Charging question.

[carguy300]

Im wondering what could my problem with my 68 300. It has been charging normal for about a year, battery is a year old, I had the alternator rebuilt about a year ago and Ihave one of those oem looking solid state regulator I got from someone here. I only drive on weekends a little, amp gauge normally stays in the middle after starting. I always unhook neg cable, last week I did not, today I had 1 volt battery. Put on charger 3-4 hrs finally boosted it. Checked amp draw at battery with high rpms, 13.2-13.4. It has always been 14.5. Let the car run about 30 mins, same reading. Shut down, voltage at battery 12.1. So im not sure if alts not putting out enough now or something with battery. After sitting one week hooked up, battery went completely dead, nothing was left on, dont know what would cause that or how to check if there is a draw on the battery. Sorry so long but I dont want to start changing stuff again until I know. I will check the battery in the morning see what it reads. Any ideas or thoughts would be great!

 

[carguy300]

I will add that the alt gauge now is running way high.

 

[Big_John]

today I had 1 volt battery

Is this correct? Your battery only read 1 volt?

Was there anything left on to draw the battery down?

Taking the battery down to 1 volt will shorten the life of the battery dramatically.

 

[carguy300]

Is this correct? Your battery only read 1 volt?

Was there anything left on to draw the battery down?

Taking the battery down to 1 volt will shorten the life of the battery dramatically.

No there was nothing left on. Im not sure if there is something drawing power or not. Like I said I have always unhooked neg cable, last weekend I did not and this is what I found. And it show 1.7 volts only.

 

[Big_John]

No there was nothing left on. Im not sure if there is something drawing power or not. Like I said I have always unhooked neg cable, last weekend I did not and this is what I found. And it show 1.7 volts only.

That's not good... You must have a bad parasitic draw somewhere. There's a ton of videos on YouTube about the subject, so watch a couple, then get out your meter and figure it out.

A little warning... When you draw a battery down like that, you can get a cloud of hydrogen gas under the hood. I've seen a car battery explode and it makes a real mess. So, be careful of sparks etc.. If you jump start it, connect to the discharged battery first so no spark at the battery.

Just so you know... The battery might come back and it might not. The plates in the battery get covered with lead sulfate crystals that don't break down with charging like a well maintained battery and performance goes way down.

Funny this came up... I was just going to order a different style disconnect for the batteries in my cars. These seem to work really nice as I tried one this year in my convertible and like it a lot better than others I've used. https://www.amazon.com/dp/B0DKXYNYYV?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

 

[carguy300]

That's not good... You must have a bad parasitic draw somewhere. There's a ton of videos on YouTube about the subject, so watch a couple, then get out your meter and figure it out.

A little warning... When you draw a battery down like that, you can get a cloud of hydrogen gas under the hood. I've seen a car battery explode and it makes a real mess. So, be careful of sparks etc.. If you jump start it, connect to the discharged battery first so no spark at the battery.

Just so you know... The battery might come back and it might not. The plates in the battery get covered with lead sulfate crystals that don't break down with charging like a well maintained battery and performance goes way down.

Funny this came up... I was just going to order a different style disconnect for the batteries in my cars. These seem to work really nice as I tried one this year in my convertible and like it a lot better than others I've used. https://www.amazon.com/dp/B0DKXYNYYV?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

Thanks, I will check them out. Going to recheck battery voltage in the morning, it is now unhooked, and see what it reads. Hopefully it didnt trash my battery.

 

[halifaxhops]

I fast way to see if you have a draw is put a Volt meter between the battery and the cable before it is hooked up and the battery is charged. Should be zero volts. Make sure things like clocks on radio's etc are disconnected also. If there is a draw you have to figure out where. Easiest way to get a idea where it is is to pull the fuses one at a time till the draw goes away when it does it is that circuit the fuse protects.

 

[CBODY67]

Trunk light switch failed can do the same thing. Easy enough to just unhook it, if equipped.

BTDT,
CBODY67

 

[carguy300]

Well I went out awhile ago and rechecked my battery after all night unhooked, shows 11.8 volts. Cranked right up. Voltage while running 13.4-13.5 any rpm. Took it on a 10 mile trip, going down the road alt gauge pegs on C, at an idle it pulses about 1/2 way. Back at the house, same reading while running. Shut off, unhooked, now 12.4 volts. Ill have dig in more later, thanks for the imput on tracing the draw issue.

 

[3175375]

Well I went out awhile ago and rechecked my battery after all night unhooked, shows 11.8 volts. Cranked right up. Voltage while running 13.4-13.5 any rpm. Took it on a 10 mile trip, going down the road alt gauge pegs on C, at an idle it pulses about 1/2 way. Back at the house, same reading while running. Shut off, unhooked, now 12.4 volts. Ill have dig in more later, thanks for the imput on tracing the draw issue.

Sounds like things might be ok. I would put the battery on a trickle charger and retest after the battery gets fully charged.

 

[Chryslerdon]

Sounds like things might be ok. I would put the battery on a trickle charger and retest after the battery gets fully charged.

A 12 volt battery should not go below 12 volts. 12.7 is around normal with the car off. Also, the alternator is there to maintain the battery charge, not to charge a dead battery. Charge it fully with a charger and have a load test done. The battery is probably toast.

 

[Dante64]

Well I went out awhile ago and rechecked my battery after all night unhooked, shows 11.8 volts. Cranked right up. Voltage while running 13.4-13.5 any rpm. Took it on a 10 mile trip, going down the road alt gauge pegs on C, at an idle it pulses about 1/2 way. Back at the house, same reading while running. Shut off, unhooked, now 12.4 volts. Ill have dig in more later, thanks for the imput on tracing the draw issue.

Greetings. Love your car. Always wanted the 300 with headlight covers. 1968 is THE Year. Anyway, the charge pegged to “C” scares me. I’ve read all the replies, as always, very informative. I’m leaning towards a defective regulator. Doesn’t matter how new it is. Sometimes trash right out of the box. Best to you brother.

 

[MoPar~Man]

If you have a volt meter that can also measure current (amps), then do this:

Disconnect the car's positive battery cable from the battery. The negative can be connected, or not, it's your choice. Connect a battery charger to the battery, bring it up to a full charge (as best as you can figure out based on what your charger tells you).

Disconnect the charger, connect the negative cable to the battery BUT NOT THE POSITIVE. Wait a few minutes, maybe 30, and use the volt meter to measure battery voltage. If it's over 12 volts, thats good - proceed to the next step.

The typical volt meter that can also measure current will have 4 ports for connecting the probes, 2 of those are for current - one of them usually labelled as 10A. Use that port (plug one of your test leads into that), turn the meter selector dial to measure current, the 10A setting, DC (if you have DC and AC use the DC setting). Plug your other test lead into the ground or common port on the meter.

Before you do the next step, make sure all switches are turned off in the car. All lights are turned off, interior lights, glove-box light, radio is turned off, heater fan is turned off, doors are closed, take the key out of the ignition. If there's a trunk light or under-hood light, take the bulbs out if you're not sure they're working. Go to next step.

Touch and hold one meter lead to the battery positive post, the other meter lead to the car's positive battery cable. Touch and hold them in that position. Note if you see a spark when you do that. See if the meter is showing a current measurement. It should be zero (no current). If it's not, then it could be in the MA (milli-amp range) or the AMP range. It could be positive or negative, don't worry about that. Just focus on the number.

If the reading is not zero, then stop the measurement (take the leads away). I would then disconnect the big alternator wire from the alternator (the big wire that's connected with a spade and nut). Remove the nut and pull the wire off, and let it hang but don't let it touch the engine or anything metal. Wrap a rag around it if possible. Then take another current reading with the meter (one probe on the battery positive, the other on the positive battery cable). See if you get zero current now.

All of this is to see if something is drawing current from the battery when everything is off. If there is some current draw, the first suspect is the alternator, so disconnecting it will confirm or eliminate it as a suspect.

 

[carguy300]

I do have the battery on a charger, shows fully charged. Been gone all weekend but am going to do more checking tomorrow.

 

[carguy300]

Well I got out awhile ago and checked on my 300, after 3-4 days on slow charge, my battery shows 13.8 volts. I decided to check charging before checking for drain issues. Hooked battery up, car cranked right up and dash gauge went to normal mid point like normal. Drove around a few miles, gauge stayed good. Got back to the house, checked volts while running, 14.8-15., running High rpms. Shut off engine, now 13.1 volts. Im happy with that. I installed a negative post disconnect that big john sent me a link for. Worked perfect. Now I can go after my cause of battery drain. Thanks for all the imput as always.

 

[Vinny]

Im wondering what could my problem with my 68 300. It has been charging normal for about a year, battery is a year old, I had the alternator rebuilt about a year ago and Ihave one of those oem looking solid state regulator I got from someone here. I only drive on weekends a little, amp gauge normally stays in the middle after starting. I always unhook neg cable, last week I did not, today I had 1 volt battery. Put on charger 3-4 hrs finally boosted it. Checked amp draw at battery with high rpms, 13.2-13.4. It has always been 14.5. Let the car run about 30 mins, same reading. Shut down, voltage at battery 12.1. So im not sure if alts not putting out enough now or something with battery. After sitting one week hooked up, battery went completely dead, nothing was left on, dont know what would cause that or how to check if there is a draw on the battery. Sorry so long but I dont want to start changing stuff again until I know. I will check the battery in the morning see what it reads. Any ideas or thoughts would be great!

Make sure your cigar lighter is not jammed in, or the trunk light may be on. Do you have an under hood light?

 

[jww427]

Just an FYI.
I add in line battery switches to all my Mopars.
I also use Genius 10 chargers at all times.
I test all my batteries 4 times a year.
This makes it easier to diagnose alternator and charging problems.