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Opeler
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Discussion Starter · #1 ·
What is the best battery to use in a GT?
Understand size constraints...have a 100Amp charger but old cheap battery now...any advice...thanks
 

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boomerang opeler
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5,636 Posts
hi glenn my owners book says 44 amp hour for the battery size but a bigger A/H one that will fit he battery box would be ok
 

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Old Opeler
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New!

One of the new "Gell" batteries that have no liquid sulphuric acid in them are a good choice for a GT as then the poor old battery tray will not get eaten away to the same extent - they are a "must" if relocating the battery inside the GT. IMHO
 

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My basic rule of thumb is to put in the largest battery that will fit the box. On a GT with AC it gets to be a pain, gotta jack up the front of the car to get the battery out of the hole in the belly pan. But with a large amp-hour battery you only have to do it every 5-6 years. HTH.
 

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Opeler
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Discussion Starter · #7 ·
Thanks for the feedback...going to go for the largest possible...Interstate looks good...Gel type too expensive for my budget and need someone to try and fit...not easy locally..thanks again
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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651 Posts
Thanks for the feedback...going to go for the largest possible...Interstate looks good...Gel type too expensive for my budget and need someone to try and fit...not easy locally..thanks again
I just replaced my Battery today and while the Optima Yellow top was interesting I felt it was too expensive, and the reviews were mixed, so based on that and other threads I went for an Interstate battery, maintaince free, MT-35 2 year replacement with 5 year total coverage-last three years are prorated, see picture below.. While OGTS told me that a 26R is now the recommended size I just went with measurements in hand and ended up with the the above mentioned battery measuring 9 inches long, 6 3/4 wide and 8 inches tall - the 26R is somewhat smaller. See pictures for more details. Price was 134.90 with trade in. Compared to 300.00 for the yellow top.
Additional I replaced the alternator with a stock rebuild, from OGTS as I wanted to be sure that it fit properly and felt good knowing that they have someone that has rebuilt a lot of these and knows what they are doing, however, according to Gil, the stock 70 GT had or has a stock 28 AMP anternator and GT's years were rated at 35 amp alternator - so I have been up graded to the more powerful alternative. I did not go for the 55 amp as I don't intend to add a lot of power hungry accessories and also wanted to keep it simple, like the original amp warning light to still function, that is based on what I have read. So I also replaced the voltage regulator wiring harness so, I should be in good shape. Can't wait until I have finished this project to see how it starts compared to before. It is exciting to think that this will make a major difference as like the replacement of the master cylinder and the newer larger big brake booster - such a pleasure to actuall have brakes that really work and feel like a modern car. Also glad to report that this battery comes with a carring handle which means I was able to install it myself, without the handle it would have been a little dfficule tl control
And I think that is part of the attraction of the upgrades that we go through, the physical feeling and the feeling of accomplishment that always comes with a big improvement and a job well done. On to the next thing/project. I will follow up regarding the results of the replacement of both battery and alternator at the same time. Both while not totally shot were showing their age - similar to many of us I think. Never think about it until I walk infront of a mirror. Anyway, Cheers.
430663
 

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Detritus Maximus
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Interstates always seemed to be pretty good. I had one that I ran for years that was a hand me down.

What kind of headlights are you running? I switched to halogens around the time I rewired the headlights and I already had one the euro alternators Gil used to sell that was of higher output (I don't remember what amperage).
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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651 Posts
Running the old fashion round headlight that was the only choice for most of my life time. Last time I checked the lights they were really dim but don't remember what it was like when I first started it up when I thought I was done with the restoration, never dirven it at night in the past 30 or so years, so will be curious to see if the battery upgrade and the new alternator takes care of that dim bulb problem, if not then I have yet another problem to over come - but not ready to start that conversation yet and when I do, much to the delight of the powers that be, I will simply pick up a related post/thread and go for it....Hoping that this new amp/power boost will take care of not only the hard starting issue but the dim lights as well. Will keep you posted. As always many thanks to all of those that have helped me, figure it out. Without this forum it would be a whole different, more difficult, process. Also a lot of those thanks go to Gil Wesson for taking the time to explain it in layman terms in the event a part does not automatically cure the issue - sort of like practicing medician they call it practicing medician for a reason - it is not cut and dry,,,,Cheers, Carl
 

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Detritus Maximus
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The halogens were simple Sylvania sealed beam replacements, not the separate halogen bulb in a bulb type.

They did make a significant improvement over the old type sealed beams.
 

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Well this may be heresy, but I got my battery at WalMart. I have a '71 GT, essentially stock without A/C and with all stock electrics. When I bought the battery four years ago, all I was looking for was enough cranking power to get the car started after sitting for two decades in some guy's garage. I figured when the time came, I would get a more appropriate battery. The time seemed to arrive about a year ago, once I got the vehicle on the highway. So I went looking. Turned out that my WalMart Value Power 26R (the battery size specified for the car) has the same cold cranking power (540 amps) as NAPA's Legend, and 90 more amps than NAPA's Power line. The $55 price tag compared favorably to the $140 number for the Legend and $109 for the NAPA Power.

Autozone's Duralast offers 575 CCA, but costs $145, while its cheaper batteries are still more expensive and only give 510 CCA. Interstate Battery will sell you their mid-range 26R offering 550 CCA for $137. Apparently the 75 BCI also fits. It is a bigger battery that offers more power and also costs more across the board, with WalMart's product again is cheaper but I could not find any specifications form comparison purposes other than price.
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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I looked at the Wal Mart battery however the only one availabe was a one year warrantee - just personal preference - looking for something with more backing, however with that said if you purchased the 1 year battery and it is still going strong after 4 years then I would say you did really well.
 

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Not that anything on my car should be considered normal.

The first battery I bought was the Duralast. It really never got used but I tried to charge it occasionally but it died of old age and had nothing to do with use. So next time I bought the Walmart one and it starts the car a lot but only gets charged when I put it on the charger. It is still going after three years.
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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651 Posts
Actually the last battery, prior to the new one I installed today, that I purchased, was in Kernersville, NC. There was a place on RT. 66 just off I40 that sold blemished batteries, what ever that means. The store was called Southern States Battery and I made several purchases there over the years. I never knew the brand but my last battery lasted 15 years and cost about $65.00 came with a 70 month guarantee. Those were the days. Hopefully I will have the same kind of luck with this last purchase. Batteries have pretty much become a commodity purchase wtih built in obsolesence. Remember the old days getting a battery with an 84 month warrantee, not now. I looked at the Optima but with only a 3 year warranty and a cost of 300.00 just did not make sense to me. If it came with a ten year warranty then OK but companies these days just don't seem interested in backing there product. Everything is disposable, just buy another one. Don't get me started, I could go on and on.....
 

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Detritus Maximus
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I've got an Ellis battery in my '08 GT. Ellis also has 'blem's. They said one definition for their blems is that they were in a store/on a shelf for a year without selling. So they brand them blemished and sell them cheaper with a shorter warranty. Since I had two old batteries to turn in (they buy scrap batteries as well, I think $10 each by weight), I walked out with a 'new' battery for under $40. That was two years ago, no issues. I figure if I get 3-4 years out of it, it was worth it. On the other hand, when the battery in my 90 Safari van crapped out a couple years ago, I ended up shelling out $140+ at Autozone.

On my old Opel GTs, I always got the biggest battery I could physically fit between the radiator support and the front of the hood opening. That was usually a group 24 from a Ford. Those were usually the hand me downs from my parents 60's Thunderbirds or the 76 Caprice. Pretty big batteries.
 
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