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b3000 Battery/Starter Question

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stevebn2bj7

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I am having a bit of a problem recently with my BJ7. The battery seems to be holding a decent charge and reads 12.3 or so on the multi meter. However, unless it is at least 12.5 volts the car will not start. It just turns very slowly. What would be the first logical thing to check, tha starter or the battery. The battery is a 4 year old Optima and the starter is original Lucas and was rebuilt about four years ago by a professional shop.

Thanks,
Steve
 
Well leis see. If you have another car kicking around the garage with a good battery in it you could swap it for the optima and see if the problem clears up. If not start at the battery and check ever power line connection for cleanliness and tightness all the way to the starter. Also try using the button starter solenoid push button and see if it turns over quicker. Also check the ground strap to engine for tightness too. Should these previous checks fail to resolve the problem it leaves the starter as the suspect.--Fwiw--Keoke
 
Do you have a voltmeter? If so, do a voltage drop test. If not I recommend you purchase one. Indispensable tool when one owns several decade old LBC.
You know your battery voltage is 12.3, so I suspect you do have a voltmeter.

Next step would be to test to see what the voltage is entering the starter when engaged. Needs to be above 9.6 volts. If less than that(ideally no less than 11.3 volts) you have a restriction somewhere between the battery and the starter. Then do a voltage drop on the ground side. Looking for no more than 1/2 volt.

Yup, reread your post and you said you have a multimeter. If you are unsure of how to perform a voltage drop test, may do a google for voltage drop test. I remember several years ago there were several sites that showed, in detail, how to conduct a voltage drop test.
 
stevebn2bj7 said:
I am having a bit of a problem recently with my BJ7. The battery seems to be holding a decent charge and reads 12.3 or so on the multi meter. However, unless it is at least 12.5 volts the car will not start. It just turns very slowly. What would be the first logical thing to check, tha starter or the battery. The battery is a 4 year old Optima and the starter is original Lucas and was rebuilt about four years ago by a professional shop.

Thanks,
Steve
Click to expand...

Steve,

12.3 volts (checked on the battery terminals) is not a decent charge for a car battery, it is an indication of a problem. A good fully charged car battery should be close to
12.8 V. As you have said, your car starts when your battery is at 12.5 V but not when it is at 12.3 v.

One of three things causes this;

1.. No or low output from the the generator.
2.. Bad electrical connections to the battery.
3.. The battery has really gone bad and can't be fully
charged.

Next time you get the car started, check the voltage output of the generator. You should see around 14v at 1500 rpm.

Ed
 
Well yeah ED, With regards to item #3, if you have a pulse type charger with a desulfation circuit in it like the VDC Battery Minder line. A battery at 12.3 volts can easily be revived by removing the sulphate from the plates. As a matter of fact batteries checking low as 10.4 volts can be restored, it just takes longer. What the restored life span will be, is subject to the age of the battery and maintenance program thereafter. With the AGM type battery [Optima] restoration takes a special process.--Fwiw---Keoke
 
Keoke,

No argument from me about what you said, but my #3 means that the battery is past the point of being able to be revived using any charging methods, including the way you mention.
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Ed
 
While I was out in the garage today replacing my brake pads and repacking my wheel bearings, I checked the voltage on my Optima battery just in case the reading on an Optima battery is significantly different than a regular lead/acid. It was
12.8 V just like a good, fully charged lead/acid battery....
Back to this problem, if the battery is only showing 12.3 V then the battery is not charged all the way up . The key to fixing it is to find out why.
 
OH ! OK ED, I didn.t make that interpretation of the statement the first time.---Keoke
 
Thanks for all the info. Charged the battery up today and started it tonight. The alternator puts out 14.3 volts so that part is OK. The battery was at 12.9 volts after the drive and I will see what it is in the morning. Keoke, what is the special restoration you talk about for the Optima?
 
stevebn2bj7 said:
Thanks for all the info. Charged the battery up today and started it tonight. The alternator puts out 14.3 volts so that part is OK. The battery was at 12.9 volts after the drive and I will see what it is in the morning. Keoke, what is the special restoration you talk about for the Optima?
Click to expand...

Steve,
If you were able to get the battery back up to 12.8 v then it is probably OK. Your generator is OK, that leaves bad connections as the prime suspect.; corrosion in the battery connections, bad ground from battery switch, bad cutoff switch, loose connection on the starter solenoid, partially cut wire, etc.
Ed
 
Hi Steve, The AGM batteries for some reason tend to develop a symptom like memory in a Ni-Cad. Consequently, the automatic chargers generally used on them also contains a function that automatically charges the battery then discharges it before starting the next charge cycle. It is this cycling that breaks the battery's tendency to under charge.---Fwiw--Keoke

P.S. Get a Battery Minder and keep it on the battery when the car is Idle in the garage.
 
stevebn2bj7 said:
Thanks for all the info. Charged the battery up today and started it tonight. The alternator puts out 14.3 volts so that part is OK. The battery was at 12.9 volts after the drive and I will see what it is in the morning. Keoke, what is the special restoration you talk about for the Optima?
Click to expand...

A couple of things to think about:

What kind of battery terminals do you use? The original or the type with the two screws that clamp to the wire.

When was the last time the wire from the battery to the solenoid was replaced? Probably never. It does get old. Most people who work on their cars after restoring them or minor repainting,, almost never scrape the paint off down to the metal to get good "grounds".

The last time I had starting problems I took it to one of those "drive on up & test it" places. It wasn't the battery that time but it did save me a lot of troubleshooting time and guessing if it was the battery.
patrick
 
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