24v USB chargers

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Garth
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24v USB chargers

Hallo, I have had problems with some cigarette type USB chargers rated for 12-24v. They work fine on 12v systems and regulated 24v, but when I use them at my work ( operating construction machinery) trouble strikes. With the engine running, voltage can go 28v and this seems to be to much. Chargers that are only rated for 12v have no problems up to 15v, so should 24v chargers not be good up to 30v. Ordered 3 Chuwi 12/24v after very positive review by HKJ and took one to work. Tried to charge an iPad and IT blew a 10 amp fuse. I checked the review again and saw that they are not tested at more than 24v. Anyone Else have these issues?

Edited by: Garth on 09/08/2018 - 06:13
HKJ
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It may not be the 28V that is a problem, but transients, i.e. short spikes with higher voltage.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Garth
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Thanks for the promt reply. I guess my point is that I would expect 24v chargers should handle spikes as well as 12v chargers do (within their respective ranges), and tests should reflect real life situations. Must add on here that I am a big fan of your work.

HKJ
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Garth wrote:
Thanks for the promt reply. I guess my point is that I would expect 24v chargers should handle spikes as well as 12v chargers do (within their respective ranges), and tests should reflect real life situations. Must add on here that I am a big fan of your work.

They should, but your machine may have more spikes that a typical car.
In my test I do not test with spikes, I do not really have equipment to do it and I do not know what is realistic in a car.
I believe that professional tests uses a “load dump” for testing, but that is not really realistic for a removable device and it is a rather nasty test.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Garth
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Understood. Thanks again.