Auxiliary battery dead, problems charging

If it's a die-hard AGM and it was replaced last August you still have a decent warranty left on the battery so I would take it to a die-hard dealer and let them deal with charging it trying to charge it through the auxiliary report way up in the front of the car is kind of a joke to be honest You really need to access the battery in the back and plug your charger right to the battery terminals that are sitting right there under that tray You have to take the larger black tray in the folding cover out and set it over the HV battery and then lift the little triangular-shaped cover to access the battery your charger may not be up to snuff to charge an AGM battery I don't know I can't see it from here but given the fact that the battery is just at a year old or something similar I would certainly get it over to a die-hard dealer and allow them the chance to pronounce it dead or good seems to make good sense to me and then more than likely the car will be quite ready to go somebody will need to take it out for a drive and charge up the HV battery and literally see what you got

 

And this car is in Niagara falls New York oh boy well not sure about the condition but if it's been indoors most of it's time it should be in quite good condition

 

It's possible your charger isn't working correctly. Also possible something is wrong with "charge port on the front." Ideally you want to pull the 12volt out of the car and clean it up and inspect it and then put a smart charger that goes up to 10amps on it for a day or so. Old junky 12v chargers, especially low-amp ones will not revive a long ago discharged 12v like a high amp smart charger will.

 

My 8 amp charger works fine at the battery I have a Schumacher doesn't have a gauge or anything on it just some lights to tell you if the terminals are connected backwards and another light that tells you it's fully charging and another light that tells you it's maintaining and is fully charged I use it all the time on powersports equipment and everything when I connected it to the front porch on any of my Prius no matter what the year the charger terminals get excessively warm or warmer than I would like It's not melting anything but it's pretty warm when I connect it directly to the battery nothing happens except it charges goes green then goes yellow and says it's maintaining very quickly that's the only reason I mention the front ports for charging in it's like 12 gauge wire or something running up there doesn't look that stout.

 

Most cheap automatic chargers will not charge a battery that is this low. You can connect a light bulb in parallel with the charger for a few minutes to give the charger a load.

 

Show your mechanic my message. If he doesn’t know what it’s about, then he probably won’t be able to charge it.
You can also jump a charged battery to this discharged one for 10-15 minutes and then try your charger again.

 

Your combination meter could have failed. I sent mine to Texas Hybrid Batteries for repair

 

Can the mechanic, or somebody, do a capacity test on this battery just to see how much juice it can supply when charged?

We could have a situation where its capacity is greatly reduced, so it looks charged when you charge it, but still doesn't have much to give. Or there could be something in the car drawing a crazy amount of power and draining it fast. Getting a number for the battery capacity would help judge.

The car has a funny feature where it tries to remember its previous state when you reconnect the battery. If it was ON when the battery conked out, it wants to still be ON when you reconnect after charging.

I would try to use that brief period, before the battery conks out again, to turn the car OFF. And then see how fast the battery charge drops. That could be a first step toward finding out whether whatever is draining the charge is always powered when the car is OFF, or just something powered when in ACC or ON.

 

Take a coat hanger cut a hoop piece about 15 in long when the hangers unfolded take two pairs of pliers you know the plastic handle pliers pliers now touch not the pliers but an end of the coat hanger to the positive and negative terminals of the battery The center of that coat hanger should start turning red very quickly If it doesn't you have a problem this is with a standard dry cleaners steel twisted coat hanger this is basically what your old type of silly tester was of the wires were a little bit thicker and there's a screen event screen on the front of the doohickey and you push the button down and you hold it till the meter goes to where it goes and then you let go and if you look through the screen while that's happening you see the wires turn red hot You're just essentially shorting the battery for X amount of seconds Do what it does or do it in the carport whatever If you don't make red on a coat hanger you got nothing basically That's a quick way to do it If you got so much power it turns the coat hanger red and melts it in the middle well no worries you got plenty of power generally speaking and if that happens right after you melt the coat hanger and set the pliers down measure the voltage on the battery now it should be back up to 12 by the time you round up the DVOM the test leads and are standing there with a thing on If it's sitting at 11 volts no good. Yeah this is not the correct way to do this or any of that Is it unsafe I certainly hope not You might could get burned if you're not careful but you'd have to be really sloppy.

 

Generally it seems to me you're 12 volt battery should be able to sit there with the car on with no exterior lights on the car not running the air conditioning not running The fan not blowing or any of that in ready mode or in ACC mode with all the dash lights lit up for at least 45 minutes without causing any faux pas.

 

Get it tested with an "conductance tester". You connect the tester directly to the battery posts, input a few criteria (battery type and Cold Cranking Amp spec), push a button, and it comes back with the as-measured CCA plus an assessment. Beats conducting an opinion poll here?

Dealerships use such testers, will check it for you, typically for a fee though. Automotive retailers selling 12 volt batteries often have such testers as well, and will usually test for free; it's good for business, only takes 5 minutes. For DIY, I'd recommend Solar BA9 for this.

My 2 cents: sitting for a year, it's probably toast.