Battery and tender troubleshooting question

5

5632

TJ Addict

Original poster

Joined

Jul 22, 2020

Messages

1,707

Location

Phoenix, Arizona

• Aug 22, 2026

• #1

I have check my battery twice. Once with my my own checker and once at O'Reilly's. Both say it's ok. I have put 2 different battery tenders on it and neither one will work. I tested them on another car and both work with no problem. Connections are are good. Any suggestions or ideas what might be wrong or what to do would be appreciated. Please don't advise me to get a new Jeep.

 

KennethS

TJ Expert

Joined

Jan 15, 2023

Messages

3,472

Location

Phoenix, AZ

• Aug 22, 2026

• #2

What do you mean by “checker”? Was this a voltmeter, a load tester, or a hydrometer?

 

5

5632

TJ Addict

Original poster

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Jul 22, 2020

Messages

1,707

Location

Phoenix, Arizona

• Aug 22, 2026

• #3

Load tester

 

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Reactions: NskLJ

Gilaguy23

TJ Addict

Joined

Sep 21, 2021

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1,227

Location

Kentucky

• Aug 23, 2026

• #4

What is the tender doing flashing light wise? The only issue Ive had is a very low battery and some tenders need a reference voltage close to 12v to work. But..your saying your battery will start the jeep and checks out OK.

 

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A

Ashim

TJ Enthusiast

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Aug 24, 2024

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290

Location

North Olmsted, OH

• Aug 23, 2026

• #5

A battery needs to be fully charged to do a proper load test. Put an old style charger on it and keep it on until the ammeter drops down to a low rate.

 

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Reactions: 5632

NskLJ

TJ Addict

Supporting Member

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Oct 19, 2021

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Long Beach/ Colorado

• Aug 23, 2026

• #6

5632 said:

Load tester

Click to expand...

Was it fully charged when you tested it? If it fully charged the tender should just maintain it when it drops in voltage. What make you think the tender isn’t working?

 

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Reactions: 5632

bucky

E CLAMPUS VITUS

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Dec 25, 2020

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SoCal/North Dakota/ N Az

• Aug 23, 2026

• #7

What brand are you using. I’ve used Batteryminders for years with no issues. They work on dead batteries as long as the battery is recoverable. They work great at recharging my trailer brake backup batteries. I also have disconnect switches on both my YJ and TJ because they sit unused for long periods and the parasitic drain will discharge the batteries quickly.