You didn't say what battery, my '80 sits for extended periods of time but it fires right up. The Optima in it is at least 5 years old.
It's only battery. :) I have had Optimas etc and right now it's a plain old battery.
That said your issue is more likely due to a slow drain than a weak battery. I'm sure you know this and have probably tried to find the drain, but finding one can be difficult. My old MGB would kill the battery in a day or two... but let's not discuss Lucas electronics...
Well a slow drain was what I have never been able to find. Nothing over the usual drain for the ECM. But I finally got out there with the inductive amp gauge....
After all these years I finally figured it out. The alternator isn't big enough to run the car and charge the battery. Start up amperage pegs the gauge at 400 amps or so.
Idling the engine everything is sucking down about 80-90 amps or so. A little less after start up and the battery has recovered somewhat. If I turn on the wipers and a few other things I can easily get amp draw over 100 amps.
Chrysler cooling fans 35 amps (fairly new) HVAC blower pulls 35 amps (fairly new)The alternator is pumping out 110-115 amps pretty much all the time including at idle. CS alts will usually charge at full amperage even at idle.
I'm just not producing enough amps to run the car and charge the battery adequately at the same time.... All these years I always looked for a drain and never looked at what the car was pulling when running.... It's a first for me. All the cars I have fixed were always a constant drain. Being an ASE master tech I have never run into this problem. I have had what I thought were battery drain problems for years... So what's happening is the battery is getting charged just enough to last a couple days but anything past that and it doesn't have enough power to start it. I know with a stock starter there is no way I'd get the thing started if it sat more than 2 days but the mini permanant magnet starter and MSD have really covered up the problem cause they can get the engine to start with 8V. If the engine will start turning over it'll start. Kinda like an old model T and hand cranking it. The MSD will fire it right over and get it going.
So I need to look at reducing amp draw in the car and increasing amp output. Looks like I'll have to make a CS144 fit my serpentine brackets. So it looks like John will probably be getting my nearly brand new alternator for his elky.
Things I haven't checked are the draw of the fuel pump and I couldn't get to the wiper motor to see what it pulls. Will have to go through and check everything and see what's drawing the most current and what I can do to decrease it.
Just think if I was going down the road with the wipers going the AC running the headlights on and the radio on. I'd be pulling 150 amps and the alt would really be complaining....
On the subject of a battery maintainer, I overanalyzed those and ended up buying the Schumacher SEM-1562A Maintainer (does 12V and 6V - I mainly use it for Power Wheels). Battery Tender products have a good reputation and can be found relatively cheap on Amazon, but the Schumacher is ~$18 at Wal Mart. Hard to beat that price. The Schumacher comes with a couple two pronged adapters, I'd hard wire one to your battery. Chris
I have a Shumaker 2/6 charger and it has worked great. Shuts off if overheated or hooked up backwards. My welder is made by them as well. Got a deal on it and I like it. It has internal spools for both size rolls of wire. No adapters just two spots to put a roll on. Never seen that on any other one.
The battery maintainer I was looking at is one that mounts in the engine compartment and you just plug an extension cord into it. No messy boxes and I can plug it in anywhere.
Robert AdamsRobert Adams
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