24v battery, 24-12 40a step down buck converter, DC devices not working...

[Tecnodave]

I have been using Samlex SDC-30 (non-isolated) and IDC-30 (isolated) DC-DC converters in my 24 volt solar system to run small 12 volt loads for 15-20 years now without a single problem. More expensive than chinese but built with very good quality. Definitely tier-1 stuff

 

[ChrisFullPower]

Ah, so the voltage should NOT have changed when the pump started running? Yeah that makes sense given I was taking the measurement at the input terminals. I don't think I understand how that would help me since the input being too low to start with, but if there is a wiring issue with the pump... I think I just realized a trouble 'area'. The pump started running as soon as I added the fuse when there is an on/off switch wiring into that loop, supposedly. That is definitely something to look into LOL I'm still not sure my big problem will change, but the whole point is to test all the electrical system, so, thanks for the patience.

If you’re measuring the voltage (output) under load and it falls substantially then it could be a faulty converter. (This should be measured as close as possible physically/electrically to the output)


If it stays where it should be (12ish-volts) then measure at your loads. If your getting a low reading here it could be a wiring problem.

 

[Owen Parker]

Ah, so the voltage should NOT have changed when the pump started running? Yeah that makes sense given I was taking the measurement at the input terminals. I don't think I understand how that would help me since the input being too low to start with, but if there is a wiring issue with the pump... I think I just realized a trouble 'area'. The pump started running as soon as I added the fuse when there is an on/off switch wiring into that loop, supposedly. That is definitely something to look into LOL I'm still not sure my big problem will change, but the whole point is to test all the electrical system, so, thanks for the patience.

I'm such a moron. The pump came on when I inserted the fuse because the damn switch was in the on position. All my issues should be solved so easily. All I have left to try is redoing those butt connectors. Fingers crossed...

 

[brum]

Measure the voltage first. With and without load. Both at the pump and at the DC converter output. Once done you'll be certain where to look for the problem.

Post pictures of your wiring. What is the wire size between the DC/DC converter and the rest of the 12V system? Small wire sizes will also lead to such problems.

 

[Owen Parker]

For the record, I received my new Victron 12-24 70A convertor that defaults output at 13.2 and I just connected it and everything worked as expected. My research found lots of evidence that the simple converter I had was supposed to be outputting 12.2v and that simply was not enough. If I had know of the Victron product to start with I would have chosen it simply because it has a max of 70a and I have 2 12v fuse blocks and even though I have nothing that eats much power, it's preferable to have more than enough moving forward versus dancing on the line... Thanks everyone for you suggestions and advice. I rarely post as I'm pretty good with google, but when you're spinning your wheels, it's comforting to have a forum of people with similar situations and years of first hand experience. Maybe someone can help me determine why my battery isn't charging as expected! Post to follow.

 

[skull_shipwreck]

I have been using Samlex SDC-30 (non-isolated) and IDC-30 (isolated) DC-DC converters in my 24 volt solar system to run small 12 volt loads for 15-20 years now without a single problem. More expensive than chinese but built with very good quality. Definitely tier-1 stuff

so would a 12V 30W load be okay for this device?

 

[JRH]

Reading comments, I think it is supposed to be putting out basically what it is. I'm not sure what else to purchase? Anyone have any idea?

I bought a similar device from Victron.. 24v to 12v …. 70 amp output at 12v ….it works wonderful…look into it…they are pretty low cost… built like a tank.