I'm liking night riding...(battery question!)

Christopher Robin said:

Ahh ok thanks. I thought guys like Gemini were maybe just re-branding some inexpensive battery packs from elsewhere.

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Lots of stuff on Amazon: bike light battery 8.4v

2 day shipping and lots of positive feedback.

I have 2 sets (one for me, one for my daughter) of last year’s Gemini Duo 2200 (helmet) and Titan 4000 (bar) lights. The batteries are 4000 and 8000 mAh respectively.

I don’t profess to have the technical acumen of many of the folks at this sub forum. In fact, I have none. What I can attest to is that these lights and batteries have been heavily used in extreme temps, and have performed as advertised.

I got these at a significant discount, but they were still not inexpensive.

I have commented on them in other threads. In short, I have not encountered any better lights on the trails in Fernie, Canmore, Banff, Kananaskis, Golden or Revelstoke. That’s not to say there aren’t any, only that I have not seen any. To the contrary, a number of times I have been stopped on the trail and asked what brand and model they were. Some have actually made notes on their phone on the side of the trail in the middle of nowhere.

We have often ridden for 5+ hours in the dead of night in very cold temps, and they have not been anywhere near fully drained. That said, I don’t have any need to run them in anything brighter than the stock low and middle settings.

A word of caution - be careful when disconnecting the battery from the bar light in extreme cold. Do not over twist the wire when disconnecting the leads. I replaced the two large batteries under warranty, I believe on this basis. Zero hassles with Gemini on this. It was painless.

Once I changed the crap batteries they came with, the bar remotes have worked flawlessly, in sync for both the helmet and bar lights.

There may be better lights out there but I can’t imagine they could be that much better. I am really happy with these lights. I wish I could say the same about all the bike components and accessories I have. If these were not top notch, they would be gone and replaced. Life is short and biking is a huge part of my life. I have zero tolerance for anything the slightest bit substandard.

My 2 cents - buy Gemini batteries and be done with it.

Christopher Robin said:

The handle bar light uses a small 2-cell 7.4v/2600mah battery and my helmet light uses a 4-cell 7.4v/5200mah battery. I don't remember the run times on those but I need/want something bigger. But based on what's new on the Gemini site, I can get 4-cell 8000mah batteries packs now.

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I have a different question, but similar enough that I think it fits in this thread. I also have a small 2-cell 7.4v/2600mah battery, in my case for my helmet light and would like a bit more runtime. My battery is one of the newer Magicshine's with pass through USB charging and I have some Aukey 10000mAh powerbanks lying around that'll source 12W (2.4A @5V). Naively it looks like the combination of battery and power bank should have capacity similar to a 9000mAh/7.4v battery.

I've verified just playing around in my garage that I can daisy chain the power bank to the battery to the light and everything seems to work. What I'm wondering is whether there are any hidden issues with this approach (other than the slightly clumsy battery + power bank stack in my pack). My helmet light is pretty small and I don't think uses more than about 12-15W at max so the power capacity of the power bank should be almost enough to run the light on its own, and even if not it should be close enough to significantly extend the runtime of the primary battery.

Is there anything else I'm missing here and do I need to buy a separate higher capacity battery or is my bastardized power bank extender approach sound?