jagman Posted December 5, 2022 Report Share Posted December 5, 2022 Lately I have noticed that my 720 after sitting overnite my battery loses its charge. I have checked the wiring for obvious wear or bare wires and have seen nothing. The battery has been checked and seems OK and the alternator is putting out 13+ amps. As far as I know, only the clock is running after shutdown. Anyone had this problem? Quote Link to comment
datzenmike Posted December 5, 2022 Report Share Posted December 5, 2022 A fully charged battery has less power as it cools down. It's getting colder out so it will be normal to notice that your vehicle might turn over slightly slower in the morning. 13 amps?? You mean 13Vots??? Charging at 13v is a little low, just over 14v is better. To push a charge into a 12v battery a 2v difference is best. Take in to NAPA??? and have them run a load test on the alternator. It should put out 14.3 or so volts. Less could be one of the three diodes are bad. At night just disconnect the battery and see if this solves the problem. If it does not help, the battery is maybe toast. If it doesn't then something is drawing power....... Is the interior light off at night? the brake lights off? Does your horn work or disconnected? Quote Link to comment
thisismatt Posted December 5, 2022 Report Share Posted December 5, 2022 Alt needs to do 13.5v to charge/maintain the battery. If you have a meter you could pull one terminal from the battery and put the meter in series on the 10A setting (with the leads switched accordingly) and see what draw there is, then start pulling fuses to narrow it down. 1 Quote Link to comment
datzenmike Posted December 5, 2022 Report Share Posted December 5, 2022 13.5 will work but 14.5 is faster and the usual amount. Vehicles have to recharge the battery as fast as possible or multiple stops and starts will deplete the battery. Quote Link to comment
thisismatt Posted December 5, 2022 Report Share Posted December 5, 2022 Didn't say differently, just the minimum. Napa/vatozone/O'Reilly's will say an alt is working even if less than 13.5v, which technically it can be and will run the vehicle after a jump start, but next time you try to start the battery will still be too weak. Quote Link to comment
datzenmike Posted December 5, 2022 Report Share Posted December 5, 2022 I agree with you. 14+ would just be faster. Yeah a pass just because over 12.6 charged battery is lame. You would think they would fail it and sell you a new one. Quote Link to comment
jagman Posted December 6, 2022 Author Report Share Posted December 6, 2022 Yes, my horn works. I will try the disconnect next then the voltage test. Quote Link to comment
Thomas Perkins Posted December 7, 2022 Report Share Posted December 7, 2022 Just go to the Auto parts store and get your battery and alternator tested.if the battery is bad,that will end the test.In order for them to test your alternator,your battery has to be good.If battery is bad,get new battery,then have them retest battery and alternator.If alternator is over charging ,they will say it is good.The volt meter in your 720 will read 12 volts when it is bad.Also you may have the wrong alternator.My 85 with A.C. uses the 60 amp one.50 amp is too weak.I had a 50 amp in mine by mistake and it didn't last but 3 months and had all kinds of electrical issues.When I put my Pink Floyd C.D. in,it sounded like they did too many shrooms... Quote Link to comment
banzai510(hainz) Posted December 8, 2022 Report Share Posted December 8, 2022 (edited) YOu have a volt meter in truck? drive with the lights ON and maybe wipers or heater. what does the volt meter read? if low while driving with a load then the alternator is weak. I had a guy at work he could drive to work fine(2nd shift). leave at midnight use his lights then in morning a NO start.Was a weak alternator. I gave him the cig lighter cker and he didnt believe it . https://www.harborfreight.com/12v-batteryalternator-tester-57331.html?_br_psugg_q=alternator+testers you ck if the battery cables good. end not cracked? one can read 12 14volts with NO LOAD but loading it down can tell if the cable ends is weak. Battery pushing 5 years old????? Be honest I got 12yrs of of a yellow Opitma/ The good ones before they went bad in manufacturing them Edited December 8, 2022 by banzai510(hainz) 1 Quote Link to comment
Stoffregen Motorsports Posted December 9, 2022 Report Share Posted December 9, 2022 Yeah, Optima batteries suck now. Quote Link to comment
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