matt2matt2002 wrote:I need a new rear light.
Looking at Cateye and they are either battery or USB
Never had USB before.
Pros and cons/ opinions please.
Yes, other brands available but question about power source.
Sources of power for rear lights are largely:
1. Lithium polymer (can be made flat) - will be built in or a battery pack
2. Lithium ion (usually cylindrical) - will be built in or a battery pack
4. CR2032 (watch battery) - a stupid idea generally due to low capacity
USB is not the source of power, it's the charging mechanism.
Their best rear light was the Volt 50. This used a removable li-ion pack switchable with the front lights. The battery was 2200 mAh (though they have larger sizes)https://www.cateye.com/intl/products/sa ... 60RC-REAR/
The Cateye batteries now are:
Sync Kinetic 500 mAh
Rapid X3 900 mAh
Rapid X2/X2 Kinetic, probably 500 mAh
Rapid X - not sure but probably 320 mAh
Rapid Mini 320 mAh
It depends what you are doing with your light, but lumens are directly proportional to power consumption effectively, and flashing will cut power usage a lot.
So the Rapid Mini claims 3 hours constant 25 lumens, from a 0.32Ah = 1.18Wh battery. That is 0.4W for 25 lumens, or 62.5 lumens per Watt.
The Rapid X3 claims 150 lumens for 1 hour, from 3.33 Wh, which is 45 lumens per Watt.
Their brightest AAA battery light is the Reflex Auto, which has 30 hours constant.
Two AAA batteries give around 900 mAh at 3V (vs. 3.7V from a li-ion battery), the difference is that alkaline drains faster at high loads, but 30 hours at 900 mAh is equivalent to only 0.03A/0.09W, which is almost nothing. Assuming 75 lumens/Watt, you are looking at around 7 lumens from the AAA light.
So if you want a VERY bright light, then AAA just won't be an option.
This curve shows the difference between disposable alkaline batteries and rechargeable NiMh:
Lithium is similar to NiMh.
Hence if you use alkaline it will get steadily dimmer throughout its life, whereas rechargeables will tend to simply die at some point.
It is for this reason that it's a good idea if buying a rechargeable light to get one that has a multi-stage battery indicator. More expensive lights (the Cateye ones do not really fall into this category) have this. Personally I think all the Cateye rechargeable models are quite cheap and nasty and not a patch on their AAA models.
If wanting a lithium light I would steer clear of Cateye and buy a Lezyne, Lupine, Exposure or similar. The Lezyne have a multi-stage battery indicator (depending on the model). And the Rotlicht is obviously very high quality. https://www.lupine.de/products/tail-lig ... tlicht-maxhttps://exposurelights.com/products/bike/rear-lights