Ckforker

Year 3 and battery 3. I have a new alt, all grounds and battery cables have been replaced, so I'm at a loss as to why it keeps killing them to the point where they won't hold a charge. I have interstate batteries. I alternate daily drivers 2 weeks at a time and no issues with my other car sitting. Do others have better luck with other brands. Thanks

Kdo58

I have a exide battery in my old Toyota truck that is 8 yrs old.

Ckforker

Hopefully when I take it back to Costco, I can just get my money back and shop around.

GSLSEforme

Read this thread and what's been replaced...tells me you're chasing something... Some specific questions for some specific answers: What year/model? Why was alternator originally replaced,is replacement original type? Has the complete starting/charging system been tested? Ever had a draw test done on car,first suspicion is parasitic draw. How long a time period between driving it and coming back to it finding a no-start? Law of averages says three batteries in same car,same brand battery or not=it's not the battery. How long can a battery last in a 1st gen? 19 years and counting. Interstate battery bought in 1998. Interstate batteries are made by Johnson controls,their quality for about a 5 year stretch was not so good but they seemed to have gotten their problems ironed out. Only 4 battery manufacturers in this country and they make the batteries for all the brands sold here. The name on battery doesn't tell the whole story. Post up some answers to above questions,see if can give you some assistance on this.

t_g_farrell

iTrader: (1)

I agree, you have a parasitic draw somewhere. Sometimes when the diodes are bad in an alternator
it will do this. I would take the alternator in for a test and see what happens. Reman alternators are
notorious for have quality control problems.

If the alternator pans out as ok, then get a DVM and start measuring voltages at the alternator when
running and at the battery. It could be the alternator is not charging well due to some wiring issue.

I had a very similar issues for, god for a couple of years, and I finally replaced the SA alternator with an
S4 (more amps, plug and play) and it fixed the charging issues and the perceived parasitic draw that I
thought was causing my battery to be weak after a week or so. Now I can start my car after several
weeks of sitting with no problems (except its got 130K on the engine and needs to spin a bit to get
going at first).

As to batteries, I get mine at Walmart and take them back for partial credit after a few years if I
remember to do it. Its like getting them on sale! My rule of thumb on batteries is replace after 5 years
no matter what. Most batteries become unstable after that 5 year mark. I've seen it happen enough
times now in new and old cars that I always look at the date on the battery and schedule replacement
when its at that magic 5 year mark.

Ckforker

There are only 2 small (milli amp) draws from the original clock and the headunit clock/ memory. Replaced the alt (February 2017)with an FC one and had not thought about it being bad. I have 85 FB GS, all stock. The old alt would only charge around 3500 rpm.

Starter was just tested and was newish anyway.

The battery works perfect every time till it doesn't and will not hold a charge once it dies.

I'll keep digging and get the alt checked, seems odd that it runs and lasts a year.

Maybe the old alt did the damage to this battery.

GSLSEforme

You need to or get system tested and get specific #s on milliamp draw. Anything over 125-150 milliamp draw is going to cause problems in a car that's not started and driven every other day. Unless there's something in the radio unit not shutting down all the way,those two items are not the cause. This can quickly be determined during a draw test by pulling fuses for those items-there should be 0 draw at that point. Fc alterators have been known to have a shutdown draw when installed on an FB,not all,some. This can also be proven during draw test by unplugging alternator. Most these days are remans and that is the key to some. This alternator can test fine on the parts store "machine",likewise the starter. THE best way is to test all three,battery+starter+alternator in/on the car as a SYSTEM. This will uncover possible wiring faults between these items also. A VAT(volt-ampere) tester with an adjustable carbon pile can load battery and alternator to determine if they're working properly. Any good automotive repair shop will have this equipment,testing doesn't take long and shouldn't be overly expensive. Between this and draw test,the problem(s) will be found.

GSLSEforme

Lastly,the old alternator may not be solely responsible for "killing" the battery. From what you say,it,didn't charge well and not at all til over 3k rpm. Pattern failure of an alternator diode/rectifier failure which cuts output by at least 1/3,not getting battery anywhere near fully charged no matter how long car is run+likely spiking electrical system with ac voltage. The suspected draw is likely the real problem here as a new "good" alternator is now in place with same recurring issue.
Even a brand new lead/acid battery left in a 100% discharged state for how long?can be brought back with proper charging, but repetitive dead battery/recharge cycle events like this will take their toll on battery power/reserve and likely real reasons for the battery being assumed bad.

Ckforker

Good idea on testing the whole system together. I'm gonna take it in next week. I've triple checked the wiring and is correct, so we will see what the test says.

Ckforker

The guy who looked at this today does a lot of RX stuff and he can't find anything wrong with the car now that it has a new battery. He told me to drive it a week or so and bring it back to recheck. He seems to think that the old battery went so long with out full charge it got damaged, but that seems odd. He checked all the wiring and he feels good about it. I'll post back.

Ckforker

I think I found the culprit. My power antenna seems to stay going up or down randomly. Perhaps a bad manual switch. I'll have to dig into it tomorrow.