No bubbles whilst charging

[Fuzzymuff]

Hi all. I got a flat battery on my car. Its been parked for 3 weeks because my hydraulic clutch linkage needs a new cylinder. I'm short of readies and monthly pay has left it be for 3 weeks. I thought I'd best start the engine, to keep it happy. Battery dead. My cheapo charger gave up the ghost, so I've used a transformer out of an old charger. Its huge, it used to be able to start a car, but one of the big diodes blew. S I took the tranny, stuck a 25amp bridge rectifier on it and a 6,800uf cap.
No Load = 16.5v
Load = 13.5v
Batt = 13.3v
Drawing 500mA, fully topped up 2 year old battery. It won't start the car. I hear a single click of the solenoid, then nothing. I have topped it up with distilled water and the specialist I bought it off, tested it and said it was fine.

There are no Hydrogen gas bubbles coming off the plates, that can't be right. And is my charger correct?

Can you shed some light, please? The car has never had a starting issue.!!!

[Perry Babin]

What does the voltage on the battery terminals (not on the cables/wire terminals) drop to when you try to start the vehicle?

[Fuzzymuff]

Sorry sir, can't answer that just now. I have the battery indoors at the mo. Its 12:40am, so I can't connect it till later in the morning.

Thankyou, Fuzzymuff.

[DigitalJunkie]

Flooded lead acid batteries don't usually out-gas much under "normal" charging. The voltage would have to be a bit higher ('equalization' charge) to really start bubbling noticeably. Usually if you take the caps off,and stick your ear over one of the filler holes you can hear it 'hiss' a bit,kinda like fizzy soda-pop does.

Be sure it's good and charged,and your battery connections are clean and tight.

On a somewhat similar note,I've noticed on these newer cars that dirty/corroded battery terminals can really screw with the electronics/computer stuff.Our car was doing some odd things,the ABS light coming on,etc. for no apparent reason. Once I cleaned up the (mildly)dirty terminals,it hasn't misbehaved once so far..Kind of odd,because poking around with the DMM while not running/starting/running showed that all voltages were in range of what's to be expected,but for whatever reason the 'brains' weren't happy.

[dangus]

You should see a little higher voltage than that on the battery. 13.8 to 14.4 is a normal range for a lead-acid battery.

If you have a regular bench power supply that current limits without destroying itself, set it to 14.4 volts and charge the battery from it. I saved myself from a walk home more than once that way. It only took about an hour to get enough juice into the battery to start the truck. An overnight charge should be plenty. A 15V laptop supply with a 1 ohm resistor in series ought to work, too.

And, yes, corroded terminals are bad. Emery cloth, a wire brush, a knife, or there must be some chemical that will work. If the battery has been load tested, that's gotta be the problem.

[Fuzzymuff]

Hi all, Clean battery terminals I have. Whats good for RCA's and Scarts is good for the car too. Charging all night gives 12.47v this morning, car won't start, with a voltage drop to 10.43v says its not good. Take it, its dead then

Thankyou, Fuzzymuff

[Perry Babin]

Did the specialist that checked it, check it after you drained it or before you drained it?

[Fuzzymuff]

Before, Hi Sir, I charged it, took it to him and he put a car lamp on it and a DMM. The lamp stayed bright, e stated that because it didn't begin to dim, it was okay. He didn't load test it. He's the expert?

Thankyou, Fuzzymuff

[Fuzzymuff]

Update....Charging at 13.9v 2Amps being drawn. I've borrowed another charger. Its basic 12v 4 Amps with a basic 0 - 5Amp ammeter on the front. With my DMM in parallel, it measures 13.9v
Thankyou, Fuzzymuff

[Perry Babin]

If it remained completely dead (flat) for a significant amount of time, it's capacity may have diminished. If after charging for several hours it still drops immediately to below 11v when you try to start the engine, it's probably going to have to be replaced.

If the voltage remains well above 11v when you try to start the engine but you only get the single click, you need to check the wiring and connections.

A headlamp isn't a reliable test for a battery. It probably only draws about 5 amps of current. To test an average starting battery, you need to charge it fully and draw at least 50-100 amps from it for 10-15 seconds while monitoring the voltage.