How would you power this LED instead of using 8AA batteries?

[Joe.S]

The LED light is for a moth trap (identifying not killing).

At the moment I'm using 8 AA batteries. The batteries are 2000 mah so 1.6 amp hour in total (I think my maths is correct on that- 2000mah x 8 = 16000 divided by 1000 = 1.8 amp hour).

The boost buck regulator has 9.6 volts going in and I've set it at 13.5 volts out. The bulb is a T10 LED wedge type (I think they are used in cars).

For portability, it needs to be a battery instead of mains supply.

It's a lot of work to keep recharging the batteries so I was looking at alternatives. This one on ebay for example. Would that work? just attach it to the Boost Buck regulator and off I go?

I thought about using a drill battery- something like the erbauer 12v 2.0 amh. But I'm not sure about this.

12 VOLT 7AH BURGLAR ALARM BATTERY RECHARGEABLE BATTERY (12V 7AH ) | eBay - http://www.ebay.co.uk/itm/12-VOLT-7AH-BURGLAR-ALARM-BATTERY-RECHARGEABLE-BATTERY-12V-7AH-/221141097735?hash=item337d095d07:g:88gAAOSwTglYkFKH

HIGH QUALITY 12 VOLT 7AH BATTERY NP7 12 VOLT 7AH

THESE BATTERIES REPLACE 6AH, 8AH, 9AH AND ARE THE SAME DIMENSIONS

DIMENSIONS: L 151 X W 65MM X H 98MM INC TERMINALS

For use with Burglar Alarms, Toy Cars, Small UPS applications, Lawn Mowers, Power Backup, Mobility Scooter, Wheelchair and Bait Boats.

Fitted with Standard 4.8mm Terminals

 

[Specialist]

Yes it should do what you want but Just remember, those batteries are not meant to be fully discharged & re charged.
The other thing you'll need is a suitable charger, they're not intended for use with your normal car battery charger. A normal car battery charger can cause them to overheat and explode.
If you look online at the door controls direct website, they're listing the Yuasa 12v 7 a/h battery at £11.90

 

[Specialist]

Sorry just re read your post, 8 x 2000 ma/h = 16 a/h (1000ma = 1A) not 1.6 a/h or did you mean 200 ma/h ?

 

[Specialist]

OK Joe: I do apologize, been up all night & my heads messed up. 8 x 2000 ma/h aa batteries in series will give you 12v at 2 a/h so yes the 7 a/h battery will still do what you need.

 

[Joe.S]

Thanks for your help, Specialist. I wasn't sure I understood your second comment (I'm not used to electrical speak: ma mah amp hours and what have you).

I bought two batteries from door controls direct: Yuasa 12v 7 a/h. By my reckoning this is overkill because I'm probably only using 1.8 a/h a night- however, I keep reading that these batteries don't like being fully discharged and recharged so the larger size won't hurt (the 2.1 a/h would be nearly discharged in a night).

The AA rechargeable batteries give about 9.6 volts, but with the Yuasa I'm guessing it will be nearer 12 volts. The boost buck regulator was needed to get the 9.6 volts upto 13.5 volts but now I'm wandering if I need the boost buck regulator at all? just go from the battery to the LED. The LED is a T10 mount (also know as wedge base). The same as these:

T10 194,168,W5W 5 5050 SMD LED Purple Ultraviolet UV Car Light Lamp Bulb DC 12V | eBay - http://www.ebay.co.uk/itm/191076014260?_trksid=p2057872.m2749.l2649&var=490268273473&ssPageName=STRK%3AMEBIDX%3AIT

 

[Specialist]

Hi Joe: As I said, the confusion was mine.
How many hours a night do you use the lamp ?
The Yuasa batteries are top quality & if looked after should last you a long time, terminal voltage when New & fully charged may be as much as 12.6 volts Unloaded but will drop when the lamp is on.
For charging, there are suitable SLA Automatic chargers on the bay for around £11.00.
Hope that helps & apologies again for the earlier confusion.

 

[Joe.S]

The lamp is used for 9 - 12 hours per night (depending on the season).

I bought a charger off ebay for £10.99

Do I need the boost-buck regulator?

 

[Specialist]

Hi Joe: The beauty of the Boost Buck is that it will boost the lower output voltage of your Rechargeable aa's up, But will also buck the higher voltage of your alarm battery down if it's too high to start off with (Theoretically better lamp life).
Personally I'd leave it in circuit to start with & adjust the converter output to suit your lamp, another advantage should be that the batteries can be discharged to a lower voltage while still powering your lamp.
If your converter has the facility to set input cut off voltage, try setting it to 8.5 volts initially.

 

[Joe.S]

Thanks, Specialist. Think I've got all the bits I need- will let you know how I get on.

 

[Specialist]

Your welcome mate, good luck with it

 

[DPG]

Your welcome mate, good luck with it

You're

 

[DPG]

Where's the 'sad, apostrophe-obsessed nit-picker' emoji ??