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1800 Cold-Cranking Amps from (2) Optima 6-Volt Batteries (39 LaSalle)

Started by Fred #23106, January 24, 2007, 11:31:24 PM

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Fred #23106

I previously installed an 8-volt battery to try for faster cranking and better starting for my 1939 LaSalle Convertible. While the 8-volt battery worked well, there were other problems that I had not anticipated, in addition to having to recalibrate the voltage regulator. For one, Doug cautioned that I should not connect the radio to the 8-volt battery (I did not). Another was that the gauges (since they work on resistance) did not give accurate readings. I dont know about the accessory 6-volt fuel pump, clock or lights, but feel that their life would be shortened.

I first installed a heavy-duty 6-volt battery (600 cold-cranking amps) and it worked fairly well, but not with the power that I was hoping for. Accordingly, I bought two (2) 6-volt Optima batteries that took up the same space (side-by-side) as the above 6-volt and 8-volt batteries.  I connected these in parallel, so the voltage remained at 6-volts. However the cold cranking amperage increased from 600 to 1800!!  There was no modification of the battery box - everything fit nicely under the drivers side front floorboard.

I have large color photos of the installtion, along with detailed instructions that can be seen at my web site:   http://www.fzoldcars.com TARGET=_blank>www.fzoldcars.com     Click on "Technical Stuff" at top of page to get to the section on the hookup of these 2 batteries.

Fred

JIM CLC # 15000


Bruce Reynolds # 18992

Gday Fred,

Yes, looks good, and as it works, even better.

With all that cranking power available, you could nearly attach a couple of fans to help propel the car along, saving petrol.

Bruce,
The Tassie Devil(le),
60 CDV

Doug Houston

FRED! For crying out loud, why dont you get a vacuum cleaner, instead of sweeping the crap under the rug???  

The car didnt need two batteries in parallel when it was new, and it doesnt need them now, if youd only put the fool thing into proper condition. I just installed a grounding stud and a SINGLE Optima battery on my 41 convertible, and it starts like a demon.

Hows come, OK for me, and no OK for you? Simple. The starter has had new bushings insralled a few years ago. The armature hasnt had the iron it butchered in a lathe; the brushes are good, and even before the grounding stud was on it, it yanked over that engine like new.

Ive harped on this for 40 years or so, nand I sill get the same old sob story about how sluggish the starter is, when, if somebodyd only do what needs to be done, the car would start like new. Is it such a monumental job to take out the starter and replace the bushings, lubricate it, and now, to install a grounding stud on it? Youd think I was recommending removal of the body or the engine. The starter on my 41 convertible sedan runs as fast as if it had 12 volts on it, and I havent put a grounding stud on it yet!

Your installation is beautiful, and very unnecessary. Not wrong, understand, but unnecessary. One Optima is all youd need,

Doug Houston...again

One item more. A few years ago, I was  working on my 41-60S, and didnt have a group 2 battery on hand, so I swiped the battery (Group 1 size) from my 41 Chevy. The starter still spun the engine over like a champ.

Now, whattya gotta say about that??!!

Fred #23106

Thanks for the info Doug,

Can you tell me exactly how and where to connect each end of the starter ground strap and size of strap and where it can be purchased?  My starter is brand new and always quickly started the car, but I wanted to do something unusual and functional, as I do not like an old car to be hard-starting (or even slow starting) at any time - winter or summer.

If you recall, I tried (for a short time) an 8-volt battery (with radio disconnected at the time) and loved the way it cranked the engine. At your suggestion, agreed that 6-volts was the way to go and I am glad that I went back to 6-volts. The battery cables on my car are as original and very heavy (not the type used today on the 12-volt cars) and I plan to soon recheck and sand/tighten all ground connections, as well as a grounding strap on the starter per your suggestion.

However, will say that the 2 Optima Red-Top Batteries fit into the existing battery box better than one and that the difference is cranking the engine is substantial. With better grounding, it can only get better.

Whats wrong with a little "overkill" once in awhile? Thats the way I do things and it helps that I was able to buy the batteries at cost, since my sons company sells the batteries.

You must admit that my solution is far better than the 6-volt/12-volt battery setup that some use, and also will be easier on the starter. My car now starts exactly like my new HHR (in an instant) and while it always started with the previous new 6-volt Group 1 battery, it was not the same.

In my opinion, the Group 1 battery (used in 1939)is not quite enough for the Cadillac engine. Why did Cadillac go to a Group 2 battery in 1941 and later to 12-volts? There must have been a reason.  When it comes to a battery, I always want the best, regardless of cost.  There is nothing more discouraging than to have a beautiful antique car that is slow starting.

Doug - didnt you ever do something to improve things, even though not necessary?  I wanted to see the difference and wanted to see if I could do an installation without any modifications to the battery box, floorboards, or metal cover and I did just that. I put a lot of thought into this to be sure it would do what I was expecting, and it did. Thanks for looking at the pictures and for your comments, which (as usual) are quite correct. In conclusion, want to say that I agree with you, but wanted to do even better.

Fred

JIM CLC # 15000

01-25-07
Fred, I also considered puting in two 6 Volt batteries ( wired in Parallel) except I was thinking of useing the Wet Cell Batteries. The one I have in the car now has been good, I use a
"kill-switch" with it and it seems to increase the life. I also like to try to improve things that I work on. IAM a frustrated inventer, If you know what I mean. I have cleaned the starter on my car and put in new battery cables. Fred, Put in new cables,where they corrode, you can not see and it takes new cables to get full voteage to the starter.
HTH
Good Luck,JIM

Doug houston

I cant dispute your feelings. If you get a warm, fuzzy feeling over what youre doing, there cant be any wrong in it. I personally dont subscribe to the idea that "If enough is good; too much is better". Heck, if youre gonna put 4 optimas in oarallel, go for it!  At least, you sobered up about using 8 Volt or 6-12 Volt batteries!!

My feelings are that if the proper things are done to put the car in as-built condition, and have it operate as it did originally, Ive gotten what I wanted. If you have to have the starter crank the engine like a new car, for Gods sake, drive a new car! As it is, youd be astounded at how fast those starters will yank over a Cadillac engine, when everything is done up right.  

The Cadillac engine was as up to date as an engine could be. It was good enough to propel medium tanks during WWII, and was one of the most envied engines in its day. Its power, quietude and smoothness cost more, because you could have it in only a Cadillac or a LaSalle. And LaSalle had the reputation of a fast car, and a marvel for highway travel. Actually, so was a Cadillac, but a LaSalle was a Cadillac at a lower price (Thats the big reason that LaSalle was dropped).

To me, the challenge is to have the car operational as new. Too many opinions say that those engines are doggy, and that they never were easy starters. I, and many others have disproven that many times. As Ive already said, the car needs only one battery to start easily and properly. And again, if you like more current capacity, you have the right way to do it. But the down side to connecting two batteries in parallel is that no two are ever totally equal in characteristic. So, when at rest, some current, regardless of how small, flows from the battery with the higher charge to the other. Ultimately, youll  have one battery low, and the other charged. You can never have two perfectly identical batteries. The nice thing about Optimas is that they self-discharge slower than conventional lead-acxid batteries, and they have high cranking capacity for their size. Theyre more or less made for us. I have three of them.

Now, on the topic of batteries. Cadillac always used a 17 plate battery in their V8 cars. More displacement plus higher compression = more battery. The battery type in the thirties was 17K, if I recall correctly. Today, its known as they 2 group size. Chevrolet, Plymouth, and several others used a type 15AA battery (15 plate), and known today as Group 1. I could, (and probably will) put an optima in my 41 Chevy, but youd never get a group 2 battery in it!

The fact that our cars sit unused for several months of the year  means that the faces of the starter get a bit of corrosion between them. This means resistance. With the added resistance between parts of the starter motor, and the attaching face to the bell housing, you  need only lose half to one Volt, and the starter hardly cranks the engine at all. The loss of one Volt in a 12 Volt system is insignificant, so you may never know it. So, thats why Im a Heller on installing the ground stud on the commutator end plate of the sterter. Corrosion be damned, the battery is always grounded right to where the brushes meet ground. That will never deteriorate with storage, or even slop thrown up from the road onto the starter. They did it on my 41 Oldsmobile, but why  Cadillac, Packard, or even Duesenberg didnt  do it is beyond me!    

Now quickly, on the topic of battery cables, use welding cable, and battery clamp terminals are sold in several places. I sweat solder the terminals, cover with heat shrink tubing, and you have as good a battery cable as you ever could have had.

POB

I know this post is 10 years old.....

I have recently (last week) purchased a 1939 LaSalle Coupe that was completely restored a few years back.  The owner had passed away and I bought the vechile from his daughter that did not have much information to give me about the electronic "workings" of the coupe.  (The wiring looks completely redone.... and done well, but not all the electronics work (clock, radio, speedometer..,)  Currently I'm having and issue with the battery.  It's not holding a charge. It's a specialty battery that was built in California by a company last June.  It's a lead acid 6 volt with 4 terminals.  I was told that it was two 6 volt batters in parellell to start the vehicle with 12 volts, but then to step down and run all electronics on 6 volts. I just purchased one Optima battery from Amazon to replace the exsisting battery. (One side of the lead acid battery is dead so I figured to start new instead of messing with the old battery)

Question:
Do I need 2 6volt Optima battery's in parellel to match the set up of the existing battery, or can I just hook up one 6 volt considering it has 800 cold cranking amps?

....I don't know the CCA of the battery already installed in the 39

Thanks for any advice

-Patrick
Patrick O'Brien
thepatrickobrienemail addresses not permitted

1939 LaSalle Coupe

dochawk

Quote from: Doug houston on January 26, 2007, 01:41:42 PM

But the down side to connecting two batteries in parallel is that no two are ever totally equal in characteristic. So, when at rest, some current, regardless of how small, flows from the battery with the higher charge to the other. Ultimately, youll  have one battery low, and the other charged. You can never have two perfectly identical batteries.


This is the critical part.

With two batteries sitting connected in parallel, there *will* be a flow at all times.  And it may well change directions as the charge levels vary.

You would need a way to make sure that only one battery is in circuit except when starting.  Which probably means a way to switch back and forth as to which one is in circuit and charging or supplying extra juice at any given moment.  And a smooth way to switch.  (maybe a gizmo that triggers on start, using both, and then toggles which one is in circuit?)

hawk
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

POB

I get what your saying Hawk but how is it that Golf carts (for example) connect many batteries in parallel without any electrical issues?  I don't think they have a switch.  I really don't know but I found this on the internet....

If you connect two same specification batteries in series, you actually double the voltage supply but the capacity (Ah) remains the same.
If you connect them in parallel, the capacity is doubled whereas the voltage supply is that of one of the individual batteries.

Thanks for replying, owning a old car for me is brand new and any info helps!!
Patrick O'Brien
thepatrickobrienemail addresses not permitted

1939 LaSalle Coupe

Glen

Quote from: POB on April 15, 2017, 11:52:27 PM
I get what your saying Hawk but how is it that Golf carts (for example) connect many batteries in parallel without any electrical issues?  I don't think they have a switch. 

All the golf carts I worked on the batteries were in series.   The total battery voltage on those golf carts was 36 volts. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

TJ Hopland

That 4 terminal 6/12 thing sounds interesting but I can see some extra complexity and variables when it comes to making it work.  Does the whole system turn to 12v during cranking?   So this 'switch' has to change the configuration between series and parallel?   In concept this is easy but to do this at say 1000 amps even for fairly short periods presents some challenges, so many that I would think it would just be a lot more practical and reliable to just convert to 12v or get the 6v working properly.

If you choose the 1800 amp option like in the start of this thread how does the generator and regulator deal with the possible extra load?  I know from experience if you do manage to drain an optima they try to suck all the power they can get and then some.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Scott Anderson CLC#26068

Quote from: POB on April 14, 2017, 10:06:27 PM
I know this post is 10 years old.....

I have recently (last week) purchased a 1939 LaSalle Coupe that was completely restored a few years back.  The owner had passed away and I bought the vechile from his daughter that did not have much information to give me about the electronic "workings" of the coupe.  (The wiring looks completely redone.... and done well, but not all the electronics work (clock, radio, speedometer..,)  Currently I'm having and issue with the battery.  It's not holding a charge. It's a specialty battery that was built in California by a company last June.  It's a lead acid 6 volt with 4 terminals.  I was told that it was two 6 volt batters in parellell to start the vehicle with 12 volts, but then to step down and run all electronics on 6 volts. I just purchased one Optima battery from Amazon to replace the exsisting battery. (One side of the lead acid battery is dead so I figured to start new instead of messing with the old battery)

Question:
Do I need 2 6volt Optima battery's in parellel to match the set up of the existing battery, or can I just hook up one 6 volt considering it has 800 cold cranking amps?

....I don't know the CCA of the battery already installed in the 39

Thanks for any advice

-Patrick

Believe this page lists the product you have:
http://antiqueautobattery.com/accessories.html

I replaced one standard Optima in a repro Delco case battery from them that was about 10 years old and not maintained by the previous owner (charging / desulphating cycle, corrosion removal) with another and it's starts just fine with bright front turn/running lights too. At the same time I went through all connections and cleaned them up  with great results in the end. POB I'd suggest you do this first. Depending on the car things may benefit from some cleaning up in that way.

The grounding stud on the end of the starter sounds great and is on my 'some day ' list. POB while you're at it. Say can anyone repost the SS article here on how to do it for him?

I read with great interest Fred's post on his restoration some years ago and frankly if my car had the hidden battery compartment I would have done it long ago just for a 'belt AND suspenders' approach as I do when I am able...
1941 Cadillac 6267X Convertible Coupe
2014 Cadillac CTS-V Coupe

POB



Thanks Scott, I will go through and try and clean all the connecting points.  I attached a picture of my battery in my 39 LaSalle along with the double 6 volt optima idea I found on www.fzoldcars.com
Patrick O'Brien
thepatrickobrienemail addresses not permitted

1939 LaSalle Coupe

Bill Ingler #7799

Here is a picture of the ground attached to the starter. If you do not want to directly attach the ground to the starter, then attach the ground cable to one of the studs holding the starter to the housing as in picture 2. Using 00 welding cable for battery cables, proper grounds to engine and above all cleaning all grounding connections especially where the starter is bolted to the housing.This should give you all the power needed to the starter using only one Optima battery.  Bill


Caddy Wizard

Jay Friedman and I are big proponents of the auxiliary ground strap on the starter.  Yes, it really does help.  Here is what it looks like on one I did recently...
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

Jay Friedman

I would follow the advice from Bill, Scott, Doug Houston and others about clean ground connections, thick cables etc., as well as a grounding stud at the end of the starter.  A 6 volt Cadillac can be made to start well on its original battery system.

Art Gardner and I were the authors of the Self Starter article describing in detail how to install a grounding stud on the "commutator end plate", which in plain English is the end of the starter that doesn't go into the engine.  It's not a particularly lengthy or technically difficult job; the hardest part is lifting the heavy starter motor in and out of the car.  Once the starter is on the bench it's a 30-45 minute job, though unless you have a stock of nuts and bolts at home you will probably have to spend some time at a hardware store buying those you'll need.  I'm out of town until April 26, after which I can email a copy of the article to you.  Send me an email at jaysfriedman@yahoo.com and I'll send you the the article by reply email. 

Jay
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

Bob Schuman

I have become a firm believer in the addition of the grounding stud on the commutator plate of six volt Cadillacs. My 41 came to me with two six volt Optima batteries in parallel, 2/0 cables, all connections clean and bright, but would crank very slowly when hot, not a way to feel confident it would start. I installed the grounding stud described in Art and Jay's article, and replaced the master electrical disconnect switch with a heavier duty similar switch rated for 175 amps but otherwise looks identical(available at NAPA stores). The switch gained me 0.2 volts when cranking. Now the car starts easily hot or cold, which I attribute almost entirely to the grounding stud.
A much easier modification that may give equally good improvement does not require starter removal or disassembly. Remove the outboard bolt through the starter, weld a 3/8" hex head bolt to the head of the through-bolt, reinstall the bolt in the starter, and then connect the added ground strap from the starter mounting bolt to the new stud. This is what I did on my 49 and 51 Cadillacs. Admittedly, they started well before this modification, it was just for added peace of mind. All three of my cars have two six volt Optimas, and charging or discharging has been no problem. A car can sit for months without a battery maintainer, and will start easily, so current flow from one battery to the other, as mentioned by other persons, does not seem to be an issue.
Bob Schuman
Bob Schuman, CLC#254
2017 CT6-unsatisfactory (repurchased by GM)
2023 XT5

POB

All the info is greatly appreciated.... Once my batteries get here and I can install them, I will defiantly add some sort of grounding strap/straps.  If everyone who has replied says grounding straps make a world of difference on starting it has to a positive improvement!!!
Patrick O'Brien
thepatrickobrienemail addresses not permitted

1939 LaSalle Coupe