Reynolds 

I have an old rod brake Raleigh with a Miller 12V 6w bottle generator. It works ok (lots of drag of course, but I don't ride fast), but I'd want to have a standlight too. How could I wire a 12V 2Ah SLA battery to power the lights when the bike isn't moving? Thanks.

Unknown Cyclist

If you aren't going to run a separate bulb from it, you'll need a rectifier or at least a diode.

Do you want to be able to charge it from the dynamo ?

ModoVincere

For a stand light, it would probably be just as easy to use a 5mm LED and a small battery pack. Run time on something like that would be a long time, maybe even 100 of hours. Then just recharge the batteries and your good to go again.

Reynolds 

I have a charger, don't need the generator to charge the SLA.
I do want the standlight to connect and disconnect automatically, however.
I'm trying to keep things as original-looking as possible, so I want to keep the same bulbs as standlight (no LEDs) and put the SLA in a box resembling this:

calina

Why don't you use a super capacitor instead of a battery?

Here's a good thread on stand lights: https://www.candlepowerforums.com/vb/....php?p=2951100

Reynolds 

Thanks for the link, but it seems to refer to LEDs only, and I want to run bulbs. For how long will a super capacitor deliver 12V 0.5A?

calina

Bulbs are too inefficient to be run as standlights with a supercap for a significant amount of time.

Reynolds 

The original Raleigh auto on - off Dyno - Luxe used dry batteries. I think something similar could be arranged with a SLA, but don't know anything about circuits.

Unknown Cyclist

Can you get a SLA to fit in that ?

Reynolds 

Not exactly, I thought about a rectangular box about the same size.

Unknown Cyclist

Why a SLA ?

A 12V SLA puts out about +14V on a fresh charge, that might not do your bulbs any good.

You'd be better off with Nimh for the most part.....

Reynolds 

I use auto bulbs, they are nominally 12V but can run at 14V (auto generator tension) all day long.