MINCHEN 8.4V Battery Pack Case for 2/4x 18650 li-ion Battery Waterproof Safety Cycling Battery Pack Case Box Cover with DC and USB Interface for Bike Light Headlamp Cell Phone, no Battery Included

Contrary to some of the negative reviews.. I find this product to of good quality. Sturdy and rugged. Works as expected. I bought the 4 pack version and nothing seems out of place. Need to be careful not to put the batteries the wrong way.Only recommendation to the manufacturer is to design a fool proof mechanism to avoid short circuit the pack by putting the batteries the wrong way.

Very Good!

The USB only supports 1A/100ma so it is not very useful.

Does not work for my bicycle light as it should. It kept shutting off and appears to be out of charge in less than a 30 minute ride. I checked to make sure that the batteries are good and installed properly.

Works good for bike lighting as long as the road is smooth. Sharp bumps will cause the power to drop out, and the light goes out. The battery springs need to be stronger.

Nicely designed and easy to use

These battery packs don't have 5V discharge protection. The 2S circuit will output power until 3V, running each cell down to 1.5V. This is territory to kill a Lithium cell, and a leading cause of battery explosions if the batteries are charged again.

The little blue lights that indicate the battery charge has stopped working. I have used this about five times.

This seems like a decent battery box for the money. It has a couple of flaws but those can be fixed (I think).First is the cord. It has no retainment mechanism. I secured the cable to the lid with small zip ties and it prevents the cable from twisting and potentially breaking the wires at the pcb board.Second is the box is shiny plastic and is slippery. On a bike it could slip down a tube if the riding is bouncy. I’ll simply spray something like Plast* D*p on the main portion of the box.Otherwise it should hold up fairly well. The description says waterproof but I think you’d be better off thinking it’s water resistant.

After a couple.months of use, I'm still satisfied. I usethe battery pack to power lights for cross country skiing and winter biking. The run time is much longer than the original battery packs. I am hopeful that since each battery is charged separately they will also last for years, but we'll see about that.

Pour ma lampe de vélo. Parfait et étanche

Basically it is it does what it states. Although, one must keep in mind that the USB is the only switchable output. The 12v is both output and input, but not able to be switched off.

I bought this hoping to replace a manufactured battery pack for a bike light, that has started to fail. I figured, since I have 18650's and a confident quality cell charger, this holder makes sense.It works. It provides an enclosure and outputs the voltage needed through the right size cable plug.However, for my intended usage, for the advertised usage, on a bike... it's horrible. It's huge, the plastic is "crispy" (tap on it, it sounds hollow and you get the feeling it will likely crack into pieces if you drop it), and the one piece "Velcro" strap is not sufficient to hold it in place anywhere on any non-flat frame. It does however fit into a bottle cage. Reminds me of the BLT days... but those were designed like bottles.If it was not so needlessly big, or if it was slightly contoured to hug something round, or if it had a silicone/rubberized surface so it can help keep it from moving around when strapped to the frame... any ONE of those.. and it would be a 3-star, relative to price. But for what it is, I don't think the value is there for 21CAD, unfortunately.It works. It is as described. There's nothing broken. It was shipped by Amazon, so everything was speedy and good.