I rode 20 miles Saturday and 20 mile Sunday with the Biologic charger hooked up to the Astro E1 battery. When I started it had three out of four bars of charge. At the end of the ride, Sunday it still showed three bars- ie no discernible increase in charge. I have an old iphone that shows percentage of battery charge that I am going to hook up to see if the charger is making a difference.

Were you drawing from the battery on these rides?

No. I was simply trying to charge it.

Oh. So far, not so good.

I was playing around with auxiliary batteries this weekend. The one that takes 4 AA batteries only charged my phone from 48% to 65% overnight; the Li ion took it from 58% to 83%, overnight in each case.


My conclusion? I've got a darn big battery in my cell phone, and it's going to take a heck of a lot of juice to recharge it.


I'll continue to use an auxiliary battery for the GPS, but I think I'll plug my phone charger into a wall socket.

how big was the liion battery? I might have to get a bigger battery for some long rides this year

As I think I said earlier (and I know you weren't asking me), My Astro E1 keeps my iphone fully charged for hours with apps and GPS going and with the screen on the whole time. It can charge an iphone from empty to full about 2.5 times. It's not a big battery. I think it has two 18650 cells in it.

I have a Limefuel battery, too, but it's absurdly big. It weighs 16 oz! But it sure can deliver a lot of watt hours.

5.2 A-hr external battery; it was part of the Costco package deal when I bought the phone with a 3.0 A-hr battery. (I refuse to play the milliamp-hr marketing game!) I've had it for over a year and never tried to recharge the phone battery before. I don't know why it wouldn't recharge the phone battery all the way. Maybe the voltage dropped during discharge so it wasn't high enough to push current into the phone?