<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>The trickle charge is what allows them to recover. Leave them on the charger at .1C for an extended period of time to help the cell stabilize at a full charge. In a 12v pack, a small solar cell and a solar voltage controller can get you a pretty good trickle to pump as much charge in as possible.</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Gregg<br><br>Sent from my iPhone</div><div><br>On Jul 14, 2017, at 4:06 PM, Robert Bruninga <<a href="mailto:bruninga@usna.edu">bruninga@usna.edu</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"><meta name="Generator" content="Microsoft Word 15 (filtered medium)"><style><!--
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--></style><div class="WordSection1"><p class="MsoNormal">Lesson relearned on NiCd charging: Several years ago I made three 12v batteries from D cell NiCd’s.</p><p class="MsoNormal"> </p><p class="MsoNormal">They have been a huge disappointment. They are only used once or twice a year on critical field work and always fail far earlier than estimates. But I always just charge them the night before with a fixed voltage charge of 14 volts since I most often forget about batteries I put on charge and end up ruining most of them. Charging at fixed voltage is safe…</p><p class="MsoNormal"> </p><p class="MsoNormal">For the AT Golden Packet event tomorrow, last night I left them on my usual 14 volt overnight charge and they were “fully charged” by morning, only drawing a 50 mAh each in the morning at 14 volts..</p><p class="MsoNormal"> </p><p class="MsoNormal">Put them on a battery analyzer and their capacities came in at 10%, 8% and 3%. Then the battery analyzer quick charged them at 1C rate for 1 hour with them getting up to 16 or 18 volts, then a 4 hour equalization charge of 0.1C or 400 mA. </p><p class="MsoNormal"> </p><p class="MsoNormal">Then it retested them and got 75%, 65% and 85% of rated capacity!</p><p class="MsoNormal"> </p><p class="MsoNormal">So, Apparently little-used NiCd’s are not going to get a good charge from a FIXED voltage charge!</p><p class="MsoNormal"> </p><p class="MsoNormal">Wish I had time to cycle them two more times. On batteries at work we see huge recoveries from little used NiCd’s when “rejuvenated” which is the 3 cycles of charge and discharge I started with above.</p><p class="MsoNormal"> </p><p class="MsoNormal">Bob</p></div>
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