single-throw switch can also be used. LiPos are supposed to
have a limited lifetime of charge/recharge cycles, as do most if
not all rechargeable batteries. So when I’m done operating, I
switch the unit off either with a tiny magnet attached to a fig-
ure [8], a small wand, or other device.
The reed switch is a single-pole double- throw switch, whose
“normally on” side is used, such that when the switching mag-
net is taken away it assumes the “on” position. I was able to
locate these easily on eBay
A
mechanical switch will also do well, but it requires more han-
dling of the model to operate. Small reed switches like these
are easily hidden, and can be activated by a small magnet
without direct contact. This is a nice feature to build into a
model. If the model is not used for a long time (say a week),
it may be necessary to use the switch to disconnect the load,
and recharge the battery back-up.
I have been able to operate the twin motors of one diesel
(described later), for over an hour with no other power source.
Current draw was about 180 ma. For lower-power LED lighting
in cars, operation is much longer. While this will not provide
7
7. Battery manager board with built-in DC-DC 5V
converter.
