battery replacement

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james m. houston
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battery replacement

#1 Post by james m. houston » Thu Jun 15, 2017 10:03 pm

what is best battery, 12 v,
to put into my recently restored 61 T5.

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Jonathan Halpern
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Tag: 1964 356C built 7/16/63 1987 911 Carrera
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Re: battery replacement

#2 Post by Jonathan Halpern » Fri Jun 16, 2017 8:13 am

Optima Red top is the usual choice. I use them in my cars.

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David Jones
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Re: battery replacement

#3 Post by David Jones » Fri Jun 16, 2017 10:07 am

You may want to consider an Odyssey battery if you need a 12 volt. Cheaper than Optima which has been known to have some QC issues and supposedly more power, and may fit you battery location better than an Optima. Nothing against Optima, I have a 6 volt one in one of my cars.
If I had known I would live this long I would have pushed the envelope a little harder.
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James Learmonth
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Re: battery replacement

#4 Post by James Learmonth » Fri Jun 16, 2017 12:58 pm

I have used the Optima Red Top 12v for over 4 years and it has been a battery all this time. Every now and then I have to look to see if it is still there. Caution, be sure that you have a voltage regulator that also regulates current. More than 25 amps and you will be in the market for new generators. Joe Leoni put me wise to this problem while I still had a 6v system and had a series of generator failures after switching to an Optima battery.

Jim Learmonth
Houston, TX

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David Jones
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Re: battery replacement

#5 Post by David Jones » Fri Jun 16, 2017 1:40 pm

Jim, I have to ask. If the generator failed because it was generating excess current, why was it generating excess current? Were you driving with all the lights on with H4 bulbs and a tube radio or was the battery very low so the generator was trying to charge it up. Logic tells me it was one of those two things unless there is another reason i have completely overlooked.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
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James Learmonth
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Re: battery replacement

#6 Post by James Learmonth » Fri Jun 16, 2017 5:07 pm

David,
According to what I've read and been told by Joe Leoni, when the Optima battery is low (20-30% off fully charged) it will demand very high amperage to regain its fully charged state. While I was saving money not buying a battery tender to keep the charge up I never hesitated to use all the lights and radio (H4's and tubes). On a trip to Arizona at night I flipped on the wipers and there goes the gen. A couple years and about 4 generators later I met Joe Leoni in Sedona, AZ while on a quest for yet another generator. Joe had a generator and adjusted My regulator's current limiter to 23 Amps. Joe not only provided the hardware, he helped me install it and spent the time explaining what had happened.
So if you let your battery self discharge by ignoring it for a long period you will want to use a charger/maintainer to top it up. The Optima is said to self discharge about 10% from fully charged in one year. Now that I drive my car pretty regularly I'm not too worried but still hook it to the maintainer periodically. I also have LED lights all around and transistor radio.

Jim

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Dave Wildrick
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Re: battery replacement

#7 Post by Dave Wildrick » Fri Jun 16, 2017 5:30 pm

Part of the problem is that for years, both Jim and I were using the small silver 6V regulator that was standard on late 1965 C coupes. If I recall correctly, this regulator will let up to 40 amps pass if the generator is working hard enough to produce that, and the armature will throw solder.
The big black 6V regulator can be set to limit generator output to the electrical system to about 23 amps, which is what Joe Leoni recommended and is what he set the big black regulator at when I switched to that about 5 years ago. I believe Jim may have also done the same before he converted his coupe to 12V.
I don't believe you can adjust the current that passes through the currently available brand new 12V regulators for the 356.
So, if you are using one of these (or the old small silver 6V regulator), it would be wise to not have all your lights and accessories running at night when your battery is low, because the generator may try to deliver sufficient wattage to keep up with the demand and thus destroy itself.
Dave Wildrick
Houston, TX
#10230
64C coupe
65C coupe

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Craig Richter
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Re: battery replacement

#8 Post by Craig Richter » Fri Jun 16, 2017 5:42 pm

Speedy is on its third 12v Optima since they first came out about 20 years ago. Just replaced the second one a few weeks ago, so the service life has actually been completely acceptable. What seems to have ended their already elderly life is letting them go completely flat. No type of charger can bring them back to life after that. Unfortunately for my batteries, we live in Austria a large part of each year and I'm too lazy to hook up the tender. Not a problem when they're new, but time catches up with everything.
I also noticed the newest Optimas are slightly smaller than before and fit great.
 

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PaulLima
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Re: battery replacement

#9 Post by PaulLima » Fri Jun 16, 2017 6:48 pm

My experience with several Optima batteries is that if it is good for one year, it will probably be good for many more. But several have failed in less than one year. I'm now an Odyssey fan.

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David Jones
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Re: battery replacement

#10 Post by David Jones » Fri Jun 16, 2017 7:09 pm

I guess I am lucky in having an early "C" actually Jan 64 build and I have a spare 6 volt black regulator. I also keep my cars on battery maintainers. I never know when I will drive them again after a run so I always plug them in. I have a pigtail attached to B+ and ground and I leave the engine lid up which reminds me to check the oil before I drive when I unplug the maintainer. I just wish I could remember to turn the fuel off every time. For some reason that escapes me constantly.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

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