I always have use for a portable floodlamp when I'm working on my car, doing house repairs at night or even exploring in the bush.
I wanted an led floodlamp that has onboard charging capability and dimming feature. Searching on Amazon yielded nothing that tickled my Fancy. Being a trini hobbyist, I decided to build my own using spare parts. Read on for this instructable.
Step 1: Enclosure and charger.
I used a fibre glass hinged enclosure to put all the necessary electronics and to mount the led array. In the pic I'm holding a 12 volt adapter to power the cc cv charger module inside the enclosure. This module I got from Amazon for 6usd. It's a two stage charger which is perfect for any lithium battery. To use it first adjust the cv potentiometer to the battery voltage, 4.2volt per series cell. Next adjust the cc potentiometer with your multimeter in ammeter mode and the leads shorting the output terminals.
The 12 volt adapter I secured onto the outside of the enclosure to allow easy charging of the floodlamp.
I used a two color led to indicate charge status. RED for charging and GREEN for fully charged.
Step 2: Battery bank.
I had a stash of lithium rechargeable 9volt 600mAh batteries I ordered from Amazon. I used 6 of these beauties in parallel to provide the power for my project. Each battery is protected meaning they will turn off if drained too low.
Any lithium battery that is drained below a certain threshold voltage will be permanently damaged and cannot be restored to service. If you invest in lithium batteries then try to get the protected types.
Step 3: Add selector switch and dimmer knob.
The selector switch on the right will allow either use of the floodlamp or charging of the battery bank.
The top right corner has the dimmer potentiometer installed. This will allow dimming of the leds via the pwm controller.
The third pic shows the charge indicator led plus the 12 volt adapter.
Step 4: Insert the pwm controller and connect leads.
I used sticky squares to secure the controller to the inside of the enclosure. The potentiometer has a 3 pin JST connector which plugs into the pwm controller. The power leads into and out of the controller were connected.
Step 5: Secure the led drivers.
These led drivers and leds came from some old flashlights. I used two drivers to power a total of 9 leds (3 parallel strings each having 3 leds).
Step 6: Install leds, shoulder strap and initial test.
I used double sided tape to secure the 9 leds to the outside of the enclosure. The second pic shows the leds being powered up. The brightness was easily adjustable via the potentiometer.
Step 7: Weatherproof the leds.
I needed a guard to protect the led emitters and also to provide weatherproofing. A pane of glass was secured using clear silicone (an unsung hero). Water, dirt or grime would be kept away from my precious leds.
Step 8: Final test
Full range dimming, at full brightness I'm getting 5.5 hours and recharge time is 1.5 hours. This project has fulfilled my requirements and is now a part of my tool set.
A future improvement will be an energy Guage to let me know how much run time I have on the battery bank.
Step 9: Add ons
I needed padding in case the floodlamp fell on the glass pane or by simply resting on a surface. I used foam pads to provide some level of protection to my new led floodlamp.
I decided that I wanted charging regardless if floodlamp was on or off. I replaced the three position switch with an illuminated toggle switch. In the on position it lights red as shown in the pic. I used a diode after the cc cv module to allow charging anytime.
The shoulder strap was unwieldy. I replaced it with a hand strap for better handling.
Step 10: Energy meter
My energy meter is a lithium multi cell voltmeter. I have it wired to measure a 2 series arrangement. Now I can tell how much energy I have remaining plus how fully charged it is!