alioth wrote:
For me going to lithium would hurt my weight and balance, the battery is required as ballast!
I would think about solving this problem by installing a bigger battery or more of them. It would provide me with longer run time. Perhaps not a relevant option in your case.
TSO certified 28V lithium battery – Gill242 / RG24-15 replacement
This seems new and very interesting.
FAA TSO certified to C179a
ETSO certified to C179a
RTCA DO-311 qualified
RTCA DO-160G qualified
UNDOT/IATA qualified
Dimensions are obviously intended to replace the above two commonly used batteries:
Dimensions: 7.2” L x 7.4” W x 6.0” H
RG24-15: 7.15 × 7.11 × 5.95″
BUT much lighter: 7.3kg versus 13.4kg
Full internal electronic charge control and protection.
The catch is likely to be the price. I can’t find any availability or even listings. But somebody has just paid €1000 for the RG24-15, including VAT!
Another catch, evident from the 500A rated output current, might be that it probably has a substantially lower internal resistance than the RG24-15 and definitely lower than the relatively crappy Gill242. This will make for better starting but the extra current may shag the relays – even if they were correctly sized to start with which is not always the case (e.g. Socata passes the starter current through a N/C contact rated at just 30-50A and these often melt together, which is discovered only when a GPU is needed).
It will be interesting to see what positions the airframe certification authorities take on this. In FAA-land, the Concorde RG24-15 is routinely installed to replace the G242 as a Minor mod and every IA I have ever known agrees and one pilot has a written FSDO opinion confirming it (though, as always, opinions exist to the contrary). Logically this seems correct because the battery change is not a “basic change” to the electrical system. But this new battery is a further step ahead; it is a battery with a load of electronics which appears like a normal battery from the outside. Interesting times….
While getting my autopilot fixed by Avionik Straubing, I noticed this battery in their display case and spoke to their manager about it. As it turns out, it’s not exactly a drop-in replacement, there is a mod involved (at least in terms of battery’s internal sensors, for which it features a dedicated 4-pin connector), and he mentioned a total price in the neighbourhood of €6000. I suspect there are better ways to spend this amount of money.
They will sell zero at that price, so I wonder if there is a breakdown of the cost e.g. it needs some battery condition indicating product installed in the cockpit (the site does say “Communicates battery status to the cockpit”) and much of the 6k is the installation cost, and getting the EASA approval for the whole thing, and then a subsequent battery would be a lot cheaper. IMHO it has to be something like that. NICADs do cost thousands (i.e. there is a market at that price level) but those are big ones, for King Airs and such.
They would probably sell some (not many) at €2k. They claim 6-10 years life, but an RG24-15 lasts 6-7 years.
Maybe there is something in the small helicopter business?
Peter wrote:
They will sell zero at that price
I doubt that, especially as you indicated as well, that NiCad batteries can be also very expensive, and are also sold.
I think it can make difference for helicopters, as they also have a Robinson 44 STC. They also have an internal heater, which might make them a better choice in very cold climates.
especially as you indicated as well, that NiCad batteries can be also very expensive, and are also sold
NICADs do cost thousands (i.e. there is a market at that price level) but those are big ones, for King Airs and such.
Anyway, where is the market for a 17Ah 28V battery at €6000? If indeed the cost of the battery alone is €6000… that is not clear at this point.
Peter wrote:
Anyway, where is the market for a 17Ah 28V battery at €6000?
In this helicopter business, where the difference might be sufficient to just squeeze in an extra passenger or so.
The other I would see is in very cold climates where the battery can get damaged by the cold, or that it needs an heater. The battery comes with an STC for Robinson 44 as well.
Peter wrote:
Anyway, where is the market for a 17Ah 28V battery at €6000?
Aerospace – satellites and launchers ?
Well, sure, but this battery seems to be aimed squarely at GA… size, voltage, the marketing comparison above, etc. It is not a specialist aerospace/industrial product.
Maybe there really are applications where 6-7kg saved shifts the W&B envelope in some critically useful way, but I doubt there is a fixed wing case of that. Helicopters, maybe?
It would be interesting to know the breakdown of that €6k.
Peter wrote:
Maybe there really are applications where 6-7kg saved shifts the W&B envelope in some critically useful way
Unfortunately in our case, it would shift the W&B in a useless way! Even though in permit aircraft, the installation costs will be much lower, I’m sticking with lead acid because helps with the W&B (the aircraft is a bit nose heavy with the Lycoming engine, and the battery is in the back, so it helps move the W&B back a bit).
