Joined: Aug 2017 Posts: 604 Threads: 19
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Location: Hampshire UK
Hi Ian
The 100 Watt rating for this type of metalclad resistor applies when it's bolted to a heatsink. If you choose to leave it sitting in free air the rating is more like 20 Watts. That should still be fine though, the reduced field current through it when it's in use will be roughly 1 amp and the dissipation will only be about 2 watts. This means the surface temperature won't be too high and you can mount it wherever it's convenient.
Joined: Aug 2017 Posts: 79 Threads: 8
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Location: Findon West Sussex UK
I was led to believe that an ammeter shows the current being drawn from the electrical system.
Joined: Aug 2017 Posts: 908 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
The ammeter will show the nett current in to or out of the battery, not the current drawn. This will be dynamo output less whatever is being drawn by electrical equipment.
Joined: Aug 2017 Posts: 604 Threads: 19
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Location: Hampshire UK
Hi again
I have a traditional 6 volt battery with the usual small vent holes in the filler caps. To deal with the slight acidic fumes coming from these, I place a piece of "battery mat" on top. This stuff is claimed to neutralise acid, so presumably is impregnated with something alkaline. It's primarily intended to be placed under the battery to protect the mounting tray. Only downside is that it's bright yellow !
Joined: Aug 2017 Posts: 978 Threads: 6
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Location: Scottish Borders
If you use a battery conditioner the battery will be fully charged when you set off. The 3-brush dynamo will then be very likely to overcharge it.
We use a battery conditioner but our dynamo doesn't work so no problem.
Jim