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Old 02-27-2013, 07:08 PM   #376
_cy_ OP
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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.

_cy_ screwed with this post 02-27-2013 at 07:22 PM
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Old 02-27-2013, 08:31 PM   #377
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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
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Old 03-03-2013, 07:29 PM   #378
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Alright, Just finishing some load tests on all sizes of Antigravity from 4 cell through 20 as well as the ETX18 and 24 earthX. Also been playing with a lab freezer so I can freeze batteries down to whatever specific temperature desired and as always a lead/acid battery thrown into the mix for perspective.

Other then time, any other tests anyone can think of to differentiate these very different batteries? All of them are blowing the doors off of Shorai but I'm having difficulty figuring out how to simulate durability beyond the acid test of seeing what failure rates are in a few years.

FYI until I can get videos and graphs up know that two things are obvious. earthX can really put out a lot of current for it's AH above and beyond any other battery I have tested to date and also it self heats and ramps up current output quicker then any other LiFePO4 battery I have tested to date.

_cy_ I have tested the balance and AH capacity of every battery I have tested to date down to the individual cell and both at low rates and high rates to get at the pekurret, or however you spell that word and found that despite a great body of writing on the web to the contrary, LiFePO4 exhibits a considerable pekurette, meaning the AH out is heavily dependent on the rate of discharge.

So, thoughts anyone? What can we do to get at which of these battery qualities are best before finding out the hard way???
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_ screwed with this post 03-03-2013 at 07:41 PM
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Old 03-03-2013, 09:57 PM   #379
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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?
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Old 03-03-2013, 10:20 PM   #380
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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.

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Old 03-04-2013, 12:05 AM   #381
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a clarification about importance of cells remaining in balance within a series/parallel cell battery.

it takes 4x LiFePO4 cells in series (4s) to make up correct voltage that mates to 12v system. prismatic cell batteries uses cells of different sizes to make up different AH batteries. number of prismatic cells always remain 4s for a 12v system.

cylindrical cell LiFePO4 batteries also use 4s configuration to achieve proper voltage to match 12v system. there are several sizes for cylindrical li-ion cells. for instance 18650 denotes 18mm x 650mm ... the most common size used for motorcycle batteries are 26650 or 26mm diameter x 650mm long.

A123 makes the highest quality cylindrical LiFePO4 cells... one 26650 = 2.3AH at 3.3v nominal ... so 4x 26650 in 4s = 13.2v @ 2.3AH ... an 8 cell 26650 uses two stacks of 4s cells in parallel to make a 4.6AH battery.

12 cell 26650 uses three stacks of 4s cells in parallel = 6.9AH battery... add 2.3AH for each additional 4s stack in parallel, so a 24 cell battery has 6x stacks of 4s cells in parallel.

if/when a single cell goes out of balance, that stack has a lower voltage than rest of stacks in parallel. which immediately will reverse flow to weaker stack. if out of balance cell is severe, due to lithium batteries low internal resistance, discharge to weaker stack will destroy battery.

if I understand correctly, Joel has purposely unbalanced LiFePO4 cells in 4s to approx 8% differences and watched cells achieve balance again towards end of charge.

will be recreating this scenario and many others during balance tests in progress ... more to come on this topic
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Old 03-04-2013, 12:30 AM   #382
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_cy_ This is WAY ahead of actual knowledge. earthX is using nice thick intercel connectors that are 2x what Shorai is using, but they are no stronger then Antigravity. Their case does not appear to be as tough or water proof as Antigravity but I believe I have an early production unit so will reserve judgement. There or so many variables that go into a battery you can trust your life to beyond good warm weather current output and the presence of something that is stated to be a balancing circuit that does not break after a few weeks of testing..



This is indeed modern theory which changes regularly but does not necessarily have bearing beyond a piece of paper that it is written on.
1: I have two 16 cell Antigravity A123 26650 batteries that I buzzed the tops off of for testing individual cell balance via micro volts and low and high rate capacity testing as well as an Antigravity 4 cell and 20 cell. Even on the test units that have cells that are bulging since testing super high current draw, every cell is still balanced better then 1%. These are batteries that have not only been tested in ways that proved destructive to both Shorai and Ballistic but have spent every day since testing in actual modern adventure bikes being used daily. All of these 56 cells have been once again tested for balance in the last two weeks cell by cell and ALL ARE STILL in balance. One 16 cell has been in testing and use for just over a year now and the other 3 batteries have been in testing and use for greater then 7 months.

In what way is a battery with a balance circuit better then one that through imperial data does not need a balance circuit?



In what way is a battery that has a balance circuit better then a battery that does not have one because it does not need one? If you don't need a balance circuit then all the presence of a balance circuit does is create more things that can go wrong compromising the battery on its own?

I have never seen a prismatic cell that didn't need a balance circuit because the nature of the cell being unconfined and vulnerable to being squished and giggled as well as the tendency I have observed for manufacturing tolerance to be larger with large prismatic cells versus the amazingly tight tolerances A123 26650 cells are manufactured to. So... On larger prismatic cells a properly designed and quality manufactured balance circuit is a plus, but it is NOT a plus over a cylindrical circuit that does not need balancing on it's own.



Where are you seeing over-voltage protection on the earthX battery? I may have missed a few electronics engineering classes due to being hung over but am still reasonably certain that I would notice something on a circuit card that could dissipate hundreds of watts or disconnect the battery during an over-voltage event. It isn't there! earthX has no over-voltage protection that I can find.


NOW...... I am absolutely NOT giving earthX a thumbs down, nor a thumbs up. It will take at least a few more months more before I start forming a significant opinion of any kind. The inclusion of a balance circuit is tolerable IF it is well designed and of high quality IF some other advantage is to be had from using prismatic cells. BUT, what actual knowledge do you have that these are good batteries beyond the very first tests that do indeed show the battery can put out current.

Also, how is 4s (4 cells in Series) superior to a greater number of smaller cells in parallel from a real world standpoint? Cells in parallel are virtually never a problem from a balance standpoint because cells in parallel will virtually always balance if if they are low quality. Cells in series are where the balance problem will occur if the cells are not perfectly matched and a 4S-1P battery has the same balance issues all other things being equal as a 4S-5P battery.

Further regardless of weather you are talking the worlds largest prismatic cell or the worlds smallest cylindrical cell, one hard short, one solid dendrite, one breached container and dry out.... will destroy that cell. The difference is if a battery is made up of 4 cells in series and one cell fails then the battery is completely useless. If on the other hand the battery is made up of 4 seriesed stacks of say 4 cells in parallel and one cell hard shorts, then theres a better then even chance that that single cell will pop its current interrupt check out, and you will still have a working battery though a battery with one fourth less capacity that is going to develop a balance problem over time.

4S and one fails, your walking. 4S-4P one cell fails and odds are you can ride out and replace the battery at your convenience.

Once again, I LIKE earthX so far but don't have nearly enough time testing or experience with them in the real world to say they are better or worse, good or bad compared to anything beyond Shorai which every test and real world come back ratios revealed was a piece of junk.

Through intensive and extensive testing AND over 100 sold by my dealership without a single failure I can and do recommend Antigravity batteries. earthX may turn out to be a better battery, better in some applications, not as good, or a piece of junk.

Where _cy_ are you seeing a real world proven advantage of earthX batteries to recommend them beyond a load test and advertising about a balance circuit and what I believe to be the incorrect assumption that they have over-voltage protection?
true enough Earth-X still has to prove it self in long terms tests. overcharge protection is limited to 3 amp on Earth-X balance circuits.

as each cell reaches a set voltage, excess voltage is shunted off until a set point is reached. this allows cells that have not reached cut-off voltage to reach full charge.

balance circuits will not work until full charge is reached. so balance circuit also acts as an overcharge protection circuit within limits. which are 3 amp on Earth-X boards.

provided one doesn't jack up volts to push current into a 4s stack. LiFePO4 cells naturally reduces amount of current it will accept closer it gets to full charge. so a 3 amp limit should be plenty to prevent overcharge within normal charge voltages of a 12v charger.

Antigravity is an excellent battery as proven by your dealership's zero failure rate for Antigravity. but don't underestimate advantage of your recommendation of correct size Antigravity battery for each bike. will the bike be used for Starbuck duties or Adventure bike duties to parts unknown?

IMHO a major reason for failures for LiFePO4 motorcycle batteries is mfg under sizing recommended batteries. the dreaded combo of Cold short motorcycle rides with heated gear will result in a motorcycle that will not start the next morning.

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Old 03-04-2013, 12:47 AM   #383
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I see what your saying. The balance circuit that earthX is using will prevent the kind of over voltage damage that occurs when a series of cells is badly out of balance through shunting from one cell to the next provided that the charging voltage does not exceed normal charging voltage. Yes I agree 100%

But this isn't actual BMS over-voltage protection and will do nothing to stop the whole battery from being destroyed from over-voltage if the charging voltage becomes excessive.

Something not that uncommon on a modern shunt regulated bike with a PM charging system is for the shunt to fail or the shunt ground to go bad. In this case system voltage climbs above 20 volts and even at idle, the F800GS for example has 11 amps of excess current available with all accessories switched off.

In this case the earthX battery is likely to dramatically fail just as any other LiFePO4, or lead/acid battery for that matter because it does not have actual BMS over-voltage protection, nor for that matter does any other LiFePO4 or lead/acid battery for power sports i'm familiar with.

Agreed?
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Old 03-04-2013, 01:07 AM   #384
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yes .. totally agree there is no overcharge protection in cases of regulator failure where voltage goes way over normal. Earth-X battery's 3amp limits would be swamped probably resulting in a melted battery.

a BMS that could handle 200+amp loads would probably be bigger than the LiFePO4 battery itself. which is not to be confused with MOSFET that could be made to switch on/off 200amp under set trigger conditions. but as you pointed out earlier, more complexity = additional points of failure.
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Old 03-04-2013, 01:56 AM   #385
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Transistors have come a long ways in the past few years

'152218-2

200 amp continues at 90c amb
600 amp for 5ms 90c amb
2ma drain, thats problematic
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Old 03-04-2013, 07:43 AM   #386
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I see what your saying. The balance circuit that earthX is using will prevent the kind of over voltage damage that occurs when a series of cells is badly out of balance through shunting from one cell to the next provided that the charging voltage does not exceed normal charging voltage. Yes I agree 100%

But this isn't actual BMS over-voltage protection and will do nothing to stop the whole battery from being destroyed from over-voltage if the charging voltage becomes excessive.

Something not that uncommon on a modern shunt regulated bike with a PM charging system is for the shunt to fail or the shunt ground to go bad. In this case system voltage climbs above 20 volts and even at idle, the F800GS for example has 11 amps of excess current available with all accessories switched off.

In this case the earthX battery is likely to dramatically fail just as any other LiFePO4, or lead/acid battery for that matter because it does not have actual BMS over-voltage protection, nor for that matter does any other LiFePO4 or lead/acid battery for power sports i'm familiar with.

Agreed?
amazing how far modern electronics has come. should be easy enough to key trigger point for said MOSFET to open/close at say when an over voltage condition exists.

LiFePO4 reaches full charge at 3.65v per cell, 4s = 14.6 .. 4s x however many stacks in parallel = 13.2v nominal with a max charge voltage of 14.6v needed to achieve full charge.

as you've found out during over voltage abuse tests ...cylindrical LiFePO4 cells will absorb an amazing amount of abuse and still keep working. li-ion cylindrical cells typically contain safety valves designed to open at set temps to release internal pressures. vs prismatic cells will balloon to vent pressures.

normal 12v charging system operate 13.8v to 14.2v ... so if said MOSFET triggers at say 14.8v or what ever voltage slightly over 14.6v full charge condition.

above would prevent battery from being destroyed by severe overcharge conditions like say when F800's voltage regulator fails. then when volts drops below say 14.8v, MOSFET goes back to it's Normally closed condition.

_cy_ screwed with this post 03-04-2013 at 07:53 AM
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Old 03-04-2013, 11:06 AM   #387
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2ma drain, thats problematic
How so?
Shunt regulators, clocks, memory etc. themselves eat a little current all the time. I also know many people using alarms with anywhere between 5-20 mA drain....


As for cy's suggestion of employing such MOSFET, it sounds really good "on paper".
Could there be a drawback apart from extra conplexity? If such system fails, will the normal state be battery-connected (i.e. no problem) or battery disconnected (problem )?
Could you make additionally this same mOSFET to disconnect the battery at LOWER than set voltage?

Than we'd have a battery that cannot be destroyed by failure of charging system, nor by cell reversal by severe discharge/imbalance!!
And yet still be able to start your bike in the morning!

Now, I've seen enough to know things are never this good and simple, so what am I missing?

Only thing I can guess at is need for cooling since a MOSFET will be passing all battery current...
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Old 03-04-2013, 12:12 PM   #388
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The current drain would be any time the battery output was on, and you would also need a control and sensing circuit that would draw current.

You wouldn't likely need much cooling because it isn't normal for the battery to be passing large amounts of current for very long.

Components like this are used in full BMS systems which do have over-voltage, under-voltage, and balance management already, just not in any power sports batteries I am aware of.

The disadvantages are cost, some reduction of full output, complexity increasing odds of battery failure, fires, and that 2ma drain.

If the circuit were very high quality then any increase of failures would be extremely small as well as chances of fire being hugely reduced. But we're talking more money.

But 2 ma constant drain is a problem. By itself it would cause an earthX ETX18 to go stone cold dead in 4 months. Ad in some current for the sensing. circuit and the typical 1-3 ma most bikes draw all the time and your down to needing to charge the bike every 3-4 weeks of which avoiding is one of the primary sellers of LiFePO4 batteries over lead/acid.

Also factor in that although the internal BMS could be well designed, what the industry usually opts for kills more batteries then it saves. On a smaller scale these circuits are already on nearly every li-ma and li-co battery pack on the market and when you find a failed one, more often then not if you tear out the protection circuit the cells are still just fine.

It's a great idea and as technology gets better and cheaper it may hit the market and be an improvement, but so far has not.
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Old 03-13-2013, 09:00 AM   #389
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Hi Cy, can you recommend a 6v 4ah LiFe replacement for a vintage Japanese motorcycle.bno electric start, only lights and horn. No turn signals.

It was using the 6n4a-4d-1
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Old 03-13-2013, 09:28 AM   #390
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Hi Cy, can you recommend a 6v 4ah LiFe replacement for a vintage Japanese motorcycle.bno electric start, only lights and horn. No turn signals.

It was using the 6n4a-4d-1
sorry not aware of anyone offering a LiFePO4 6v motorcycle battery. you'd have to build one yourself in 2S config.

but why go to all that trouble? put the stock 6v battery back...
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