120V DC Lead battery desulfator! Lightbulb and Bridge Rectifier!

[antigrav1117]

I have ordered and recieved 3 large "run" capacitors from EBAY, but have as yet to hook them up. I'm going to follow anonymous's suggestion and install them with a non-shorting selector switch. They are sized to provide 200ma, 500ma and 1 amp.
Thanks Anonymous!

[antigrav1117]

Katie N Dad- even 2 miles should be enough to recharge the batteries from cranking I would think, given the Jag should have a 35-60amp alternator. I would double check the battery water AND examine the belt. I JUST had an experience with my F250 batteries getting low, I found the alternator belt had worn enough that it was a tad loose AND riding in the bottom of the drive pulley, causing it to slip. Replaced the belt and no more problem.

[KatieandDad]

Jag has a sealed battery and the belt is new.

A slipping alternator belt is normally pretty obvious with it screaming as it slips.

I know the battery is getting OLD - I just want to limp it through to my march payday without loosing my job because I don't get to work.

I could just walk to work, it onlt takes 20 mins.

As it runs perfectly after a few miins I know that the alternator is fine - No RED alternator warning on dash either.

[AndrewT]

Originally Posted by KatieandDad

...............
It has, what I think is its original battery - now 10 years old.................. I tend to drive to work which is only 2 miles every day.....................

Is there anything that I can do to give it a bit more life during the winter ?.........

A sump heater will give the starter an easier job to turn the engine.
Reducing the electrical load during all runs, long or short, will help keep the battery up near full charge.
Needing periodic recharging during periods of heavy electrical use is quite common. It should get you another season.

[Djenka018]

Originally Posted by antigrav1117

Katie N Dad- even 2 miles should be enough to recharge the batteries from cranking I would think, given the Jag should have a 35-60amp alternator. I would double check the battery water AND examine the belt. I JUST had an experience with my F250 batteries getting low, I found the alternator belt had worn enough that it was a tad loose AND riding in the bottom of the drive pulley, causing it to slip. Replaced the belt and no more problem.

yes, but not really.

2mi drive will recover, perhaps, cranking loss but for Pb-Acid batt to reach fully charged state it takes much longer, specially if batt was flat at the beginning.
Gasing is normal and required recovery cycle when charging batt with low charge over long period and to reach that stage in the car, it takes 2+ hrs.

@ KatieandDad

You could use 2.7A cheap trickle charger, perhaps once a week, 4-6hrs or maybe overnight. It should be enough to top up what normal drive cannot achieve. All you need is to reach gassing state.
If you're planning to keep the car as weekend driver, better choice is to have smart chargers that will cycle the batt for you and keep it in 110% shape.
I f-up few batt on my weekend driver because of heavy sulphation until I learned the lesson.
IMO, SLA is not a good choice for non daily driver.

[nigelwright7557]

Originally Posted by luka

If battery if "dead" you can't lose anything, trying doesn't hurt. So I guess if it works for you, it could/will for others too.. good job

You just have to be careful with gassing and sparks.
Disconnecting a lead and sparking with gas in the air could cause an explosion.

When i was a mechanic one of the apprentices disconnected the charging lead from the battery before switching it off at the mains and there was an explosion and the battery blew apart spraying acid everywhere.

[Mooly]

As the battery ages its internal resistance increases. That drastically decreases the recharge ability on short runs. Think of the battery as a "perfect" 12 volt source in series with an ever increasing resistance. Doesn't matter whether one cell or all cells are affected.

That internal resistance both causes the terminal volts to drop under load and limits the current that can flow back into the battery under charge. The alternator may have an output of 14 volts and a max current of 100 amps. That 100 amps is only above a certain RPM too. So you only have 2 volts "to play with" in forcing current back into the battery. If the battery internal resistance is high the current is reduced.

A new battery will accept charge at virtually anything the alternator can pump out current wise.

The voltage regulator in an alternator is compensated to allow higher voltage when cold. It can be as high as 16 volts for a minute or so from a freezing start to help force current back into the battery. On a hot summers day stuck in traffic the output can go as low as 13 volts.

My dads Toyota is 9 years old, on its original Yuasa battery and has covered only 25K miles from new. It gets the worst use imaginable for a car. It does a 0.5 mile "paper run" daily + shopping... that's at least two and sometimes three or four starts a day. Heated window on, blower on full and sometimes headlights too and its still going strong.

[AndrewT]

Your Dad is a battery abuser.
Is there a Quango I can report him to?

[Jacksonn]

I found the battery restoration info interesting. One note worth adding, re a battery with a dead cell. Often this is due to lead sulfate scales that fall, and accumulate until they short between plates.

Individual cell voltages can be compared with a DC volt meter. Add a few inches of wire to each test lead, with insulation left on one end. Insert insulated wires in adjacent cells, only to electrolyte surface. Covered wire ends prevent shorting cells.

This cure often works, but is messy. Empty all cells into a glass [or other acid proof] container & save. Fill battery cells with warm tap water & dump. From a safe distance, with battery on side, carefully spray garden hose into each cell, to help remove loose scales. Turn battery on other side, then both ends. Final rinse water should look clear & particle free.

I use a hole on back of my acre to dispose of rinse water, & the hose rinse. Add soda, then fill dirt. Much dilution + soda = minimal pollution.

Either buy battery electrolyte from auto store, or
filter electrolyte, through a coffee filter, into a 2nd clean glass container. Filter again if needed. Top up battery to just over cell plates.

After charging, the liquid rises; finish topping cells.

I warned you this was messy. Long rubber battery gloves, eye protection, battery filler, & old clothing advised.

By now, new batteries may not look like such an expensive investment. I love my LifeLine sealed AGM batteries, & my E-bike LiFePO-4, but keep a Battery Tender & a Battery Minder on 3 restored relics. My electric mower doesn't care.

[speakerfritz]

where does all the sulfur go....you know...the sulfur that was on the sulfated plates? well it collects at the bottom of the battery with the lead particles that get dislodged from the battery. what to do? You need to shake the battery up and pour the contaminated acid out. refill with new acid. Otherwise, you run the risk of shorting a few cells.