dj.chapman Posted March 29, 2010 Report Share Posted March 29, 2010 hi all. i am i bit of a tight ***. great way to start a topic i know, i am now in the process of making a magnet and i have just sourced a ford fiesta wiper motor after rerading they will work on the magnet, cost me £10. i have someone to do the welding needed. now to the point of the battery. i have read you need a 12v 17ah. i have a 12v 7ah battery and i was wondering if that would be up to the job? can anyone help? Quote Link to comment Share on other sites More sharing options...
Cosd Posted March 29, 2010 Report Share Posted March 29, 2010 hi all. i am i bit of a tight ***. great way to start a topic i know,i am now in the process of making a magnet and i have just sourced a ford fiesta wiper motor after rerading they will work on the magnet, cost me £10. i have someone to do the welding needed. now to the point of the battery. i have read you need a 12v 17ah. i have a 12v 7ah battery and i was wondering if that would be up to the job? can anyone help? To work it out you have to test the current draw on your magnet, then divide the battery amps into that. On average I'd say the motor will draw around 3amps, so 3 into 7 = just over two hours at full strength, then the speed will start to slow down. where as a 17 amp battery will last almost 6 hours. If you make light weight arms and use say Hyperflaps on there, your battery will last longer. Quote Link to comment Share on other sites More sharing options...
dj.chapman Posted March 29, 2010 Author Report Share Posted March 29, 2010 ah i see so it will work but not for as long, i think i got 2 or 3 batts laying around from old alarm pannels at work so that may help. cheers for the help Quote Link to comment Share on other sites More sharing options...
mosa Posted May 4, 2010 Report Share Posted May 4, 2010 my 12v 7ah lasted 3hrs 30mins from start to stop Quote Link to comment Share on other sites More sharing options...
Dr_T Posted May 5, 2010 Report Share Posted May 5, 2010 (edited) With a speed controller added, how much longer run-time do you achieve with either 7ah or 17ah batteries? Edited May 5, 2010 by Dr_T Quote Link to comment Share on other sites More sharing options...
wymberley Posted May 5, 2010 Report Share Posted May 5, 2010 Hi, To be honest, no one can answer your question until you have the answer to the test that Cosd detailed. Even then, many speed controllers are the same as light dimmers, they still draw the same power but the types that don't are available usually at extra cost. I made mine from a Sierra motor which had the wiper speed control mechanism built in. On 12 volts it went around like a whirling Dervish on a bad LSD trip and I ran it satisfactorally on the slower speed setting with a 6 volt battery. Quote Link to comment Share on other sites More sharing options...
fendrover90 Posted May 5, 2010 Report Share Posted May 5, 2010 i use a big amp hour jobie off a mobility scooter it runs my magnet for about 9 hours with my home made long arms ..i know a place in wisbech where you can get some lovely 6 mill hi tensile sprung steel for your arms for free .pm me if interested Quote Link to comment Share on other sites More sharing options...
vampire Posted May 5, 2010 Report Share Posted May 5, 2010 I use varta 12v 14ah,which came off one of those ride on lawn mowers,its about 150mm wide and high x 75mm,but its not the sealed type,i carry it in the bag that my folding chair came fits perfectly and its green and it has strap Quote Link to comment Share on other sites More sharing options...
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