Value of 6-8 amp 13.7 volt power supply?

softdownsoftdown Solar Expert Posts: 2,405 ✭✭✭✭
Found this unused item used for about $8. Weighs about eight pounds and looks alright so I figured it might be made to last. Circuit Specialists CSA 1862 13.8v 6-8amp linear power supply sells for at least $43 on Ebay. 

Not sure what "linear power supply" means? 

Thought it might be good for equalizing due to steady power supply. Then I remembered that equalizing normally runs ~ 15.5 volts as memory serves. Good for anything normal?

Another Subject - sort of -
On a run, I also found a vintage Montgomery Ward 8 amp battery charger for $10.  Kind of partial to reliable and rugged heavy weight electronics of yesteryear. It appears to be slightly useful for equalizing. It keeps feeding 2 amps at 15.1 volts to a charged battery. Which makes a little bit of bubbling. Perhaps that is why the last owner got rid of it. It would eventually cook a typical car battery from "appearances".


First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • EstragonEstragon Registered Users Posts: 3,965 ✭✭✭✭✭
    Not sure what linear means either. Maybe fixed in relation to input voltage (as opposed to proportionate, in which output would vary in proportion to input)?

    15.1v would cook most modern AGM car batteries real good, I'd expect. It might have kept an older flooded one warm for a trusty start on a cold morning though :smile:
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • softdownsoftdown Solar Expert Posts: 2,405 ✭✭✭✭
    I keep my spare batteries in a separate room. Wonder what a 15.1 volt charge at 2 amps would do over a few days. In case I forget or something. Always have a few dozen small projects it seems. While ignoring the big ones best I can. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    softdown said:
    Found this unused item used for about $8. Weighs about eight pounds and looks alright so I figured it might be made to last. Circuit Specialists CSA 1862 13.8v 6-8amp linear power supply sells for at least $43 on Ebay. 

    Not sure what "linear power supply" means? 

    Thought it might be good for equalizing due to steady power supply. Then I remembered that equalizing normally runs ~ 15.5 volts as memory serves. Good for anything normal?

    Another Subject - sort of -
    On a run, I also found a vintage Montgomery Ward 8 amp battery charger for $10.  Kind of partial to reliable and rugged heavy weight electronics of yesteryear. It appears to be slightly useful for equalizing. It keeps feeding 2 amps at 15.1 volts to a charged battery. Which makes a little bit of bubbling. Perhaps that is why the last owner got rid of it. It would eventually cook a typical car battery from "appearances".


    Generally,   a Linear Power Supply,   has a linear voltage regulator,   the series regulator,   essentially acts like a variable resistor to maintain  the output voltage,  independent of load or line voltage changes.

    Many linear power supplies are not well suited for battery charging,   as,  the voltage regulators are often not designed for "loads"  that can source current (as can a battery).   Many of these supplies can be protected from a battery's ability to source current when the supply is turned off,  by placing a diode in series with the output.   But this protective diode adds a voltage drop,   further-reducing the output voltage.

    FWIW,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Linear supplies are what Vic said... And to add, they can be very inefficient (depending on design of the stage upstream of the series regulator and voltage drop across the series regulator).

    Linear supplies are generally designed to run DC loads without a battery (bank)--And designed to be very "quiet" (electrically). Generally not near as much as an issue when a supply is connected to a large battery bank.

    Also, generic power supplies can be designed to have a "crowbar" on the output. If the regulator fails and tries to output >13.8 volts, the crowbar turns on and shorts the output to protect the DC loads from over voltage. Having a crowbar on a good sized lead acid battery (bank), is not a good idea (crowbar is designed to be a near dead short on the power supply output).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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