Range of Relay Load  - Page 1
Forum section: electronics / beginners

author: vidarr
author_rank: Frequent Contributor
timestamp: March 04, 2025, 11:41:19 pm
content: I made a 5 channel relay board (12VDC/127VAC) that is controlled by an Arduino. Originally, the design was to turn on/off five 127VAC lights (the load) and everything worked well. Then, the lighting system was changed to 12VDC.My question is: can a 12VDC/127AC relay be used with a load of 12VDC instead of 127VAC?The power supply to the lighting system is something like thishttps://www.newegg.com/p/2VH-00CP-007E4Turning the power supply on and off isn't an option (and probably not the right way to do this anyway).Thank You!

author: bdunham7
author_rank: Super Contributor
timestamp: March 05, 2025, 12:19:43 am
content: They'll more than likely be fine with 12VDC, but the current will likely be higher. How much current do the lights draw and and what is the part number of the relay?

author: vidarr
author_rank: Frequent Contributor
timestamp: March 05, 2025, 03:28:53 am
content: I don't know yet about the lighting system (other than 12VDC), but hopefully soon I will get the technical specs for them.The relays are AX1RC2. The datasheet is here:https://datasheet4u.com/datasheet-pdf/METALTEX/AX1RC2/pdf.php?id=1264798It is in Portuguese and English; the English is in grey text. I looked on this earlier, but couldn't find what I was looking for.Thank You!!!

author: bdunham7
author_rank: Super Contributor
timestamp: March 05, 2025, 03:45:33 am
content: The power supply you linked puts out 3.7A maximum, the relay is good for 15A so it should be just fine.

author: vidarr
author_rank: Frequent Contributor
timestamp: March 05, 2025, 04:09:23 am
content: Quote from: bdunham7 on March 05, 2025, 03:45:33 amAwesome! I understand it much better now too I think. The amps go up (probably, but not necessarily) because of the kind of new lights and PSU; so the limiting component becomes the relay, the current going through it.Thank You!

author: BennoG
author_rank: Frequent Contributor
timestamp: March 05, 2025, 06:33:27 am
content: For this kind of power supply (meanwell) do not try to switch the input (127/230 VAC) side.They are known to have a 50 - 80 A inrush current (this model has 50A inrush)Holy shit those power supply's are 4 times as expensive as here in europe. (we pay 29 euro for this model)O digikeyhttps://www.digikey.nl/nl/products/detail/mean-well-usa-inc/RD-125-1224/7705973is the same as here in europe.Benno

author: BeBuLamar
author_rank: Super Contributor
timestamp: March 06, 2025, 12:48:08 pm
content: Switching power supplies always have high inrush current but I had one of the 480VAC 3 Phase input and 24VDC 20A output and it tripped the 480V 10A breaker often on power up.

author: gcewing
author_rank: Regular Contributor
timestamp: March 09, 2025, 02:00:33 am
content: Be aware that switch and relay contacts sometimes have different ratings for AC and DC, with the DC ratings usually lower. It looks okay in this case, though, as the datasheet specifies 15A for both AC and DC.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 10, 2025, 01:38:21 pm
content: Quote from: gcewing on March 09, 2025, 02:00:33 amYeah. Generally, DC is "more demanding" to switch due to lack of zero crossings (which offer good points for arcing to stop), but 12VDC is such low voltage it's rarely a problem. Very significant problem already at 48VDC, though, so always a good idea to check relay specifications.

author: Jeroen3
author_rank: Super Contributor
timestamp: March 10, 2025, 02:14:51 pm
content: It is probably fine. The relay seems rated for 110 Vdc as well.You may like the attached document, since you posted this in the beginners topic.