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Lithium Ion
Battery Charger Circuits
Page 1
Battery Charges
Alkaline
Lead Acid
Lithium
Nickel
Last Updated on:
Thursday, November 30, 2017 01:57 PM
Lithium Ion, Next Page
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Circuits Designed by Dave Johnson, P.E. : |
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8
Solar Cell Lithium Ion Battery Charger
A single lithium ion
battery cell needs 4.2v from a current source to insure it is fully charged. A
solar panel with just enough individual cells wired in series to produce the needed
voltage would be more efficient than one with more cells for a given surface area.
If you divide 4.2 by eight you come up with a figure of 0.525 volts....
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Battery Amp-hour Capacity
Tester
I bought some lithium ion rechargeable batteries a while back. I was planning on
using them to modify some solar powered LED spot lights. What I like about
these new batteries is that they are the same size as a standard 1.5v alkaline AA
cell. With such a package, I can use a standard AA battery holder. The
battery manufacturer claims an amp-hour capacity of 2.2 amp-hours. Usually,
these amp-hour figures are made using rather small loads, conducted over a long
period of time. If I’m going to use these things for some solar powered
pathway spot lights, I need to know what operating time to expect. How long
would these cells last if I pull about 20ma from them? What voltage should I
use to terminate the test?...
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Eight Solar Cell Lithium
Ion Battery Charger Version 2
Jim Wilber looked at my design
for a battery charger and sent me some suggested changes. He suggested using the
LTC4412 ideal diode IC to switch off the current path from the solar cell to the
battery in darkness. He also noted that the 2.5v regulator from Seiko I had
selected was no longer in production and suggested using the shunt reference. I
think his suggestions made a lot of sense. In my design, in dark conditions, the
first MOSFET Q1 would not turn off until well after the point where the solar panel
no longer produces current, allowing some leakage current to flow from the battery
into the solar panel......
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Lithium Ion Battery Charger Using
LT1129
I have been designing a number of solar powered devices lately. Many of them
use just a single 3.6v lithium ion battery. These batteries like to be charged
from a fixed 4.2v source with a charging current limited to about C/8, where C is
the milliamp-hour rating of the part. When being charged from a small solar
panel, the panel should be selected so the charging current does not exceed C/8.
In such cases, there is no need for additional charging current control.
However, some mechanism is still needed to prevent the battery from discharging back
into the solar panel, when the panel is in darkness. Usually, a diode is inserted
between the battery and the charge control circuit....
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Battery Charges
Alkaline
Lead Acid
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