Why not integrate Jaguars with Diodes?

[techhelpbb]

Originally Posted by Kevin Sevcik

You're over-complicating things. If you're already willing to go to the trouble and expense of tossing a relay into the circuit, then you simply use the relay to energize the power stage. Heck, with a double throw relay, you could have the relay swap your polarity on the power stage for you. Your only problem is that you need a relay that can handle 40A continuous. Those relays aren't small or cheap.

The better open would be a standard mosfet based pass-protection eric described, which I'm pretty sure is already too expensive for the product.

I agree if you were switching the actual power leads to the H-Bridge you'd need a relay of that size. That's exactly why I didn't suggest it. You can under-rate a relay if you're planning on operating it infrequently. The goal was to create a circuit with the relay that wasn't going to frequently operate (preferably not at all). If you can work the idea with the capacitor out the currents involved will reduce themselves.

I also agree that Eric's suggestion is perfectly reasonable of course the cost of the MOSFET is the issue. Then again, if you can work it out such that the parts in question are the same as those in the H-Bridge perhaps the cost advantages of quantity would kick in and trump any of the other ideas I've provided.