Battery question.....

Here is the math:

55AH battery. A high quality battery decays at about 15-20% per year in available (AH) Amp hours. You need about 20% of initial AH left to start truck, if it starts quickly. Flasher/stop/turn bulbs are 25 watts each while parking lights are 3 watts each. Say you have two bulbs in front and 2 each on each rear light assembly for a total of 6 bulbs flashing. 25x6=150 watts 150 watts/12 volts=12.5 amps when they are lit. If they are only lit 50% of the time then you have an average of 6.25 amps. Now assuming you did NOT leave the ignition on or the parking lights on and the battery is fully charged and battery is only a year old. 55AHx80%=44ah Need 20% to start =11ah So you have 33AH left 33ah/6.25a = 5.3 hours till it will not start truck.

Since you said you have replaced the battery twice lately either your alternator is not furnishing enough current or the battery voltage during charge is too low to fully charge the battery or you have a high constant drain of something left on discharging the battery.

Check the battery dra>Ok...lets talk about batteries since maybe this one is a turd.

Reply to
John_F
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That's kind of what I figured as well.

Reply to
Carolina Watercraft Works

are those numbers with a VAT 40 load test??? how steady did voltage stay?

Reply to
Chris Thompson

Not sure of the name of it but they performed the test at the Batteries Plus where I bought the battery. Trying to find out. Will let you know. Don't recall seeing any indicator of the voltage...just current which was as indicated.

Reply to
Carolina Watercraft Works

Isn't VAT 40 about 30 years old now? That's what we were using before I got out of that racket. Remember the VAT 28? The inductive pickup on the

40 was a big deal to us.
Reply to
BigIronRam

I am not the one to answer that as I was just trying to answer a general battery problem you seemed to be having. Tom Lawrence would be more likely to be able to answer that part.

Budd

Reply to
Budd Cochran

yes the VAT 40 is old but it is a true resistive load test. these little micro junk things I'm not personally sure I entirely trust to diagnose an alternator.

the VAT 28 is a little (well ok maybe more than a little) before my time.

Reply to
Chris Thompson

Well, heck, check out this antique on eBag. I used some of these for several years before the vat 40 came out.

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Reply to
BigIronRam

Ok, stopped to get my haircut today...friend stayed in truck listening to radio. 25 minutes...completely dead battery. Push it to start, make one quick 5 minute start and left motor running then completed the 15 minute trip home. Got the charger and set to 40 amps and charger read full and shut off. Set to 20 amps and charging commenced and continued. WTF is going on?

I'm always bragging about my Ram and it never giving me problems....still will but I need to figure this out. Plan on getting that power cable recall done next week.

Reply to
Carolina Watercraft Works

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