lawandorder Posted April 11, 2009 Posted April 11, 2009 Faulty backup battery, biggest killer of Optima panels Think I may have a xm panel in the office (if it hasn't been bin) I will post a photo of it Tues if you haven't found out by then. I agree, and looking at that picture I am certain it is the resistor which you often see burnt on Optima panels. Almost certainly an old battery which has caused this problem but if you to replace the panel you should certainly replace the battery as well. It is possible that something else is causing excessive load but you suould be able to measure the current consumption of all external devices before connecting them to the new panel.
luggsey Posted April 11, 2009 Posted April 11, 2009 Ref: GMP on Intruder Alarm policy. I entirely agree with with all who have offered useful and informed opinion on this matter. There can be no question that a faulty old alarm should be replaced with a more viable new product. It is pretty clear that from the aspect of crime deterence and insurance premium compliance, each of you has indirectly or otherwise, provided practical advice, not just to me but to any who might be considering home security systems. In passing, one of you suggested a photo of the offending pcb. This, for what its worth has been attached herewith. The value of the resistor (if indeed that's what cooked) is a mystery without the circuit diagram, but though largely academic now, since I'll act on collective advice, raises an interesting question, namely what external device may have caused it to burn in the first place? Other than the 12v 3Ah battery replacement, what if the fault remains unidentified and cooks the new board? From that perspective there is merit in replacing the resistor and measuring results for a while before committing to its replacement. Looks like the current limit resistor between the regulator and the battery, should be ohms law to work out the battery charge current [anyone?] and then the value of a suitable resistor. Just a thought what is the fuse size 1A or 500mA? Make the value of the resistor less then the current required to rupture the fuse. ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum
SUBS Posted April 11, 2009 Posted April 11, 2009 Looks like the current limit resistor between the regulator and the battery, should be ohms law to work out the battery charge current [anyone?] and then the value of a suitable resistor.Just a thought what is the fuse size 1A or 500mA? Make the value of the resistor less then the current required to rupture the fuse. From that photo, it certainly looks like its in series with the battery fuse As long as your SURE thats what all resistor does, try something between 4.7 ohms and 10 ohms 1 Watt. shouldnt be critical really as long as theres enough current to charge and maintain the bettery. Best to try and get a picture of a good panel, if its a colour coded resistor it should be easy. But, if thats all it does - wouldnt the panel still work without it ? is the battery monitored in a panel that old ?
Alarm Protection Posted April 11, 2009 Posted April 11, 2009 Just replace the panel for gods sake lol! !
luggsey Posted April 11, 2009 Posted April 11, 2009 From that photo, it certainly looks like its in series with the battery fuseAs long as your SURE thats what all resistor does, try something between 4.7 ohms and 10 ohms 1 Watt. shouldnt be critical really as long as theres enough current to charge and maintain the bettery. Best to try and get a picture of a good panel, if its a colour coded resistor it should be easy. But, if thats all it does - wouldnt the panel still work without it ? is the battery monitored in a panel that old ? They are much to low value subs I think, the fuse is max 1A, if the battery 'can' draw more then 1A then the fuse will blow, the resistor value needs to be at a value to allow the current to be less then the fuse rating. I think the 4.7 would allow almost 3A. ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum
SUBS Posted April 12, 2009 Posted April 12, 2009 4R7 .....2.55A 10R.......1.2A Assuming full 12V across the resistor ie, a S/C Battery. should blow the fuse, thats what a fuse is for. Otherwise resistor would burn up. Don
A-G Posted April 12, 2009 Posted April 12, 2009 should blow the fuse, thats what a fuse is for. Otherwise resistor would burn up. .... er.... It did! . . . PM me for access to the SSAIB members discussion area.
SUBS Posted April 12, 2009 Posted April 12, 2009 .... er.... It did! See, my isuggestion is an improvement on the original poor design. LOL its probably meant to be a fusible resistor, a fuse wont blow till 75% over its rating. and better to have a resistor burn up in the panel than the wiring catch fire when some DIYer has put silver paper round the fuse.......... IMHO
lawandorder Posted April 12, 2009 Posted April 12, 2009 I think it's a bit of a dodgy design with those ADE panels, most panels charge the battery at a constant voltage of about 13.6 - 13.8 volts, this voltage is usually obtained via a 12 volt regulator which is tricked into given out an extra 1.6volts. With the ADE panel a 15 volt regualtor is used (you can see it in the top right of the PCB). I'm guessing that because the voltage is too high to charge a 12 volt battery the resistor is used to limit the charging current. Old A&G panels used to charge at 17 - 18 volts but used a current limiting resistor in a similar way. I still havn't got a clue what the value would be though!
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