ok, poor choice of words. after all I'm just an alarm installer as u no who loves to point out how ignorant we are. how about documentation
correct. which is more than your method gives. to answer your question according to the $100 plastic box with alligator clips if a 4 Ah falls below 2.6 Ah it is bad. if a 7 Ah falls below 4.55 Ah it is bad. it takes less than a minute and if it's wrong I can blame the manufacturer. not some box I made. As for changing readings, not that I would, but if anyone were to falsify the data I'm sure they would just say the battery was bad so they could sell another battery which would in no way jeopardize the operation of the system. I'm also pretty sure that your method is acceptable for testing batteries. I just needed something for the AHJ that was industry wide acceptable and gave me a reading that I could 'document'.
Hmmm. Why would a 7Ah require more life than a 4 Ah to be considered good? I would think that either (a) both would require the same ( just for the sake of keeping it simple) or (b) the 7 Ah could accept a lower reading because of it's larger capacity it could sustain a drain of a specific amount of current for longer period of time.
Or that the current draw and amount of perscribed standby requirement for the system the battery was being used in ..... over what period of time .... would be thrown into the calculations.
Not just a preset number. (?????)
Regardless where you got the reading ..... it would be wrong.
Even with the recent increase in battery cost, I'm of a mind that it's better to change a battery, if it's been in for a few years, even if it reads good. I don't feel I'm just "selling them another battery". I'm taking precautions that surely reduce the possibility of a battery failure. It's not a "rip off" That's what they pay me for ..... to anticipate and head off potential problems. I'm sure they'd rather do it that way then wait until they get a low battery signal and have to pay me for a service call just to change a battery that I could have changed a year ago .... the last time I was there.
When Yuasa, first came on the scene, finally providing the trade with reliable rechargeable batteries, the method I use was recommended by them. Since I do primarily residential now, and in the event that all else fails, the newer alarm systems provide a low battery alert, there's no reason for me to have to document a battery condition. So I just continue to go with what's worked for so many years. (Other than a burned finger every once in a while)
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