volts problem

[dodge28]

Hard starting problem with 6 volt system can be resolved  by using two batteries side by side if you have the space, or if you can create the space.

AMAZON  has on sale gadgets  that you can wire up the 2 batteries  for starting. When started it will switch back to one battery for normal running.

[Larry Schramm]

50 minutes ago, dodge28 said:

Hard starting problem with 6 volt system can be resolved  by using two batteries side by side if you have the space, or if you can create the space.

AMAZON  has on sale gadgets  that you can wire up the 2 batteries  for starting. When started it will switch back to one battery for normal running.

 

If you are having a problem starting a 6 volt car with a 6 volt starter with a 6 volt battery there are three things that could be wrong. 

 

The first one is to be sure the battery is good and charged up. 

 

Provided you have a good starter then the problem is corroded failing battery cables, bad connection on each end of the cables, or someone put 12 volt cables which are smaller than 6 volt cables. 

 

I would start by getting new cables probably at lease 00 size or larger.  Welding cable works well.  Clean all connections & contact points and then try to start the car.  Cables are usually the number one problem on 6 volt cars having difficulty starting. 

 

Just my experience. 

Edited December 29, 2022 by Larry Schramm (see edit history)

[alsancle]

There are dozens of threads on the forum on this problem.

 

issue 1:  bad ground

 

isdue 2: 12 volt cables 

[edinmass]

Tens of millions of cars started on a single 6 volt battery without any issues.  Fix the car. 

[Swear57]

Been there done that. Bad ground, 6-volt cables had the green growing inside. Replaced with correct cables. The car has never started so good.

 

 

Jim

[dodge28]

Hi Larry, you are right. I have no problem starting my 28 DB. I made the battery cables with 2 zero welding cable. It is a little overkill but so what ? The engine is tuned up. generator works fine and battery is 95 % charged. I ordered a 8 volt diode at 1.2 forward voltage to install inside the cutout housing just to prevent accidental feedback to battery.

The reason I wrote that article is I see constant griping about setbacks of 6 volt systems. I see people selling cars "upgraded to 12 volts". Why ? 12 volts wired vehicles carries  a voltage regulator to maintain an 8 volts charge to the instruments gauges. Am I correct on that ? So, for example, if I should go for a 12 volt system I will have to replace all the bulbs,rewire the starter motor and charging system. What will happen to the gauges ?  How to deal with that ? I think I will be looking for more problem than I could solve.  JUST A THOUGHT. 

[Larry Schramm]

3 hours ago, dodge28 said:

Hi Larry, you are right. I have no problem starting my 28 DB. I made the battery cables with 2 zero welding cable. It is a little overkill but so what ? The engine is tuned up. generator works fine and battery is 95 % charged. I ordered a 8 volt diode at 1.2 forward voltage to install inside the cutout housing just to prevent accidental feedback to battery.

The reason I wrote that article is I see constant griping about setbacks of 6 volt systems. I see people selling cars "upgraded to 12 volts". Why ? 12 volts wired vehicles carries  a voltage regulator to maintain an 8 volts charge to the instruments gauges. Am I correct on that ? So, for example, if I should go for a 12 volt system I will have to replace all the bulbs,rewire the starter motor and charging system. What will happen to the gauges ?  How to deal with that ? I think I will be looking for more problem than I could solve.  JUST A THOUGHT. 

 

See Ed's note above.  I agree, just fix the car.  Anything else you end up with a Frankencar.

[Hans1]

On my vehicles the battery is grounded to frame rail, next to battery.

The path for ground current next goes in the frame rail then  thru rivits to left rear frame mount for engine support.

The Engine rear support plate attached to engine is insulated from frame mounting by rubber insulator.

Only the bolts holding engine are grounding conductors.

Therefor there is a  very imperfect current path, that with age gets worse. 

////////////////////////////////

I have cleaned connectors, ground attachment for battery and bolts.

 

BUT I ALSO USE A SUPPLIMENTAL 5 FOOT LONG CABLE TO CONNECT THE BATTERY GROUND CABLE TO STARTER MOUNTING BOLT. This supplements the frame path.

THIS IS A DEFINATE IMPROVEMENT IN ELECTRICAL TRANSMISSION.

 

///////////////////////////

Several friends now realize that rivited frame connections are their BIG problem. They now are using  additional wireing to by pass the frame connection issues.

 

 

[Frank DuVal]

Right. Over 80 years two pieces of steel riveted together could have rust forming between them and the rivet. Hard to remove the rivet, clean all surfaces back to bright steel and install a new rivet (proper repair). Easier to run another cable around this issue, and much better than other band-aid repairs (8 volt, 12 volt, etc.)

[Larry Schramm]

On one of my vehicles I bolted the ground cable from the battery directly to one of the bolts  that hold the starter in place.  The ground can not get any closer to the starter than that.  Just make sure the surfaces are clean.

[jdome]

If you have room for 2 - 6v batteries in your tray/box, your battery is too small. Doesn't matter if its a brand new battery, fully charged or what the useless "cold cranking amps" rating is. Just as important as having 6v cables larger diameter than 12v cables to handle the higher current demand of long, slow 6v cranking, you also need larger battery cells, plates and internal post connections to supply the higher, longer current draw and more importantly; dissipate the internal heat it will create.  The more you crank on these dinky modern 6v batteries the higher the internal heat it creates. As the internal heat of a battery goes up, so does the internal resistance which causes voltage drop and rapid discharge. Battery manufacturers should spec the "hot cranking amps" of 6v batteries so we can determine how they will function in our old cars. Buy the biggest damn 6v battery you can find that will fit your tray. There is no substitute for big battery plates except maybe 2 - 6v batteries in simple fixed parallel connection that will divide the current demand between the 2 batteries. Much better solution than some hokey 6/12 gadget made in a communist country and sold on of all places, Amazon.

[Steven G]

Path to ground is critical. After canles and connectors have been sorted out GRIND chassis connection point to "white" metal cover area with dielectric grease and make connection. 

[Gary W]

I ran ground cables to a central chassis "hub" and directly to the starter.  It's worth the extra effort to be sure your lights are bright, the starter spins effortlessly and you eliminate a lot of those pesky electrical gremlins.  

In my '37 Buick, I used 2  2-0 cables off the battery (-) to ground.  Then a large 4-0 cable from the positive terminal to the starter.

 

Here's a hand written schematic of my starter circuit.  

From the "frame ground" hub, I ran separate ground wires to the fuel sender at the tank, the accessory fuel pump, the tail lamps.

Up front, I grounded the headlamp sockets, fender lamps, fog lamps, dash...

 

All my separate ground wires are 12g wrapped in period correct conduit, soldered ends.

 

 

In the car, the optima sits snugly at an angle in the box.  You can see the double ground wires off the (-) post.

 

 

One cable bolts to clean metal "hub" (above the chassis) and the separate ground wires feed off that bolt to their destinations.

 

 

The second ground cable is attached to the starter, and another braided ground strap runs from that bolt over to the frame.

 

Heavy cables, clean connections, good grounds, strong battery...  You're 6V system should work as originally designed.

[dodge28]

Gary, good job .  Just for clarity, switches for 12/24 combinations are nothing new and may be inventors have come up with 6/12 conversions as well. Some folks are just technically savvy. In 1986 Hino trucks with diesel engines has such system. Starts on 24 vols and the switches back to 12 volts. I worked on these. I am an old truck mechanic Happy new year.