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Discussion in 'The Garage' started by _cy_, Jan 20, 2012.
Thanx! I'm reading that article.
Cy- You mentioned this in the thread; otherwise Shorai LFX36 with about 12AH (actual) might do it.
That is 12 actual ah´s. Hovv much does the ETX36 push(real ah´s).
You are vvay to smart for me, keep it lovv please.
apologies for all the hard to plow through info ... for really bad stuff ... an glazed eyeball alert will be posted
it's my goal to convert difficult to understand/time consuming information into easy to read material... if at all possible, will refrain from posting technical jargon. unless there is just no way around it.
the 12 AH figure was measured at an 8 amp discharge rate limited to my testing gear. mfg will measure at 10 hour, 120 hour, etc. rates. temperature and discharge rates affect Amp Hour capacity delivered.
in other words .. I don't have the patience to wait 10+ hours for results. LiFePO4 battery mfg inflate their Amp Hour numbers so much, IMHO they are doing a disservice in promoting acceptance of LiFePO4 batteries.
IMHO most mfg charts show LiFePO4 sizing correct for summer use under ideal starting conditions. what you see in this thread is results of real world testing, backed by data generated by world class instruments. laid out hopefully in an easy to understand manner.
currently the only two LiFePO4 batteries that I can recommend for Adventure duties... Shorai LFX 36 (left) and Earth-X ETX36 (right) .. if your requirement are less, you can get by with less.
Thanks for all the work cy!
I stumbled onto this thread because I'm looking into lithium for my KTM 250 4t electric start,light.
Anyway, I see you're running lithium in your r80g/s.
A few years ago in old school, I was honing In On cold starting ability on my r80g/s for all season commuting.
My coldest successful start and ride on my r80g/s was 11°F with the pc680, magnacore plug wires, dynacoil red, original ignition computer with green part number(5sec ign power with key)
Do you think the earthX could start the r80g/s at 11°F?
yes ...based on extensive 200 amp cranking tests, Earth-X ETX 36 should start at 11f .. unfortunately it's not been cold enough in Oklahoma for me to do a live test at 10f yet ... Shorai LFX 36 did start R80G/S at 10f last year. took a few tries to warm up battery, but it started after a few crank cycles.
folks that have not started an airhead at cold temps don't understand the amount of cranking sometimes needed. provided it's in tune, modern fuel injected bikes start much easier at cold temps ...
I wanted to have someone build me a battery replacement t for my 87honda xl600r. The original is 12v and quite small.
Its kick start only, but the battery does need to run a headlight, horn, turn signals and indicator and instruments lights.
There's very few other weight saving opportunities .
I thought of trying to build my own but I think there needs to be a balancing circuit.
What do you think?
A pre made up earth x or maybe some custom soldered cells? What is a balancer? Do I need that on an 87 xl600r?
if you've got access to a spot welder .. go for it... LiFePO4 cell suppliers often will also offer BMS mated to your configuration.
there's many different types of balancing circuits. simplest are shunts that connect to every cell. when voltage goes over a set point. current is shunted off, allowing rest of cells to come up to full charge.
4 cell LiFePO4 20 AH (actual 19AH @ 8amp discharge rate) using Thundersky prismatic cells... uses four balance circuits (one shown)
batteries that have balance ports have a separate wire to each cell. this allows charger to balance cells ... some by shunting off excess voltage, some by regulating current to needed cell, etc.
for a smaller LiFePO4, my recommendation is to go with Earth-X. which has an internal BMS and has outperformed Shorai on smaller sizes during 200amp crank tests. both Shorai LFX 36 and Earth-X ETX 36 give outstanding cranking amps and perform at about the same levels.
Shorai doesn't say much about internal BMS, but Shorai LFX 36 bleeds down to about 13.85 after a full 14.6v charge. indicating an internal BMS is in action. further when a balancer charger is used on LFX 36, cells are very close in voltage.
LiFePO4 batteries without BMS will bleed down to about 14.1v-14.2v after sitting overnight. then when a balancing charger is used, differences in cell voltages shows up on Powerlab 8 during charge.
here's a snapshot of four cell LiFePO4 battery finishing up a balance charge .. when all four cells reaches 3.65v .. charge is finished.
Thank you for taking the time to process and publish your results and I especially appreciate your open-mindness and that you accepted Joel's more aggressive testing methods!
I have a feeling that your softer methods used early on in the thread are good to differentiate between "very weak" batteries, whereas, say, Shorai's 18 and 24 and 36 would show identical (and satisfactory) behaviour.
It is only when you get them into the realm of hard, long, demanding tests that these higher-capacity batteries begin to differ in performance.
Of cource, when I spend 10000 Rubles on a battery, it's good to know what to expect when the "unexpected" happens. Or, how far into the s--t I need to ride to get myself into the "unexpected"!
I'm looking forward to further testing of the earth-x, especially if you can measure individual cell voltages with them (can you with no external port??) and judge the effectiveness of their BMS.
So...earth-x with BMS or the already tested by Joel antigravities?
An important aspect I'm sugesting to test is water-tightness!
Can you drown the earth-x and report on results?
Finally, have your thoughts changed on this, given the performance of these high capacity 36's?
If you still think it is viable, how far would that 2.3 Ah really get a modern EFI bike, if your charging system gets busted and you have to rely of reserve charge to power the electronics?
Also, isn't it recommended to store LiFePO4 at 50-60% charged for long term storage??? :huh
Thanks for reading!
As an example, I measured the BMW K7X (F800GS, F650GS ect) current draw while stator disconnected and with the headlight also disconnected and all switchable accessories off it was 4.9 amps regardless of engine speed.
So..... an extra 2.6AH would get you perhaps 35 additional minutes of run time.
thanks very much for reading ... reason for adopting Joel's testing methods is simple ... they are based on solid reasoning/experience for what's needed to support a modern adventure bike.
we are very fortunate to have on board someone knowledgeable as Joel W ... and willing to share their expertise.
Li-ion cells in general like to be stored at about 40% charged condition vs PB like to be stored at 100% charge.
yes Earth-X passed the bathtub dunk test with no bubbles. Shorai leaks at balance charge ports. an important factor for adventure bikes crossing streams.
Shorai LFX 36 has passed a one year long term test with flying colors in all sorts of conditions ranking from 110f+ to 15f ... with and without full heated gear ... including dreaded combo of short rides/heated gear/20f starts next morning.
Earth-X ETX 36 is just getting started, so jury is still out... but all indications ETX 36 is performing superior in all categories.
for smaller size LiFePO4 batteries ... Earth-X are coming out on top in terms of sustained 200 amp performance by a substantial margin over Shorai of equal size.
smaller Earth-X used cylindrical A123 cells, larger Earth-X uses prismatic cells. advantage of using prismatic cells in larger size batteries is cell stack remains at 4S. vs cylindrical LiFePO4 batteries to achieve equal amp hour has to increase number of parallel stacks of 4x cells totaling 16 cells or more.
for instance it would take 24 2660 A123 cells without BMS @ about 13 actual amp hour to equal Earth-X ETX 36 with 4x prismatic cell @ about 13 actual amp hour with internal BMS.
Assuming both deliver equal cranking performance .. Advantage would go to Earth-X due to internal BMS and only 4 cells in series. easier to keep 4 cells in balance vs 24 cells.
but ah .. that's not all .. cylindrical cells due to rigidity delivers higher sustainable amps. so advantage cylindrical batteries for sustained amps.
hi CY, whats the smallest lightest LiFe that can replace a 3Ah 12v CB3LA?
for the 1987 honda XL600R, no electric start? the best replacement in your opinion
thanks again so much!!
3Ah 12v CB3LA weight = 2.5 lb
Sycl four cell 2.3AH (actual) weight = 11.9 oz
Sycl 4 cell is made out 4x A123 26650 cells (excellent quality small AH battery)
since your bike has no starter, AH requirement are modest. the smallest of LiFePO4 battery will likely meet your needs.
question that comes up: is it worth hassles of changing over to LiFePO4 worth saving 1lb 12oz?
if you decide that it is worth the modest costs ... be sure to take extra care to strap new much smaller LiFePO4 battery down solid. then take extra care to make dead certain positive connections cannot ground out. the connector kit offered is recommended.
lithium batteries has very low internal resistance, resulting in high discharge rates .. easily equal to heat created by arc welding.
i have a Q, not moto related, well not directly anyway.
i run a small camper on my truck and have a deep cycle battery as "house power". about 80 amp hour and prolly 60 lbs. i run a fridge and lights and other things off of it and during the day its either charging via the alternator or solar panels.
heres the Q, can i replace that battery with a lifepo or similar? would be nice to have similar amp hour battery thats i dont know 6lbs or so. but i dont know if this new tech is deep cycle or should even be used as such.
oh, i should add that i have low volt cut off that is selectable, i run it at 11.4v now.
thanks for any info
sure it's possible but probably not cost effective. for we are talking actual amp hours, not PB/EQ used by most all the LiFePO4 mfg. for instance an 12cell LiFePO4 battery made from A123 cells would be 6.9AH actual, but labeled as say 24 AH (pb/eq).. your inverter doesn't understand pb/eq .. it draws actual amps... what this means is 12 cell, 6.9AH battery would deliver 6.9amps for one hour. if battery was 24AH actual, it would deliver 3.48 hours at 6.9amp draw.
probably the cheapest LiFePO4 battery available are Thundersky prismatic cells. 4x cells to make up 20ah actual for a 12v system costs about $140 without cell balance boards.
4x 20AH Thundersky battery = $560 + BMS and lithium charger costs ... total $750+ or IMHO not worth it. each thundersky 20AH weight about 7.5lb x4 = 30lb + cabling ... so you save about 28lb ... vs a deep cycle AGM battery that costs say about $230.
unless you are running a race car .. saving 30lb or so probably doesn't mean a lot. but on a Motorcycle saving say 15lb to some folks are very cost effective weight savings .. compared to say carbon fiber parts.
and thats why we ask questions, interesting stuff even though it wouldnt make sense to do. at least not now, but maybe in the near future as technology improves and costs come down.
thanks for the info cy
good to have you verify Earth-X cranking performance. IHMO unless someone else pops up with a stronger battery design. Earth-X incorporates the best of available components into a very strong LiFePO4 battery.
Earth-X and others takes advantage of cylindrical cell's inherent rigidity to make connection straps that can deliver punishing currents. but cylindrical cells liability shows when larger amp hour batteries are created.
the larger number of cells, the greater chance of cell(s) going out of balance and/or fail. this is assuming mfg has done their due diligence by matching up like cells. SOC or state of charge difference between cells can happen simply by aging.
Earth-X uses cylindrical cells for smaller AH batteries. but switches to prismatic cells for larger AH batteries. advantage for larger AH in 4s configuration, only four cells are used. 4s: 4x 14AH prismatic cells vs 24x 26650 A123 cells (4s: 6x 2.3AH = 13.8AH)
disadvantage of prismatic cells are less rigid construction making internal connection straps more difficult to achieve. Earth-X has really done their homework by using beefy internal straps on prismatic cells that delivers high current loads.
All Earth-X batteries are built with an internal BMS that balances cells and prevents overcharge. so most any automotive charger will work.
in the process of doing cell balance tests with chargers with balance ports and with charger using pulse technologies. more to come on that topic...
Cy, do you think I need to leave some cooling area around a 4 cell sycl/ballistic on the87 xl600r? The flat 4 cell sycl is no longer available. In general do LiFe batts need can cooling air?
see if an Earth-X is available in smallest size that fits your battery tray. cooling space is not necessary unless there's some special reason it's needed.
most applications require enough AH to support a starter... an 8 cell 26650 A123 battery would be 4.6AH actual and weight 24oz or closer to your original 2lb 8oz PB battery.