Cut-out - What to buy: Diode or Relay?

[LizardsA]

Hi all,
Me again. I'm experiencing some issues with my A's cut-out switch. When I look at the catalogues, I see that two types are available, a diode or a relay type. I have a gel battery installed (which I know don't like to be charged), so what would be the best cut-out to buy, bearing in mind I do a lot of long-distance motoring, and am not afraid to pay that little extra if necessary.
Kind regards
Mike

[msmaron]

Just call A&L and order their cut out..done and over..no worries after that.

[SDJason]

Why not get a voltage regulator?

Tom Wesenberg makes an inside-the-generator one I believe, and the Fun Projects one is available direct from them, or from many of the usual vendors.

[fredski]

Originally Posted by msmaron

Just call A&L and order their cut out..done and over..no worries after that.

what is special about their cut out ? is it diode or relay type?
\I am also interested in a cut out where I don't have to
worry about over charging battery.

fredski thanks

[SeaSlugs]

a diode is much better than a relay but a voltage regulator is much better than all of em.

so comes down to price vs what you want.

[Purdy Swoft]

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I use the Fun Projects can style voltage regulator. It takes the place of the cut out, requires NO modification to the generator and looks just like the early cutout. The six volt version gives a 15 amp maximum charge and and cycles from low to higher amps on demand as a modern car. There is also a 12 volt version that operates the same but at lower amps. With this setup you won't have to constantly adjust the third brush for night driving. A diode cutout will allow the generator to charge at whatever rate that the third brush is set for but doesn't give voltage regulation. Neither the Fun Projects can style voltage regulator or the diode cutout have points to stick, but only the Fun Projects unit gives voltage regulation. There are at least two other voltage regulators for the model A generator both are good but still require the use of the cutout. The Fun Projects unit kills two birds with one stone. I use them in both six and twelve volt versions and love them. Try wwwfunprojects.com .

[Patrick L.]

There is usually more than one way to milk a cow, this is one. I like to use an original properly adjusted cut-out and an internal voltage regulator in the generator. Our own Tom W. makes such a regulator and you won't be disappointed.
As with almost everything I have a preflight and postflight mental checklist and the Model A is no different. One of those is looking at the ammeter when getting out to make sure there are no discharges and there haven't been any surprises in a long time.

[Purdy Swoft]

Original Cutouts are good, Some have lasted over eighty years. Cutouts have points and points do at times stick. When the points stick the generator tries to motor but can't. When the points stick and the generator can't motor it gets very hot. When the generator gets hot it kills the battery and sometimes the generator as well. If you use a cut out you had better watch the ammeter close as Pat says. The repro cutouts are not good and sometimes don't work right out of the box. Bratton sells a six dollar diode that can fairly easily be installed in an original cutout shell . If you are good with three brush generators, you can disassemble the generator and install one of Toms EVRs that takes the place of the third brush, but you will still need to use the cutout. There is also the Peterson band style regulator that moves the third brush but still requires the use of the cutout. Its your choice.

[LizardsA]

So Purdy, if i follow what you are saying, if my cutout is faulty I can kill the battery quite easily?

[MrWzrd]

The cutout prevents the generator from trying to be an electric motor when the engine is not running.

Whether you go with a EVR (voltage regulator) or not you still need a cutout.

The original is a mechanical relay that opens when there is no power on the generator side.

The "modern" cutout uses a diode. This behaves a a one-way or check valve to allow power from the generator to the battery but not allow it to flow from the battery to the generator.

I prefer the diode over the mechanical since mechanical things will eventually fail.

If you have your old mechanical casing, and can work with tools and solder, you can buy the diode "kit" for a lot less. (you will gut the old cutout "can" and solder in the diode.)

Tom's EVR has a jumper that allows for either type of cutout.

For a daily driver .. I like the ability to not worry about my battery charge so I added the EVR and, since my cutout was fried, I installed the diode "kit". I give this combo 4 thumbs up. (the wife voted too)

[Willie Krash]

Keep in mind the diode will drop .7 Volts, and that may be a good thing, but if you drive at night you may see a difference.
I use a mechanical cutout and have spares. Points can be a problem particularly if you run a generator on the car that is reverse polarity with respect to the battery.
Otherwise they work well and do a good job and best not to monkey with them.
As mentioned pre and post flight checks are essential.
I would use Tim's or John's (Fun Projects) VRs and will get around to it eventually. I'm in the business so it's not a big deal for me...money wise.


If you're not living on the edge you re taking up too much room.

[Purdy Swoft]

Originally Posted by MrWzrd

The cutout prevents the generator from trying to be an electric motor when the engine is not running.

Whether you go with a EVR (voltage regulator) or not you still need a cutout.

The original is a mechanical relay that opens when there is no power on the generator side.

The "modern" cutout uses a diode. This behaves a a one-way or check valve to allow power from the generator to the battery but not allow it to flow from the battery to the generator.

I prefer the diode over the mechanical since mechanical things will eventually fail.

If you have your old mechanical casing, and can work with tools and solder, you can buy the diode "kit" for a lot less. (you will gut the old cutout "can" and solder in the diode.)

Tom's EVR has a jumper that allows for either type of cutout.

For a daily driver .. I like the ability to not worry about my battery charge so I added the EVR and, since my cutout was fried, I installed the diode "kit". I give this combo 4 thumbs up. (the wife voted too)

With the Fun projects can style regulator, you don't need the cutout. The Fun Projects regulator mounts and takes the place of the cutout and gives voltage regulation without going in to the generator or makeing any modification to the generator. Here is a pic of mine.

[Purdy Swoft]

Originally Posted by LizardsA

So Purdy, if i follow what you are saying, if my cutout is faulty I can kill the battery quite easily?

Yes, a faulty cutout can kill your battery or in some cases ruin the generator. I've had my share of problems with points sticking in the cut out. If you don't want to invest in A fun Projects regulator or a diode cut out, you can build your own. If you have a Brattons catalog, look on page 68 center column bottom of page. Part number 15600 price $6.95 instructions included. You gut an original cutout and all you will need is a soldering gun and some rosin core solder. Rosin core solder is fairly easy to work with and doesn't run all over the place like acid core solder.

[30ccpickup]

Originally Posted by LizardsA

Hi all,
Me again. I'm experiencing some issues with my A's cut-out switch. When I look at the catalogues, I see that two types are available, a diode or a relay type. I have a gel battery installed (which I know don't like to be charged), so what would be the best cut-out to buy, bearing in mind I do a lot of long-distance motoring, and am not afraid to pay that little extra if necessary.
Kind regards
Mike

Hey Mike,

I know this isn't part of your question, but if you have a nice original cutout it can be taken apart cleaned and put back together with little effort.

Paul