How do I re-charge THIS battery...
 

I left my key turned in the ignition for several hours yesterday, so I wanted to charge up the battery a little, but when I examined the battery a bit closer I noticed that it's probably not a maintenance free battery that I thought it was - see the cap in the photo that I have removed... Last time I saw a battery like that was back in Europe 25 years ago where I used to live.

So the question is: should I remove the battery out of the car and place it in a dry spot outside, then pop all the caps off and THEN hook it up to the charger? I remember way back when my dad was recharging a battery like that the acid in it was boiling pretty vigorously...

Thanks in advance -
James

You could get some spillage . . . so I'd remove it, and set it on a piece of cardboard to catch/absorb the leaks, and if your low on "water" only fill it to the bottom of the tubes . . . until after it is charged.

If it still starts the car, I'd just let the alt charge it on the next drive, if it will be soon.

Hi
Should be no need to remove the battery if you use a slow charger like 10 amps. Take the caps off to check if the acid levels are where they should be and observe the bubbles in each cell while charging - all cells should bubble at about the same rate. Better yet, get a hydrometer at the parts store and check the specific gravity of each cell - all the cells should be close to the same. If the above tests show a big differance between cells, the battery is defective

The bubbles are hydrogen gas which will explode with a spark - so don't connect or disconnect the charger leads with the caps off.

That said, just leaving key on for a few hours shouldn't drain the battery. If it will still start, just let the alternator charge it while driving.

Good Luck,
Joseph

The key turned in the ignition uses hardly any power, just some juice to activate the gauges and climate control....and a couple teeny lights....that's it. Just fire up the car and let it run for 10 minutes, that will charge it right back up.

Distilled water.
 

If you do decide to "top off" the cells, be sure to use only distilled water. I'm in agreement r.e. not wasting too much time charging the car. If it starts, well, why worry? Alternator bad?

For charging in situ, trickle. 2 amps, and keep an eye on the meter.

Jay.

Well, I've been having a bit of bad luck lately - got in the car today to try to initiate the starting procedure after I've drained the tank, hoses, changed filters, etc... turned the key and.... the engine turned over twice (just barely) and then it would not turn over again... the battery is dead. My leaving the key in the ingnition for several hours must have drained it - and the battery is an original one too so it may not have been the strongest.

I removed it from the car (just in case), placed it outside, removed the caps and set the charger on a slow 2A recharge overnight - hopefully I can bring it back.

Here is the puzzler: since I have another Benz I thought: why not hook up the battery from my 300D to start my SDL - I started my 300, hooked up the jumper cables to the SLD, I revved it up so the RPM stayed higher and tried to start the SDL.... same d&^n thing: it would only turn over once or twice and that's it!!! Why is that? My 300D has a strong fresh battery - does the SDL require a much bigger battery than that to turn over? I was surprised and confused at that - what's up?

Attaching the photo I forgot to attach in my original post.

Sometimes you're limited by the capacity of the jumper cables; if the battery is dead all the current has to pass through those cables.

Do you know the year of that battery?

That battery looks just like mine, and mine is not even 3 years old.....I highly doubt it is the "original" battery.....it is an OEM battery, but not the one that came with the car.

Yours may be several years old, in which case it might be at its end....

Yeah, the cables sure got warm in just few cranks... I just checked - there is no indication what year the battery is - it's not on top or on any of the side labels...

I didn't see any indication in the receipts when the battery was replaced, it's either original or the receipt was not kept - though the records appear to be in good order on the car.

At any rate - I hope that I can recharge it overnight and then some and it will work tomorrow. If not, I probably would like to get an Interstate battery, if I can find one. If not - probably another Group 49 battery (1000 CCA)?!

My parts car has a pretty new Interstate Battery in it, the biggest one. Its for sale, but I don't think it'd be cost effective shipping it to CO. :eek:

BTW - what is a hydrometer - and what does it measure?! Water to acid ratio in each cell!? Maybe it would be worth it for me to try to 'cook' the battery before I junk it - hate to discard a battery that looks practically brand new.

Hydrometer
 

"A hydrometer is a device for measuring the specific gravity of a liquid relative to water, which is assumed to have a specific gravity of 1.00000."

With the correct liquid level in the battery,it may take more than overnight @ 2 Amps.

'Had a set of Marine outboard batteries that some one had let sit all winter,hooked up, in the boat...Tested BAD... 72 hours later @ 2 Amps
they LOAD tested GOOD and the Specific Gravity tested O.K. Too.
(I'm assured their Lifespan was substantially shortened as a result of the Total Disharge.)

Hi
I just bought a Group 49 MAXX battery from Wal-Mart for $75. Interstate is also good - my last one lasted 7 years. As you likely know, the little paper round code stickers that they date batteries with - the first letter is the month and the number is the last didgit of the year.
Joseph

It's not uncommon for group 49 batteries to have the caps on the cells. Being sealed however doesn't mean you won't get spillage from a charge.

I took out and charged my sealed group 49 Die Hard two nights ago and noticed last night that it was sitting in a huge puddle of battery acid. I wiped it up with an old towel (that will soon dissolve into lint). The epoxy garage floor is now very clean in that spot now.

As for jumping with cables, you only get a partial connection through the jumper cables. To really work well, you need to clamp on cables from battery to battery, which isn't very practicable.

So you hooked up a battery from another car to just empty battery cables? I don't think that is good, as the battery needs to absorb ripple from the alternator. Even if you had a shorted cell or something, it is important for the battery to be there.

Sounds like you didnt have a good connection. It takes a LOT of 12V current to start a diesel...

Getting a new one would be the last resort, but in preparation: where could I most likely find Interstate (AutoZone, Napa, Advanced Auto Parts)?

Regarding the sticker... no, I did not know that coding technique - I'll need to check the battery cover again.

A battery hydrometer, then, measures the level of charge on a cell.
Measure the value on each cell and record in your notebook.
If the cells readings are way off, it might be easier just to get a new battery.
If they are spot on or real close, the battery will probably take a charge.
You can also buy a container of battery acid and equalize the cells specific gravity if you feel experimental - after all, if you've got a hydrometer, you have the tools.
All cells should be topped off to puckering with distilled water when you're done. Any addition of water will alter SG.
A trickle charge will deep-charge the battery and is the best kind of charge. Also, deep charges don't tend to shorten battery life.

Some questions regarding taking measurements (Need to purchase the hydrometer later today):
1) Do I then take out some liquid out of each cell to measure SG of each cell in the hydrometer, or do I just dip it in each cell?

2) Am I looking for any specific value with each measurement, or just simply making sure they are about even across all cells and adjusting the low readings by adding battery acid and topping off with distilled water?

thx

As the jumper cables warmed, their resistance went up, which is probably why the engine only turned over a few times then stopped. There's usually a very thick coating of insulation on cheap jumper cable wires, I presume to make the user think they are getting their money's worth. If they felt warm through all that insulation, the wire inside was probably quite hot and well into a higher resistance zone.

FYI even "sealed" car batteries are vented, else they'd explode. I've seen one case where they just recessed ordinary cell caps and put a sticker over them to hide it.

I see - I'm just not used to seeing them, but that makes sense - if I thought about it it's basic chemistry and physics...

When jumping, connecting the cables to both sets of terminals causes some of the power to go into the dead battery. Connecting the negative cable from the good battery to the chassis ground on the bad car is supposed to divert the full current to the starter. That's why they recommend that procedure.

I'm not really sure what connecting a set of cables to an empty set of terminals would do - if that's really what you were doing.

I tried it both ways with identical results: first, I hooked jumper cables positive to positive terminal on the dead battery and negative to the chassis - where the neg. battery terminal connects to the body. Turned the starter - went 1.5 revolutions and stopped.

Then upon removing the battery I hooked it up directly to the open terminals on the battery-less car. Same results - not enough power to crank it.

Was thinking about and realized two things: 1) The car was pretty cold since it's been sitting in a cold for several days and 2) I have not yet changed the oil on it since I just purchased it and I think the PO was using /50 weight diesel oil (for whatever reason), so it's pretty thick....

Today while recharging the battery I've also hooked up the block heater for several hours. It's toasty warm now - just checked it.

Should be reinstalling the hopefully fresh battery now and giving it another try in about an hour - so keep your wrenches crossed for me... hehe

I reinstalled the fully charged battery into the car tonight - it recharged fully with no trouble in about 24 hrs. I topped off each of the 6 chambers with distilled water. Placed the battery in the freshly finished battery tray... said a little prayer, then glowed and cranked.... it started in less then one revolution - yippie yahoo yeah!!!

Checking the voltage on the battery - it looks like it was holding steady at 12.96V with the car off and about 13.3-13.6V with the car idling... The Voltmeter was jumping around a lot, so I'm going to check the voltage regulater on the back of the alternator - see how those brushes look. But I think we're done here.

Thanks all for seeing me through this. Now on to other challenges... :)

12.96 is indicative of a "surface charge", which is not a true voltage. Full-charge OCV is roughly 12.65-12.72V.

Nothing wrong with getting a reading of 12.96V, just mentioning that long-term after a tiny load, or just sitting, don't be suprised if you see more in the range that I mention - which is true "full charge".

13.3-13.6 is what I was getting at the readout from my cigarette-lighter voltmeter. Seems a bit low for my liking, but it is consistent with my car, so I think you're OK. I would prefer a regulator that provides ~14-14.2V when cold (the regulator will decrease voltage with temperature amongst other things). Keep in mind that lead acid batteries start to gas around 2.37V/cell, or 14.22V/battery. Some chemistries are doped to modify that slightly.

Glad to hear it worked out.

The connect-and-start method works on smaller gas engines, but last time I jumped my diesel (from a smaller charging system) I found precisely what I expected -- that there wasn't enough current capacity from the Jeep through the cables to the Benz to crank it immediately. The trick is to sit there running the charging vehicle, connected with jumper cables terminal to terminal on the dead battery, for fifteen or twenty minutes, sometimes with slightly elevated RPM.

After you do that, you've essentially used the jumping vehicle as a "battery charger" for twenty minutes. Then, the dead Benz battery should have enough current to help the support vehicle pick up the rest of the slack and spin the thing over just enough to start it, if you're lucky. That's how I did it last time I drained mine, which was a 25 degree day last winter. Jumped it from a 600 or 700 CCA Jeep system by letting it charge fifteen minutes before attempting the start (after demonstrating that it wouldn't work instantly).

Food for thought. Probably old knowledge to most. Just because it doesn't crank immediately when you connect the cables doesn't mean you can't charge the dead system with the running good system for a little while and then try again.

X2 Jumper cables for these and other diesels need to be made from some good welding cable I use 2/0 and attach it to heavy clamps . walmarts might work on a gasser but wont cut it on these. heres a good link for some cables http://www.peachparts.com/shopforum/diesel-discussion/265969-bmw-battery-cable-battery-relocation.html