My 2007 FEH can't hold a charge overnight (131,000 miles)

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Old Jun 22, 2022 | 01:53 PM
  #11  
Erodea's Avatar
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Default Re: My 2007 FEH can't hold a charge overnight (131,000 miles)

Update:
Okay so a couple of things

So my original volt readings in my recent post were completely wrong. Silly me I forgot to set my multimeter to DC voltage (I had it at AC Voltage). So here are my accurate readings


@S Keith Yes I did take everything apart before effectively troubleshooting so that was a mistake on my part. I didn't know there was another AC unit dedicated to the battery, I thought that it relied on cabin AC alone. I will say that the AC for the cabin was starting to go out so I will recharge the AC once I put the battery back together.

Should I replace all of the sticks that are below 6 volts?
Should I replace all of the sticks that are below 6.3 volts?
Or should I just completely get a new set of sticks?
 
Old Jun 22, 2022 | 04:18 PM
  #12  
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Default Re: My 2007 FEH can't hold a charge overnight (131,000 miles)

Any stick that is 0.05V below the highest stick is suspect. if you have a single stick that is notably higher than the others, it is likely bad, should be disregarded and use the next highest stick. Your high point should be pretty obvious as you have a lot of sticks in the 6.4X V range.

Looks like your high is around 6.45V. Anything below 6.40 is suspect. Anything below 6.35V is likely bad or at least needs some reconditioning. I count 21 sticks that may have dead cells.

Arbitrarily replacing sticks is typically not successful UNLESS some effort to recondition is made.

Given your described A/C performance, it's likely the battery was rarely charged due to high temp and maintained a relatively low state of charge most of the time.

The fast solution:

1) replace anything below 6.35V.
2) use the Hybrid battery jump start (where you buy a power supply and manually charge the battery) to charge the battery with cooling (fan) for 24 hours.
3) Wait 24 hours and check for outliers.

Slow solution:
1) Hybrid battery jump start - charge for 24 hours with cooling.
2) Wait 7 days.
3) measure 50 sticks
4) replace any that are 0.05V below the peak or below the second highest if you have a high outlier as described above.
5) Steps 2 and 3 in the fast solution.

After either solution install battery and hope for the best. Ensure A/C is working at optimal performance. Note that the A/C will engage even if you have the interior A/C off. if your interior A/C is performing marginally, turning it off will improve battery A/C cooling due to the use of only the smaller evap.
 

Last edited by S Keith; Jun 22, 2022 at 04:20 PM.
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