IXLR8

That one only goes to 200 mA DC whereas some will have a 10 A DC setting and an extra input. It would be easy to blow the fuse. Normally if you are unsure of what you are measuring, you always start at the highest setting. Unfortunately, if you had a dome light on while trying to measure current, the internal fuse in your meter blew.

mgianzero

So what you are saying is I probably blew the internal fuse to this meter? If so, is it replaceable?

I bought Greenlee because I thought it was a reliable brand, no?

Where should I buy a meter that measures what I need for this purpose?

I like to buy local (Home Depot, Lowes) for electrical equipment should I have a problem with it.

IXLR8

In every meter I have, yes.

The fuse rating is noted in the meter manual.

You can get this one at Wal-Mart for under $15.

mgianzero

Okay, I opened up my multimeter and found the fuse. To test it, I removed it and did a continuity test with the SAME multimeter and, voila! ... It's blown. So I must have blown it in the past somehow.

If I replace this fuse, this multimeter should work to measure a drain on my Porsche, no? A normal drain is less than 50 mamps. Correct?

Thanks for all your help Alex.

IXLR8

Yes, provided nothing else comes on such as interior lights, etc.

Don't open the driver's door even if the front hood compartment latch is latched closed to keep that light off. Opening the door will turn it on.

mgianzero

Okay Alex. I went to my favorite electronics store and replaced the fuse in my multimeter. Brought it home and measured my drain current, which came to 24.5 mamps. So I guess I'm okay. As a test, I put on the interior light and the drain went to 82.5 mamps. I also measured 13.9-14.0V from the battery with car running. So I take it my system is good.

I also opened my battery and checked the water levels. They were all pretty reasonable. Although maybe one or two cells was a little low. The way I was taught is you want just enough water to create a meniscus in each cell. Did I do this right? Just added a little distilled water and put it back on the trickle charger.

So I think my battery, although it charges fully, is perhaps on its last leg and should be replaced.

I'm having a tough time finding an East Penn (Deka) 648MF battery to replace it with. Those batteries don't seem to be so popular on the west coast of US. But I can easily find another Interstate MP-91 battery. So I think I'll just go with that. Your thoughts?

IXLR8

Spot on and what I measured with my alarm off.

A tad low, but so is mine at 14.1-14.2V.

I used a cheap plastic vernier caliper and use the depth probe to set my "max" fluid level in the battery. The battery case is hard to see through, so I just use the max indication on the case of the battery to set the caliper.

I'm sure the other brand is fine. Install a permanent voltmeter in the car. One of the better improvements you can make.

mgianzero

Well, as Alex helped me determine, my battery at 7 years was shot. Wouldn't hold a charge more than 1-2 days and then couldn't start the car.

I researched the East Penn Manufacturing who made an exact replacement for our 993's and I discovered that they are making our battery under the name of Duracell (SLI48H6). So I bought a SLI-48H6M since I wanted to stick with a lead-acid (AGM batteries are a bit more expensive) and the SLI-48H6M has even more CCA and CA than the standard replacement at 730 CCA and 895 CA and only weighted a 1/2 pound more than the SLI48H6. Found one at Batteries Plus for $135.

Here's now a question for our engineers (Alex, I hope you read this):
when I went to pick up the battery I asked for a hydrometer so I can closely monitor all cells on this battery. Several guys told me "do NOT open this battery" as it is not made to be opened. They insisted that I do NOT use a hydrometer on this batter. I asked why as this is NOT the AGM version of this battery but rather a standard wet-cell lead acid battery. They still told me that I should not open it. Alex, I thought you told me it's always good to check the water level and even test the individual cells if I wanted. So what's the correct way of caring for these types of batteries?

IXLR8

If is is a Flooded Lead Acid battery, they can be topped up with distilled water when necessary. Those caps can be opened by using a quarter or thin large washer that fits well into the slots in the caps.

You won't be able to see the level through the black case which is why you'll have to measure the level once the caps are removed.

What did the battery voltage measure when you picked it up?


I'll have to remember their advice so that I can get more than 14 years, and still going, out of my batteries.

mgianzero

Alex,

Thanks for reading and responding to my thread.

I insisted they charge and load test my battery. They said "okay" but it seemed to me that it wasn't the norm, which I was surprised.

They measured voltage at 12.9Volts (I recall) and load tested on their handheld tester (took about 1 minute) and it showed it passed, which they showed me on the screen. Is that adequate?

Once again, when I walked out with the additional purchase of a hydrometer they said they'd sell it to me but told me once again NOT to use it on this battery. I said it's for another battery (white lie) but I thought they we're just not understanding the basis of wet acid (standard lead acid) technology. I confirmed with them that this is NOT an AGM battery and they agreed. So what are they thinking?

mgianzero

Alex,

Since you highly recommended as East Penn (Deka) battery, I went with the Duracell SLI48H6M since this was their best group 48 lead-acid battery made by Deka and it's a drop-in replacement battery (see pics above). I agree with your comments that an AGM battery limits the ability to service your battery since ALL lead-acid batteries lose a bit of water over time. So I went with the conventional wet-cell over the AGM.

But they didn't sell a cap for the positive post. I always like keeping this post covered somewhat since I always worry about something shorting against it. The older cap that I took off my Interstate just doesn't fit right. Do you cover your positive post on your battery and, if so, what do you use?

Marc G.

IXLR8

Marc, with the 14 years (presently) in my daily driver battery and 16+ years in my mom's last car, I don't see the point to spending more money unless I am going to get more life out of the battery. I doubt a specialty battery at twice the price will get me 28 or 32 years.


If your battery looks like this, it appears to have two small holes to accept a cover at each terminal. They appear to be identical to those on my East Penn battery. See if you can get a pair from East Penn or a local battery shop...they may have used batteries that they can take the covers off of.

Note though that my East Penn battery did not come with covers either and neither did the factory Porsche Moll-Kamina battery that was in my 993 when I got it (unless someone lost them).

Unless you have loose metallic objects floating around in your luggage compartment, with the carpet atop the battery, what can short circuit?

I have a Battery Mat under my battery and placed a Battery Mat on top of my battery to neutralize any acid misting, just in case.

mgianzero

Yes, I called East Penn and they confirmed that the Duracell was indeed their brand battery and they said that they do NOT sell a positive post cover for it. So I will not use one. I guess I'm old school and used to the ones that came from Interstate and Duralast that had them. Oh well!