Midyear electrical discharge problem

[David W.]

Re: Midyear electrical discharge problem

Bill,
You are probably right about the battery not being up to full charge. I put it in the car but only drove it for 5 mins based on the funny amp reading. I'll take it out now full a longer drive. Will revert shortly.

[David W.]

Re: Midyear electrical discharge problem

Ok, after 20 minutes of 60mph driving, the amp gauge reading didn't change. It appears to be working as it flickers with each click of the turn signal. After the drive, the voltmeter showed a reading of 12.8. That's lower than the 12.9 I started with so it does appear that something is drawing down the battery. Additional info - the amp gauge when the car is off does not return to zero but about 1/8 inch to the left of zero. When the car is started, the gauge returns to zero. After 1-2 seconds it flciks to the discharge side. That's all I have, any suggestions appreciated.

[Bill I.]

Re: Midyear electrical discharge problem

Dave, sorry to read that info. You have reached my level of knowledge on this one. Hope someone else can guide you. Sorry, Bill.

[David W.]

Re: Midyear electrical discharge problem

Thanks Bill. I'm going to clean all the connectors I can find and hope there might be some bad connections. I don't drive it as much as I should so maybe some moisture or other foreign matter has developed.

[David W.]

Re: Midyear electrical discharge problem

Ok, cleaned the main terminal fuse block (?) on the firewall. Let it idle for a few minutes, still shows a good charge at the battery. Turned the car off and now the battery reads 12.95 so maybe she is charging fine. Can the ammeter gauge somehow get out of calibration?

[Bill I.]

Re: Midyear electrical discharge problem

Dave, that I don't know. It sounds like your on the right track, but the battery still is too low. More driving, OR a Small charger, less than 2 Amp on a Red Top overnight may help. Bill.

[Gary C.]

Re: Midyear electrical discharge problem

Dave, get one of the digital voltmeters that plugs into the cigarette lighter. Roy Braatz or another one of the TDB frequent users posted info a while back. Walmart has them for around $15 bucks. That way you can see what the charging circuit is putting out when you're driving around. Gary....
http://www.amazon.com/Vector-VEC008-.../dp/B0002ISEQW

[David W.]

Re: Midyear electrical discharge problem

I will do that. Thanks.
Some additional info - after charging overnight the battery shows 13.6 and with the car running 14.8. Looks more and more like the gauge is whacky. I will get the cig lighter device to confirm.

[John C.]

Re: Midyear electrical discharge problem

David
I have a 64 that never shows a charge , it only discharges more when the lights are on . I put a extra amp gauge under the dash and it shows the system is working fine . Hope you find the problem .
JOHN
P.S.
I have done 8 body offs with complete wirer harnesses , I think the problem is the gauge , if I had time to work on my car I would have changed mine.

[Jack H.]

Re: Midyear electrical discharge problem

I wouldn't be that concerned about the 12.8-12.9 VDC reading! The rule of thumb is 2.2 VDC per cell. Most automotive lead acid batteries have six individual cells connected in series. So, you would expect 2.2V x 6 = 13.2 VDC from a fully charged battery.

Now, not every battery meets the 2.2 VDC per cell rule of thumb. They'll vary with the specific design/construction characteristics of that battery. Plus, you can expect some variation based on the accuracy of your test voltmeter as well as the 'health' of that specific battery (are all cells EXACTLY identical?).

The approach to take here is to DISCONNECT the battery from the car (either the POS or NEG terminal) to 'float' it. Now, apply your charger and let 'er pump up to full charge state.

Remove the battery charger and let the battery sit for an hour or so to 'stabilize' in the absense of the battery chargers' current supply. Now, go measure the battery voltage and THAT is your yardstick for that specific battery's fully charged condition.

Last, re-connect the battery to the car and give 'er a few minutes to 'stabilize'. There are circuits in the car that are un-switched, always active (e.g. cig lighter, interior lamps, clock, engine control computer, Etc.) that will momentarily draw 'fill the pipeline' (transient) current when you first connect the battery. Some of these will draw low levels of constant and or 'burst' mode current from the battery with the ignition switched OFF and the battery itself will exhibit a discrete level of internal self-discharge.

So, expect there to be SOME degree of static voltage difference between a fully charged battery, disconnected from the car's electrical system and that same battery, sitting 'idle' but connected to the electrical system. This difference should be rather MODEST...

If it's not, it's time to troubleshoot the individual circuit branches to document who's drawing what level of current with the ignition switched off.

[John C.]

Re: Midyear electrical discharge problem

David
I have the same problem with my 64 .I put an after market amp gauge under the dash and it is charging fine . If I ever get a chance to work on my car i am going to change the gauge .Good luck
JOHN .

[David W.]

Re: Midyear electrical discharge problem

Thanks for the excellent advice Jack, as usual. I bought a brand new battery yesterday so that eliminates one major variable.

I bought one of the charging indicators mentioned by Gary. What a sweet little gizmo. Plugs into the lighter and gives a digital readout. I went to my usual parts store, they had no idea what I was talking about. So, as recommended, I went to my local WalMart and they had it. (If you want to feel rich and thin, head off to WallMart.) The new sweet little tool showed 13.6 so I guess all is well. I'm going to let the ammeter do what it wants to do with its crazy reading. The car is Top Flight, Bloomington Survivor certified, and approved for Bowtie star judging so I'm not going to even think about taking the ammeter out. As long as I know I'm charging, I'm ok with it. But it is a bit annoying to stare at that goofy reading.

Thanks to all for the excellent advice.