Rich Janouskovec Posted December 23, 2009 Share Posted December 23, 2009 Is there any advantage to using an 8 volt battery for starting an old 6 volt system? Also wouldn't it be too hard on your generator and voltage regulator.it seems to me that the charging system would be working harder if not all the time. Link to comment Share on other sites More sharing options...
F&J Posted December 23, 2009 Share Posted December 23, 2009 I have heard many oldtimers talking about them for decades. Common discussion was their use on 50s Chryslers and also farm tractors like the Ford N.My son just inherited an N with a 8volt.No it won't hurt the charging system. Those old regulators are adjustable as far as voltage. Just a slight tweak will keep an 8volt charged up. The windings on 6v systems is heavier than 12v, so it won't burn up.A 6v system actually charges at over 7 to 7.5 volts..Reason for using an 8 is that it spins faster, but also allows better voltage to the coil when cranking. Some vehicles just don't want to start well when it is very cold and the coil voltage drops to below 5v when cranking. These 8v's really work wonders.Now some will say that a 6v is fine and if you need an 8v, you have a problem. But I have seen some cars that really improve with an 8. Link to comment Share on other sites More sharing options...
Steve Braverman Posted December 23, 2009 Share Posted December 23, 2009 Get a 6V Optima Battery instead. It's worth every penny. Link to comment Share on other sites More sharing options...
DavidAU Posted December 23, 2009 Share Posted December 23, 2009 8 volts is really tough on 6V light bulbsDavid Link to comment Share on other sites More sharing options...
Guest DeSoto Frank Posted December 23, 2009 Share Posted December 23, 2009 8-volt batteries are a quick "band-aid" for other problems with the vehicle.If your starter / generator / regulator / wiring are in good order, a six-volt vehicle should start fine on six-volts.Search this site on the topic, you'll find lots of discourse.I've been DRIVING six-volt vehicles (mostly flathead MoPars) since I got my license, over 25 years ago, and have never had to resort to an 8-volt battery or 12-volt conversion. Link to comment Share on other sites More sharing options...
MCHinson Posted December 23, 2009 Share Posted December 23, 2009 Rich,The short answer is No. There is no need for an 8 volt battery. If you think you need an 8 volt battery, you need to check all of the wiring and find the problem. Good clean connections and replacement of any defective wires or components will allow a 6 volt system to work like it was originally designed to work. Use of an 8 volt battery is simply a "band-aid" approach to attempt to patch a problem without having to actually figure out what the problem is. Link to comment Share on other sites More sharing options...
Guest kencary Posted December 23, 2009 Share Posted December 23, 2009 Get a 6V Optima Battery instead. It's worth every penny.I have an Optima red top 6V on my '51 Pontiac Straight 8 along with a high torque starter. I also have VERY heavy guage wire running from the battery to the starter. With 6V you can't afford resistive losses. In fact the first thing I would do is to upgrade and replace both battery cables with ones as heavy as you can find. Ensure that the clamps are very tight on the battery terminals.In most cases, my Pontiac starts in less then 2 seconds even after sitting for a few days. This is a rebuilt motor with a milled head and she cranks just fine. In fact it starts faster than most of my modern cars.My headlights run rather dim at idle and I'd like to upgrade the generator to an aftermarket one at some point. I want to keep it stock looking so I don't want to go to a 6V alternator even though that is the best solution.Ken Link to comment Share on other sites More sharing options...
Rusty_OToole Posted December 23, 2009 Share Posted December 23, 2009 An 8 volt battery will give a little more oomph for starting and brighter lights. It will not hurt anything but may shorten light bulb life.Adjust the voltage reg to 9.6 and away you go.I do agree with the other posters that if your electrical system is in top shape you don't need 8 volts and that it is better to fix any defects than to cover them up with an 8 volt battery. But if you insist, now you know how to do it. Link to comment Share on other sites More sharing options...
Steve Braverman Posted December 23, 2009 Share Posted December 23, 2009 I never had any problem with starting or lighting, but the Optima makes the car crank faster, the lights a little brighter, and the generator even charges a little more. I've had the battery in my Franklin for three years, and have never had to charge it. Link to comment Share on other sites More sharing options...
MCHinson Posted December 23, 2009 Share Posted December 23, 2009 I should have mentioned this one as well....A common problem in 6 volt cars heppens when someone has installed aftermarket battery cables that are designed for 12 volt systems. If you have those instead of the correct heavier 6 volt battery cables, you will often have problems. That would need to be one of the potential problems to check for in diagnosing the problem. Link to comment Share on other sites More sharing options...
West Peterson Posted December 23, 2009 Share Posted December 23, 2009 00 gauge battery cable. More costly, but it works. I'll just agree with the others that if "your house is in order," you don't need the 8 volts. Clean all your connections. Link to comment Share on other sites More sharing options...
Rich Janouskovec Posted December 23, 2009 Author Share Posted December 23, 2009 Thanks for all the input guys I'll check the size of the battery cables but I'm pretty sure they are the heavier ones. I just thought a little more umph wouldn't hurt. Thanks again Rich Link to comment Share on other sites More sharing options...
Guest CaptainGTX Posted December 23, 2009 Share Posted December 23, 2009 Guess I'm one of those old-timers, cause I ran an 8-volt battery in my 53 Dodge hemi back in the 60's. On the upside it sure made the starter spin over faster. On the downside - well - I was leaving my night job about 1am one night when on the outskirts of town I revved up the car to pass another vehicle and blew every single light bulb in my car. It was a moonless night & all I could do is drop behind the other car & follow his lights. When I turned off the highway on the last leg home, all I had was the light of my flashlight to find my way. I would have liked to see the look on the face of the guy I was passing when he saw my car disappear.I'm with the other guys who say stick with the 6-volt if at all possible. That's what I'm going to do with my "new" 53 Dodge Red Ram convertible. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted December 23, 2009 Share Posted December 23, 2009 One of the reasons they went to 12 volts in the first place, was that 6 volts was marginal for starting the new high compression V8s. If anyone has a reason to need more juice it would be the owner of a 1949-55 high compression V8. Link to comment Share on other sites More sharing options...
F&J Posted December 23, 2009 Share Posted December 23, 2009 One of the reasons they went to 12 volts in the first place, was that 6 volts was marginal for starting the new high compression V8s. If anyone has a reason to need more juice it would be the owner of a 1949-55 high compression V8.exactly That's why I wrote in post number 2, that some will say you are just masking a problemI got used to people "generalizing" an issue on all car sites. You just can't make the statement that NO 6 volt vehicle EVER needs an 8v. That would be saying that every single make and model that had a 6v system were all designed exactly the same, and the loads placed on any of these systems would be exactly the same.Most people have never even thought about doing a coil voltage test during cranking, on a hard starting 6v car. That severe drop in voltage to the coil in many cases, is why a car won't start. Take 12v coil/points systems for example. The car designers made a circuit that bypassed the ceramic resistor for the coil on those cars while the car was cranking. The car did not need the available 13.5 to 14.2 (when running)volts to run, but it did need the most voltage available while starting/cranking. Once the car starts, now the coil is fed through the resistor to extend point life.What I am trying to say is that on a marginal design like the big Mopar engines that would crank real slowly on fridgid temps and 30w oil, is that the slow cranking car would start fine if a charged-up 6v "second" battery was just feeding the coil. No one would bother to do that, but you can do it as a test on the next problem car you work on. It does work.Coil voltage drop during cranking is the real issue on 6v systems. Link to comment Share on other sites More sharing options...
Guest kencary Posted December 24, 2009 Share Posted December 24, 2009 exactly That's why I wrote in post number 2, that some will say you are just masking a problemI got used to people "generalizing" an issue on all car sites. You just can't make the statement that NO 6 volt vehicle EVER needs an 8v. That would be saying that every single make and model that had a 6v system were all designed exactly the same, and the loads placed on any of these systems would be exactly the same.Most people have never even thought about doing a coil voltage test during cranking, on a hard starting 6v car. That severe drop in voltage to the coil in many cases, is why a car won't start. Take 12v coil/points systems for example. The car designers made a circuit that bypassed the ceramic resistor for the coil on those cars while the car was cranking. The car did not need the available 13.5 to 14.2 (when running)volts to run, but it did need the most voltage available while starting/cranking. Once the car starts, now the coil is fed through the resistor to extend point life.What I am trying to say is that on a marginal design like the big Mopar engines that would crank real slowly on fridgid temps and 30w oil, is that the slow cranking car would start fine if a charged-up 6v "second" battery was just feeding the coil. No one would bother to do that, but you can do it as a test on the next problem car you work on. It does work.Coil voltage drop during cranking is the real issue on 6v systems.Does someone make an aftermarket coil with more voltage output for 6V systems? There seems to be a market for this.Too bad nobody makes a CD sustem for 6V. That would certainly help and also extend point life. The CD unit would be easy to hide to keep the stock look. Link to comment Share on other sites More sharing options...
F&J Posted December 24, 2009 Share Posted December 24, 2009 (edited) I have no idea on a hot coil for 6v. Worth checking into.I forgot to mention a hard starting 6v truck I worked on for a guy.... with a tired motor and a tired starter. That truck would sometimes finally start "after" you were cranking...as you let go of the key, the coil finally got more volts because the starter was now not drawing, and that last final rotation of the motor...the darn thing would fire up. edit: years ago, Bosch did make a hot coil, I just can't recall if it came in 6v as well as 12v...but I think it did. It was referred to as a "blue coil" It was blue and if I recall, I think it was slightly larger than a standard Bosch black coil. Edited December 24, 2009 by F&J adding (see edit history) Link to comment Share on other sites More sharing options...
Guest cben09 Posted December 24, 2009 Share Posted December 24, 2009 While looking at the electrics,,,Get out the compresson tester,,,low compresson will leak past the valves to a greater percentage at lower cranking speeds,,,,a valve grind may do wonders,,,,been there done that,,,Cheers,,Ben Link to comment Share on other sites More sharing options...
Guest simplyconnected Posted December 24, 2009 Share Posted December 24, 2009 If in doubt, ask yourself, 'What system did the OEM's use'? If your car was a Ford, up to and including 1955, your system was a six-volt. MILLIONS of Fords ran ok with that charging system. Ford NEVER sold an eight volt battery at a dealership. Ford never had their logo on an eight volt battery, either.So, what's the use for 8-volt batteries? They were used to start race cars, then they were disconnected. The next idea was, 'Hey! If racers use it, I must need one for my car.'Wrong. How much voltage do you need to CHARGE an eight volt battery??? (Hint... it's over eight volts, or the battery will be eternally UNDERcharged.)If your charging system was designed for six volts, either stick with it, or change it to a twelve-volt system. The operative word is SYSTEM, not component. If you want 8-volts, then change everything including generator, battery, regulator, relays, horns, light bulbs, motors and gauges to eight-volt.If you adjusted your six volt regulator to charge an eight volt battery, you better be doing a constant 50-mph +, because your generator needs very high RPM's to make power at that kind of voltage. - Dave Link to comment Share on other sites More sharing options...
Steve Braverman Posted December 24, 2009 Share Posted December 24, 2009 I believe 8 volt batteries were used in old industrial equipment, like fork lifts and such. Link to comment Share on other sites More sharing options...
rons49 Posted December 28, 2009 Share Posted December 28, 2009 Check your cables, use 00 gauge cable, especially on 49 and newer GM cars with 6v use proper ground strap. Do not use little green wheel type batt kill switches.They can only pass 250amps,Big GM starters pull @ 325amps. Use an Optima if you can afford it. keep it charged. if you try an 8v battery you will need to adjust your regulator to 9-9.5 v or you will drain the batt every trip. If you have an electric fuel pump you will probably burn out a 6v motor on 8v. And the radio will possibly say good night as well. Link to comment Share on other sites More sharing options...
Vila Posted December 28, 2009 Share Posted December 28, 2009 (edited) Also check all the grounding points; battery to chassis, chassis to engine, etc.I'm a fan of the 8 volt battery. The same one has been in my 1933 Chevrolet for over 12 years and I have never had to recharge it or keep a Battery Tender on it over the winter. I can park the car in October after the Hershey car show and go out in April and it will start right up . The original 943J Generator with a generator cutout is putting out 8.1 volts with the car at cruising speed so the cars electrical parts would be seeing 8 volts anyways. I have never had to "Tweek" anything on this car.No extra battery switches either, and I have not changed a bulb in 10 years either. The original Delco 714L starters on early Chevrolets were always slow cranking from new on 6 volts.In any case, I would call it personal preference after you have looked into all other issues that could cause slow cranking.Bob BeersAACA, VCCA, VTR, TRA, CPTC1933 Chevrolet1962 Triumph TR41984 BMW 633 CSi Edited December 28, 2009 by Vila Added name and corrected Gen # (see edit history) Link to comment Share on other sites More sharing options...
Guest Gotta Posted February 9, 2012 Share Posted February 9, 2012 I have an Optima red top 6V on my '51 Pontiac Straight 8 along with a high torque starter. I also have VERY heavy guage wire running from the battery to the starter. With 6V you can't afford resistive losses. In fact the first thing I would do is to upgrade and replace both battery cables with ones as heavy as you can find. Ensure that the clamps are very tight on the battery terminals.In most cases, my Pontiac starts in less then 2 seconds even after sitting for a few days. This is a rebuilt motor with a milled head and she cranks just fine. In fact it starts faster than most of my modern cars.My headlights run rather dim at idle and I'd like to upgrade the generator to an aftermarket one at some point. I want to keep it stock looking so I don't want to go to a 6V alternator even though that is the best solution.KenAll generators are capable of charging 100 volts, it is the regulator that controls the current that the generator delivers to your battery.Gotta Link to comment Share on other sites More sharing options...
rons49 Posted February 9, 2012 Share Posted February 9, 2012 Is it true that 00 battery cables are now disignated 2/0 or are they two different sizes? Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted February 10, 2012 Share Posted February 10, 2012 Same thing . Ben Link to comment Share on other sites More sharing options...
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