM and gel cell batteries are similar that both are sealed. they are not the same. Gel batteries should not be charged at over 14v ... permanent damage will occur.
    #16
  17. _cy_

    _cy_ Long timer

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    new information surfacing..... Shorai batteries are not compatible with EnDuraLast aftermarket charging systems for Airheads. does anyone know why?

    No clue contained in Shorai spec's http://www.shoraipower.com/downloads/lfxspecs.pdf
    note Amp hour ratings are listed as PB EQ, not conventional Ah hour
    ------------------------

    Part #: EDL-VoltRect

    Combination Electronic Voltage Regulator & Rectifier. Replaces BOSCH 3-phase diode board / rectifier and voltage regulator. Advanced metal ceramic heat transfer technology replaces the BMW R Airhead & Moto Guzzi diode board system. Mounts remotely outside the alternator cover for high reliability and performance. Not Compatible with lithium iron batteries as supplied by Shorai.

    http://www.euromotoelectrics.com/Bosch_Alternators_and_our_Exclusive_EnDuraLast_Charging_Kit_s/1.htm

    [​IMG]
    #17
  18. J117

    J117 Battery Tech

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    There are a couple of things to clear up here. You guys may know all of this already, but then again you may not.

    When you are dealing with a lead acid battery of any chemistry, you have to take into account Peukert's law.
    <dl><dd>[​IMG]
    </dd><dt>The basic idea here is that the realized capacity of a lead acid battery goes down proportionally related to the amperage of the load placed on the battery. Example, look at any deep cycle battery's 20Hr rate, vs. 10Hr rate. A perfect example is that BMW 51913 batteries used to be rated on a 20 hr rate to give the 19AH rating. They are now rated at a 10 hr rate to give the 18AH rating. Ampere Hour ratings mean that a load of (X) was placed on the battery for a certain number of hours, standard rating is 20 hours, and that is lasted that full 20 hours before flat lining. For example if a battery is rated at 100AH @ a 20Hr rate, then they placed a 5 amp load on that battery, and it lasted for 20 hours. The problem comes when you try to then mentally translate that to a 10 Hr rate. So if you say, want to run a 10 amp load on the battery that is rated at 100AH @ 20 Hrs, you think it will last for 10 hours, but that is not true. As your amperage increases, the realized capacity of the battery will decrease in proportion to the amperage. If you have two ratings, eg. a 20Hr and a 10Hr, then you can use Peukert's law to figure out what the exponent that determines the proportional change is. That is far more complicated that I need to go into here, but what you need to know is that different types of lead acid batteries of differing qualities will have different rates of discharge.
    </dt></dl>When you then translate the AH rating to Lithium you are faced with some challenges. The standard for so long has been lead acid, rated at a 20hr/then 10 hr rate. To further complicate things, when you are dealing with starting engines, the construction of the standard standard starting lead acid battery is heavily in favor of the short term discharge rate, and not so much on the deep cycle side. This leads to ratings like CCA, taken at freezing temp. for 30 seconds at 1/2 voltage. That sort of situation is absolutely impossible to put on a lithium based battery, because they cannot put out power at 1/2 voltage. So the CCA ratings on lithium batteries are essentially the short circuit current possible for the cells they are constructed with through their BMS systems.



    The problem with amp hours though, continues. Some manufacturers of Lithium starting batteries, Shorai, Braile battery, and others, have chosen to differentiate between AH, and AH PBEQ. If Shorai or Braile ever makes a deep cycle application battery, then they will have to rate that battery in actual AH @ 20 Hr rate. Which, btw does not change for Lithium. There is no Peukert's law for lithium batteries. A lithium 100AH would discharge in 20 hrs at 5 amps, and 10 hours at 10 amps. But I digress. For starting motorcycles, Shorai and Braile know there are all of us persnickety BMW guys out here who want an 18 AH battery Darn it! So, they use AH PBEQ to compare their batteries to the Lead Acids we all have been using forever. The issue is that there are people who don't read the warnings, like (DONT USE ON ELECTRIC VEHICLES!!) because they figure that they have just figured out a way to power their electric tike off of a 2 pound battery. A Lithium battery that had an actual 18AH rating would weigh a lot more than 2 pounds. But, if you are just trying to start engines, and run lights while your bike is running and producing a charge, then you don't need a true 18AH. You need the equivalent to your old lead acid 18AH battery.


    Moral of the story boys and girls is to use these batteries for what they were designed to do. (And when you disregard their purpose and try to run your laptop/coffeemaker/fridge/freight train off of them and it doesn't work :huh, don't yell at their makers, go look in the mirror and have your anger management session.) A Shorai/Braile battery that is rated at 18AH PBEQ will only have an actual 6 AH inside of it in flat prismatic cells, not A123's, I have taken them apart. Granted, you can actually use 96% of that 6AH, but it will not run a 2 amp electric motor for 9 hours, it will run it for 3. And for the record, your BMW 18AH @ 10Hr rate starting battery will only run it for 3 hrs as well. :freaky
    #18
  19. _cy_

    _cy_ Long timer

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    #19
  20. anotherguy

    anotherguy Long timer

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    Well good thing my AGM is showing no sign dying.
    #20