Not to go off topic, but I wish I could find some 4.2 volt 18650's or 26650's which don't sag down their voltage under small to moderate loads. RHD, did you make a deal on those? If you test them, please tell me how they work out for you in regards to voltage drop under load, if you could?
I'm having a problem finding 26650 batteries which don't sag a few tenths of a volt when under load, my JetLasers PLE Pro won't put out full power without a better battery and I've tried four different types of 18650's which are supposed to be rated far in excess of the current my laser is pulling, under 4 amps.
maybe. I decided to charge the batteries, was curious to see if they fit on my charger. they barely do. I'm glad I checked, one of the batteries is DOA and will not charge and has no charge currently. I'm going to email cnquality goods and see what they say about the defective one. I may complain a bit about the item description being wrong too, which is why we are here. well, I will email them as soon as the dang site works again, argg
RHD, I'll keep you in mind when I find out more. I'm sure we can arrange something if you still want these large cells, now numbering three
If shipping to China was not such a cost prohibitive venture given the value of these, they'd be returned already. I don't see how shipping to canada could be more, it's probably possible, will let you know
do you have the AC adapter to confirm the laser does not behave this way when power is no problem? what cells are you using? 4.2V is kind of a high cut off level for freshly charged li ion, most do 3.7V
My NiteCore charger takes my Li-Ion batteries up to 4.20 VDC and then stops charging, after letting them sit out all night they drop down to 4.15 VDC or so, but after a very short period of use down to 4.10. My understanding was that the 3.7 VDC Li-Ion batteries are all charged this way, up to 4.2 VDC of charging voltage is used.
I don't have the AC adapter, but I will run a test later at 5 VDC input through the lasers side plug. When plugging in four paralleled 18650 batteries at about 4.15 volts into the side plug, the laser put out markedly less power than if using a single battery charged to 4.15 VDC in the tube. This tells me there is additional voltage drop when using the side plug input.
Here's a thread I found showing some voltage curves when some Li-Ion batteries of different manufacture are being discharged, they all start up around 4.1 VDC:
yes i see that is correct, but look how much of the chart is in the 3.7V range. it's not desirable for a unit to run on a single battery's max, when it does not take too long for that to drop. notice the more is drawn from the cell, the faster it sags to 3.7 and below.
This is the problem I face with the JetLasers PLE Pro 532nm laser I purchased from Pogo, unless the battery is at maximum, it will not put out the power I was told it would at over 1 watt. He is telling me his 26650 5000 maH battery will run it that hard for a watt out, but I am not finding a battery which will do that. Pogo advised that he saw more power out because he can get batteries with higher maH capacity than we can get in the states, or perhaps that he can legally ship to me, and thus he saw that kind of output power with his battery he could not include with it, as I also agreed, that and another contributing factor Pogo was warning about is the temperature here in Alaska being so cold which could also cause the lower output due to the laser crystal in the DPSS setup needing to be warmer....
The temperature outside here is completely moot when I only use the laser inside when making power measurements and in a warm house, so that has nothing to do with the sub spec'd output. As far as the batteries I have not been able to stay up at over 4.10 V for very long with either a single 18650 or 26650, it makes sense though, the higher the maH capacity, the longer it takes for the battery to loose peak voltage after a fresh charge. My solution was to buy a battery holder which will hold 4 each 18650 3000 maH batteries for a total of 12,000 maH capacity which I did, and it indeed does allow the laser to put out a watt, four of those in parallel does a better job than a single 26650 4200 maH battery in the tube. However, I need to have a battery holder tube custom made for this laser to use them, holding the 4X battery holder against the main battery spring with the normal battery tube removed is awkward. If I could find a 26650 which will hold its voltage up around 4.1 volts for much longer, I wouldn't need to have a modified battery holder tube for full output, thus my search