G8MNY  > TECH     25.05.25 07:30z 54 Lines 2407 Bytes #82 (0) @ WW
BID : 33443_GB7CIP
Read: GUEST
Subj: 1A Float/charging Pb Acid Batt
Path: ED1ZAC<ED1ZAC<GB7CIP
Sent: 250525/0727Z @:GB7CIP.#32.GBR.EURO #:33443 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                                            (Updated Oct 05)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

Here are 2 simply circuits for small discharge current batteries.

1/                On Insulated Heatsink
                      in ÚÄÄÄÄÄÄÄ¿out            1N4001
      +24V >ÄÄÄÂÄÄÄÄÄÄÄÄÄ´ 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        O   _³_       ³  1K              floated/charged
& 17V AC       ³ BOOST \o   \_/ 0.5V  ³  _³_-> Charge
@ 1.5A         ³        ³   _³_       ³  \_/-> LED
               ³        ³   \_/ 0.5V  ³   ³
        0V >ÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄ> 0V

Voltage set by Zener + Reg - output diode loss. 13.5V recommended for floating
Gel & sealed types. 13.8V for wet ones that 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 output diode voltage drop lets the PNP light the LED
when the diode has 0.7V across it. The diode also protects the regulator from
reverse voltage if 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       Variable
BRIDGE     30V===  Multi 10k    ===       Output
RECTIFIER      ³     Turn ³      ³        Voltage
               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 FT290R(i), & 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


Read previous mail | Read next mail