Transistor switched low voltage disconnects

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KC-watts
KC-watts Solar Expert Posts: 37 ✭
in Advanced Solar Electric Technical Forum #1
I have a few questions about the C-40 LVD mode. PWM is not active, right, so switching on the power transistors is one ON and one OFF? I will lose some power through heat, but will not a voltage drop, how does that work? I'm asking because the C-40 is noisy on the radios when used as a charger, but didn't seem noisy in LVD mode, and would like to repurpose this device. So, I just wanted to make sure LVD didn't have too many drawbacks.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Re: Transistor switched low voltage disconnects

    PWM is turning on/off at 10's to 100's of times a second--To get an "avergage current/voltage" for the battery bank. Lots of switching noise.

    An LVD only turn on/off when it needs to change state--So, hardly any electrical noise except when actually switching.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #3
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    Re: Transistor switched low voltage disconnects

    LVD will be a bunch of mosfets in parallel. Each with a 4 odd milliohm rds on resistance. Should be reasonably efficient.

    Bear in mind it isnt intended for inverters, doesnt have the capacity. Maybe a tiny one?
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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  • KC-watts
    KC-watts Solar Expert Posts: 37 ✭
    #4
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    Re: Transistor switched low voltage disconnects

    I'm repurposing it to my boat. I can load it up with non-essentials like 12v outlets, AM/FM, 9 amp deck flood lamps; i.e. the batteries will make last call so captain can join in the fun.
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