Hello,
I've been browsing around trying to fine a schematic for a 48VDC low volt disconnect. So far I've only turned up LVD's for 12 & 24v schematic.
It would be super if the dropout voltage was adjustable with a pot between 40~50vdc.
From the circuits I've seen they look like pretty simple things to design? But I'm a little lost and would greatly appreciate the assistance of some individuals more knowledgeable in this field than myself
(while I'm aware there are a limited amount of 48VDC LVD available to buy on the market, for the project I'm working on I already have to get a custom PCB made, so I might aswell integrate everything on the single PCB)
Thanks in advance for any assistance
Hello,
I've been browsing around trying to fine a schematic for a 48VDC low volt disconnect. So far I've only turned up LVD's for 12 & 24v schematic.
It would be super if the dropout voltage was adjustable with a pot between 40~50vdc....
? see post #2.How much current can the disconnect circuit draw from the batteries while the voltage is > 48V; presumably you want the current draw to be zero after it has disconnected to protect the batteries?
What load current are you disconnecting?
YES please!If you are interested in this approach, just post and I will modify the circuit to suit 48V. The modified circuit to suit 48V can probably be simpler too
the "load" output will be connected to a relay, current draw will only be 50ma, so a small transistor could switch on the relay coil?What load current are you disconnecting?
if you are thinking of the small amount of power required to operate this circuit and drive the relay, this won't be an issue.presumably you want the current draw to be zero after it has disconnected
Will do.YES please!
My pleasure EF. Many thanks for kind offer, but that is really not necessary.I'd like to make a small donation for a beer on me. You've been a tremendous help to me
Is the 50mA the load current, or the current you expect the relay coil to take. For such a small load current, I wouldn't even use a relay. The relay coil current is likely to be a sizable fraction of the load current......the "load" output will be connected to a relay, current draw will only be 50ma, so a small transistor could switch on the relay coil?
The 50ma is the relay coil. The load on the batteries is 54ampss the 50mA the load current, or the current you expect the relay coil to take. For such a small load current, I wouldn't even use a relay
the voltage increases during charge. If so, at what voltage
If automatic, then you need some hysteresis between cut-out, and cut-in.
So to be clear, the relay that switches the load has a 48V 50mA (960Ω) DC coil?The 50ma is the relay coil. The load on the batteries is 54amps...
CorrectSo to be clear, the relay that switches the load has a 48V 50mA (960Ω) DC coil?
Yeah I had the same thoughts after reading your last post . Well spottedWithout this hysteresis, the relay would constantly cycle on/off because as the load on the battery bank is removed
The circuit in post #2 will reconnect when the voltage rises and it also has hysteresis, which can be adjusted as can the cut-off voltage. The circuit has also been built and tested successfully by another ETO member. It is best to discus circuits with their designer/poster to avoid confusion.So the IC in Spec's schematic wouldn't reconnect once the voltage is raised?
The circuit in post #2 will reconnect when the voltage rises and it also has hysteresis, which can be adjusted as can the cut-off voltage. The circuit has also been built and tested successfully by another ETO member. It is best to discus circuits with their designer/poster to avoid confusion.
spec
Freakn amazing Spec! love the design!Post #2 has now been updated with a 48V nominal cut-off schematic and notes. If you have any questions, just ask.
Thanks- hope it works OK.Freakn amazing Spec! love the design!
All the packages would be suitable and that is a good choice: TLV3701ID (SOIC-8). I will make sure that the pin numbering on the schematic matches the TLV3701ID pin numbering. (UPDATE: the schematic does show the matching pin numbering- the NOTES now state this)is this the right TLV3701? **broken link removed**
(UPDATE: the schematic does show the matching pin numbering- the NOTES now state this)
Thanks again for your efforts Spec, You'll have to forgive me, perhaps this is a noob question? since you're unable to edit the pin numbers on the schematic to match the pins on the TLV3701, how do I determine the correct pin inputs/outputs? (Figured there is a key bit of info I don't know or am overlooking?)
I'd like to say I've had a rough day, but that would be a lie. I read the above as 'doesn't' twice! hahahah. Thanks again spec, I'm ordering the parts now. I'll let you know how it works when assembled!the schematic does show the matching pin numbering
The electronics industry has made a complete hash of the pin-outs and package descriptions with about ten different reference numbers for the same package. On data sheets there are package numbers splattered all over the place and it is a hell of a job trying to tie it all together.I'd like to say I've had a rough day, but that would be a lie. I read the above as 'doesn't' twice! hahahah. Thanks again spec, I'm ordering the parts now. I'll let you know how it works when assembled!
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