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Reason for the pin contact in the 8A “buck” (hope it were boost-buck) driver is conductivity, as even high conductivity springs could have problems at 8A or close (with just 10mΩ of resistance a spring dissipates 0.64W as heat when 8A crosses it). Simon and/or the driver manufacturer played it safe this way, but it has drawbacks, namely for people who really need damping or shock absorbing contacts (i.e. hunters for example).

The solution, of course, are really high conductivity springs. A bypassed spring can do, but a durable spring bypass requires careful work, giving the wire a coiled shape. Problem is the contact surface under the pin of the driver, it just has the size of the pin contact and is too small, unnecessarily forcing spring modders to remove the solder mask around it.

Let me also say that, in all honesty, I think 8A is probably a bit over the top. We know the CSLPM1.TG peaked at 8A or just a hair above, and imho it's over the top for it. The wrong thing about this is we don't have any CULPM1.TG tests. So actually we still don't know how much higher is the 4040 CULPM1.TG going to peak over the 3030 CSLPM1.TG. And honestly, it's the same led, only the footprint changes. Nothing else to say, except that being able to configure a driver's output current in firmware would be a godsend.

P.S.: low voltage cut-off is overall set too high in drivers. Bear in mind that drivers don't see the actual battery voltage, they see it after it goes through springs, contacts and switch. All of this causes voltage drops, the higher the current the larger the drops; therefore, the actual cut-off ends up being at a higher voltage, namely if running in high current modes. In essence, I think driver cut-off voltages should at least drop down to 2.7 or 2.5V. After all, I've yet to see a battery complain about a low cut-off, namely when datasheets specify 2.5V (and I've seen lower).

Fri, 11/20/2020 - 04:55