My ahooga horn sounds great with the engine not running but unable to adjust when engine is running. I suspect this is probably because I'm using a 6-volt alternator. I haven't checked the output voltage but suspect it is probably a volt or two higher than 6 volts. Any ideas to fix this problem. I'm guessing a resistor. Thank you.
Ahooga with an alternator
- Thread starter goodcar
- Start date
Bruce of MN
Well-known member
It has some other problem. A generator charges at more than 6 volts.
nkaminar
Well-known member
A 6 volt battery needs 7 volts to charge. Measure your alternator voltage when charging.
You could try a resistor but I think that a resistor will not solve the problem because it will also lower the voltage when the alternator is not charging to below 6 volts. What is needed is a voltage regulator that will keep the voltage at the horn to a constant 6 volts.
You could try a resistor but I think that a resistor will not solve the problem because it will also lower the voltage when the alternator is not charging to below 6 volts. What is needed is a voltage regulator that will keep the voltage at the horn to a constant 6 volts.
BButturff
Senior Member
You should check the alternator output and battery condition. I drove my A for a year with a failed generator without even knowing it. I had always put it on a battery tender while in the garage. It's possible your alternator and battery aren't supplying enough amperage to support both the engine and horn.
Joe K
Well-known member
Unregulated, the Model A generator can put out up to 32 volts. Tied to a battery you might get 7-1/2 volts.
Many use a voltage regulator adaptation. This to get past the Model A era issue of "boiling off the electrolyte" which can happen as a lead-acid battery is "overcharged."
Prominent in the Model A Instruction Book is the instruction "frequently check and add to your battery cell electrolyte."
In the case of your alternator, a voltage regulator is probably included - the system NEEDS to be regulated lest you burn out your alternator.
I'm suspicious that there is something in your system regulation that is differentiating between just the battery being charged, and other components of the system added. It could very well be the battery itself, especially if you're using the AGM style battery - which historically are less tolerant of "out of design" condition.
An AGM battery once it has been frozen, even if it is thawed out, becomes a very "small" battery in comparison with its former self. And yet it will show proper voltage.
Load test will tell you more.
Joe K
Many use a voltage regulator adaptation. This to get past the Model A era issue of "boiling off the electrolyte" which can happen as a lead-acid battery is "overcharged."
Prominent in the Model A Instruction Book is the instruction "frequently check and add to your battery cell electrolyte."
In the case of your alternator, a voltage regulator is probably included - the system NEEDS to be regulated lest you burn out your alternator.
I'm suspicious that there is something in your system regulation that is differentiating between just the battery being charged, and other components of the system added. It could very well be the battery itself, especially if you're using the AGM style battery - which historically are less tolerant of "out of design" condition.
An AGM battery once it has been frozen, even if it is thawed out, becomes a very "small" battery in comparison with its former self. And yet it will show proper voltage.
Load test will tell you more.
Joe K
rotorwrench
Well-known member
The alternator conversions that I have used were related to the 10si GM type with 6-volt positive ground. Two things could affect system voltage. One is that the little self contained regulators generally put out too much voltage. The other is that they need rpm to turn on the alternator unless the have a generator out light switch circuit. This has always been an issue with one wire 10si conversions that I'm familiar with.
The conversions have their own design regulator plus the jumper to switch grounding. I've had some fail pretty quickly and some that last forever but the ones that last the longest are the standard 12-volt negative ground types. I suspect the regulators for the conversions are not very high quality.
The conversions have their own design regulator plus the jumper to switch grounding. I've had some fail pretty quickly and some that last forever but the ones that last the longest are the standard 12-volt negative ground types. I suspect the regulators for the conversions are not very high quality.
The Master Cylinder
Well-known member
I don't have a 10si alternator (I have a PowerGen) but I am curious how you wire a "generator out light switch circuit". Do you have a wiring diagram? Sounds interesting. Thanks
I am using an alternator also, and find that adjusting the horn with the car not running I could make it sound great. With it running it sounds like a dying cow. Realized I had to have the alternator excited and engine running and then adjust. Still sounds like dying cow with engine off but great otherwise.
philosofriend
Member
Your first step is to measure the voltage with the engine off, then with the engine running. You will probably also want to measure both of those with the horn on.
Those four pieces of information will help greatly in knowing where to look for the real problem.
Those four pieces of information will help greatly in knowing where to look for the real problem.