Shorai Batteries

anybody using these ??, more power less weight Alot less weight, seems to be a popular topic on ALL TYPES of motorcycle forums
www.shoraipower.com/

tk11b40 just bought one. kzrider.com/index.php?option=com_kunena&...it=20&limitstart=480

I'm not sure that he's had it long enough to give you much feedback, other than installation and size/weight considerations.

It's a lithium battery. When I was at National Semi, we developed some of the charge control and protection ICs that work with Li batteries. The only disadvantage I know of for Li is that they are very intolerant of charge voltage variations. Sony and Sanyo required the charger set voltage to be held to a 0.5% tolerance. In a car/bike, the charge voltage is typically about 14V +/-0.5V which is more like a 3.5% tolerance on the charge voltage.

The typical final charge voltage on a single Li cell is 4.200V, so three in series would be 12.600V. I don't think the standard 14V system voltage is a good fit for it. I wonder if they just overcharge them or do they require a voltage regulator retrofit?

Found this on a Beemer forum:

All lead-acid batteries can outgas hydrogen. In the case of AGM/Gel, it only happens during an overcharge situation, typically. Statements to the contrary are urban myth.

ANY battery must have its terminal charge voltage carefully controlled, or the battery will be damaged. In the case of Lead-acid (All types) an overcharge condition is also potentially dangerous. In the case of Li-Cobalt (laptop/cell battes) over-voltage charging can lead to thermal runaway (fire). Shorai LFX use LiFePO4, which are NOT subject to thermal runaway due to over-voltage charge conditions. Over-voltage charging will damage Shorai LFX, as it will any other battery, and that is it.

LiFePO4 have exactly the same charge requirements as a typical lead acid battery, 14.2~14.6V, 14.4V nominal, and the same charge curve, CC/CV.

CCA Ratings for lead-acid don't translate well in comparison to SHorai LFX, because we typically hold up to 2V higher during cranking than an equivalent-rated lead-acid battery. Since it is WATTS that starts your vehicle (A*V), this means that we crank much better than our CCA specs indicate.



David Radford
President, Shorai Inc.

www.i-bmw.com/showthread.php?t=32193

they're being talked about on various forums seems to be a hot topic

One of the experts on goldwings over at the GL1800 forum is currently testing 2 of these. One in a GL1800 and one in a new Concours. Shorai provided the batteries to him for test and evaluate. So far to sum up as these have only been out for 6 weeks or so, not a huge time, the CCA is somehow figured different on these lithium iron batteries. The rating sounds higher than what you actually get. They don't like cold and work better after "waking up". By waking up I mean, don't turn the key on and start, you turn the key on let the lights blast for 2 minutes or so th battery will crank better than it would have as strange as this sounds. So far this is the only negative Fred has found. They are small and take included spacers to fit the airbox, and light. Fred reports less apparent cranking volts vs a regular battery at low temps, starter turns slower. Seat of the pants, no volts tests have been done. I was close to buying one, but need the cold starts so held back. No one has said if these are Chinese product, but I would wager they are, so I think I'll wait a bit to see what others say about them before I plonk down the $100-$150. Not cheap if they are Chinese.

Interesting if they found an Li chemistry that mirrors lead acid for charge and discharge profiles.

It is true that Li don't like cold temps... or hot either. The temp range for the ones we were designing around was about 0 to 40C. At the edges of that range they had problems delivering or accepting the higher currents.

Not sure about them saying that their cold crank Amps are "better" because they deliver them at a higher voltage. The battery's terminal voltage at any value of crank amps is a direct measure of internal battery impedance. The starter is a load that requires a specific current at a certain voltage. As the battery voltage loads down, the starter needs more current.

As the gentlemen with the gold wing pointed out on the other forum, these Li batteries have trouble turning the starter cold. He has to "warm" the battery by running the lights to get good starter power. That indicates a lack of CCA until the battery is heated up inside.

ill be spending $30-35 at standard battery this spring buying the same battery i buy every year till i hear more feedback on these.
my bike draws a lot of juice and doesnt get ridden a lot,so i dont want to spend that much on something that only lasts me a season here in snoberia!

Interesting info fella thanx, alot of people at the sportster forum we going gaga over the weight and size difference, In a custom setting where size could be a factor per se, but performance over the season is still up in the air.

steell wrote:

Found this on a Beemer forum:

CCA Ratings for lead-acid don't translate well in comparison to SHorai LFX, because we typically hold up to 2V higher during cranking than an equivalent-rated lead-acid battery. Since it is WATTS that starts your vehicle (A*V), this means that we crank much better than our CCA specs indicate.

David Radford
President, Shorai Inc.

www.i-bmw.com/showthread.php?t=32193

Well, I don't think I follow what he's saying. It sounds like a little bit of double talk.

You can't raise the voltage on a passive load and expect the current to be lower. If his battery provides 2 more volts, then the CCA would have to be higher, not lower.

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And to put it in a more complicated way, (just for fun):
Yes it's true that it's wattage that starts your vehicle.

Wattage can also be calculated as Ri^2. If the CCA is lower, then wattage is lower.

Wattage can also be calculated as (V^2)/R
If voltage is higher then wattage is higher.

See the discrepancy. Wattage can't be higher and lower at the same time... faulty math. Cannot compute.

The way it really is:
If a battery can provide more cold cranking amps, it does it while also providing more cold cranking voltage. It has to be this way because the load is the same. The only way to get more amps through the same load is to put more voltage on the load. Conversely, the only way to have higher voltage on the same load is to force more amps through it. It's two ways of saying the same thing. That is the whole entire point of ohms law. Notice, now, if you use any of the three power formulas, you get the same result.
1) Higher I : RI^2 is higher
2) Higher V : (V^2)/R is higher
3) Both higher : IV is higher
ahh, all three results agree... does compute... processor happy.
Physics gods not frowny.

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He is violating physics, or is failing to explain what he means.

In the end, all that matters is that Ron's buddy found the battery to turn the motor over slower. What else do we need to know?

I'm hearing the warmup time isnt as bad as previously mentioned, only about 10 to 30 seconds

I wish i had one to test. Like Lou says in simple terms all you need to check is battery voltage while cranking to decide if this battery has more or less CCA. Less volts=less CCA.