Aux switches unavailable battery charging

[ED-209]

If I were in your shoes, I would get a couple of basic tools, like a volt ohm meter and an AGM charger. Start by isolating the two cables at main negative post. Take them off of the top plate. One is your Aux neg and the other is your fender ground. Don't let them touch anything or each other. Charge both batteries fully. There is no need to remove either battery. Your positive charge cable connects to the main battery post. There is no need to disconnect anything here. The negative charge cable will connect to the main battery negative post. When it has finished, simply move the negative charge cable to the Aux negative cable, one of the cables that you removed and isolated. While the batteries are charging, disconnect the IBS connector from the negative post of the main battery. You will reconnect this as your last step. When you have finished charging each battery wait 30 minutes and read the voltage level while they are still isolated. You are looking for 12.8vdc or better. Reconnect the aux negative cable to the main negative top plate and then reconnect the fender ground to the main negative top plate. Reconnect the IBS sensor connector.

This is great info, thank you. The tech at Autozone certainly didn't disconnect the two cables at the main negative post when he "tested" the battery and told me it was fine. Wondering if there is an affordable AGM charger you would recommend.

Update on my vehicle after replacing the main battery a little over 24 hrs ago. The error has gone away. I only got it once on the first start after the swap and it hasn't come back since. The auto stop/start isn't kicking on at stop lights (so far) but we do have freezing temps here at the moment. I'm going to keep an eye on things and plan to grab those two tools off Amazon in the interim.

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[Lost1wing]

This is great info, thank you. The tech at Autozone certainly didn't disconnect the two cables at the main negative post when he "tested" the battery and told me it was fine. Wondering if there is an affordable AGM charger you would recommend.

Update on my vehicle after replacing the main battery a little over 24 hrs ago. The error has gone away. I only got it once on the first start after the swap and it hasn't come back since. The auto stop/start isn't kicking on at stop lights (so far) but we do have freezing temps here at the moment. I'm going to keep an eye on things and plan to grab those two tools off Amazon in the interim.

The NOCO above is what I have permanently installed in all of my AGM vehicles.

The Battery minder will give you a better idea of the condition of your battery, but not so much on load capacity. I use this to charge a battery before I install it.

The Fluke meter is what I keep just about everywhere. It is accurate and is great for troubleshooting. At the time I bought mine they where only $40. I have one in several vehicles. You can use a cheap one, even HF Centech meters. They don't seem to last long if you leave then in the vehicle. I think moisture, cold and heat play hell with them. No issues with the Fluke leaving in the vehicle. Except, they disappear when someone uses it. HF meters tend to make it back.

 

[Lost1wing]

This is great info, thank you. The tech at Autozone certainly didn't disconnect the two cables at the main negative post when he "tested" the battery and told me it was fine. Wondering if there is an affordable AGM charger you would recommend.

Update on my vehicle after replacing the main battery a little over 24 hrs ago. The error has gone away. I only got it once on the first start after the swap and it hasn't come back since. The auto stop/start isn't kicking on at stop lights (so far) but we do have freezing temps here at the moment. I'm going to keep an eye on things and plan to grab those two tools off Amazon in the interim.

So when the tech tested your batteries, they were tested in parallel. That is a good sign that your message went away. If you are not real handy or just not confident working aroud the batteries, you would still benefit from connecting an AGM trickle charger on your batteries overnight. They will charge at the same time by connecting to the main positive and the top plate at the main negative. Disconnect the IBS sensor connector while they charge over night. Remember to plug it back in before attempting to start. I would still recommend isolating the batteries before charging. But I get it, not everyone is comfortable doing this.

 

[XraytecH]

Might wanna consider Auxiliary Battery Delete.

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