Parallel Charging of 10440s?

[ENX]

Hello,

My name is Eric from South Florida and I am new to this laser obsession.

I really enjoy reading the posts here at LPF. I have made it pretty far reading and experimenting on my own using all of the excellent resources of information here. LPF really has a solid core of super talented people who are amazingly helpful… I appreciate that! Above all, I think safety and respect for the power of lasers is the most important lessons to be learned.

My first laser was an O-like Power Rock 445nm that runs off 1 X 18650, so out of convenience, the first couple lasers I built used these batteries as well. As I have gotten a little better at building into hosts, I have gone smaller, using 16340s, 14500s, and now my new project using 10440s.

I have done a lot of research on the forum and find there is some difference of opinion when it comes to charging these different sizes of batteries safely, especially the smaller 10440s. I currently own only the Ultrafire WF-139. Some say it’s not the best charger, but seems to work pretty good for my purposes thus far (no explosions or fires yet:yh. From what I read on another post, there is recommendation to use a charger that uses a 100mA - 200mA charge rate and the WF-139 will not safely charge these 10440s.

Leaning toward safety, I am assuming that the WF-139 will not charge a single 10440 safely.

In another posting, I found one member who in a host conversion 3 X AAA flashlight, rewired the cylinder battery holder to connect the cells in parallel and then used 3 of the 10440s to maintain the 3.7V – 4.2V and get better mAh than the standard AAAs. As I understand the logic, wiring the batteries in parallel, the voltage remains consistent and the capacity is added, so 3 X 10440s at 600mAh each yields 3.7V – 4.2V and 1800mAh.

If this logic works for battery use in operation, can I charge these 3 X 10440s connected in parallel using the WF-139? Should work, right? Is this a safe solution?

Any help or information on a better solution (maybe a new charger recommendation) would be appreciated.

Thank you.

 

[justinjja]

Would your build be using all 3 10440 batteries at the same time?

This could would if the batteries were well matched.
if your planing on using each of the 10440 batteries individualy, then charging them all together it may not be a good idea.
as over time some of the batteries may end up with a higher/lower internal restance than the others

 

[ENX]

Great point! I was only thinking about the initial charging and was not considering down the road

The current build i am working on would be using 3 together, but not as a hard pack. There is always a possibility that batteries from other sets could get intermingled, which could cause an issue later for charging and use.

I think I am going to just opt for a new charger specifically for these smaller 10440s. Safety over time is a better idea.

Thank you.

 

[LarryDFW]

ENX;

As long as the three 10440's are fairly close in voltage,

you can charge them in parallel with the WF-139.

This charger has a higher end point voltage (~4.35VDC) , so you must monitor and take the cells out when charged to 4.2 VDC.

Avoid the aggravation . . .
For new builds, stick with quality 18650 cells.

The "name brands" have been U.L. tested,
and offer the energy needed for high power laser builds.

LarryDFW

 

[HaloBlu]

It seems to be hard to find a quality low current charger for 10440s. Let us know what you decide to get or use.
There is a custom built usb charger on cpf but its costly for what it is. If you can do fine soldering (SMD sot23) you can use the max1555 or max1551 chip with a usb power source & no other components at all.

I would recommend a xtar charger for larger batteries, not expensive & much safer then any ultrafire stuff.

 

[ENX]

I really appreciate the input.

I went shopping today and was considering buying one of those hobby chargers that allows you to select the voltage and current, but thought that would cost a lot of money (I could be spending on laser parts). Plus with my lack of any real electronics knowledge, I would probably end up just blowing up batteries left and right.

I decided to lean toward cheap and available. I bought an Ultrafire WF-188. Again, not the best reviews for this charger either, but what I liked about this charger is that the current is selectable for either 300mA or 650mA. This should accommodate both the smaller and larger batteries and 300mA will be perfect to charge my 16430s too. It also looks like you can use it to charge various size/length batteries without needing spacers as the clips have a longer glide path than the WF-139 I have now.

I was able to find the WF-188 for under $20 shipped from a US company and should have it next week. I will post a follow up to let you know how it works.

I also found a little Ultrafire WF-138 that appears to be specifically designed for the 10440s and 14500s, but there are warnings that some of the protected cells do not fit in this charger. It was roughly the same price as the one I bought and think I will get more use out of the WF-188.

As I get further along, I’m sure I will make more of an investment in better quality batteries and at that time, hopefully there will be a good quality charger on the market.

Funny side note: I stopped last night at the store and bought a pound of dry ice. The plan was to play today and take some beam shot photos and movies to post. I put the bag in the freezer. When I got up this morning the bag was empty I was like NO WAY!!! I just started laughing and pulled the empty package out of the freezer... We learn something new every day!

I guess if my new charger doesnt work, I can use it and my 10440s to make some smoke for beam shots... or maybe I'll get a fog machine.

Anyway, have a great weekend.

 

[Wolfman29]

Remember, li-ions are no laughing matter. There is a story of someone nearly blowing his hand off from a li-ion. A room got totally damaged by an exploding li-ion. If you are charging a li-ion and it starts to even heat up, that's when you remove it from the charger and place it in a steel box... if it's smoking, you should already be ducking and covering.

 

[ENX]

I totally agree!!! Hence my apprehension about charging the 10440s in parallel or even trying the hobby charger.

I think I should be OK with charging the 10440s at 300mA if I keep an eye on the voltage and heat, don't you?

BTW: I keep a steel ammunition box near by when charging and even store the lasers and all spare batteries in the box when not in use.

Safety first!

 

[HaloBlu]

Honestly with what I've read (& pictures of burned chargers) I wouldn't trust ultrafire chargers at all. As long as you never leave them charging unattended you'll reduce your risk.
One issue as LarryDFW mentioned is that some of them charge to over 4.20v which is hazardous. If you going to use one you really need to check that end voltage of your particular charger is below 4.20v. Also always charge inside a metal box. I'm guessing you've seen videos of lipo fires since you've done some research. :tinfoil:

Hope you share your 16340 or 10440 projects sometime. :beer: I'm very found of small builds.