8 volt battery

[Alan O'Connell]

Is it ok to use an 8 volt battery in a 55 T-Bird and if so can anyone give me the size battery that will fit in the battery box without having to modify the box?

[Ole Don]

To use an 8 volt battery, two things need to line up. One, you must adjust the voltage regulator to push 9.5 volts. Two, its best to live near a battery builder. Take in the measurements of the battery you have, and hope they have someone around old enough to know this was once SOP. I was in one such shop when I was about 17, and it was done while I watched another customer get his 8 volt done. I'm 75 now, so the guys who did this may not have passed down the knowledge.

[dmsfrr]

What problems are you having that make you want to change?
As Don mentioned, an 8v battery that fits may be hard to find.
In some places even finding the usual 6v batteries is difficult. A tractor or industrial supply shop may be a good place to look if your battery needs replacement.

The 6v systems can usually be made to function quite well with some general maint and repairs.
All six ends of the battery & starter cables must be clean and tight. Including the cable end on the starter, that's not quite as easy to get to.
Those battery and starter cables (all three of them) should be the larger "0" (zero) gauge version, not the smaller more commonly found 2 or 4 gauge... the size of your thumb, not your little finger. The smaller ones can't carry the current needed for the starter.
The other end of the battery 'ground' cable should be fastened to the head or engine block. In your '55 is it the '+' or '-' battery cable?
Don't forget to check and clean the ground wire between the engine and car body, and all the connections on the generator & voltage regulator.
Clean connections and the proper sized cables can take care of most problems.

Here's a link to a good 6v to 12v conversion info page...
https://www.ctci.org/gilsgarage/6to12.php
.

[56markII]

8 volt batteries are easy to find at most battery supply places and are the same size as the one in my 1950 Mercury Sedan. Setting your regulator for an 8 volt battery isn't that difficult as long as you have a very accurate multimeter and do it correctly BUT
it pushes the hell out of your headlights, tail lights, radio and like dmsfrr mentioned check your cables. 8 volt batteries are easier to find than 6 volt head lights
I turfed the 8 volt after having a difficult time finding a battery maintainer and my battery got ruined from sitting dead. I bought a 780 CCA battery from a local farm and hardware store that is the exact size as what is used in my Mercury and BTW the 8 volt was the same exact dimensions as the 6 but had 4 caps instead of 3.
This is how I diagnose poor starting problems:
First of all we want to test how well your charging system is. You should have 7.1 volts and actually mine is charging at 7.5 which is a bit high but my new battery is not sweating or gassing or getting hot so I leave it alone. A sick battery is often wet on top with water sitting around the vents due to excessive gassing such as a sulfated battery. A friend of mine lent me a battery that was sitting dead for many months and being on a trickle charger for over a week brought it barely to life and even sitting not in use the top is always wet. I yanked it out due to carrying a 12 volt and booster cables in the trunk. We will most certainly not flog this dead horse anymore!!! My God the car came to life with the new battery with all cables good with the charging system very good (why would I convert it to 12 volts and open another can of worms) and I also knew everything was good except the battery
Also your charging system might have the correct voltage with everything OFF but can it handle the radio, headlights, heater blower motor (in cooler weather) all turned on at the same time or have the current to charge a battery fast after starting? The generator has a current regulator as well and this 35-40 amps might be low. Voltage regulators are usually quite reliable but they are controlled by a relay working against a spring. The tighter the spring, the higher the voltage and current. I have found these springs relax with time and sometimes need a tweak. If your current is a bit weak take a peek at your generator at the brushes to see if they are arcing quite a bit due to excessively worn brushes not being able to contact properly with the commutator bars. Gently pushing your regulator relay top arm with your finger tip to increase the spring tension momentarily will also give you clues if your generator is a bit under the weather as well. The voltage and or current will jump depending on whether it's the current, or voltage regulator relay when you do this to IF the generator can supply the demand if your regulator needs to be repaired or tweaked.
On the other hand a sweating boiling battery might be good but is being over charged such as constantly in the high 7's or low to mid 8's. Keep one thing in mind here, voltage regulators are temperature compensating and will always charge at a higher voltage when cold and as their temperature rises as they operate or the temperature outside rises they lower the voltage using bimetallic springs in the relays and when I set these regulators I always carefully place the cover back on not causing a short WHILE using a FULLY CHARGED GOOD battery, and place your engine on a slightly high idle as well so the generator can properly charge. Also another thing I failed to mention in this long story is if your voltage is slightly too low such as below 7 volts the battery will always be in a state of undercharged and will eventually deteriorate and become sulfated. A long slow low current charge will usually correct this if this is the case. The hotter the climate such as Arizona and Nevada, slightly lower voltages are required whereas the colder, slightly higher so your location and climate becomes a bit of a factor.
The current regulator is tested by placing a slight constant load on the battery with a carbon pile or all accessories on (providing they draw enough) with an accurate ammeter in series with the output of your generator or a clamp on inductive amp prob and the generator should be limited to 35-40 amps or your brushes wont't last but at the same time should be capable of supplying this current or the voltage will also be too low.
Your cables MUST be heavier like dmsfrr mentioned and what I do is I use the voltage drop method to test. PLACE one test lead DIRECTLY on your battery post, and the other on your cable terminal of the same post with your multimeter set to a low voltage. Next crank your engine with the ignition wire disconnected and read the voltage. There should be VERY LITTLE voltage, the lower the better. The heavier and better the connection the lower the voltage to the point of being a fractional voltage. If you have higher than normal, this indicates resistance causing your starter to struggle and a cable that is too light such as a flimsy cable meant for a 12 volt application or a corroded connection will show a higher than normal voltage. Don't stop there! Keep that same test lead on the battery post, and move the other test lead down to the next terminal or connection including both sides of the starter solenoid. If you have a poor solenoid IE burned contacts, and or cable ends yes you will have a voltage reading higher than normal. Keep going all the way down to the starter terminal. Do this for both cables positive and negative and your voltage should be very low doing this test. This test is for the condition of ALL of your cables and connections.
Okay your generator/charging system is good, your cables are good, but your starter is dragging it's ass, lets do another voltage drop test to see if the starter or battery is roached. Crank the starter again and see how low the voltage drops. If it really plunges, test the battery and by testing it, again make sure it is fully charged and place a carbon pile or load tester on it and see if this battery can do it's job. If your battery is very good but the voltage still drops quite hard your starter is probably drawing excessive voltage due to worn dry bushings causing the armature to drag, or a shorted armature or field windings.
On the other hand if the voltage barely drops but the starter still drags your brushes are possibly worn and cannot transfer enough power to the armature. A current draw test on the starter is also a good idea but if you cant get your hands on a load tester capable of doing this you have to improvise and get around this another way such as process of elimination IE ^^^^ (raise eyeballs)
Using a good meter which usually doesn't cost much and performing these easy tests usually prevents you from just throwing parts at your ride and needlessly throwing your money away.

Don
PS
Check your belt to see if it is loose This should be step number one

[Alaska Jim]

8 volt batteries are for people who have an electrical problem and want a patch. 6 volt and 12 volt systems both work well if all wiring is of the correct size, all grounds are clean, and tight, and there is no corrosion. of course the starter and the gen/alt. must also be in proper working order

[Ole Don]

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Keep in mind, the factory installed star washer was between the block and the cable, not under the head of the bolt. This to cut through paint and in to metal.

[56markII]

And that is where mine is as well with a flat washer against the lug of the cable on top so the bolt doesn't dig into the lug. Braided ground straps are hard to come by up here so I do this to protect it including spraying this cable with clear coat to keep it looking like new without corrosion. I missed out on a NOS Ford braided cable on ePay a while ago so a repop will have to do for now. Help your starter and appearance and throw one of these under the hood.
Under normal routine maintenance if my starter gets a bit tired I disassemble it, replace bushings but if they are still good I just lubricate them, turn the commutator bars, and solder in new brushes. Often the brushes don't look that bad but it is amazing how much new brushes help. I even have an armature lathe that I got years ago from a garage that closed down years ago. I'm almost 56 and this lathe is a bit older than I am but it is very good quality and works very well complete with an electric motor to turn the armature instead of those stupid hand crank lathes that Snapon sells.

[Daves55Sedan]

Originally Posted by Alaska Jim

8 volt batteries are for people who have an electrical problem and want a patch. 6 volt and 12 volt systems both work well if all wiring is of the correct size, all grounds are clean, and tight, and there is no corrosion. of course the starter and the gen/alt. must also be in proper working order

I'll second that. I ran this '55 Ford 60 miles or more a day for over 40 years and the 6-volt electrical system never had any problems that couldn't easily be solved with routine maintenance. The worst thing I ever had to do is replace these cheap chain-store batteries every few years as they do not last long. In all that time, I replaced generator brushes once, but that is childs play.

[19Fordy]

Alan, you would be better off and happier getting your 6 volt system repaired correctly.

[fjz]

I agree with all said. I have been thinking of going with 8 volt for my 48. Like the result of faster cranking and brighter lites. I have an issue with my cranking. Acts as if my battery is dead which is not the case. Battery is new and has been load tested by supplier. Starter has been checked out by a local rebuilder. All connections have been polished. About the only things left is no star washer under the ground and ground cable is not as heavy as the others but I tried using my booster cables as an extra ground and no difference. Not sure where I can locate a heavy red ground wire. I think my issue may be as my engine has been rebuilt and not driven it may be a little tight hence going 8 volt may be the solution. Can I charge 8 volt with a 6 volt battery charge?

[dmsfrr]

Originally Posted by fjz

..... ground cable is not as heavy as the others but I tried using my booster cables as an extra ground and no difference.

.....Can I charge 8 volt with a 6 volt battery charge?

All the battery and starter cables should be the larger "0" (zero) gauge version (about the diameter of your thumb) a "1" gauge cable could work, but not the smaller 2 or 4 gauge ones.
If any one cable or connection isn't as good as the rest it defeats the current flow of the circuit.
It's a 'weakest link' thing.
Adding on the extra jumper cable ground was a good try but it may not be where the problem is.
Double check the power cable connection on the starter. If it isn't clean and the nut isn't tight it will act up. I've seen several that had been loose and arced to the bolt/stud threads. Damaging the threads so the nut seemed tight but the cable lug was still loose.
The starter bushings or brushes may be worn out and need replacing? But you said it was checked out.

6v charger for an 8v battery?
I wouldn't expect it to charge the battery fully, and might overheat the charger.

.

[40 Deluxe]

Should not need an 8 volt battery! When your '48 was brand new it was started and driven out of the factory on 6 volts. If it was built in the winter, it sat in a cold storage yard until started and driven onto a transport. At the dealer it also started on 6 volts for the new owner.
A full service parts store or tractor/equipment dealer should be able to custom make a proper 6 volt ground cable. Do a starter draw test on the car under real world conditions. It may have spun fine with no load at the rebuilder's but still drag on the car. I don't recall how many amps it should draw but post the results; someone will know. Do a voltage drop test while cranking-the solenoid may have high resistance, or a cable connection that looks good may not be. Also read battery voltage while cranking. Again, what seems to test good on the bench may fail in the real world. Make sure your generator is putting out about 7.2 volts at the battery so the battery stays charged. If you go to an 8 volt battery, you will have to adjust your regulator to put out 9.6 volts at the battery. Will your lights, radio, instruments and ignition be happy with this much voltage?