What batteries should I get for this laser

[EfoDom10]

If you end up with unprotected cells, it is still possible to over discharge your batteries before you become aware of it. You would do better with protected cells as they will shut off before they become over discharged. I suspect you can get items from GearBest where you are and they have some good chargers on their site.

I think I'll buy 2 of those Efest 16340 850 mAh batteries. I really need the batteries to arrive in December. I think I'll also buy that Opus BT-C3100 charger you've been talking about. It costs 30 euros on aliexpress https://www.aliexpress.com/item/Opu...lgo_pvid=269e23c7-8f11-4c0b-baf6-32c345ad6293 So with the Opus charger I wouldn't over discharge the batteries? The problem is the charger would arrive after the batteries. The batteries will be precharged so I assume I could use them in my laser before the charger arrives, couldn't I?

 

[GSS]

Do you mean over charge with the Opus?
Did your laser come with Ultrafires and a charger? even a 2 bay cheapie charger? It would be nice to know if your laser works before ordering.

Ok, never mind I went back to the original post and see you did receive the Ultra fire batteys. I admire your regards to safety and research and regards to your battery's being safe and un abused but there really isn't anything wrong with using the charger it came with in a pinch to top off your new battery's as long as you do not leave it un attended to long and never over night. It has a red, orange, to green charge light i'm, assuming. A couple charges on the these new battery's won't destroy them premature.
Plus most battery's do come almost fully charged..
I have 2 Nitecore i2 chargers but still use my cheap ones plenty.

 

[paul1598419]

The Opus charger won't over charge or discharge any of your batteries. You needn't worry about that. Even unprotected cells won't over discharge on the Opus. Make sure you test the dynamic internal resistance of your fully charged batteries. They should measure around 50 to 70 mOhms. Once your batteries are fully charged you can test their capacity by discharging them in the Opus.

BTW, most batteries are sent discharged as it is safer to transport them this way. The exception to this are Chinese batteries which always seemed to come fully charged.

 

[GSS]

Huh??
Other than a completely dead blue wrapped cheapie's iv'e yet to get even good battery's without at least 3.7v.
Not to derail this thread but i'm due 6 cells from IMR so lets see..

 

[RedCowboy]

EFest IMR cells are good and they don't sag under load as badly as lesser cells, still you need to check voltage regularly until you learn how much runtime you get, in a 2 cell unit the driver cutoff may not give you all that much headroom, I would recharge when either cell hits 3.6 - 3.7v

 

[paul1598419]

All my cells from Liionwholesale.com come almost completely discharged because, if the package is broken and the cells are punctured, they are less likely to catch fire or explode than fully charged batteries. Even the unprotected cells come with ~3.4 volts on them. My experience with these are you can discharge them to 3.2 volts and they will recharge just fine. The fully charged Chinese cells I have received come with over 4 volts on them. Usually at or close to 4.2 volts.

 

[GSS]

All my cells from Liionwholesale.com come almost completely discharged because, if the package is broken and the cells are punctured, they are less likely to catch fire or explode than fully charged batteries. Even the unprotected cells come with ~3.4 volts on them. My experience with these are you can discharge them to 3.2 volts and they will recharge just fine. The fully charged Chinese cells I have received come with over 4 volts on them. Usually at or close to 4.2 volts.

When you mean almost completely is it at 2.75v at the reccomended never go below point?
And yup the cheap cells iv'e gotton were always 4v or more unless completely dead like I mentioned..
Today i'm due some Efest's and Sanyo's after ordering them from IMRbatteries going on at least 10 days ago which seems quite long even with a one day shipping delay on top of the shipping lithium battery's methods requirements..
Curious to see how they come
Wait you did say 3.4v?

 

[RedCowboy]

All my cells from Liionwholesale.com come almost completely discharged because, if the package is broken and the cells are punctured, they are less likely to catch fire or explode than fully charged batteries. Even the unprotected cells come with ~3.4 volts on them. My experience with these are you can discharge them to 3.2 volts and they will recharge just fine. The fully charged Chinese cells I have received come with over 4 volts on them. Usually at or close to 4.2 volts.

It's not the preservation of the cells lifespan that I was thinking of but the unknown driver cutoff, however if the laser dims down before the cells get too low then he will be ok, so keep a close check until he knows.

I would want to maintain full output so I would recharge around 3.6 - 3.7
I do run a ndg7475 at 1.8a on 2 x 18350 EFest and it has a good runtime, I only run it 30 seconds at a time but probably 50 times before recharging and the cells are not that low, about 3.7 when I recharge, I also have a m-140 that runs on 2 18350 EFest and it holds up just fine although I recharge at 3.7 but maybe I could go lower, I usually don't.

 

[paul1598419]

Oh, I agree that unprotected cells can be over discharged. If fact I have said this many times in other threads. I also have a couple builds running on two 18350s, but they are 1.8 amp drivers so they do last maybe 20 to 30 minutes between charges. Anything higher in current, I heat sink and use larger batteries. But, my Opus charger will discharge unprotected cells down to 3.2 volt and they always come back with the same capacity and internal resistance. Since my cells come discharged, it gives me a chance to test them before using them. If any fail badly, I would ask for a replacement or refund. But, Liion tests all their cells right before shipping them out, so it hasn't come up in a long time.

 

[GSS]

Just another derail but the IMRBatteries Efest's and Sanyo's came at 3.8V.
A little dissapointed though 1 of the 4 Efest's came corroded and DOA. Hey they were an odd size 13450 on sale for .97cents so no big loss, shipping was $7 though and did ruin using them as pairs.

 

[paul1598419]

Wow! They actually shipped you a corroded battery?! That is a site I would avoid in the future. Especially if they are charging you $7.00 for shipping. I pay Liion $10.00 to ship 4 batteries, but they always test the batteries right before shipping them out. And I guess they do the capacity test last as they come fully discharged.

 

[GSS]

The 4 Efest's each came in a small individual marked boxes. So I doubt they opened each one up to check??
On the bad one the top was corroded and the wrapper was way off as it almost covered the top and the bottom neg end was almost just about bare. Moisture might of gotten to it as the label was weird too.
The 2 Sanyo's came open but in a 4 bay plastic case.
I sent them a message and will see but I won't push the issue. I believe shipping is free over $50.