Archon DH26 from ebay

[fmerkel]

+1, poor lithium batteries, and/or charger.
If you are going to use them you need to educate yourself about the chemistry; the good ones...the BAD ones, AND for pity sake get a DECENT charger. The chargers that come with those cheap package deals are cheap package chargers, and likely batteries also.
A good analyzing charger (Liitokala 500 Engineer, Opus BT - C3100 V2.2] allows you to actually tell what the capacity of the battery is.

One of the things that you unknowingly pay for when you buy a high end canister light is someone else has done the learning, shopping and is shielding you from the problems. Go to China directly, you kind of go it alone.

 

[KevinNM]

So I picked up an Opus BT-C3400 and ran charge and test and it said that I have a 4368 mAh and a 4574 mAh, and 3.48v and 3.43v. Put the batteries in the light and it flashed on once and then wouldn't respond. Then unscrewed the canister and closed it again and the light seemed to work. I'll have to test it actually diving in a day or two.

I also ordered a focus handheld, which hopefully will arrive in a week or two.

 

[fmerkel]

So I picked up an Opus BT-C3400 and ran charge and test and it said that I have a 4368 mAh and a 4574 mAh, and 3.48v and 3.43v.

That was the end/discharged voltage, correct? Fully charge Li-on should be ~4.2v.

 

[Doby45]

So I picked up an Opus BT-C3400 and ran charge and test and it said that I have a 4368 mAh and a 4574 mAh, and 3.48v and 3.43v.

You will LOVE that charger..

 

[KevinNM]

That was the end/discharged voltage, correct? Fully charge Li-on should be ~4.2v.

That was what it showed at the end of the cycle. I'll run a charge cycle on it. The generic labeled in Chinese batteries have written 4000 mAh and 3.7v on them.

 

[fmerkel]

3.7v is 'nominal', think of that as middle operating voltage, about 30-40% of capacity. The charger should have pulled them down to ~ 3.0v on the discharge test but you always have some voltage bounce back after the load is off. Though 3.48 seems like there ought to be something left, there really is not.