Hi Doug, Most modern LVD circuits are much overkill. With new electronics the energy required is pretty modest on the grand scale of things considered to days of older technology.
I bought NewMar LVD 12-30 and LVD 12-75 units for a rapid install (almost an emergency) and they have turned out to be exactly what the doctor ordered in many other lmr applications. NewMar makes two different types of LVD... one series being the overkill rack mount unit mentioned above and the basic box lvd series I mention below. The only difference between the 30 and 75 amp rated disconnect is the internal relay. One could be sneaky and buy the specific 75 amp relay to roll your own... but I haven't been able to find it anywhere (and I have serious resources at hand). The Newmar 12-30 circuit is what you ask and hope for in a simple low voltage disconnect circuit. It's a pretty neat two transistor circuit with supporting resistors, caps and diodes. Two small pots adjust the low disconnect and connect set-points. Current draw is on the order of a relay coil and small zener reference through a transistor, which is about as good as it can get in most cases. There should be lots of LVD Circuits on the net often hiding within other packages. Solar and standard battery charger circuits come to mind as having battery monitor circuits within. I've built a number of LVD circuits so I could help talk you through some circuits if you plan to roll your own. Otherwise the Newmar 12-30 is a very practical buy. cheers, skipp skipp025 at yahoo.com >"dadavies3" <[EMAIL PROTECTED]> wrote: > Looking for a fairly simple low voltage disconnect circuit that will > allow battery operation when the power supply/charger shuts down and > will disconnect the battery when its voltage drops below a pre- > determined level. I checked the files section but couldn't find > anything. If anyone has such a circuit, please let me know. Thanks > for any and all help. > > Doug VE7DRF >
