YWBL-WHVoltage Monitoring Relay Over-Voltage and Under-Voltage Relay 35MM Rail 13-17V 10-14V(DC12V)

Used this voltage monitor on my golf cart to alert (turn on a 12v light) when lithium battery voltage falls below 40. Didn't come with a Din Rail for mounting so had to make one using old power supply casing material. Furnished sample wiring diagrams don't show using separate power on the alert (relay switch) side but just used one set of connections (one NC and one Com).o

This DIN rail mounted device checks my UPS 48V nominal battery bank for voltage above a lower set limit and below an upper set limit, and enables bank for my UPS system if voltage is in range. The built-in 6A 250VAC DPDT relay has a delay 0.1 to 15 seconds before out-of-range (voltage too low or voltage too high) switches relay, which in my app prevents a defective battery bank from being used. When voltage returns to in-range, the delay is not used, and the relay indicates in-range immediately. There is 1.0 to 1.5 V of hysteresis on the limit threshold settings to prevent oscillation and relay chatter when a voltage is at a low or high extreme, right on the limit threshold. The upper and lower limits, and the time delay are set by clearly-labeled screwdriver-turnable controls on top of device. There are two tiny but bright indicator lights on top of device that indicate voltage out of range (red) and voltage in-range (green). When the red indicator lights, it indicates the beginning of the time delay before relay switches to indicate voltage out of range. Device power consumption is less than a watt, and it gets its power from the voltage that it is sensing. For this 48 V nominal model, the input voltage limit values can be anywhere from 40 to 68 V. I noticed that they also have other models for one, two or three 12V batteries in series, as in nominally 12, 24, or 36 V DC.

The directions are a combination of horrible and wrong. You'll need a magnifying glass and maybe a head lamp. Then they are wrong so you need to test to convince yourself it's ready for your circuit. There are 2 SPDT dry contacts. One is #25 is common with #26 NO, and #28 NC (the directions are backwards.) Second is #15 is common with #16 NO, and #18 NC (also backwards from instructions.) They are dry contacts so most people will wire the same V+ to the instrument to either/both commons. Then the negative/common of your load needs to go back to the negative/common associated with the V+ to the common of the SPDT. Best not to power the 2nd SPDT if you're not using it. You can wire both NC and NO of the same SPDT if you like.I saw 0.25V deadband between normal and trip. The timer is the amount of time the switch setting needs to continuously see the voltage condition. Not the time from 1st seen to trip.

Used this in the construction of my solar mini pump jack; its wired so that if the battery is low, the pump doesn't turn on. Delay is great to have, as if the motor draws too much current during start-up, it doesn't just keep turning on and off.Instructions are weird - but diagram on the unit is clear as day.Power leads on top, switch on the bottom terminals; just like most DIN rail components.

The cable connectors are a little narrow, and close together, but the adjustment dials work very accurately, so im very pleased!

The diagram is wrong or not meeting the engineering standard so you have to do the guess work!!Anyway it did not do what it told to do. Contacted support with no luck.I have set the low voltage cut off at 42v and High at 52v. Both relay trips (NO closes) if the voltage is within the range 42-52 and NO opens out of this range. So if you think ONLY low voltage cut off relay (as per the description in QA section) trips/releases when the voltage is below the low voltage cut off and ONLY high voltage relay trips/release above high voltage cut off, then you are fooled by the product description like me.This was the seller response in the QA section "Overvoltage and undervoltage are not set properly" which is absolute nonsense, he/she should have explained what is wrong and how to correct it !!!

Cuts off exactly where its cut-off voltage is dialed into.

Hard to get get set into exact range. Get one with digital display.

I found the instructions and the diagram confusing. I used a variable voltage power supply to test the devices operation. I found that it has two SPDT relays that operate together when either an over or under voltage condition exists. It appeared that the relays operated about 0.5V lower and 0.5V higher for the low voltage and high voltage cutoffs (respectively). For example I set the LV setting to 11.8 VDC with the expectation the relay would operate at about 11.4 VDC.