Need advice on LED lamp project

[elamp]

Hello All,
I am trying to design/build a battery powered LED lamp that is solar charged. My electronics background is fairly basic. The specific components I would like to use are:

1. Four AA 2500mah NiMh batteries. I may use four "C" size 5000mah for increased operating time if needed.
2. A one watt LED 3-3.4v 330ma max( I will be running it at 200ma to extend battery run time. I would like to get 6-10 hours if possible) and running it at 200ma it outputs plenty of lumens for this project.
3. One Solar PV panel. Output: 6+ vdc @ 580ma

I am looking for help with some kind of over/under voltage cut out to protect the battery pack. Parameters are:

1. under voltage cut out approximately 4.4-4.5v (1.1-1.125v per cell)
2. overvoltage cut out at 5.72v (1.43v per cell)
3. minimum amount of components and any IC's preferably DIP style to enable unskilled persons to be able to handle and solder them easily. These will be assembled in developing countries.

We have had great success with a solar cellphone charger using a LDO regulator to keep the output at 5 volts. Now I'm looking at a LED lamp system.

Any help would be appreciated

 

[D.A.(Tony)Stewart]

Great intentions but poor design specs. This is harder than it looks.

Keep in mind the spec'd parts you have selected lead to poor efficiency and regulation. What is your cost budget for material, & design validation. It is not trivial to make a reliable product in this mismatched condition. Ideally you want to match the generator (PV) to the storage cell (V) to the load (V). In this case the LED is very nonlinear starts with >> 100 Lumen/watt but after power conversion the system becomes low < 50% efficiency with low simple cost budget. It would help to define volume, schedule, environmental specs. Dont specify the parts without considering the above. Also what is maximum ambient temp and cooling method of mechanical design. Also the battery should be replaced every 3 yrs.

For example it may be cheaper to run 5mm LED strings in series / parallel combination with up converter form 4.8V cells in surface mount board. So using an array of 20mA devices @3.2V to get 1~5W for 6 hrs may be better than 1 LED taking 200~300mA @3~3.6V dropped from 4.8V with lots of loss.

ALSO Buy rather than Make may be cheaper and more reliable.

---------- Post added at 15:32 ---------- Previous post was at 14:23 ----------

Consider
12.6Vdc 7Ah rechargeable Sealed Lead-Acid battery (SLA)
12Vdc LED string or bulb ~ 50~150mA (LED array)
Polyfuse current limiter protection, TVS & MOV protection The LED dropout will protect for UVP.
Auxillary outputs for Phone charger.
Or consider recycling automotive batteries and using RJ45 wire to distribute from polyfuse to 12V LED lamps. with PWM or switched R dimmers.
All depends on your target cost, weight, installation requirements, wiring and life expectancy. (What spec?) :idea: