alarm killing battery
alarm killing battery
(OP)
hello
im trying to power a 120vac alarm system for our workboat.
the alarm realy needs 16vac (plug in transformer)
the current set up they want to use is as follows.
group 24 12vdc truck battery (with charger)
small power inverter (12vdc to 120 vac)
wall plug in trans (120 to 16 vac)
well all this is killing the battery overnight.
any ideas to get 16vac to the alarm board without all the ups and downs wasting our battery away?
john t
im trying to power a 120vac alarm system for our workboat.
the alarm realy needs 16vac (plug in transformer)
the current set up they want to use is as follows.
group 24 12vdc truck battery (with charger)
small power inverter (12vdc to 120 vac)
wall plug in trans (120 to 16 vac)
well all this is killing the battery overnight.
any ideas to get 16vac to the alarm board without all the ups and downs wasting our battery away?
john t





RE: alarm killing battery
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Start each new day with a smile.
Get it over with.
RE: alarm killing battery
fun fun.....
RE: alarm killing battery
RE: alarm killing battery
So 100VA/16V=6.25A AC. Let's say for arguement sakes that the DC current is approximately equal to 6A. The max. rectified DC voltage you can get with a simple full wave bridge rectifier is about 10V. So I guess that your power alarm system uses 9VDC@6A although the true current draw is probably less than this figure. To have capacity to operate for 12HRS you need about 6A*12HRS=72A of battery capacity. I am guessing that you might be able to get away with 50A-HR of battery capacity. A typical 6V "lantern" battery has about 25A-HR of capacity so you can imagine how much capacity a typical "car battery" has. So why is it that you can't run your system on 1 "truck" battery? Should be lots of capacity in 1 battery. Why is it you need 24 batterys? Am i missing some key information here?
Open up the alarm system and find out what DC voltage your system needs. Hopefully you can locate the rectifier portion of the alarm cct board.
Use a single truck battery for your system. Install a 12v to 9v convertor and connect your battery to your alarm system and you should be ok. Ensure that the converter uses low power to perform it's task. You don't need to supply unwanted power losses.
The problem I think you will have is charging the battery properly. With a 50% duty cycle the battery may not have enough time to recharge or recover fully. Batterys are like people - they need adequate recovery time. If they don't get this recovery time they will eventually collapse and die from fatigue. I don't know if you can get a battery that can fully recharge in 12 hrs AND have a long and useful life. I bet such a battery would be expensive. And no, a "deep cycle" marine battery won't work in this application either. They die as well. I know from experience.
The easier way would be to use 2 batterys and rotate them on a daily basis. Simple timers could switch over the batterys from charge to discharge states evry other day.
Right now all you are doing is supplying power losses to rectifiers and inverters and what not. Not to mention the internal power losses due to the "paralleling" of 24 batterys.
There is an easier way.
RE: alarm killing battery
RE: alarm killing battery
i m not sure of the wattage needed by the alarm yet. its been a while since ive been down there...
oh ..it not 24 batteries we have a "group 24"battery about the size of 2 standard car batteries
it has a trickle charger that operates during working hours (8-9 hours a day) maybe not enough charge time..
it realy sounds like ive got to get to the board for more info
thanx ill let you guys know....
RE: alarm killing battery
RE: alarm killing battery
RE: alarm killing battery
-----------------------------------
Start each new day with a smile.
Get it over with.
RE: alarm killing battery
I have a wireless patio speaker that has a 16 vac transformer and internal 12V battery. Obviously, the prefered power source is the transformer to provise higher audio output from higher supply voltage.