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G8MNY  > TECH     06.01.06 20:14l 56 Lines 2380 Bytes #999 (0) @ WW
BID : 12041_GB7CIP
Read: DL1LCA GUEST OE7FMI
Subj: 1A Float/charging Pb Acid Batt
Path: DB0FHN<DB0FOR<DB0SIF<DB0GV<DB0LJ<DB0RES<ON0AR<7M3TJZ<CX2SA<GB7YFS<
      GB7CIP
Sent: 060106/1721Z @:GB7CIP.#32.GBR.EU #:12041 [Caterham] $:12041_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To  : TECH@WW

By G8MNY                                            (Updated Oct 05)

Here are 2 simply circuits for small discharge current batteries.

1/                On Insulated Heatsink
                      in ÚÄÄÄÄÄÄÄ¿out            1N4001
       +24V >ÄÄÂÄÄÄÄÄÄÄÄÄ´ 7805  ÃÄÄÄÄÂÄÄÄÂÄÄÄÄÂÄÄ´>ÃÄÂÄÄ> +14.5V BOOST
               ³         ÀÄÄÄÂÄÄÄÙ    ³   e\³ 22K     ³    +13.5V NORMAL
RAW DC   >2200u³+        com_³_       ³  PNPÃÄÄÁÄÄ10KÄÙ
FROM       30V===           /_\`    u1³    /³
BRIDGE         ³   NORMAL____³ 9.1v  ===  ³               Battery being
RECTIFIER      ³ BOOST  O   _³_       ³  1K              floated/charged
& 17V AC       ³       \o   \_/ 0.5V  ³  _³_-> Charge
@ 1.5A         ³        ³   _³_       ³  \_/-> LED
               ³        ³   \_/ 0.5v  ³   ³
      0V >ÄÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄ>0v

Voltage set by Zener + Reg - O/P diode loss. 13.5v recommended for floating Gel
& sealed types. 13.8 for wet ones tha can be topped up. 14.5v for charging
after discharge but not left on that voltage.

Current is limited to a peak of 1A. With no I/P smoothing C there will be hum
on the charging current & the battery voltage may not be suitable for floating
with electronic loads. The O/P diode & lets the PNP light the LED when the
diode has 0.7V across it. The diode also proctects the regulator from reverse
voltage is the PSU is off when connected to a live battery.

2/ Add a series R in the common leg. Most makes of regulator put about 50uA
constant current down the common leg, so a small R can uplift the voltage.

                 On Insulated Heatsink
                   in ÚÄÄÄÄÄÄÄ¿out     1N4001
      +22V >ÄÄÄÂÄÄÄÄÄÄ´ 7812  ÃÄÄÂÄÄÄÄÄÄÄ´>ÃÄÄÄ>
RAW DC         ³      ÀÄÄÄÂÄÄÄÙ  ³
FROM     >2200u³+      com³    u1³
BRIDGE     30V===  Multi 10K    ===      Variable O/P
RECTIFIER      ³     Turn ³      ³        Voltage
               ³          ³      ³
               ³          ³      ³
               ³          ³      ³
        0V >ÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄ>

I have used this one for many years to float my paket station on a 5AH gel cell
battery. Via a fused lead it powers a PacCom TNC220, a FT290Ri, & 30W PA, peak
Tx current 8A, Rx 500mA leaving just 500mA to charge for the short packet Tx
time.


Why Don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP



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