My Cygolite Hotshot (tail light) is two or three years old, and the battery no longer holds a charge. I contacted the company from their web page, and a person named Paul from the company said I could return it for battery replacement. I'm willing to pay, but he hasn't yet told me if I have to or how much it will be. So far, so good. This is the normal lifespan of a LiIon battery, so I'm not complaining.

I imagine Tesla owners hope you're wrong about that lifespan - and I think you are as long as the charging cycle is well controlled.

It's probably a Li-polymer cell and not available easily. Take pictures - be fun to see what it looks like inside.

That's the problem with Li-ion technology. It's got great power density and better characteristics/wide temp range compared to other batteries. The problem is that it's lifetime starts from the day it's manufactured. It's basically going to last 3 years until the chemistry declines and is no longer reversible (capacity diminishes). You can find devices that have a battery that lasts longer but what they do is use a larger battery and charge it very gently so that they are still in the promised capacity level after the amount of time in question. Lupine, for example, does this. So does Dinotte on their new tail light.

J.

I called a guy there and he will be sending you an email.

I am sure that Tesla has both higher purity in their cells and more sophisticated battery management than a $30 taillight. Both impurities in the cells and cheap battery management will squash the lifetime of a LiIon cell.

my habit of running these things to no charge probably doesn't help the battery life at all

is it better to keep it charged up or let it run down then recharge?

the data I have seen for lithium-ion shows that frequent deep discharges can reduce the lifetime of a cell by more than a factor of 10. I probably could find similar data for lithium-polymer, but I haven't looked. I expect it to be similar. Hybrid cars keep the charge level in a very limited band, deep discharge is bad for most battery chemistries

Generally, the circuitry that controls the charging/discharging protects the cells from damage (or at least it should). The real damage to Li-ion/Li-Polymer batteries is the number of charges, charging too long if the charger is crappy, and - the worst - age. These chemistries just only last so long from the day they are manufactured. The clock starts ticking right away.

J.

I got a reply. I have an RMA number. Cost will be $5-10 plus shipping. I'm satisfied with that. Now to package it up and send it.

If we're worrying about environmental impacts of throwing things away instead of replacing them. Have you considered the carbon cost in sending it back? That's probably pretty hefty.

J.

I assume you're joking. The marginal fuel cost to put this on a truck or plane, on top of the other stuff already going, is immeasurably small.

But if you want to gauge it by the postage cost, you can do that. I think it's still less than the purchase.

Just a side note if you've been happy with the Hotshot(I have);
new model is out - 3 times brighter than the original Hotshot
according to Cygolite. I have one on the way.

https://www.google.com/search?q=cygo...34638315141529

Costs more, probably eats battery faster. I'm happy with mine. My main commuting bike has a steady-on dynamo-powered tail light plus the Cygolite. I also use a Spoke Lit in the rear wheel, which I'm told does a good job at catching eyes. Bigger (or really, brighter) may be better, but there is a point of diminishing returns. I suspect I'm at that point already.

Yes, I was joking. But if you ship it UPS, you can pay to offset the carbon usage - marginal or otherwise.

J.

Also consider that they're complete idiots if they actually replace the battery. The cost of the blinkie without the battery shouldn't be more than about $3 (I actually have done small run development of LED based gadgets, and even in quantity 50 I can hit $2.50 with stuff of a comparable complexity).

If they have any sense, they just chuck it and ship you a new one. You can't afford the labor to crack a blinkie open just to put a new $3 battery into a $3 device when it's probably RF welded anyway.

Probably true, but it's their call, and it doesn't matter to me whether I get a new battery or a new unit.

Their instructions tell me to include the mount and USB cord, which I don't have. I hope they don't mind.

Agree. Even if it's normal life cycle it's probably easier and cheaper to just replace it than to spend $25 on each correspondence back and forth that far outweighs the cost of the light even at retail prices.

J

2 riders in our group have these and they're no fun to follow....blindingly bright. I'm happy with my 50

For best LiIon life: Use until about 50% discharged and wait just before use to recharge. I approximate this as best as reasonable with my stuff and don't sweat it too much. e.g. My f/r blinkies have about 7 hrs of life. I might do two rides totaling ~4 hrs, then charge them up the morning of (or night before) the third ride. I usually don't charge the Garmin until it's about 1/2 down. Same with my phone.

That means we should all ask the manufacturer for a new battery for $3.00 and get a complete replacement. That's a deal.

Presuming they are stupid, of course. After the first few, then wiser heads prevail.

J.

Perhaps it won't get noticed because of the other warranty replacements that get mixed in with their incoming packages.

Well, one can hope. Generally, most companies watch their warranty returns very closely because it can be indicative of a larger problem with, say, defective components or something.

J.

Oh dang I want one!! Two actually!

I run 2 Hotshots currently, one of them at least 2 years old, and I've had no problems at all with it. In summer I can go a couple of weeks on a charge since I only use them in Random Flash mode in daylight. In winter I can usually get a week out of them. I have run each of them dead a number of times, no problems recharging.

But this is the first I've seen of this newer Hotshot. Can't wait to check those out!