Power Problems

LarryE · December 23, 2003

My battery can't seem to keep a charge..

This problem has been going on for a year now..

If I drive the truck alot during the show season I never have a problem.. but once I let it sit in the garage for a week it will be completely dead.

I'm on a new battery , one now was replaced 2 months ago.

The truck is my show truck so it never really see's daylight during offseason or long breaks between shows.

I charged the battery 2 days ago, let it run about an hour and the gauge was showing around 14-15 running.

Now 2 days later NOTHING.. not even a click from the starter..

I suspected that it may be the Viper Alarm that had a brain go down but I don't see how it can be pulling a charge constant without anything hooked up to it now.

I have all my amps unhooked, and cd changer unhooked so they wouldn't be pulling anything.

Once I get it charged back tomorrow I'm gonna pull the battery terminal off and see if it's the alternator or what but I doubt that as well..

(When the shop installed the alarm they said something was pulling off of the battery then but it was very small and the truck was stock) I had it all during college since 99 and never had any trouble there till I moved back home and put it up as a full blown show truck.

I'm gonna wear my battery charger out trying to figure this mess out LOL

Wingnut · December 23, 2003

Battery cable would be the first thing I checked.

I have had a few go bad on me, they look fine on the outside, but inside they are completely rotten, and corroded out. It can make you go through batteries and alternators like socks.

Just my .02

LarryE · December 24, 2003

I'll check it weirder things have happened with these trucks

Shaners · December 24, 2003

Check your ground wires too...

It's a tedious job, but when you get your battery charged, disconnect the neg terminal. If you touch it back to the battery and there's a spark, then you have a draw on the battery. Pull fuses one at a time, and continue to touch the terminal until you isolate the circuit that is pulling the juice... ie. no spark when fuse is pulled = where battery is being drained!!!

Good Luck Larry, because these things can become a PIA!!! You made need a few of these

LarryE · December 24, 2003

Defiantly gonna need something after I figure this out..

Charged it last night and ran it about 2 hours.. came out this morning and it's dead again..

I'm gonna rip every piece of electronic equipment that I've added out of the d**n thing and redo it all

CMNTMXR81 · December 24, 2003

I know you said it's a new battery, but it could be a bad cell. You have an Optima for that thing, right?

Anyway, if it isn't that alarm, and all your stereo is unhooked, I would look into the alternator. It's not the alternator itself but rather the internal voltage regulator. That will require the whole thing needing replaced unfortunately. It may be reading that it's charging 14-15 volts, but that doesn't mean that it necessarily is. It could be geting a erroneous reading from the regulator itself.

These alternators are disposable. I usually go through about one a year!

Also, letting it sit, then starting it and charging it, then sitting again for awhile isn't the greatest for longevity. In the off-season, I'd get a trickle charger and keep that on all winter.

Mine when it gets below 32* even with the Optima, is put on the trickle. I did this with my factory AC Delco battery and it lasted for 5 years doing this and I do the same as you..let it sit, then run it once, let it sit, run it............

Have it load tested at a Napa, Autozone or other parts store. They should be able to load test it at both ends (alternator and battery) to help isolate it.

Z71GUY · December 24, 2003

It doesnt seem like he has a charging problem...sounds more like what Shaners is saying... something is draining his battery when it sits. Make sure your battery is good, then start isolating whatever could be drawing power. Good luck!

CMNTMXR81 · December 24, 2003

Everything drains your battery but not at the rates at which he has.

I point my finger towards that alarm 1st. We had nothing but horror stories with aftermarket alarms drawing such amperage.

However, if it is draining it as it is, he could be drying out his cells in his battery therefore causing them to heat and warp, then touching one another, once they touch they short out and those cells become bad. A bad cell weakens the battery sufficiently so as not to charge properly, the regulator in the alternator trying to charge it realizes something ain't right, and starts over compensating therefore damaging the battery and wearing itself out sooner.

See, the domino effect? A load test on the battery will tell you if a cell or more are bad.

Tracing electrical problems are a technicians worst nightmare because you physically can't see electricity like you can gas, oil, water, etc.

SnakeEyeSS · December 24, 2003

This is gonna sound odd at first, so pay attention:

Go to your BMW dealership. BMW makes a microprocessor controlled battery charger (this one costs 100 or more) and can be hooked up to your battery at all times. It will keep your battery at exactly the setting you choose, chargeing it when it get's low and stopping when it's charged. It is designed for cars that sit for long periods of time, so it won't overcharge it or allow it to get low, as the BMW model is NOT a trickle charge(trickle's can damage the battery by over charging). IT's kinda like Ronco's saying "set it and forget it". There is more technology involed, but I don't remeber it all. I've seen cheaper knock-off models on sale at sears for half the price, but don't know how good they are.

SnakeEyeSS · December 24, 2003

Just found the information:

The Advanced Battery Charging System is a 1.25 Amp battery charger designed to fully charge and maintain a battery at a proper storage voltage without the damaging effects caused by trickle chargers. The new BTP micro-chip technology applies the correct peak charge, then automatically maintains the battery at the perfect float voltage which virtually eliminates battery destroying sulfation! Temperature compensation ensures optimal charge voltage even in extreme weather conditions. Powder coated aluminum chassis. Spark Proof! Reverse polarity protection ensures safety. Built in 72 hour timer will protect a marginal battery from over charging.

It's 69.95 at www.bavauto.com

Just enter any model of BMW and then search for "charger". IT's the only thing that comes up