swampedout Posted September 7, 2020 Author Share Posted September 7, 2020 Not sure. I drove it this about 1.5 hrs this weekend so now I will recheck battery levels. Last weekend I charged them enough to start it but didnt have the engine running long enough for the alternator to give them a good charge. Ive had a lot on my plate this week so I havent been able to dive deeper into the rats nest. This reminded me of the jump starter because I havent had a truck that wouldnt start in a while but I am in places where it could be an issue if I need to wait for another vehicle to come for a jump (cutting firewood for instance) so its a tool that I want to have available. Just checked. Both batteries are at 12.4. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 7, 2020 Share Posted September 7, 2020 Just checked. Both batteries are at 12.4. 12.4 volts isn't all that "fully charged". Should be more like 12.8 volts. So I'm guessing you have a small draw. I'd pull the positive cable and put my DVM, in the 10 amp mode, from the positive post the positive cable. With the door shut so the dome light isn't on, you shouldn't have more than ~30 ma of draw, meaning .03 amp. If you do you need to find it. Link to comment Share on other sites More sharing options...
swampedout Posted September 7, 2020 Author Share Posted September 7, 2020 12.4 volts isn't all that "fully charged". Should be more like 12.8 volts. So I'm guessing you have a small draw. I'd pull the positive cable and put my DVM, in the 10 amp mode, from the positive post the positive cable. With the door shut so the dome light isn't on, you shouldn't have more than ~30 ma of draw, meaning .03 amp. If you do you need to find it. I just did the test as you described it, Gary and I didnt find anything. One battery is dated 10/19, the other is 12/18. Theyve both been run down a couple times when my voltage regulator wasnt working, so maybe they arent holding a full charge. Im not ruling out a draw but Ill have to look harder to find it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 7, 2020 Share Posted September 7, 2020 I just did the test as you described it, Gary and I didnt find anything. One battery is dated 10/19, the other is 12/18. Theyve both been run down a couple times when my voltage regulator wasnt working, so maybe they arent holding a full charge. Im not ruling out a draw but Ill have to look harder to find it. Did you turn your meter down after the initial test? I should have said that. You put it on 10A to make sure there's no big current draw. And then keep dropping it down until you run out of scales or find some current. In other words, the .030 amp max I mentioned might not show up on the 10 amp scale. Link to comment Share on other sites More sharing options...
swampedout Posted September 7, 2020 Author Share Posted September 7, 2020 Did you turn your meter down after the initial test? I should have said that. You put it on 10A to make sure there's no big current draw. And then keep dropping it down until you run out of scales or find some current. In other words, the .030 amp max I mentioned might not show up on the 10 amp scale. Yup, ran it through all the scales. One thing that Im thinking now is I had the secondary battery cable unhooked while I checked the main battery. Could that cause an issue? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 7, 2020 Share Posted September 7, 2020 Yup, ran it through all the scales. One thing that Im thinking now is I had the secondary battery cable unhooked while I checked the main battery. Could that cause an issue? Not if both batteries are reading the same and the cable isn't frayed and grounding somewhere... If all you have is a clock or radio memory drawing power there's no reason I can see for the batteries to lose charge. Having been dead, they may have sulphated to where they don't have the cranking amps they used to. But that's a different situation. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 7, 2020 Share Posted September 7, 2020 Not if both batteries are reading the same and the cable isn't frayed and grounding somewhere... If all you have is a clock or radio memory drawing power there's no reason I can see for the batteries to lose charge. Having been dead, they may have sulphated to where they don't have the cranking amps they used to. But that's a different situation. Sam - I'm glad you ran through all the scales. But Jim has a good point about the batteries maybe being sulphated, which is easy to do, and in that case they probably won't stay at 12.8 volts after the charge is removed. So you may not have a drain. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 7, 2020 Share Posted September 7, 2020 Sam - I'm glad you ran through all the scales. But Jim has a good point about the batteries maybe being sulphated, which is easy to do, and in that case they probably won't stay at 12.8 volts after the charge is removed. So you may not have a drain. How's that Optima holding up Gary? Does it seem any worse for wear? Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 7, 2020 Share Posted September 7, 2020 How's that Optima holding up Gary? Does it seem any worse for wear? It is doing well, Jim. I charged it for several days on the 10 amp setting, which brought it up very slowly given its size. Then as it hit the low 13's the smart switch closed and the two batteries went into parallel, so I left the charger on the 10 amp setting until we hit 14.5 volts, at which point I dropped the charger to the 2 amp setting. During that time I was working in the cab so had the doors open and the dome light and two footwell lights, all LED, as well as the parallel relay apparently pulled slightly more than 2 amps as the voltage would slowly go down during the day to maybe 12.4 volts, but then come back up to about 13.0 volts over night. And after all that it seems to stay up at 12.8 now over night w/o the charger. So I think it is good. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 7, 2020 Share Posted September 7, 2020 It is doing well, Jim. I charged it for several days on the 10 amp setting, which brought it up very slowly given its size. Then as it hit the low 13's the smart switch closed and the two batteries went into parallel, so I left the charger on the 10 amp setting until we hit 14.5 volts, at which point I dropped the charger to the 2 amp setting. During that time I was working in the cab so had the doors open and the dome light and two footwell lights, all LED, as well as the parallel relay apparently pulled slightly more than 2 amps as the voltage would slowly go down during the day to maybe 12.4 volts, but then come back up to about 13.0 volts over night. And after all that it seems to stay up at 12.8 now over night w/o the charger. So I think it is good. Glad to hear it has recovered so well. LA starting batteries, even AGM, don't usually stand a chance at those voltages. Link to comment Share on other sites More sharing options...
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