This may not work in a mobile set but it has got a lot of juce left in it to run a small poket size rechargeable with 5 ‘s.

▪ 1W High performance pocket ▪ Brightness: 30 Lumen(lm) ▪ Aluminum alloy body with keychain ▪ Operates using 1 x AA (not included) ▪ 6 hours (normal) lighting.

& . by type.

#1 Best Seller in 3.7V . $12.99 Prime. [Rechargeable] Anker Bolder LC40 Flashlight, , Super Bright 400 Lumens CREE , IP65 led torch rechargeable torch battery

led torch rechargeable | eBay

torch light rechargeable battery – Alibaba