Tom

Got to keep reminding myself you now fly a ASW27 not the (massive battery carrying) ASH26. Sorry I don't know for for sure with running those batteries in parallel, I'd check with Richard. I've always liked to run 2 x large batteries, 2 x 10Ah in the DG-303 or 2 x 17Ah in the ASH26E. I like having a roughly known clean reserve to switch to. With 10Ah/15Ah batteries I'd just run them by themselves, but thats personal preference not based on other reasons.

Darryl



On Wednesday, September 27, 2017 at 4:35:43 PM UTC-7, wrote:
On Wednesday, September 27, 2017 at 3:43:56 PM UTC-7, Darryl Ramm wrote:
And it's a reminder that modern small devices can draw significant power. As
an example an iPhone 7 Plus has a 2.68 Ah battery at 3.8 V. Just charging
that battery from flat, and assuming 80% charge efficiency will suck around
1 Ah of charge from a glider 12V battery. On top of whatever it takes to run
the device at high screen brightness. Which reminds me I want to remeasure
power use and charging of a few modern devices..... its pretty amazing the
compact compute and power capacity we carry around nowadays.

Yep... My panel pulls around 1.7 amps sitting on the ground so assuming a couple of brand new K2 10Ah batteries I'd get a bit over 11 hours runtime.. I was getting a lot less. After discovering one of my new to me, but several years old batteries was pretty much dead, I replaced with a pair of Craggy Aero LiFePO4 batteries. Still struggled to get more than 5 hours until I replaced my master switch with a high quality one.

I might be able to modify one battery compartment in my ASW-27 to take the 15Ah battery, but there's definitely no room on the other side. Would it be bad to run a big and small LiFePO4 in parallel? Let the BMS handle the taking the small battery offline after it's depleted? I also need to look into installing a tail battery since the wiring is all there so just need to find something that will fit.

Getting back on the thread, this is why I now power my iPhone with an external battery. It's easy and cheap insurance to keep my avionics going for the long flights I like to do.

5Z