alternator ???

[Cobrajet]

Have you considered some type of battery tender from PulseTech or Battery Tender? I use the Battery Tender on my Torino, Mustang, and occasionally my lawn tractor, while the PulseTech keeps my motorcycle battery ready. I used to replace a lot of batteries. Is your alternator factory original? I had a replacement alternator in my Mustang, and it would kill the batteries in only a few months. Turned out the pulley on the alternator was too large, causing the alternator to spin too slow at idle, creating too little voltage/current to maintain a charge. The lights would dim, and the radio turn off when I hit the brakes. My favorite auto electric shop installed a new pulley and it's been fine ever since.

[vt_maverick]

I've looked into those in the past but never followed up - maybe it's time to do that. EDIT: I was thinking of the Battery Brain Tom posted about awhile back. I use the trickle charge setting on my DieHard charger whenever she's going to sit for awhile (2 weeks in Wisconsin for example) and that does a solid job. The reason I'm looking at the alternator is because the computer wouldn't come on after a solid 30 minutes of driving the other day, which makes me think somehow the battery voltage isn't being fully recharged during driving.

That's a good thought on the alternator, I'll have to check for a part number later today to see. Frankly it wouldn't surprise me, I think the PO did all his repairs with the cheapest parts possible.

[Mile High VX]

Frankly it wouldn't surprise me, I think the PO did all his repairs with the cheapest parts possible.

Dang CO VX owners...

[etlsport]

Eric - I have one of those DieHard 6V/12V Battery Charger & Engine Starter units (part #28.71225) that Sears sells. Is there any difference between that unit and the battery / alternator testers you suggested? And I agree about not getting the full amp level at idle, but if a HO alternator generates 75A at idle, how much less would the OEM alternator generate? (I'm asking because I don't know.) Dude that sucks about burning up your electronics, we came close to having that happen in the wife's Axiom just before Christmas but thankfully it was intermittent so we were able to limp it to our garage without incurring any damage (at least that we know of yet).

The way it's wired is there's a power cable coming directly off the positive terminal of the battery that runs through the firewall and to a 12A noise filter under the center console (it's grounded to the screw on the e-brake handle base). From there the power is (I believe) split directly between the screen and the computer. The aforementioned safety power supply is hooked up to the computer only so that you still have power to the rear camera and touch screen even if the computer is off. The lack of a safety power supply between the battery and touch screen means there's a constant draw on the battery to illuminate the on/off/sleep status light on the dash. Whether it's actually draining the battery or the battery just has a dead cell is anyone's guess.

That is good for charging and will test cca but im not sure about voltage. To be honest i have never messed with the testing functions on one. It is fully auto so while youre in the 2a auto mode it is working like a trickle charger. Make sure that you have it set in the agm mode too.

If you do have a shorted cell you could be overcharging too and burning off electrolyte while its hooked up, that would make the problem worse. If you run by an autozone or advance auto they will put a load tester on the battery while its installed and can tell you if there is a shorted cell. Sears can do this too but it would probably take longer though if there is an issue you can fet it replaced right there.

If you can I would throw a clamp on type ammeter over the power cable going to your computer to see exactly how much it is drawing while its off. Usually alternator issues show up with other symptoms so I am not convinced but cant rule it out yet either.