MikeOH Posted January 26 Report Posted January 26 10 minutes ago, Utah20Gflyer said: Lithium Ion batteries often have their own internal charge controller, which is important because Lithium batteries are more sensitive to proper charging. I believe the earth X batteries are this way which means from an airplane system perspective you shouldn’t have to change anything else on the plane. Just install and good to go. Yes, Li-Ion must employ a BMS (battery management system). This is another level of complexity (electronics) that is subject to environmental stress and represents additional failure modes that just don't exist with a conventional lead-acid AGM battery. To what standards were those electronics designed and built; are the electronic components high quality, MIL qualified, or the cheapest COTS parts? There are decades of in-field proven reliability with AGM; seems 4-7 years for a Concorde is typical. EarthX hasn't been around long enough to know. Feel free to be the beta tester...I'll wait patiently Quote
McMooney Posted January 26 Report Posted January 26 wow wish they were cheaper, 2x earthx would still be 20lbs saved over the my concorde Quote
Shadrach Posted January 26 Report Posted January 26 4 minutes ago, MikeOH said: Yes, I was comparing the LEGAL for install in certified aircraft; hence the $700 price 'cause you need the $200 paperwork! And, yeah, way overpriced. I was looking at the RG-35AXC which is 33 Amp-hour: .75lbs for each additional Ah. For me the AXC wasn’t worth the extra weight or doing a W&B entry. Quote
MikeOH Posted January 26 Report Posted January 26 3 minutes ago, Shadrach said: .75lbs for each additional Ah. For me the AXC wasn’t worth the extra weight or doing a W&B entry. LOL! If I thought my W&B was accurate to 3.5 pounds, I might worry about that Quote
Shadrach Posted January 26 Report Posted January 26 15 hours ago, MikeOH said: LOL! If I thought my W&B was accurate to 3.5 pounds, I might worry about that It’s not that I’m worried about it. I know that my IA would not sign it off without a W&B change. “Weight change negligible” entries are limited to changes of 1lb or less. Quote
Pinecone Posted January 26 Report Posted January 26 Remember, assuming you doing the proper capacity checks at annual, you may be as low as 80% capacity for the Concorde, so 23 or 26 amp hours. And what is the low voltage at full discharge? For a 12 volt system, will things still be working at that voltage. The lithium should be a bit higher at full discharge and not have the reduction in capacity over time. With the lithium, the other thing that might be an idea would be to move the battery further back to keep the same empty CG with the lighter battery. Quote
Vance Harral Posted January 26 Report Posted January 26 I don't actually know the owner of EarthX very well at all, and I'm disinclined to get into a lengthy conversation with him about his aircraft battery business. Having said that, I have two comments, numbered Anthony-style: I generally agree with the posts above, that an EarthX aircraft battery as it exists today is not a compelling product. I think everyone's implicit assumption - that the purpose of EarthX developing aircraft batteries is to make money selling a superior aircraft battery product to piston single owners - is likely incorrect. EarthX makes batteries for many different types of vehicles, and there are literally millions more non-aircraft vehicles in their target market than aircraft. My guess is that the aircraft battery product is some combination of marketing ploy ("aircraft grade" battery for your motorcycle!), R&D side gig, and hobby, on which EarthX is not currently dependent for profit. The guy in question is not an idiot, and I'm pretty sure he's already aware of all the legitimate criticism being made in this thread. I'm extremely confident he is not confused about battery weight, current capacity, or total energy capacity, as compared to competing solutions. 2 Quote
0TreeLemur Posted January 26 Report Posted January 26 (edited) Here's an important question- how many years (typ.) does it take the EarthX battery to decline to 80% capacity? Our familiar Concorde seems to last 4 sometimes 5 years. If the EarthX has a considerably longer lifetime until it gets to the magical 80% minimum capacity the FAA specifies as "acceptable" at annual, then it might make more sense? Edited January 26 by 0TreeLemur detail Quote
A64Pilot Posted January 26 Report Posted January 26 Concordes requirement for Airworthiness is 85% other batteries, maybe Gill is 80%. We need to not group all lithium chemistries together there are substantial differences sort of like Avgas / vs car gas, Lithium-Ion is substantially different than Lifepo4, AKA Lithium-Iron, Li-Ion weighs half as much as Lifepo4 for the same power but has a nasty habit of catching fire if abused or physically damaged, it’s nearly impossible to make LifePo4 burn, so it’s bigger, heavier but very safe, probably safer than lead acid. Earth-X is I’m sure the bigger, heavier but far safer LifePo4 In my opinion lead acid is a dead technology, it’s a matter of time before LifePo4 completely replaces it, but it’s not that time yet for aircraft New aircraft if not already but will surely come Certified with it and designed for it, ideally to get the most out of LifePo4 the electrical system is designed for it, yes you can drop in a LifePo4 into a conventional system the BMS can be designed to allow that but it’s not optimal. Its really sort of like Magnetos and maybe massive spark plugs, better exists but is it worth the buy in price? How long do these things last? I don’t think anyone knows to be truthful. Almost always when you ask that question you get the cycle life answer. I’ve never been able to get the how many years do they last answer, but I’m certain that they age as well as wear out. Tesla for example warranties the batteries for 8 years and 70% capacity and I think battery replacements under warranty are very rare for whatever that’s worth. All but one model of Tesla’s are Li-Ion, but one is LifePo4, the LifePo4 should outlast the Li-ions though. As we don’t really ever cycle our batteries, starting is big amps but very short duration, an Earth-X by my guess out to last at least ten years and hopefully that’s very pessimistic, but define when it’s bad? Are they Cap checked? What charger is used for one? Many or most automotive chargers don’t control voltage very well. they are just low amperage, but Lithium has to have voltage tightly controlled, which is easy with todays electronics, you really should have a “lithium” charger. A 12V lead acid battery has 6 2 v cells in series and fully charged is close to 13V. A Lifepo4’s cell full charge voltage is 3.65V, to get a 12V battery requires 4 cells, and fully charged a LifePo4 battery is 14.6V, that’s a pretty big difference. But they tolerate partial charging very well and unlike a lead acid battery partial SOC cycling extends the life, so they work in a regular 13.8 - 14.2V automotive system like we have. Quote
McMooney Posted January 27 Report Posted January 27 litime.com/products/litime-12v-100ah-group-24-lifepo4-lithium-battery-built-in-100a-bms-1280wh-energy there you go, this thing would last longer than i have fuel range, cost less and still saves 12 lbs Quote
MikeOH Posted January 27 Report Posted January 27 2 hours ago, McMooney said: litime.com/products/litime-12v-100ah-group-24-lifepo4-lithium-battery-built-in-100a-bms-1280wh-energy there you go, this thing would last longer than i have fuel range, cost less and still saves 12 lbs Bit of a problem if you want to START your plane: Quote
Will.iam Posted January 27 Report Posted January 27 (edited) Got this for my ski nautique as the battery compartment is in the bow and tended to keep the bow low. This battery was half the weight of the marine battery it replaced. Not cheap on price at $700 but does have an 11 year warranty and helped out on the bow not riding as low too. https://dakotalithium.com/product/dakota-lithium-12v-60ah-dual-purpose-car-starter-deep-cycle-lifepo4-battery-1000cca/ On further review this battery at the same price as the earthx has way better specs. i see the price has gone down $200 since i bought mine. I have had it two years now and its still going strong. Too bad this is not certified for aircraft. Maybe i need to send them a request. If i had an experimental plane this would be the battery i would use. Edited January 27 by Will.iam Additional notes. Quote
McMooney Posted January 27 Report Posted January 27 (edited) 1 hour ago, MikeOH said: Bit of a problem if you want to START your plane: I really meant to say there was something approx in our size with more capacity. but even at 1c rate which if i remember correctly would be 100,70 or 42a should still start my birdy. I'd be there is something there with less ah and more amperage available Edited January 27 by McMooney Quote
MikeOH Posted January 27 Report Posted January 27 28 minutes ago, McMooney said: I really meant to say there was something approx in our size with more capacity. but even at 1c rate which if i remember correctly would be 100,70 or 42a should still start my birdy. I'd be there is something there with less ah and more amperage available Perhaps: Quote
McMooney Posted January 27 Report Posted January 27 (edited) 1 hour ago, MikeOH said: Perhaps: the specs from their site says a max discharge 5s of 250A i'm guessing that'd cover it but here's another one might have to change the battery box that will start your plane, car and truck all at the same time litime.com/products/litime-12-8v-100ah-max-lithium-battery-lifepo4-deep-cycle-battery-built-in-150a-bms-1280wh-energy-4000-cycles-1920w-load-power?_pos=3&_psq=150&_ss=e&_v=1.0 heck, add a starter cap and call it a day Edited January 27 by McMooney Quote
philiplane Posted January 27 Report Posted January 27 And here's your other lithium battery option, probably a bit better than the EarthX, for those with 28 volt systems: https://www.aircraftspruce.com/catalog/elpages/mcitb17-11-15375.php Quote
MikeOH Posted January 27 Report Posted January 27 1 hour ago, philiplane said: And here's your other lithium battery option, probably a bit better than the EarthX, for those with 28 volt systems: https://www.aircraftspruce.com/catalog/elpages/mcitb17-11-15375.php $6,779 each….and no stock! They must be just flying off shelves 1 Quote
MikeOH Posted January 27 Report Posted January 27 2 hours ago, McMooney said: the specs from their site says a max discharge 5s of 250A i'm guessing that'd cover it Cold start/hot start…your plane always starts in 5 seconds!? I’m impressed! Quote
McMooney Posted January 28 Report Posted January 28 19 minutes ago, MikeOH said: Cold start/hot start…your plane always starts in 5 seconds!? I’m impressed! motors require more current to start turning then to continue turning. so that prestolite may require the 190amps for only a second or two when you initially turn the key Quote
MikeOH Posted January 28 Report Posted January 28 3 minutes ago, McMooney said: motors require more current to start turning then to continue turning. so that prestolite may require the 190amps for only a second or two when you initially turn the key Sounds like you’re sold; 40% higher price, half the capacity (that would disturb me in IMC, BWTHDIK?). So, why don’t you already have one installed? Quote
McMooney Posted January 28 Report Posted January 28 1 hour ago, MikeOH said: Sounds like you’re sold; 40% higher price, half the capacity (that would disturb me in IMC, BWTHDIK?). So, why don’t you already have one installed? uhmm, i believe i also said it was too expensive I just posted a link of an existing lifepo4 battery of approx the right size and massively more capacity, mostly as an example of what could be. honestly, it was the first return from bing/google, i bet there are many that would work Quote
McMooney Posted January 28 Report Posted January 28 Just now, McMooney said: uhmm, i believe i also said it was too expensive I just posted a link of an existing lifepo4 battery of approx the right size and massively more capacity, mostly as an example of what could be. honestly, it was the first return from bing/google, i bet there are many that would work and yes, if it was appropriately priced and better than lead acid, i'd buy it in a heartbeat Quote
ttflyer Posted January 28 Report Posted January 28 I posted in the other thread but I'll repeat here: I owned a RV-6 before the Mooney and it had an EarthX battery in it. After start, it would take the FULL 60 amps that the alternator could deliver to recharge itself for about a minute or two after start. Long story short, it chewed up two alternators ($$$) in fairly short order. So.... that's a no for me. 1 Quote
N201MKTurbo Posted January 28 Report Posted January 28 30 minutes ago, ttflyer said: I posted in the other thread but I'll repeat here: I owned a RV-6 before the Mooney and it had an EarthX battery in it. After start, it would take the FULL 60 amps that the alternator could deliver to recharge itself for about a minute or two after start. Long story short, it chewed up two alternators ($$$) in fairly short order. So.... that's a no for me. It would be possible to build a voltage regulator that would limit the charging current. Generator regulators already do it. Maybe if the demand got big enough, somebody would make one. Quote
ttflyer Posted January 28 Report Posted January 28 15 minutes ago, N201MKTurbo said: It would be possible to build a voltage regulator that would limit the charging current. Generator regulators already do it. Maybe if the demand got big enough, somebody would make one. I'm a little surprised EarthX doesn't limit this in the BMS. Maybe they do now. But they sure didn't back then... Every start you could tell the Alternator was working its guts out... Until it's guts gave out... 2 Quote
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