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From: commgrp@silver.bacs.indiana.edu
Newsgroups: sci.electronics
Subject: Need switching batt. charger
Message-ID: <7200035@silver>
Date: 3 May 89 22:20:00 GMT
Organization: Indiana University CSCI, Bloomington
Lines: 32
Nf-ID: #N:silver:7200035:000:985
Nf-From: silver.bacs.indiana.edu!commgrp    May  3 17:20:00 1989




I'm looking for suggestions/references for building a switching-
regulator battery charger.

Requirements:

     Input:    12v (car electrical system).

     Output:   4-5v @ 1.5 amp max, constant voltage, current limited.

     Load:     4-volt Koehler Wheat Lamp (tm) miner's lamp
               (two 14 amp-hour lead-acid wet cells in series).

     Output should be RFI-suppressed and foolproof, i.e., short-
     circuit and reverse-polarity protected.

Application:
     Cave explorers need efficient battery chargers for expeditions in 
     remote areas.  Adjustable 3-terminal linear regulators (LM340) 
     work well but run hot, wasting twice as much energy as they put 
     into the 4-volt battery.  Charging multiple batteries in series 
     is not practicable.

Thanks in advance; e-mail replies don't always go.

--

Frank Reid     NSS 9086F    W9MKV @ K9IU   reidgold.bacs.indiana.edu
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bitnet: reid@iubacs