• 1A Float/charging Pb Acid Batt

    From G8MNY@21:5/101 to TECH on Sat Jun 29 05:32:45 2019
    R:190629/0822Z @:LU4ECL.LP.BA.AR.SOAM #:19566 [19568] FBB7.01.35 alpha $:10395_ R:190629/0813Z 31864@N3HYM.MD.USA.NOAM BPQ6.0.18
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    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 ┌───────┐out 1N4001
    +24V >───┬─────────┤ 7805 ├────┬───┬────┬──┤>├─┬──> +14.5V BOOST
    │ └───┬───┘ │ e\│ 22k │ +13.5V NORMAL
    RAW DC >2200u│+ com_│_ │ PNP├──┴──10k─┘
    FROM 30V=== /_\` u1│ /│
    BRIDGE │ NORMAL ____│ 9.1V === │ Battery being RECTIFIER │ O _│_ │ 1k floated/charged
    & 17V AC │ BOOST \o \_/ 0.5V │ _│_-> Charge
    @ 1.5A │ │ _│_ │ \_/-> LED
    │ │ \_/ 0.5V │ │
    0V >───┴────────┴────┴────────┴───┴──────────────> 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 ┌───────┐out 1N4001
    +22V >───┬──────┤ 7812 ├──┬───────┤>├───>
    RAW DC │ └───┬───┘ │
    FROM >2200u│+ com│ u1│ Variable
    BRIDGE 30V=== Multi 10k === Output
    RECTIFIER │ Turn │ │ Voltage
    │ │ │
    0V >───┴──────────┴──────┴─────────────>

    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


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