Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4)
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 $$$ for AGM, Gel, or std Wet Lead acid?
Hopefully we will answer these questions and more in this thread...
Note: this thread will constantly change as new information surfaces, errors corrected, etc. Apologies in advance for the technical mumbo jumbo that's unavoidable. Will do my best to simplify when possible.
My Electronics lab
A few tools we will be using
Snap-on Carbon pile variable load tester added, to replicate a motorcycle starter motor typical load of 75amp.
This thread has become voluminous to point of putting most eyeballs to sleep reading it all. so here's a quick review of conclusions so far ...
have posted this several times, but here goes again:
provided you actually need a new battery ...
for most folks, my advice is go with AGM. unless weight is totally critical. AGM has one of the main advantages of LiFePO4 which is very low self discharge. unless one has a large parasitic current drain. trickle charger will not be needed for LiFePO4 or AGM over the winter.
some bikes normally have a small self discharge. for those bikes a trickle charger will be needed regardless of what type battery is used. Your lead/acid battery charger may or may not properly charge LiFePO4 batteries.
if you've got a modern adventure bike and decide that it's worth $$$ 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
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
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.
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.
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.
This is one of his projects.
Again, I do not have any first hand experience, but I would like to see real test data.
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.
Anyone have experience with lithium iron phosphate batteries in their bike? They seem to offer some advantages,well other than cost.
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.
Shorai 18ah (pb eq)
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?
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
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.
|Times are GMT -7. It's 05:58 AM.|
Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015