I started out with a really common contactor choice, the Albright, basically a golf-cart, open style contactor that uses pack voltage to power up the coils. I think it’s time to move up to a little better choice – the Tyco LEV 200, a sealed unit that uses 12V for the coil voltage – for a few reasons. I like that it’s sealed. It’s “designed to be the lowest cost sealed contactor in the industry.” I also like that the contactor control switch will be running 12V instead of over 80V. I don’t really like the idea of running that kind of voltage to my handlebars, no matter that it’s running 14awg wires that will likely burn up before anything nasty happens.
There is a model, the EV 200, uses a feature called the “economizer”. This allows the contactor to stay closed by using PWM (pulse-width modulation) rather than a continuous current, which saves energy. Most of the muscle needed to close the contactor happens when you initiate the switch, and holding it closed is just a matter of maintaining the, well, “pressure”. This causes some trouble with some controllers that do, in fact, control the contactor themselves (Curtis, I believe) where you have to bypass the economizer (or presumably turn that feature off in the controller?), but since I’m running a controller that doesn’t have that feature I’m safe. However, it’s a little more money, and although it’s an elegant idea, it’s not really a big priority for me. (Yeah, I’m cheap. I’m also easy, but that’s a different story.)
Here is the product page. It also comes in a side-mount configuration, perfect for my bike. It’s also available from DigiKey and Mouser… but the folks at EV Source have it for under $100 (along with some good information on the line of products). Order up!
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That’s the contactor I also chose for my conversion. For whom lives in Europe, I bought it here: http://www.e-transportation.eu/catalog/category.php?id_category=11 and it’s actually not expensive at 69€ (~89 USD!). I chose it for the same reasons as you already mentioned, and more: it’s a high current contactor with amazing break and continuous current and voltage, that has a datasheet with the full specification (which only the Albrights have), and is one of the contactors with the lowest contact resistance from among the ones you see on sale at EV-related stores (maybe a good Albright has similar contact resistance).
The fact that its coil works at 12V has still another advantage other than avoiding high voltage on your handlebars: you’re not committed to a certain battery voltage.
Can’t turn off PWM on the Curtis…that’s how it controls coil voltage. Only way you can use the EV200 is off a DC source like battery or DC-DC converter.
They’re great contactors. I own a 24V coil LEV200. One thing to note, they’re available in several coil voltages: 12Vdc, 24Vdc, 48Vdc, 72Vdc, 96Vdc, 110Vdc, 115Vac, 240Vac.
Actually Noah, You can set the PWM of the Curtis controller to 100% pull in voltage AND holding voltage, but that puts full pack voltage on the economizer, so you’d have to make sure it’s the right model, and that it’s below the max voltage of the economizer.