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Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 16873
Experience:  15 years GM master tech
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Hummer H3: I was reading an article of yours which was 2 years

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I was reading an article of yours which was 2 years old. The article was from a man about a charging issue in his 2006 Hummer H3. I had the charging system checked and everything checked out good but the vehicle only lasts about 3 days, then I have to charge vehicle again.

Welcome to Justanswer ! my name is XXXXX XXXXX i will do my best to assist you with this problem

so when it sits for 3 days the battery will be dead and the truck will need a charge or jump start to run ?


Customer: replied 3 years ago.

I battery is not died but does not crank. After charging I t starts right up.

ok so the complete charging system and battery all checked out fine and you have to charge the battery when it sits for a few day for it to start is this correct?

are you looking to fix this yourself or looking for a very good idea what's wrong before it goes to the shop ?


Customer: replied 3 years ago.

With daily use it still won't start after 3 days. I want to fix it myself.

ok and your 100 % sure the battery was tested good for cols cranking amps and for bad cells and the alternator tested correct amp output and the battery cables are clean and tight?

im just being sure as it will matter on which way we go next here

do you have a good multi meter ? you can use it good ?

Customer: replied 3 years ago.

Sears said that the cranking amps were good. I don't know if they checked for bad cells. Is that recovered with cranking amps test? They said alternator was working properly- under load it was putting out about 70 amps.

ok before we do a draw test with a meter can you have the battery re tested for cold cranking amps and for bad cells and the alternator retested

any pep boys or auto zone will test them for free for you

I sure would hate to drag you threw a draw test and it ends up being something that simple as a bad connection at the battery or the battery or the alternator

if you have them retested and all are good then what you need to do is keep the drivers window down keys out of ignition all doors closed and everything off disconnect negative battery cable and set your meter to AMPS put one lead to the negative battery post and other meter lead to the negative cable so the meter is now in series and actually becomes the negative battery cable so to say

if the reading is over 50 MA in the under hood fuse box pull one fuse at a time until the draw drops way under 50 MA what ever that fuse powers is what is bad and drawing down your battery

BUT I will have to say one thing that bothers me if this battery will need a jump even with driving it regularly I really think your going to find a battery or alternator problem as usually when they are driven every day the alternator should recharge the battery or the battery will not take a full charge

all the signs point to that BUT if there is a big enough draw that will draw and not draw when ever it feels like it then there is a circuit drawing the battery down and its a big enough draw to clean out the battery in 1 night

Customer: replied 3 years ago.

After about 3 days the vehicle does not have enough juice to start . The battery voltage is about 12.5 volts but it won't start without charging to 13 plus volts.

ok this is where amps become an issue

if the battery can not hold enough cold cranking amps this will happen and if that alternator can not put the amps back due to a bad alternator or dirty or loose battery cables

if you have to charge it you are charging back the amps if the volts are still reading good

its all about the AMP to do the work so to say

ive had battery showing 12.6 volts but only 50 CCA truck will not start due to not enough work(amps )

so in a nut shell not enough amps in the battery or not enough are being put back when driven or when the trucks off something is using the amps when the truck is off and the draw test will show that

Gary and other Chevy Specialists are ready to help you
Customer: replied 3 years ago.

Alternator is putting out 14.4 volts at battery connection when running and all connections are secure at alternator and battery, does that rule out alternator?

the amp output and the cold cranking amps must be tested in the battery and the alternator

if both test good then it would have to be a draw and doing the meter test I said in past post will show you how to nail down what's drawing your battery down

Customer: replied 3 years ago.

The alternator load test showed 70 amps but the alternator is 120 amps is this normal?

when the alternator is loaded the output should be close to 120

70 fully loaded is too low