Would you like to carry lead in your airplane or helicopter? Probably not. How about acid? Also, a bad idea, right? Why then would you want a lead-acid battery? The answer to date has been “because every other kind of battery has tended to overheat and set the aircraft on fire.” NiCd batteries were all the rage in the 1970s and the superior energy density resulted in aircraft manufacturers engineering in temperature sensors and cockpit warning lights specific to these batteries. Ultimately they proved impractical for operators, though, and most were ripped out in favor of the older inferior technology of lead-acid.
Boeing was a pioneer in using lithium-ion batteries with the 787 and we all know how that worked out. At NBAA 2015, True Blue Power was all over the show with their newly formulated lithium-ion battery that supposedly won’t overheat anywhere near as fast as batteries with the older chemistry. The battery is stuffed full of fancy electronics to regulate and monitor what is going on within the cells, but you will still need some kind of cockpit indicator light. A battery with roughly 45 amp-hours at 24V will cost about $13,000 compared to $2,500 for the lead-acid equivalent (or $200 for a car battery with 90 amp-hours at 12V?). Supposedly the cost over time will be similar due to reduced expenses associated with annual capacity checks (for a higher-end aircraft the batteries must be removed every year and tested by a mechanic).
If “the third time is the charm” proves to be the case with advanced battery technology, True Blue Power will be adding about 5 percent to the payload of a typical light aircraft.
I use an Earth X battery in my ELSA Carbon Cub, about 11 lbs lighter than the stock lead acid and better cranking power.
http://earthxmotorsports.com/product-category/experimental-aircraft
Sticking with lead acid in the Eclipse though, nothing certified and need the weight anyway to stay in CG.
On an aviation note, spread the word for this Kickstarter campaign: $299 ADS-B receiver. I’m in.
http://www.flyingmag.com/avionics-gear/instrumentaccessories/bad-elf-launches-kickstarter-campaign-299-ads-b-receiver
Keep in mind this is single band 978 MHz receiver. No data about sensitivity and temperature range as well. Most of the equipped traffic I see is 1090 MHz. So you going to miss those until you climb into ADS-R range and even the you rely on ADSR seeming those aircrafts.
For automobiles we’re beginning to see more AGM batteries (long used in UPS backups). These are lead acid but spillproof because the acid doesn’t slosh around but is captured inside sponge like glass mats between the plates.
I did a quick search at it appears that you can get airplane batteries for as little as $500 (is the other $2,000 for installation?)
http://www.pilotshop.com/catalog/elpages/rg24-16.php?utm_source=google&utm_medium=cse&utm_term=11-05112&gclid=Cj0KEQiAvuWyBRDO_Yzhpv_4nvEBEiQANBdXMlxe8vIRNv_SldE4-KDbvGt2FFInCAdkUTA6cdgNvjoaAn0Y8P8HAQ
This is a little bit more than you would pay for two 12V AGM car batteries (which run around $150) but not an order of magnitude more.
The lithium batteries will probably come down in price. Tesla spends about $250 per Kwh (45ah @24V is just over 1 Kwh). Even if stuff for planes costs 10x as much, that’s still not $13,000.
Izzie: The original posting discusses a 45 amp-hour battery at $2500. You came up with an example of a $500 airplane battery… with 13.6 amp-hours of capacity and an explicit note “This aircraft battery is not designed or intended for turbine aircraft engine starting applications.”
I didn’t realized you were talking about batteries for turbine aircraft. Wouldn’t it make sense to leave all or part of the starting system for a turbine aircraft on the ground and save weight? You could windmill to restart in the air.
The Chinese will sell you a 45ah, 24 lithium battery today for $1,500 – you just have to figure out how to keep it from catching on fire.
http://www.globalsources.com/si/AS/Shenzhen-Polinovel/6008846691148/pdtl/24V-45Ah-lithium-titanate-motive-power-batteries/1108345888.htm
Izzie: Well, even if it were not for a turbine aircraft, a plane that is certified with a 45 amp-hour battery isn’t going to work with the 13.6 amp-hour battery you suggested. Could you restrict yourself to operating from airports with GPUs (ground power units; typically small diesel generators that can be towed out to plug into the airplane)? Sure. That adds about $50-75 per start and also requires a bit of planning (and that the FBO’s GPU is actually working). You’ll never be able to depart after-hours without paying an additional $100 to $200 call-out fee so that the line guys can be there to operate the GPU, disconnect it, etc. Finally, if you really do want to cut the airplane’s battery capacity down to 4 AAs, you have to consider what happens when the engine and/or alternator(s) fail(s). With a 45 amp-hour battery you can probably run everything except the windshield heat for about 30 minutes. That’s roughly how long it will take to drift down from a turbine aircraft’s service ceiling. Also consider what happens if the reason that the generator failed is an engine fire. It might be nice to have battery power available to operate a fire suppression system.