Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

m140 built help - suspect battery issue

Peef

0
Joined
Jan 5, 2014
Messages
9
Points
0
Greetings, I'm trying to use a single 3.7v 18650 with a boost driver (3.7-4.2V > 4.5-6.0V), to run a m140. I'm trying to get the full 1.8A to the diode, but can't get past 1.36A. There's a potentiometer on the driver and it ranges from about 0.9A to 1.36A in 200degrees-ish, then for the remaining 160 degrees-ish it's capped at 1.36A. I wonder if the problem might just be that the battery can't put out enough amps? I'm using a protected 18650 rather than un-protected, just for the ease of charging/no worry of damaging by discharging to much. Must I use an unprotected 18650 to get my full 1.8A?

Any help is appreciated, Steve.
 
Last edited:





Peef

0
Joined
Jan 5, 2014
Messages
9
Points
0
It's one of these from Odicforce: 17mm Circular Variable Boost Driver Board for 405/445nm Laser Diodes (1.5-1.8A ) | eBay

I'm in the UK so it's easy to buy from their shop for me. The m140 is one of yours bought a year or so ago, DTR. The battery I'm using is an (I know this is almost a swear word around here) Ultrafire. I got a couple of batteries and a smart charger for cheap off Ebay. It measures 4.1v across the poles and I'm just using an ammeter in series with the diode to measure amps there.
 

Peef

0
Joined
Jan 5, 2014
Messages
9
Points
0
I know the ultrafire's are cheap and nasty and I'd like to buy a better quality battery, I'd just like to know if even with a better quality battery I'll need to have the unprotected version?

any help appreciated!
 

DTR

0
Joined
Jun 24, 2010
Messages
5,684
Points
113
Boost drivers do draw considerable amount of current so decent cells are recommended. Also to make sure you are using a test load to test and set current on the driver?
 
Joined
Dec 29, 2009
Messages
3,136
Points
63
Usually switch-mode drivers will start to flicker when the power source can't supply enough power. Still, I would recommend finding a better battery. Some cells have protection circuits that actually allow them to discharge at their rated maximum discharge current, but some don't. Unfortunately, I don't buy enough protected batteries to know which ones have better protection circuits.

If you are confident that you won't be abusing this battery by overdischarging it or shorting it out or overcharging it, an unprotected battery will work fine too.

I would also guess that you might have some resistance in your circuit from things like bad contacts/connections.
 




Top