Energy storage - New gen batteries

[KJINTF]

Thought you might like to see this
Energy storage aka power aka watts
Might be my rig's next battery

Watts aka Power Aka energy

[NinerBikes]

smkettner wrote:

NinerBikes wrote:
Would bouncing around in the middle 80% be true also for smart phone batteries?

Sure but the device may still be obsolete before the battery dies. Actually it depends on the device BMS as it might already be programmed to use the middle 80%. It does speak for not letting a device sit empty for extended periods or plugged in continuous.

I'd think on cell phones, that most people burn that battery up within 500-1000 near 80-90% DOD's, power users on smart phones are power hogs that can't even make it to 5pm before needing a partial recharge. This was quite common all over the Consumer Electronics Show in Las Vegas last week, folks clambering up to 120V electrical jacks for life blood for their Apple phones. Me, I run a fat back 2650Mah on my Galaxy S4 to get through those power use days unscathed.

Good points though, I suppose indicated " 100% SOC" voltage could be measured on the battery with a DMM to confirm Voltage it was charged to. 4.21V is about max for 18650's I run in flashlights and such.

[time2roll]

NinerBikes wrote:
Would bouncing around in the middle 80% be true also for smart phone batteries?

Sure but the device may still be obsolete before the battery dies. Actually it depends on the device BMS as it might already be programmed to use the middle 80%. It does speak for not letting a device sit empty for extended periods or plugged in continuous.

[wa8yxm]

Dakota98 wrote:
ONLY 252 Lbs. !!!! :S

Well, lead acid would be what about 100 pounds per usable KWH or 50 pounds per total KWH (Somewhat rounded on both numbers) and this is a 9KWH battery

So yes, 252 pounds is in the neighborhood of 1/4 what that much Lead would tip the scales at.

And at 4 grand... About 4/1 the price of that much lead.

[reed_cundiff]

Standard 9 V batteries can supposedly catch fire if two of them are placed together with their contacts touching improperly. There was a Youtube presentation on this that went viral recently.

Smart phone batteries are probably lithium cobalt for their higher energy density.
Reed and Elaine

[NinerBikes]

smkettner wrote:
The BMS will cut power before the damage occurs. I believe the BMS will allow 100% DoD based on capacity and staying above that minimum voltage. Voltage will get into that curve toward the bottom but the cut-off is complete as the contactor opens. Not the same as a brown out as your 12v flooded battery goes below 11 volts.

The best part is you can keep your solar producing max all day as the lithium battery does not taper charging anything like the flooded battery. And no need to ever get to 100% to preserve battery life. Yes bouncing in the middle 80% of capacity is best for longevity on a lithium battery.

Would bouncing around in the middle 80% be true also for smart phone batteries?

[mena661]

X2 smk

[free_radical]

horton333 wrote:
Places like Tesla, one of the highest tech car companies in the world, still get fires in their cars from time to time and so does every laptop manufacturer out there. Tesla use titanium shields to protect people, they know the hazards. They have extremely advanced charging and temperature monitoring systems, yet still some catch fire. I think they are the way of the future, but I would not go in without investigating the very real issues and making sure the risk is contained.
I note the smaller batteries they advertise seem to have more built in safeguards than this one, may be a better choice. Not sure.

I think that Only time Tesla batts caught fire was due to damage in a road accident when these cases ruptured
not overcharging or spontaneous combustion

[time2roll]

The BMS will cut power before the damage occurs. I believe the BMS will allow 100% DoD based on capacity and staying above that minimum voltage. Voltage will get into that curve toward the bottom but the cut-off is complete as the contactor opens. Not the same as a brown out as your 12v flooded battery goes below 11 volts.

The best part is you can keep your solar producing max all day as the lithium battery does not taper charging anything like the flooded battery. And no need to ever get to 100% to preserve battery life. Yes bouncing in the middle 80% of capacity is best for longevity on a lithium battery.

[reed_cundiff]

Agree with Mena661. The plots seem to merely show the extreme drop off at 90% DOD with LFP that has been extensively discussed. This is why it is strongly suggested that one not drop below 80% DOD with LFP. I think most people consider Peukert effect with consideration of charging a battery bank. We have found that such charging is almost linear with our LFP battery bank.
Reed and Elaine

[mena661]

PT see my previous changed post. Another thing, you won't see that drop off until ~90% DoD. There is SOME Peukert with LI just not enough to notice (it's very near 1).

[pianotuna]

Hi mena,

I'm not entirely sure of the difference. It may be another way of looking at results of varying loads. It is clear that LI do show far less peukert effect--but that it is still some. Or at least that was my understanding of what I read.

[mena661]

EDIT: I see now. This isn't the same as the Puekert effect. There is a sharp drop off when you reach the end of the discharge curve in LI batts. LI users simply operate their batts outside of that drop off. You don't want to operate the batteries there anyways because you chance killing them, hence the recommendation to keep them at 80% DoD and above.

[pianotuna]

Hi,

I knew that 0 Peukert was too good to be true.

"Ragone Plot

Lithium and nickel-based batteries are more commonly evaluated by the Ragone plot. Named after David V. Ragone, the Ragone plot looks at the battery’s capacity in Wh and the discharge power in W The big advantage of the Ragone plot over Peukert is the ability to read the runtime in minutes and hours presented on the diagonal lines.

Figure 2 illustrates the Ragone plot of four lithium-ion systems in 18650 cells. The horizontal axis displays energy in watt-hours (Wh) and the vertical axis is power in watts (W). The diagonal lines across the field reveal the length of time the battery cells can deliver energy at given loading conditions. The scale is logarithmic to allow a wide selection of battery sizes. The battery chemistries featured in the chart include lithium-iron phosphate (LFP), lithium-manganese oxide (LMO), and nickel manganese cobalt (NMC). "

From battery runtime

[mena661]

horton333 wrote:
I understand there are in excess of 200 differing battery chemistries that are based on Lithium, but the comments I have read from the engineers are that any can catch, and do, fire. Whenever you have increased energy density this is something that needs to be planned for.

LFP won't catch fire unless under EXTREME overcharging. Something that will never happen with typical RV charging. First, you would have to exceed the batteries charging limits. How many people here have a 1C charger let alone 3-5C? Two, you need to extremely overcharge for hours and hours. People on the DIY EV forums have purposely overcharged their LFP batts and the most that happened was severe bulging of the case. As was stated all lithium ion batt chemistries are NOT the same. The fires you hear are from LiCo batts. LFP is a different beast. If you're afraid, I understand but please don't use your fear to spread ignorance.