Helper box for PFC charger

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Helper box for PFC charger

Doug Weathers
Hi all,

I appear to have blown up my PFC-20 charger - again - by not having the
battery connected when powering up the charger.  This is an expensive
education I'm giving myself :(

This is probably a good time to start a thread about a product I've
been idly thinking about for a little while now.  It's a helper box for
the PFC chargers, with the following features:

- An interlock that prevents mains power from being applied to the
charger if the batteries are not connected
- Voltmeter and ammeter for both AC and DC side
- GFI breaker
- 120- or 240-vac input

Is this a good feature list?  Does anyone have suggestions for features
to add or remove?

Optional features:

- A connection to the regbus, so the box can have status lights to show
if you've had a low battery.  A DC/DC converter in the helper box could
keep the regbus live while driving.
- A standard 120vac outlet, live when the mains power is connected.  It
provides 120vac even when the mains power is 240vac.
- Remote PFC controls (amp knob, dip switches, LEDs).  There's an
article on the Manzanita Micro website describing how to do this.  If
the charger is not easily accessible this might be helpful.
- GFI bypass for avoiding nuisance breaker trips (I wouldn't want one,
personally).  It would be easy enough to move the input power cord
directly to the charger if you want to defeat the GFI breaker.

Physically I imagine a plastic water-resistant electrical junction box
of the correct size (8-10 inches square), with digital displays for
volts and amps on the front (green or amber LEDs for the battery side
and red LEDs for the AC side) and the GFI breaker switch sticking out
of the side or front.  Wires would enter the sides, or plug into
receptacles on the sides.  The box should be easy to remove from the
car along with the charger, in case you want to charge something else
and don't want to give up the safety and convenience of the helper box

I imagine there would be a number of design issues, such as:

- dealing with varying pack voltages for the voltmeter and interlock
- dealing with 120 and 240vac power on the same input
- dual-voltage GFI
- power supply for the digital meters

It's a pity that Manzanita Micro (or anyone else!) doesn't already
produce this box.  I'd buy one.  It would have to be cheaper than
getting my charger fixed - twice.  Grrr.

Doug Weathers
Las Cruces, NM, USA

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