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

[captain pabst]

Originally Posted by herrhelmet

Taco, do you have a running bike you could hook it up to? If it were mine, I'd charge it up that way if possible. Otherwise, yes at this point I'd put it on a trickle charger. I try to keep mine above 13.25 volts.

are those 26650 cells in your sycl batteries safe on a battery tender plus (12 volt at 1.25 amp)?

[herrhelmet]

Originally Posted by captain pabst

are those 26650 cells in your sycl batteries safe on a battery tender plus (12 volt at 1.25 amp)?

Yes, the 26650s can be charged up to a 2 amp rate. No need to leave it on the charger for extended periods, however. Once it gets to 14.4 volts take it off.

[RozzyCat]

Chiming in with real world experience on Shorai. I've not been successful starting my KTM990 when left out overnight below 45 degrees despite following several "warm up" procedures. I went back to the stock lead acid battery. Shorai sent me a replacement but I have not been able to test it yet.

A number of other guys/gals report no problems.

[OaklandStrom]

This is good stuff.
The battery in my Wee is probably not going to make it through winter.

I'd love to take more weight off the bike, but would like to have something that is completely compatible with my battery tender (or something I never need to charge?!?) and doesn't cost a fortune.

[_cy_]

finally received my Lithium Iron Phosphate battery today... naturally couldn't wait to dive in.
rated at 3C or 60amp continuous, 10C or 200amp intermittent discharge, or plenty of amps to start any motorcycle.

first up is to charge the battery. let's see what the spec's say...

max charge rate is 3C, recommend .5C - .8C charge rate
max voltage listed 3.6v per cell x 4= 14.4V max charge

useful voltage is 11.2v to 14.4v

since my 0-40v 70 amp regulated power supply is not hooked up yet. And I don't have access to a commercial lithium Iron phosphate charger. we'll make do with a dumb 12v 60 amp charger. it's actually got several setting that allows selection of what voltage is used for current cut-off. works out very nice!

Specifications

- Nominal Voltage: 12.8V (4X 3.2 V)
- Nominal Capacity: 20 Ah
- LiFeMnPO4 chemistry
- Operation Voltage Range: 11.2 to 14.4V
- Weight: 3.0 kg or 6.6 lbs
- Dimension: 178X76X165 mm or 7.0X3.0X6.5 in
- Max Charging Current: 3C, ... .8C to .5C preferred
- Max Discharge Current: 3C (continuous) / 10C (pulsed)
- Cycle Life : >1500 (80%DOD)
- Operating Temperature: -20 to 65 C or -4 to 149 F
- Self Discharge Rate: <3% monthly
- Accessories included: jumpers, bolts or rivets, washers, split washers and cell covers
- The 4-cell pack is enclosed in a plastic box

Nominal Voltage (V)	Capacity (Ah)	Dimensions (mm)	Weight (kg)
12.8	20	178 x 76 x 165	3.0

balancer/overcharge circuit boards




weight is 7.5lb not 6.6lb claimed



shipped voltage is 13.21v



charging at 14.4v @ 8amp... not enough amps



out comes the dumb charger... 14.3v @ 17amps ... close to desired .8C rate



monitoring temp while charging to make sure battery is not getting too hot during charge
not even warm at 17 amp charge rate



battery is getting close to fully charged ... let's stop take a few readings



barely warm



resting voltage 13.97v after 5 minutes... going down to 13.53v after an hour



finishing off charge at 14.4v @ under 1amp with HP regulated power supply. when voltage reaches 14.4v, all current will terminate by HP circuitry. normally would be using my Schulze charger, but it's dead until I send it back to Germany for repairs.





after trickle charging for a few hours ... battery finally reached 14.39V



after resting for an hour... finally a resting voltage 13.92 .. what a PITA to charge lithium iron phosphate when you don't have a charger with correct algorithm. appears voltage drops by about .5 volts after resting an hour.

[_cy_]

balancer/overcharge protection circuits in action ... be interesting to see how much additional parasitic drain protection circuits causes. these cells bare are rated at 3% self discharge per month



with flash off so your can see LED light. green for safe, red for bleeding off voltage
right cell measures over 3.54V which triggers volts bleed down (slowly)



another cell goes over 3.54v, red LED lights to indicate volts bleedoff

[herrhelmet]

Originally Posted by _cy_

balancer/overcharge protection circuits in action ... be interesting to see how much additional parasitic drain protection circuits causes. these cells bare are rated at 3% self discharge per month

Will it start your bike?

[Anorak]

Originally Posted by _cy_

balancer/overcharge protection circuits in action ... be interesting to see how much additional parasitic drain protection circuits causes. these cells bare are rated at 3% self discharge per month

Those look like Sky Energy cells.

[_cy_]

Glazed eyeballs alert ... was trying my level best to avoid technical mumbo jumbo.... but in this instance, just cannot avoid it.

in fairness to Shorai battery who chooses to state their amp hour rating in PB EQ = lead acid equivalent. Peukert law has to explained ... by the way please feel free to correct me if I'm stating this wrong and/or over simplifying.

Peukert law says as amp draw increases efficiency loss in terms of amp hours capacity decreases. Peukert loss is proportional to internal resistance of battery's cells. and no I'm not going to put up no sticking formula, charts and graphs.... yet

all lead acid batteries, which include Flooded/wet, Gel and AGM has higher internal resistance vs Li-ion cells, of which Lithium iron phosphate is but one type chemistry available. Li-ion cells has very low internal resistance (li-ion discharges at high rates). on the order of 2% to 5% Peukert losses for higher discharge rates. in other words my 20 AH lithium iron phosphate would be equal to approximately 30% increase in Amp hour capacity as compared to lead acid.

I know... clear as mud

had to fabricate two copper tabs.. note this lithium iron phosphate battery was never mean for motorcycle starting duties. just that it was accidentally the correct size and configuration needed.
top plate will be trimmed to fit copper tabs.

[_cy_]

Originally Posted by herrhelmet

Will it start your bike?

yes.. test battery starts R80G/S just fine. battery measured 13.31v. note test battery rated at 3C or 60amp continuous discharge. typical motorcycle starter will draw about 100 amp for a fraction of second, then draw about 70 amps for 1-3 seconds burst. then wait 30 seconds and try again if needed.

would be really surprised if a 20amp hr li-ion battery rated for 60 amp continuous ... couldn't sustain a 70 amp load for 3 seconds for several cycles.

had to try to start my Cummins turbo diesel first which it did not start (used 20ft jumper cables). heater grid ran battery down pretty good before starting G/S. note all lights are brighter due to higher system voltage.

what a pita to install a battery on G/S... rear shock has to be removed.
Is this test battery suitable for long term use... don't know ... many more tests yet to come

yanked battery back out and charging back up to try again (it's gulping down the amps!). next time with a full charge.

[_cy_]

test battery charged to about 85% (didn't have several hours to trickle charge to full) .. reinstalled in G/S ... going for a test ride.

at first blush, the BMW gel cell battery that came out spins starter motor a bit faster. but both operates starter motor just fine at 60f degree anyways. we'll see what happens when it get cold.

all my lights are much brighter due to higher voltage at idle, instead of only seeing same voltage at higher rpm. notice my hi-tech cardboard battery cover


edit: just got back from a 50 mile night ride ... lights much brighter ... starter starting to turn over faster as battery charges up.

took an amp load reading after bike sat for about 3 hours .. garage temp 58f, engine temp 73f
measurable peak 98 amp, 78 amp continuous for 3 seconds

[_cy_]

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

[_cy_]

a bit of trivial ... this antique dry cell battery (100 yr old?) is still putting out 1.35V. probably would not sustain much if any load.

[_cy_]

Due to flat discharge curve of Lithium iron phosphate battery. Measuring remaining charge or capacity left is tricky, but doable with a precision digital meter. useful voltage range from 13.4v to 12.86v (DOD 80%) so we get a spread of .5v that represents capacity remaining.

for those of us used to measuring lead acid batteries and older chemistry li-ion (lithium cobalt) some relearning is in order. discharge curve is no longer a straight line.

1. 14.4v fully charged

2. 14.4v to 13.4v. initial drop represents about 10% of capacity.

2. drop from 13.4v to 12.4v represents 80% of total capacity.

3. below 12.4 represents 10% of remaining capacity.

Don't drop below 12.86v (80% DOD) .. battery life (number of cycles) drops dramatically, Lithium iron phosphate cells are remarkably rugged. like all types of batteries, permanent damage will occur if allowed to discharge too low.

note graph is for 2x cells... multiple x 2 for 12v lithium iron phosphate batteries

[_cy_]

Li-ion packaging and why it matters...
seems an explanation is sorely needed on just what exactly is a prismatic cell vs a cylindrical cell.

li-po or lithium polymer packs have been around for sometime in the form of lithium cobalt. which has higher energy density and voltages, along with it's drawback of becoming unstable when overcharged. thermal runaway (explosion)

what relatively recent is the development of li-po packs made from lithium iron phosphate chemistry. which has a lower energy density and voltage. aside from being cheaper to mfg, it's also inherently safer. all of the lithium when fully charged is transferred the anode. so if overcharged, cell will still overheat and expand, but doesn't go into thermal runaway (explosion).

A123 was world first mfg for lithium iron phosphate batteries. cylindrical 26650 cells was the size adopted for powertools. that's 26mm x 650mm long and the most commonly available cylindrical A123 available. Nanophosphate^® ANR26650M1-B: The ANR26650M1-B is the latest A123 offering with 2.3ah 3.3v http://www.google.com/url?sa=t&rct=j...9Gi73A&cad=rja

so to make up a 12v motorcycle pack... it takes

4 cell 26650 A123 = 13.2v with 2.3 AH rating.
8 cell 26650 A123 = 13.2v with 4.6 AH rating
12 cell 26650 A123 = 13.2v with 6.9 AH rating

now lets move on to prismatic cells, which is the same type of battery without the steel clad construction. typically in a flat square form. but can be shaped to almost any form. like the battery inside iphone4.

so why are prismatic cell li-ion batteries technically better for motorcycle batteries?
or are cylindrical A123 batteries much better?

each motorcycle battery mfg states all the reasons why theirs are better?

that's what will be covered next ...