Experience with powersport lithium batteries?

I?d like to solicit personal experiences with people using powersport lithium batteries in their installations. More specifically, Shorai batteries and other batteries with NO built-in bms. I?d like to kindly ask people to keep this thread specific to batteries OTHER than EarthX as doing otherwise seem to inevitably lead to the discussion going into thermal runaway and subsequent deletion by the moderators. Marketing pitches are not welcome. Just builders/owners personal experiences and observations.
So far, based on my research, the following provisions should make such a battery a sensibly safe and economical choice:

? crowbar overvoltage protection and a provision to monitor the voltage in the system
? locating the battery in such a way that it can be vented outside in case of a thermal runaway (engine side of the firewall or inside a sealed enclusure vented outside)
? protect the battery from sources of heat (i note that the popular lead acid battery has a similar operating temprature requirements as a lithium battery and therefore placing a lithium battery in a similar location on the firewall presumably should be acceptable)

I am about to pick a bettery for my installation. I have personal experience running a Shorai battery on my bike. So far, I?ve heard of no dangerous failures of Shorai batteries other than those induced by abuse beyond normal operating parameters or by installations lacking overvoltage protection. I am trying to count every oz in my built and the weight saving of using a lithium battery is very attractive. That and the fact that a Shorai battery is only slightly more expensive than a popular premium lead acid battery.

One data point about cost. For starting power, you can use the pbe equivalent rating of the lithium, but for reserve capacity, you will need a lithium with a pbe equivalent of 3X the ah rating of a lead acid. When I looked at the shorai that was comparable on a reserve capacity, it was 4 times the cost of lead acid.

Larry

Good point. I was thinking in terms of starting capacity. Here is a quote from The FAQ on Shorai?s website: ?The internal "completely discharged" capacity of a Shorai LFX is 1/3 the rated "PBeq" capacity.?. I am pretty sure that?s the case with all lihium batteries. So, the reserve capacity to run an electrically dependent airplane system would be significantly lower than a lead acid battery with a comparible starting capacity.

What is "pbe equivalent rating" ? Google does not return any info.

EDIT: PbEq is searchable. I can figure it out from there.

Kalibr said:

I have personal experience running a Shorai battery on my bike. So far, I’ve heard of no dangerous failures of Shorai batteries other than those induced by abuse beyond normal operating parameters or by installations lacking overvoltage protection.

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Just keep in mind that most motorcycles don't have 60+ amp alternators on them.....

Midway through Shorai?s FAQ https://shoraipower.com/faq where I pulled the sentence from

Brantel said:

Just keep in mind that most motorcycles don't have 60+ amp alternators on them.....

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You?d be suprised... In case of my BMW k1300s the alternator is 55 amps. I am pretty sure touring bikes have even bigger alternators.

Brantel said:

What is "pbe equivalent rating" ? Google does not return any info.

EDIT: PbEq is searchable. I can figure it out from there.

Click to expand...

The 'equivalent' thing can be the gotcha. It's been fairly common for Lithium (regardless of 2ndary elements) sellers to market a tiny light weight Lithium tech as 'equivalent' to a much heavier lead-acid battery based purely on its ability to spin a starter for a few seconds. That's the *power* ability of the battery. It's often *not* the 'equivalent' of that much heavier lead battery in terms of *energy*. The 1 lb Lithium will start an IO540 just fine. But if the alternator quits, and you need to run your electronic fuel injection fuel pumps plus 10-15 amps of IFR panel goodies, the battery may only last 10 or 15 minutes.

So, you need to know what the 'equivalence' is based on. Knowing the *actual* Amp-Hour rating of both the Lithium and the lead-acid it's replacing, *and* the set of voltage/current/time curves for both, is the starting point for comparing the two batteries.

Charlie

rv7charlie said:

The 'equivalent' thing can be the gotcha. It's been fairly common for Lithium (regardless of 2ndary elements) sellers to market a tiny light weight Lithium tech as 'equivalent' to a much heavier lead-acid battery based purely on its ability to spin a starter for a few seconds. That's the *power* ability of the battery. It's often *not* the 'equivalent' of that much heavier lead battery in terms of *energy*. The 1 lb Lithium will start an IO540 just fine. But if the alternator quits, and you need to run your electronic fuel injection fuel pumps plus 10-15 amps of IFR panel goodies, the battery may only last 10 or 15 minutes.

So, you need to know what the 'equivalence' is based on. Knowing the *actual* Amp-Hour rating of both the Lithium and the lead-acid it's replacing, *and* the set of voltage/current/time curves for both, is the starting point for comparing the two batteries.

Charlie

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more completely stated here, by Charlie. My 680 lead acid (18 AH)will give me about 11 amps for an hour. The Shorai 54 ah battery also delivers 11-12 amps for an hour, though it would have a MUCH greater short term cranking capacity. Lithiums are optimal for cranking, due to their low internal resistance and ability to deep cycle without sulfation. Great for VFR with mags. Not so great for IFR with EI. At least in the smaller, less expensive packages.

Larry

My experience:
I have a Yak-55. The Russian batteries were held on the firewall in 2 composite cases with lids held on by about 12 safety wired screws...24 volt system. Heavy, Complex, Over Engineered. (and broken connectors too)
I replaced it all with a pair of cheap ($140 ea!) Lithium Iron power sport batteries from an auto parts store. (Shaved 10 pounds!)
I left the battery switch on over night at an aerobatic contest. A quick boost charge got the shower of sparks working, and the air start system did the work. M-14P comes with a 95 amp generator, so probably excessive charge rate. I got away with that one. The batteries survived and operated just fine.

Months later I replaced the 23 pound generator with a B&C 10A mini alternator, (Shaved 20 pounds!) but I didn't connect the battery isolation switch, so the battery discharged at a milliamp rate and the batteries were dead in a couple of weeks.
Here is the important part:
I put a 27.3V 13 amp constant voltage power supply on them (usually used to maintain the float voltage) and returned an hour later to a pair of melted top batteries that smelled real bad.
A bit late, I re-read the literature that came with these batteries: when the battery voltage is below 10 volts, charge rate must be 1.25 amps or less.
I killed my batteries. They didn't cause any harm or make a mess.
Right now I have cheap ($50 ea) auto parts store SLA motorcycle batteries in the Yak.
Yes, I did finally install the battery cut-off switch and over-voltage protection.
I probably will go to EarthX LiFePO4 batteries which would have saved themselves from my mistreatment. The Yak uses two, and they are spendy. They sure are light tho- and that is EVERYTHING in an Akro mount!

Great, thanks! All good info. In my case — day VFR, dual Pmags, mechanical fuel pump, probably no more than 5 amp draw in the system (except when the radio is transmitting), SD8 alternator. Shorai implies that their 18 ah PbEq battery should have 6 ah true capacity. Looks good to me so far.

So, with alternator loss, you could expect *at most* around an hour of operation, with a *new*, perfect battery. Variable and unknown duration after the new wears off. Are you comfortable with that? If yes, then go for it. If no, it probably wouldn't cost you that much in money or ounces to upsize a bit.

My personal preference is what's preached over on Aeroelectric: I want enough electrons (from whatever source) to reliably outlast the fuel on board.

Charlie

Charlie, with my setup I don?t need no mystical creatures never seen by anyone like electrons or unicorns to keep my engine running! The Pmags and the mechanical fuel pump will keep the fan spinning for as long as there gas to pump and burn. And putting that aside, an hr reserve capacity is more than plenty to find a decent landing spot unless I am crossing the Atlantic or something.

Btw, i always enjoy reading your posts that often cut through BS and get to the substance of the matter. Thank you for pitching in!

Yeah, it's all about the mission. I recently restored an ancient Kolb Twinstar, and had to force myself to add any battery at all. It's only there to run the Facet style backup fuel pump (currently available squeeze bulbs don't last one season).

Thanks for the kind words; I hope my posts are at least a little better than noise.

Charlie