question

ceriw avatar image
ceriw asked

Help with DC-DC converter output voltage

Hi,

I've got a 50A DC-DC converter (TS800C) that I want to use to charge a 24V wheelchair from a 12V system.

The output voltage is always higher than the set voltage in TSConfig. I've set it at 27.5V an with no load, it outputs 29.5V. Even with a 10A load its still 28.3V.

What have I set wrong?

Screen grabs of TSConfig attacched.


Many thanks


noload.jpg

loaded.jpg


tsconfig
noload.jpg (168.2 KiB)
loaded.jpg (160.5 KiB)
1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

ceriw avatar image ceriw commented ·
Bumping post as I still haven't figured this out.

Thanks

0 Likes 0 ·
1 Answer
xxn5ac avatar image
xxn5ac answered ·

Sometimes DC-DC converters need a load to regulate. I would try a resistive load that would sink something like 20mA to see if it straightens up. For 27.5V this would be a 1370Ω. You don't have to get the exact value, of course. Something in the 1-3.5k range should allow you to test this. Do you have access to a drawer full of resistors where you could grab one and test?

2 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

ceriw avatar image ceriw commented ·
Tried that but no effect. Light loading it sits about 2V above the set voltage. I need to load it to about 15A before the voltage approaches what I'd expect.
0 Likes 0 ·
ceriw avatar image ceriw ceriw commented ·

Had a bit longer on this today. it would appear that it is just a 2V offset - output always stays 2V higher than the setting. My other voltage measurements seemed to be the soft knee of the temperature controlled current setting.

I've set the target voltage 2V lower than I want, and everything is working as expected. As it's an older unit, I'm guessing that some internal reference has drifted.

0 Likes 0 ·

Related Resources

Additional resources still need to be added for this topic