Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4) - Page 11

JoelWisman · 03-08-2012, 09:41 PM

Quote:

Originally Posted by _cy_

yes but what A123 considers to be 100% depth of discharge is not low as battery can go. Joel is right on this. what he is referring to is a glitch that causes up to a 2.3 amp discharge. which will drain battery down way below 100% discharged condition into likely unrecoverable condition. using Shorai's chart 100% discharge would be 9.2v.

I was hunting for my card reader to post the pic above as you posted _cy_

Time will tell, that Li-ion is 7.4 volt and was down to 0.11 volts. As it happens I got it into normal range using its power supply through a 10kohm resistor.

I'm still charging it in the fireplace for a reason lol

Anorak · 03-08-2012, 10:03 PM

Quote:

Originally Posted by _cy_

yes but what A123 considers to be 100% depth of discharge is not low as battery can go. Joel is right on this. what he is referring to is a glitch that causes up to a 2.3 amp discharge. which will drain battery down way below 100% discharged condition into likely unrecoverable. using Shorai's chart 100% discharge would be 9.2v.

Shorai isn't A123. I'll try to remember to consult with a friend who has seriously abused A123 cells for a project. He wound up using Ener1 cells.

_cy_ · 03-09-2012, 03:45 AM

Quote:

Originally Posted by JoelWisman

I was hunting for my card reader to post the pic above as you posted _cy_

Time will tell, that Li-ion is 7.4 volt and was down to 0.11 volts. As it happens I got it into normal range using its power supply through a 10kohm resistor.

I'm still charging it in the fireplace for a reason lol

assuming you are referring to two cell lithium cobalt 7.4 battery pack

procedure to recover lithium cobalt (4.2v max 3.7v nominal) is to charge at .01C until volt raises above 3.25v per cell. then charge rate .5C to hopefully full recovery.

recovered many a li-ion cell this method with Schulze isl 6-330d .. the new Powerlab 8 is hugely more capable. they call it a battery workstation instead of a charger for good reason.

charged many a lithium cobalt battery inside my fireplace insert with 1/4in steel construction. fireplace was the safest spot in the house. greatest danger from using li-ion (lithium cobalt) cells occurs during charging. lithium cobalt chemistry will accept a charge until thermal runaway (explosion) occurs at about 4.35v. this is why it's very important to only charge lithium cobalt cells with a charger that terminates charge at 4.2v. above link is from an article I wrote five years ago on Candlepower forums

Quote:

Originally Posted by Anorak

Shorai isn't A123. I'll try to remember to consult with a friend who has seriously abused A123 cells for a project. He wound up using Ener1 cells.

no Shorai isn't A123 .. but both use LiFePO4 chemistry. Shorai uses four flat prismatic cells wired in series, different size of prismatic cells are used to achieve desired amp hour rating. Ballistic and SYCL uses cylindrical A123 cells wired in series. then paralleled to desired amp hour rating. currently there are only about 12 different mfg of lithium cells in the world.

plans are to drill in later, advantages and disadvantages of prismatic vs cylindrical LiFePO4 cells

_cy_ · 03-09-2012, 08:59 AM

worthwhile clip to watch about accurately measuring a battery's amp hour capacity. Agilent equipment is designed specifically for phone size batteries and are limited to 100 watt range... cost big $$$.

this is why Cellpro Powerlab 8 from Progressive RC was chosen to test/charge LiFePO4 motorcycle batteries. providing power supply is large enough, up to 40 amp charge rates. 1350 watts regenerative discharge rates are possible. PC controlled software to track results is free. very modest cost $$ considering capabilities.

http://www.progressiverc.com/fma-powerlab-8.html

eakins · 03-09-2012, 09:21 AM

cool thread

until prices come down on alternative batteries types, i keep coming back to Deka AGM for the price. I find these last for 4-5 years with no issues and no maintenance needed. They are 1/2 the price of the new technology batteries and so unless these new batteries last 9-10yrs (an i doubt that) the cost benefit is not there.

Yes they weigh a few pounds less so only in light 250 thumpers would it be noticed. On heavy dual-sports and adv bikes the only thing lighter feeling is your wallet.
http://www.tristatebattery.com/produ...roducts_id=973

Anorak · 03-09-2012, 10:00 AM

Quote:

Originally Posted by _cy_

assuming you are referring to two cell lithium cobalt 7.4 battery pack

procedure to recover lithium cobalt (4.2v max 3.7v nominal) is to charge at .01C until volt raises above 3.25v per cell. then charge rate .5C to hopefully full recovery.

recovered many a li-ion cell this method with Schulze isl 6-330d .. the new Powerlab 8 is hugely more capable. they call it a battery workstation instead of a charger for good reason.

charged many a lithium cobalt battery inside my fireplace insert with 1/4in steel construction. fireplace was the safest spot in the house. greatest danger from using li-ion (lithium cobalt) cells occurs during charging. lithium cobalt chemistry will accept a charge until thermal runaway (explosion) occurs at about 4.35v. this is why it's very important to only charge lithium cobalt cells with a charger that terminates charge at 4.2v. above link is from an article I wrote five years ago on Candlepower forums

no Shorai isn't A123 .. but both use LiFePO4 chemistry. Shorai uses four flat prismatic cells wired in series, different size of prismatic cells are used to achieve desired amp hour rating. Ballistic and SYCL uses cylindrical A123 cells wired in series. then paralleled to desired amp hour rating. currently there are only about 12 different mfg of lithium cells in the world.

plans are to drill in later, advantages and disadvantages of prismatic vs cylindrical LiFePO4 cells

A123 is a unique chemistry as compared to other LiFePo. I accidentally overcharged four in series until they fail. There was a "pop" and some smelly steam. A friend tested a cell at 130 amps until it failed. After about 30 seconds the smoke came out and it fell apart. No comparison to LiPo or lithium cobalt.

_cy_ · 03-09-2012, 02:39 PM

Quote:

Originally Posted by Anorak

A123 is a unique chemistry as compared to other LiFePo.

there's only about 12 lithium ion battery mfg in the world. ALL use their own unique chemistry to make LiFePO4 batteries. so yes A123's chemistry is unique, but so is everyone else.

ALL batteries regardless of type .. if abused by severely overcharging, over discharge, etc. will probably have bad results. this includes LiFePO4. anyone that's experienced an explosion from charging gases from wet lead acid batteries will agree.

there's been documented instances of folks on RC forums. on purpose severely overcharging LiFePO4 battery packs that's resulted in fires. I've communicated with folks that's seen it happen under NDA. so they were not able to disclose how it was done.

Is it perfect? NO..fact is LiFePO4 chemistry is MUCH safer than Lithium cobalt cells.

Anorak · 03-09-2012, 05:56 PM

Quote:

Originally Posted by _cy_

there's only about 12 lithium ion battery mfg in the world. ALL use their own unique chemistry to make LiFePO4 batteries. so yes A123's chemistry is unique, but so is everyone else.

You should make that clear when you reference different batteries. Prismatic versus cylindrical cells don't mean much more than physical appearance. A123 makes a prismatic cell.

Also, the A123 will charge at higher rates and discharge at higher rates than any other LiFePo.

_cy_ · 03-09-2012, 06:35 PM

Easily one of the most knowledgeable person on the planet for testing Li-ion cells.... David Gray of Progressive RC has graciously agreed to share with ADV results of a few tests for A123 cells.

Twoupfront · 03-10-2012, 03:43 AM

Quote:

Originally Posted by Anorak

You should make that clear when you reference different batteries. Prismatic versus cylindrical cells don't mean much more than physical appearance. A123 makes a prismatic cell.

Also, the A123 will charge at higher rates and discharge at higher rates than any other LiFePo.

Is it just me, or is Anorak trying a bit too hard to argue that A123 is the best battery in the world - flawless, and miles ahead of all the others?

Anorak · 03-10-2012, 07:47 AM

Quote:

Originally Posted by Twoupfront

Is it just me, or is Anorak trying a bit too hard to argue that A123 is the best battery in the world - flawless, and miles ahead of all the others?

It looks that way to me too. Not the best battery because there are so many variables.It's a very good battery as a starting battery. Much better in my opinion than the generic Chinese lithium iron phosphate batteries.

JoelWisman · 03-12-2012, 04:45 AM

Okay, I am stumped. Consulting text books, online battery sites, and fired off an email of data to a crazy professor sort that teaches battery technology and may eventually respond.

This is what I got so far on a Shorai LFX18 used roughly for 4 months.

Noteworthy that the BMW F800GS has a wimpy pimply 13.8 charging voltage with substantial AC ripple and lots of HF switching noise.

Also worth noting that the F8 has a hot battery compartment because the basic controller (giant SCR switch bank with some logic) bakes the battery with it's heat sync pointed at one face of the battery, about .5" of air gap, asymmetrically with heat concentrated towards cells 3 and 4 IF MEMORY SERVES, it may be cells 1 and 2 that are getting the hottest, or none of the above depending on how the cells are stacked in the battery, but I think the cells towards the positive terminal are getting hottest.

In any case, here are my raw notes so far, very raw. Nothing seems to match up. AH and SOC voltage aren't linearly connected. Its late so maybe I just need sleep but right now I'm about as clued in as an ameba.

I have a high degree of confidence in the measured numerical values, but nothing makes sense of what they are saying.
Any thoughts on what on earth can be determined from this shit salad?

Shorai LFX18, 4 months of heavy service on F800GS

As arrived, at least 4 days of resting13.149
cell1 3.2965 70%
cell2 3.2962 70%
cell3 3.2938 70%
cell4 3.2633 35%
35% imbalance

Capo w F8 regulator 4.5 hours 3 starts 125a withdrawn for 10 seconds, rest 1 hour
cell1 3.2998 70%
cell2 3.2995 70%
cell3 3.2970 70%
cell4 3.2657 35%

Withdrew current from cells individually at approx 0.2 amps to 3.2165 volts (would be 12.886 volts for battery or 20% SOC) This is a 30 hour rate. Shorai says some BS about “PBEQ amp hour” as do all the LiFePo4 power sports battery manufactures I can find. Dig and you find out they rate the battery at 6 actual amp hour, but state that using the bottom 20% will damage the cells and void your warranty. This means you effectively have a battery that is 4.8 amp hour
cell1 2.56 amps 53%
cell2 2.99 amps 62%
cell3 2.87 amps 60%
cell4 0.81 amps 17%
charged cells individually same amount as withdrawn + 10% for a guestimate at charge eff

After 26 hour rest
cell1 3.2991 70%
cell2 3.2997 70%
cell3 3.2968 70%
cell4 3.2646 35%
close enough for government work

Capo 6.5 hours 7 starts, over 2 days
1 hour after 125 amps for 10 seconds
13.708 volts
cell1 3.5820 100%
cell2 3.4448 90%
cell3 3.3447 90%
cell4 3.3142 75%
25% imbalance

3 more hours of Capo riding, all freeway
cell1 3.5819 100% (rounded up ever so slightly)
cell2 3.4494 90%
cell3 3.3492 90%
cell4 3.3181 80%
20% imbalance

Withdrew current from cells individually at approx 0.2 amps to 3.2327 volts (would be 12.93 volts for battery or 20% SOC to bottom balance all cells

cell1 3.99 amps 83%
cell2 4.33 amps 90%
cell3 4.74 amps 99%
cell4 3.04 amps 63%
Charging it at 14.5 volts till acceptance down to 200mA

_cy_ · 03-12-2012, 10:13 AM

@joel... excellent raw data! collect enough and some pattern will show itself. sure is nice to see data generated that's lab grade.

there's sooo many different sources for Lithium battery information it's hard to ferret out which one is worth spending your brain cycles on. here's one worth a cruise..

Charge LiFePO4 to 3.65v per cell then terminate charge if using a regulated power supply. if your power supply has constant current triggered by volt termination feature. set to 14.4v then allow time to top off. Your battery will absorb decreasing amount of current, closer to fully charged condition. ramping up voltage up to 3.65v allows faster charge for last phase. higher the volts delivered by charger, higher the amp rate pushed into battery. this is especially true during final phase before LiFePO4 reaches 14.4v fully charged state.

intelligent chargers that support LiFePO4 will have custom algorithms to support that chemistry. best chargers will have balance options that charge different cells at different rates. others will charge all cells at same rate, then shunt off excess current.

when you pull a fully charged LiFePO4 battery off charger. voltage should read just under 14.4v depending on individual battery. then surface charge will quickly bleed off to 13.9v range. after sitting overnight with nothing hooked to battery. resting voltage should be about 13.7v range. each battery will be slightly different. then as battery ages resting charge retained after a full charge will go down. when battery reaches 80% DOD it's considered spent.

Charging

Because lithium-ion batteries can have a variety of vocathode and anode materials, the energy density and voltage vary accordingly. Lithium-ion batteries with a lithium iron phosphate cathode and graphite anode have a nominal open circuit voltage of 3.2 volts and a typical charging voltage of 3.65 volts. The charging procedure is performed at constant voltage with current-limiting circuitry (i.e., charging with constant current which should be 30% of the battery ampere hour rating until a voltage of 3.65 volts is reached in the cell and continuing with a constant voltage applied until the current drops close to zero). Typically, the charge is terminated at 7% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and typically needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less; some lithium-ion varieties can reach 90% in as little as 10 minutes.

http://lithiumstorage.com/index.php?...11233f8fcc52f3

Rajin Cajun · 03-12-2012, 02:13 PM

Finally got home and was able to check out the new pack for the SE. It arrived a little over a week ago and as it sits now it's at 13.44v. Hopefully I will be able to get the bike put pack together this week and see how she cranks over with this one vs the stock battery.

JoelWisman · 03-12-2012, 04:12 PM

What I know....

When the battery arrived from being used hard by Lost Rider for 4 or so months, it was horribly imbalanced. Lost Rider does not have any charger so like many, only the bike charges the battery.

His mount is an F800GS I know well from being a BMW dealership shop foreman and being front line on many many BMW issues.

The F800GS has a 13.8 volt charging voltage. I don't know why, it almost as if they were planning on putting a GEL VRLA battery in the F8's and changed their minds and dumped AGM's in them at the last moment without changing the regulation voltage. It is not as if BMW is stupid, the R1200GS/GSA, S1000RR, K1300S/GT, K1600GT/GTL all have charge voltages around 14.4

I would have to say it was well on it's way to complete failure though likely without symptoms since LiFePo4 batteries have a low enough internal resistance that they will put out, till one day all at once they won't.

Best I can dig up is that a Shorai LFX18 is a 6 amp hour battery, and that includes the last 20% of charge which they don't want you to use, so effectively a 4.8 amp hour battery.

This being the case, I am seeing amp hour capacity per cell that is all over the frisking board!

Cell 1 appears damaged, and this seems logical. It was the cell with the highest state of charge and in series with 3 other depleted cells, likely saw much higher voltage then designed for.

Cell 2 is sorta kinda reasonable.

Cell 3 is actually showing more capacity then spec'd

Cell 4 is also showing a reduced capacity compared to it's state of charge. Perhaps damaged by Anode damage from too low of SOC or even cell reversal?

I don't know. I don't have any special charge equipment and won't be buying any as I am not at all convinced that lithium chemistries are the way to go for adventure riding which is all I do. This may change, but not with this sickly battery lol.

What I do have is a charger that will charge across the main terminals at 800mA pairing back to 200mA at 14.4 volts, then ceasing all together when current declines further.

It will not exceed 14.4 volts under any circumstance confirmed by plotting it's algorithm on a paperless recorder.

I built a bottom equalizer with some spare parts and a bread board with a pot I can use to adjust disconnect voltage which I had set for 3.2165 volts and hit its mark on every cell within 1% It only applies a 200mA load, so waiting now for it to finish the second draw down so I can charge the whole thing equalized.

The F8 also has massive AC ripple and a lot of HF switching noise and has a battery compartment that is hot but asymmetrically hot.

Shorai keeps ramping up the size of battery they recommend for the BMW F800. The started with an LFX14 recommended and after a high failure rate with both that and the LFX18, currently recommend the LFX21.

This is odd, because compared to the R1200GS and many other bikes, the starting demands cold or hot of the F800 is a walk in the park.

As shown in tests, the Shorai will balance in series slowly when seeing the charging voltage my Capo puts out which varies greatly by load and engine speed but gets into the 14.55 volt range for brief periods and averages about 14.34 on the freeway.

Working hypothesis: Shorai does not balance either cell resistance or capacity well or has self discharge that varies widely. 13.8 volt charging of the F800 is not high enough to permit the very limited balancing LiFePo4 packs will do when voltage is continued after fully charged. The cell with the lowest capacity, highest resistance, or lowest leakage current gets damaged by high voltage as the cell the most opposite gets damaged by under voltage until the battery rapidly fails.

Just a theory, but all evidence points to high incidence of failure of Shorai in F800 application and Shorais every increasing recommendations of battery size for the F800 bares this out.

If true, this argues strongly that 13.8 volt charging systems are not adequate for the Shorai battery.

Big hedges: As stated, the F800 also has unusually large AC ripple, loads of HF switching noise from PWM pump control, and a hot asymmetrically heated battery compartment.

I have spent half my life reading up on new technical things though only 2 or 3% on batteries. I will continue reading up on LiFePo4 but any first impressions or suggestions for experiments to confirm? :)

03-09-2012, 08:59 AM	#154
_cy_ ^OP Beastly Adventurer Joined: Sep 2011 Location: Tulsa, Oklahoma Oddometer: 2,523	worthwhile clip to watch about accurately measuring a battery's amp hour capacity. Agilent equipment is designed specifically for phone size batteries and are limited to 100 watt range... cost big $$$. this is why Cellpro Powerlab 8 from Progressive RC was chosen to test/charge LiFePO4 motorcycle batteries. providing power supply is large enough, up to 40 amp charge rates. 1350 watts regenerative discharge rates are possible. PC controlled software to track results is free. very modest cost $$ considering capabilities. http://www.progressiverc.com/fma-powerlab-8.html __________________ Bringing BMW R90S back to life, R80G/S, LiFePO4 testing Which is more reliable ... Points or Electronic Ignition for Airheads? _cy_ screwed with this post 03-09-2012 at 07:03 PM

03-09-2012, 09:21 AM	#155
eakins Butler Maps Joined: May 2002 Location: Colorado - Fort Collins Oddometer: 14,427	cool thread until prices come down on alternative batteries types, i keep coming back to Deka AGM for the price. I find these last for 4-5 years with no issues and no maintenance needed. They are 1/2 the price of the new technology batteries and so unless these new batteries last 9-10yrs (an i doubt that) the cost benefit is not there. Yes they weigh a few pounds less so only in light 250 thumpers would it be noticed. On heavy dual-sports and adv bikes the only thing lighter feeling is your wallet. http://www.tristatebattery.com/produ...roducts_id=973 __________________ Butler Maps - motorcycle maps for riders by riders - Ozarks , Nor Cal , COBDR shipping, AZBDR scouting http://www.advrider.com/forums/showthread.php?t=598717 Facebook: http://www.facebook.com/butlermaps

03-09-2012, 06:35 PM	#159
_cy_ ^OP Beastly Adventurer Joined: Sep 2011 Location: Tulsa, Oklahoma Oddometer: 2,523	Easily one of the most knowledgeable person on the planet for testing Li-ion cells.... David Gray of Progressive RC has graciously agreed to share with ADV results of a few tests for A123 cells. __________________ Bringing BMW R90S back to life, R80G/S, LiFePO4 testing Which is more reliable ... Points or Electronic Ignition for Airheads?

03-12-2012, 04:45 AM	#162
JoelWisman Beastly Adventurer Joined: Apr 2009 Location: STL, MO, USA Oddometer: 1,353	Okay, I am stumped. Consulting text books, online battery sites, and fired off an email of data to a crazy professor sort that teaches battery technology and may eventually respond. This is what I got so far on a Shorai LFX18 used roughly for 4 months. Noteworthy that the BMW F800GS has a wimpy pimply 13.8 charging voltage with substantial AC ripple and lots of HF switching noise. Also worth noting that the F8 has a hot battery compartment because the basic controller (giant SCR switch bank with some logic) bakes the battery with it's heat sync pointed at one face of the battery, about .5" of air gap, asymmetrically with heat concentrated towards cells 3 and 4 IF MEMORY SERVES, it may be cells 1 and 2 that are getting the hottest, or none of the above depending on how the cells are stacked in the battery, but I think the cells towards the positive terminal are getting hottest. In any case, here are my raw notes so far, very raw. Nothing seems to match up. AH and SOC voltage aren't linearly connected. Its late so maybe I just need sleep but right now I'm about as clued in as an ameba. I have a high degree of confidence in the measured numerical values, but nothing makes sense of what they are saying. Any thoughts on what on earth can be determined from this shit salad? Shorai LFX18, 4 months of heavy service on F800GS As arrived, at least 4 days of resting13.149 cell1 3.2965 70% cell2 3.2962 70% cell3 3.2938 70% cell4 3.2633 35% 35% imbalance Capo w F8 regulator 4.5 hours 3 starts 125a withdrawn for 10 seconds, rest 1 hour cell1 3.2998 70% cell2 3.2995 70% cell3 3.2970 70% cell4 3.2657 35% Withdrew current from cells individually at approx 0.2 amps to 3.2165 volts (would be 12.886 volts for battery or 20% SOC) This is a 30 hour rate. Shorai says some BS about “PBEQ amp hour” as do all the LiFePo4 power sports battery manufactures I can find. Dig and you find out they rate the battery at 6 actual amp hour, but state that using the bottom 20% will damage the cells and void your warranty. This means you effectively have a battery that is 4.8 amp hour cell1 2.56 amps 53% cell2 2.99 amps 62% cell3 2.87 amps 60% cell4 0.81 amps 17% charged cells individually same amount as withdrawn + 10% for a guestimate at charge eff After 26 hour rest cell1 3.2991 70% cell2 3.2997 70% cell3 3.2968 70% cell4 3.2646 35% close enough for government work Capo 6.5 hours 7 starts, over 2 days 1 hour after 125 amps for 10 seconds 13.708 volts cell1 3.5820 100% cell2 3.4448 90% cell3 3.3447 90% cell4 3.3142 75% 25% imbalance 3 more hours of Capo riding, all freeway cell1 3.5819 100% (rounded up ever so slightly) cell2 3.4494 90% cell3 3.3492 90% cell4 3.3181 80% 20% imbalance Withdrew current from cells individually at approx 0.2 amps to 3.2327 volts (would be 12.93 volts for battery or 20% SOC to bottom balance all cells cell1 3.99 amps 83% cell2 4.33 amps 90% cell3 4.74 amps 99% cell4 3.04 amps 63% Charging it at 14.5 volts till acceptance down to 200mA __________________ Owned to date. Honda Aero 50, Honda Elite 80, Honda Elite 250x2, Suzuki Katana, Suzuki RF600, Yamaha YZF1000R, Kymco Xciting 500, Suzuki GS500, Suzuki Burgman 650, BMW F800GSx2, BMW S1000RR, Aprilia Scarabeo 200, Aprilia Caponord, Aprilia Sportcity 250 I love and miss you Jeneca and I'm sorry.

03-12-2012, 10:13 AM	#163
_cy_ ^OP Beastly Adventurer Joined: Sep 2011 Location: Tulsa, Oklahoma Oddometer: 2,523	@joel... excellent raw data! collect enough and some pattern will show itself. sure is nice to see data generated that's lab grade. there's sooo many different sources for Lithium battery information it's hard to ferret out which one is worth spending your brain cycles on. here's one worth a cruise.. Charge LiFePO4 to 3.65v per cell then terminate charge if using a regulated power supply. if your power supply has constant current triggered by volt termination feature. set to 14.4v then allow time to top off. Your battery will absorb decreasing amount of current, closer to fully charged condition. ramping up voltage up to 3.65v allows faster charge for last phase. higher the volts delivered by charger, higher the amp rate pushed into battery. this is especially true during final phase before LiFePO4 reaches 14.4v fully charged state. intelligent chargers that support LiFePO4 will have custom algorithms to support that chemistry. best chargers will have balance options that charge different cells at different rates. others will charge all cells at same rate, then shunt off excess current. when you pull a fully charged LiFePO4 battery off charger. voltage should read just under 14.4v depending on individual battery. then surface charge will quickly bleed off to 13.9v range. after sitting overnight with nothing hooked to battery. resting voltage should be about 13.7v range. each battery will be slightly different. then as battery ages resting charge retained after a full charge will go down. when battery reaches 80% DOD it's considered spent. Charging Because lithium-ion batteries can have a variety of vocathode and anode materials, the energy density and voltage vary accordingly. Lithium-ion batteries with a lithium iron phosphate cathode and graphite anode have a nominal open circuit voltage of 3.2 volts and a typical charging voltage of 3.65 volts. The charging procedure is performed at constant voltage with current-limiting circuitry (i.e., charging with constant current which should be 30% of the battery ampere hour rating until a voltage of 3.65 volts is reached in the cell and continuing with a constant voltage applied until the current drops close to zero). Typically, the charge is terminated at 7% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and typically needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less; some lithium-ion varieties can reach 90% in as little as 10 minutes. http://lithiumstorage.com/index.php?...11233f8fcc52f3 __________________ Bringing BMW R90S back to life, R80G/S, LiFePO4 testing Which is more reliable ... Points or Electronic Ignition for Airheads? _cy_ screwed with this post 03-12-2012 at 10:31 AM

03-12-2012, 02:13 PM	#164
Rajin Cajun Gnarly Adventurer Joined: Jan 2007 Location: Louisiana Oddometer: 287	Antigravity Finally got home and was able to check out the new pack for the SE. It arrived a little over a week ago and as it sits now it's at 13.44v. Hopefully I will be able to get the bike put pack together this week and see how she cranks over with this one vs the stock battery.

03-12-2012, 04:12 PM	#165
JoelWisman Beastly Adventurer Joined: Apr 2009 Location: STL, MO, USA Oddometer: 1,353	What I know.... When the battery arrived from being used hard by Lost Rider for 4 or so months, it was horribly imbalanced. Lost Rider does not have any charger so like many, only the bike charges the battery. His mount is an F800GS I know well from being a BMW dealership shop foreman and being front line on many many BMW issues. The F800GS has a 13.8 volt charging voltage. I don't know why, it almost as if they were planning on putting a GEL VRLA battery in the F8's and changed their minds and dumped AGM's in them at the last moment without changing the regulation voltage. It is not as if BMW is stupid, the R1200GS/GSA, S1000RR, K1300S/GT, K1600GT/GTL all have charge voltages around 14.4 I would have to say it was well on it's way to complete failure though likely without symptoms since LiFePo4 batteries have a low enough internal resistance that they will put out, till one day all at once they won't. Best I can dig up is that a Shorai LFX18 is a 6 amp hour battery, and that includes the last 20% of charge which they don't want you to use, so effectively a 4.8 amp hour battery. This being the case, I am seeing amp hour capacity per cell that is all over the frisking board! Cell 1 appears damaged, and this seems logical. It was the cell with the highest state of charge and in series with 3 other depleted cells, likely saw much higher voltage then designed for. Cell 2 is sorta kinda reasonable. Cell 3 is actually showing more capacity then spec'd Cell 4 is also showing a reduced capacity compared to it's state of charge. Perhaps damaged by Anode damage from too low of SOC or even cell reversal? I don't know. I don't have any special charge equipment and won't be buying any as I am not at all convinced that lithium chemistries are the way to go for adventure riding which is all I do. This may change, but not with this sickly battery lol. What I do have is a charger that will charge across the main terminals at 800mA pairing back to 200mA at 14.4 volts, then ceasing all together when current declines further. It will not exceed 14.4 volts under any circumstance confirmed by plotting it's algorithm on a paperless recorder. I built a bottom equalizer with some spare parts and a bread board with a pot I can use to adjust disconnect voltage which I had set for 3.2165 volts and hit its mark on every cell within 1% It only applies a 200mA load, so waiting now for it to finish the second draw down so I can charge the whole thing equalized. The F8 also has massive AC ripple and a lot of HF switching noise and has a battery compartment that is hot but asymmetrically hot. Shorai keeps ramping up the size of battery they recommend for the BMW F800. The started with an LFX14 recommended and after a high failure rate with both that and the LFX18, currently recommend the LFX21. This is odd, because compared to the R1200GS and many other bikes, the starting demands cold or hot of the F800 is a walk in the park. As shown in tests, the Shorai will balance in series slowly when seeing the charging voltage my Capo puts out which varies greatly by load and engine speed but gets into the 14.55 volt range for brief periods and averages about 14.34 on the freeway. Working hypothesis: Shorai does not balance either cell resistance or capacity well or has self discharge that varies widely. 13.8 volt charging of the F800 is not high enough to permit the very limited balancing LiFePo4 packs will do when voltage is continued after fully charged. The cell with the lowest capacity, highest resistance, or lowest leakage current gets damaged by high voltage as the cell the most opposite gets damaged by under voltage until the battery rapidly fails. Just a theory, but all evidence points to high incidence of failure of Shorai in F800 application and Shorais every increasing recommendations of battery size for the F800 bares this out. If true, this argues strongly that 13.8 volt charging systems are not adequate for the Shorai battery. Big hedges: As stated, the F800 also has unusually large AC ripple, loads of HF switching noise from PWM pump control, and a hot asymmetrically heated battery compartment. I have spent half my life reading up on new technical things though only 2 or 3% on batteries. I will continue reading up on LiFePo4 but any first impressions or suggestions for experiments to confirm? :) __________________ Owned to date. Honda Aero 50, Honda Elite 80, Honda Elite 250x2, Suzuki Katana, Suzuki RF600, Yamaha YZF1000R, Kymco Xciting 500, Suzuki GS500, Suzuki Burgman 650, BMW F800GSx2, BMW S1000RR, Aprilia Scarabeo 200, Aprilia Caponord, Aprilia Sportcity 250 I love and miss you Jeneca and I'm sorry.

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