ebay XL6009 DC voltage step up woes - Page 1
Forum section: electronics / projects

author: akis
author_rank: Frequent Contributor
timestamp: January 05, 2016, 01:16:15 pm
content: Some time ago, probably before summer, I bought a largish number of those step up modules as seen here (not this vendor)http://www.ebay.co.uk/itm/XL6009-DC-DC-Voltage-Step-Up-Boost-Converter-Module-3-30V-Input-Replace-LM2577-/390743148006?hash=item5afa1b45e6:g:ukoAAOSwZ1lWgi-hToday (more than 6 months later) I am trying to use them, and all three I have tried are useless. They go into some sort of oscillation/hiccup their output voltage drops and the input current shoots through the roof, and not spent on the load. Utter rubbish.Has anyone got experiences with these modules?

author: MagicSmoker
author_rank: Super Contributor
timestamp: January 05, 2016, 01:39:01 pm
content: Hmm, well, let's see... a genuine LM2577 costs $3.58 in 1000 quantities and this whole board only costs $2.81... So the LM2577 is almost certainly counterfeit, and so it is not really possible to speculate on why it is misbehaving.Though to at least be minimally helpful, it sounds like the inductor is saturating, perhaps from too low a switching frequency (should be ~52kHz). Conversely, it could be that there isn't enough of a minimum load present, and the fake LM2577 can't skip pulses or stop switching when unloaded.

author: mij59
author_rank: Frequent Contributor
timestamp: January 05, 2016, 01:50:26 pm
content: Got the same modules, so far no problems encountered, what voltage and current settings are you using ?

author: akis
author_rank: Frequent Contributor
timestamp: January 05, 2016, 02:19:58 pm
content: These are NOT made with the LM2577 but with the "new" chip XL6009.Input 12V, output tested with anything from 15V to 25V (target is 23.5V and 1.5A).Best load I could get was 0.6A, and not always, basically every time I powered it up it was touch and go it would go into this oscillation/hiccup and start drawing lots of amps and so on. Trying to draw more than 0.6A is a no no.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 05, 2016, 02:43:16 pm
content: Let me see if I am understanding you.You bought a "largish number" of these too-cheap-to-be-true modules over six months ago, without first testing a single unit.You received something other than what was advertised in the listing. (Different chip part number.) But you didn't test or complain at the time.You are just now testing what you got.They aren't working as advertised.Is that a fair summary of the events and timeline?

author: akis
author_rank: Frequent Contributor
timestamp: January 05, 2016, 02:47:43 pm
content: No. I bought them on ebay, a largish amount (because they are cheap), they are what I bought (XL6009), each is individually wrapped in sealed plastic/antistatic bag, I opened three so far, they are exactly what I had bought, however they do not deliver the current I require.And I think I know the reason. I was looking at other step up modules on ebay, some 100W and 150W, and they are beasts with large chokes and heatsinks, even fans, so this little puny thing obviously cannot deliver the Watts required (24V x 1.5A).In other words it is not broken, just weak.

author: MagicSmoker
author_rank: Super Contributor
timestamp: January 05, 2016, 02:58:14 pm
content: Okay, so the XL6009 is a poor derivative or copy of the LM2577.That said, it still sounds like the inductor is saturating, and as you have subsequently stated that you are trying to boost 12V to 23.5V @ 1.5A I would say that is almost certainly the case.

author: mij59
author_rank: Frequent Contributor
timestamp: January 05, 2016, 03:02:02 pm
content: Quote from: akis on January 05, 2016, 02:19:58 pmTested my module with your settings, works fine but runs very hot very fast.Input current is 3.5A.

author: Emo
author_rank: Regular Contributor
timestamp: January 05, 2016, 03:09:58 pm
content: Hi,In the notes, bottom of the bay page, it is mentioned that the unit has a maximum output power of 20W. So if it does work, it definately will get hot

author: Seekonk
author_rank: Super Contributor
timestamp: January 05, 2016, 03:14:20 pm
content: I seem to remember a video with these and they were limited to about 10W. Without looking at any details that seems reasonable for the components used. I have purchased many of these and think they are quite useful for light applications. Even the 150W versions are questionable above 60W.

author: akis
author_rank: Frequent Contributor
timestamp: January 05, 2016, 03:14:29 pm
content: Input 12V @ 3.5A, out 24V @ 1.5AThe output contains a large oscillation at 398KHz. It runs hot quickly, I stopped it at 50C after around 10-15 secs.So yes it seems I am over driving them. Sorry guys, all my bad.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 05, 2016, 03:18:28 pm
content: Quote from: akis on January 05, 2016, 02:47:43 pmSorry, but the link you provided in the first post shows several photographs of units that have the LM2577S chip on them, and has this text:QuoteSo you will forgive me if I thought that you didn't get what was actually advertised and ordered.

author: akis
author_rank: Frequent Contributor
timestamp: January 05, 2016, 03:23:51 pm
content: Ah yes it does at the bottom of the page, however the title says "replace LM2577 " and the main 3 photos have the correct module the XL6009, and if you notice the output caps are 50V whereas the LM2577 modules have 35V output caps.