Diode with low voltage drop?

JLNY said:

closest thing I could find to a datasheet was this:

https://www.datasheets360.com/pdf/819528069679232962

No mention at all of being a schottky diode. I think this may just be a standard silicon diode. No Vf vs. I plots, either. I think there are better options available.

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1.4V @ 60A confirms what I said

Do you mind telling us what function the diode will perform?

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It is a silicon diode.
From the datasheet Vfm = 1.4 volt. No mention of the If or Tc conditions where Vf was measured, which would significantly change that voltage value.

crutschow said:

Do you mind telling us what function the diode will perform?

Click to expand...

My original problem was something else but using a diode here is also solving my another problem with the ups.

My ups/inverter has a low battery cut off voltage of 10.4v, which i think is pretty damn low for a 12.0v battery.


So by using a diode here between the charging cable and battery terminal, and using a diode's voltage drop, i think i can make my ups think that it is disconnecting the battery at 10.4 but in reality it will be cutting off at 11.1v if the voltage drop of diode is 0.7v.

Did you get what i am trying to do here?
10.4v + 0.7 = 11.1v, so when battery voltage reaches 11.1v ups would think it is 10.4v and will disconnect the battery.

I have a small solar panal which efficiently charges the battery so i don't need the charger inside ups.

So is there such a stud diode with 0.7 or less voltage drop with current capability for handling about 30 to 40Amps or even 50?
Don't worry about heat sink... I think i can manage it.. but voltage drop shouldn't be more than 0.7 under any condition.

Hmm,
Won't that diode block the UPS from charging the battery?

Have you considered an ideal diode. There are 2 types - one based on a PFET and one on an NFET. At that sort of power, an NFET would be a far superior solution. LTC do NFET ideal diode controllers and you can (to a certain extent) pass as much current as you like

https://www.linear.com/parametric/powerpath_controllers_*_ideal_diodes

simonbramble said:

Have you considered an ideal diode. There are 2 types - one based on a PFET and one on an NFET. At that sort of power, an NFET would be a far superior solution. LTC do NFET ideal diode controllers and you can (to a certain extent) pass as much current as you like

https://www.linear.com/parametric/powerpath_controllers_*_ideal_diodes

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Max is only 20Amps?

Have you consider locating the nefarious 10.4 V comparator in your UPS and adjust the resistor ratios to get 11.1V and cutoff. Significantly easier to change...

Tony Stewart said:

Have you consider locating the nefarious 10.4 V comparator in your UPS and adjust the resistor ratios to get 11.1V and cutoff. Significantly easier to change...

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If only i could....

then learn to be qualified... get a meter and look for an LM3xx chip to switch voltages on the output pins of the datasheet , when battery runs out, measure the input voltages on same IC, power down look for connected R's , take pictures , ask questions.

Tony Stewart said:

then learn to be qualified... get a meter and look for an LM3xx chip to switch voltages on the output pins of the datasheet , when battery runs out, measure the input voltages on same IC, power down look for connected R's , take pictures , ask questions.

Click to expand...

I guess no harm in trying...

If it's a relay cutoff, you can trace back from the coil to the driver transistor which will probably be fed by the comparator I.C. (8pin?) doing the voltage trip. If the relay driver is NPN or N channel then the comparator output swings high to trip. Vice versa for a PNP or P channel Relay coil driver.
It's possible but unlikely that they used a couple transistors biased to do the tripping.
If they used an ADC voltage sampling microcontroller , well, it gets a bit more complicated to alter, but it can be done by resistor biasing the ADC pin to shift the voltage by the right amount.