overdrive solenoid question

[Doc Dave]

For my PW, I have the stock 6 volt system.
I installed a Dennan overdrive, which has a 12 volt solenoid to activate it. Problem is I can't get the solenoid to work with 6 volts, even though others have been able to do so with less than 12 volts.
I checked the solenoid and can hear a click when I apply 12 volts across it, but with 6 volts, no.
Any suggestions?
I know I can hide a motorcycle battery by a frame rail and use that to power it, but would prefer to find an easier solution.
Mr Dennis Gronan, the person that sells them, said he thought 6 volts would work, but be slower to activate. He said at first it might take several miles to activate it. I drove it for a mile or two and it did not cut in.
He said they don't make a 6 volt solenoid that fits in the overdrive.
Suggestions?

[maineSS]

You might be in danger of frying a 12V solenoid when applying 6V- amperage will double across the winding for an equivalent load. You may want to double voltage electronically using a "voltage doubler" circuit. I don't know if there's a commercially available product that will fill your need- you have to find out the solenoid draw in watts. There are converters for running gauges, don't know if these would handle your solenoid. The circuit can be made up if necessary out of diodes and capacitors- Google "Voltage Multipliers" for explanations of how they work. This is how Image Intensifiers used in Starlight Scopes get 30,000 volts out of a 1.5V battery.

[Gordon Maney]

You might not like my idea, but how do you feel about converting to 12 volts? It can be done pretty unobtrusively, and if you are adding an overdrive, you have parted company with originality. That is not criticism, it is just to offer some perspective on what would be the easiest solution to this particular problem.

[Doc Dave]

Logically, I think you are correct Gordon. I guess I would like to hang on to some originality however, at least for now. One thing I like about the overdrive is that it can be removed in less than a few hours if desired.
I bought it 3 or 4 years ago and it has been inside a garage. I only tried to use it a few days ago for the first time.
I talked to Mac (Texas) on the phone today and his 8 volt system powers the Dennan overdrive very well. He wondered if the solenoid is sticking some and preventing activation. I may see about removing it and bench testing it.

Maine, I Googled voltage multiplier and saw that many of the headings were for an AC to DC set up, but I did see some DC doubler notations. That is a consideration if I can't solve the problem. Do you know a source for these things are does on have to make on up on a circuit board?

[Charles Talbert]

Powering with lower than spec voltage is a killer

Fellows, attempting to power any component with lower voltage than spec is not a good idea and will cause issues with a burned out component prematurely at best. It just doesn't work. Maine SS already explained why this is true in a previous post, so I won't get back into that. Gordon has the best answer to this issue; convert the entire system to 12 volts, then forget about it and enjoy a good long lasting result.

[Doc Dave]

Thank you all for the comments. I will keep them in my memory bank if I have problems in the future with the voltage difference.
I did want to note that I figured out the immediate problem I was having. After a call to Dennis Gronan (who sells the o.d. units), he asked about the grounding situation. The overdrive is mounted to its cross members that he supplies in the kit with GM style rubber mounts.
I took great pains to ground the truck well during the resto, with a seperate ground strap from the engine to the frame, cab to frame, bed to frame and fuel tank to frame. The one thing I did not think about was the overdrive.
So, yesterday I ran a seperate wire from the ground lug of the solenoid to the frame and took the truck out.
Success! I really like the overdrive, it is more like a 2 speed rear as you can get gear splits, and is really drops the rpm's down in 4th. I can see why those that have them are very happy they do. Also, I can remove it if desired fairly quickly, for example if I ever decided to do some rough off road travel in rocky ground, etc.
BTW, Dennis told me he personally tests each unit in his truck before he ships them, so he knows they perform well. I was impressed to learn that, especially since some vendors we have to deal with now do poor quality control on the products they sell.

[Doc Dave]

6 to 12 volt converter

Here is device that allows you to get 12 volts out of a 6 volt system to power newer components needing the extra voltage.
This would help to prevent damage to the solenoid mentioned in this thread from too little voltage/too high amps.
One could also power a CB radio off the same circuit, I would imagine.
Of course as mentioned a person could convert totally to 12 volts, but if for some reason they want to stay "stock" in appearance, this is an alternative.

http://www.pressenter.com/~cmeyer/

[maineSS]

I went thru a power supply handbook from 1977- they had lots of DC/DC converter circuits, but some of the parts might be obsolete by now. There was a Siemens circuit that converted 6 to 12v, but at way more power than you likely need for that solenoid.