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dc2374afa

DEMO MANUAL DC2374A

MPPT QUICK START PROCEDURE

TheLTC4013hasamaximumpowerpointtrackingfeature

that regulates the input voltage to the maximum power

The LTC4013 MPPT function periodically stops charg-

continues charging while regulating the input voltage. As

solar panel by changing R2, R8, and R10. To change the

Power Point Tracking section in the LTC4013 data sheet.

There are a number of ways to test the MPPT function of

theLTC4013.Themostaccuratewayistouseasolarpanel

in sunlight, however it is difficult to control the sunlight

conditions. Another method is to use a covered solar panel

(dark panel) biased thru a controlled current source from

in Figure 3. The solar panel can be replaced with a string

of silicon rectifier diodes that can handle the power dis-

for a full light condition. Reducing this current simulates

lower light conditions.

A more simple method is to supply a voltage to DCIN with

thedesiredsunlight.Setthepowersupplytothemaximum

voltage simulates lower light conditions.

To evaluate the LTC4013 MPPT function follow the pro-

cedure below:

1. Set the DC2374A to operate in MPPT mode with a three

stage lead acid battery charging mode by positioning

the jumpers as listed below:

JP1

ENABLE - ON

JP2

MPPT - ON

JP3

MODE2 – LO

JP4

MODE1 – HI

JP5

NTC – INT

JP6

TIMER – CAP

JP7

PULL_UP PWR - DCIN

2. With power off, connect a 0V to 16V, 6A power supply

(PS2) to BAT and GND terminals with a series ammeter

and a voltmeter as shown in Figure 1.

3. With power off, connect a 5.1A load (LOAD1) to BAT

and GND terminals in parallel with PS2 as shown in

Figure 1.

4. Set PS2 to 10V and turn on PS2 and LOAD1.

5. With power off, connect a solar panel or solar panel

simulator as previously discussed and refer to Figure

3 and Figure 4 as needed.

6. With a full or close to full light condition, observe that

the battery charger current is only about 1A, 20%, and

the voltage on the ISMON terminal measures about

time. This is because the battery voltage is below the

Low Battery threshold. If the battery voltage remains

below low bat for 25 minutes then the charger cycle

is terminated. The solar panel can supply more power

to the charger than needed at this point.

7. Slowly increase PS2 until the battery current jumps

up to above 1A. The battery voltage is now above

the low battery threshold. If the IMP is less than the

input current needed to provide full charge current,

the LTC4013 will regulate the charge current below

8. If possible, vary the light conditions for the solar panel

orsimulatorandobservethechargecurrentisadjusted

NOTE: If the charge current is reduced below C/10,

~ 500mA, and the battery voltage is over the low battery

threshold, then the TEOC timer will start even if the battery

voltage is not approaching the absorption voltage.

9. If possible, return the light source to near full light

condition.