[aprssig] NiCd Lessons relearned
Brian D Heaton
ky9k-lists at ky9k.org
Sun Jul 16 23:46:43 CDT 2017
OH8STN has built a couple of different Lithium Ion packs, including a
more recent 10Ah LiFePo4 pack. There are very good writeups on his web site.
This link is the full series on his off-grid portable setup -
Newer and better tech. Time to retire the old NiCd and NiMH portal packs.
On 7/14/2017 16:17, Glenn Little WB4UIV wrote:
> Nicads are current charged.
> SLA are voltage charged.
> On 7/14/2017 5:06 PM, Robert Bruninga wrote:
>> Lesson relearned on NiCd charging: Several years ago I made three 12v
>> batteries from D cell NiCd’s.
>> 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…
>> 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..
>> 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.
>> Then it retested them and got 75%, 65% and 85% of rated capacity!
>> So, Apparently little-used NiCd’s are not going to get a good charge
>> from a FIXED voltage charge!
>> 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.
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