Boost Converter choice for 7.4v to 12v - Page 1
Forum section: electronics / beginners

author: stiffman
author_rank: Contributor
timestamp: April 21, 2023, 05:28:29 am
content: Hey,I'm working on building a battery distribution system for my location sound recording bagI'm currently using a Aliexpress boost converter based on the XL6009 chip. I haven't had any issues with it thus far, but I'm a little hesitant to trust the fairly expensive gear in the bag to a couple of dollars of unknown components.I need a peak of about 12v at 2A from a 7.4v lithium battery (npf970)Are these relatively safe to use, or are there better options? I know High frequency noise can be an issue, but I haven't had an issue.What would be the next step up, as far as regulator modules?I've found the Pololu models, that look like they have a bit more going on, but they are a lot more expensive. It's not a major issue, especially for reliability, but if there is something that is reliable and more affordable, I'd love to hear about it.Doe anyone have any suggestions of where to look, or what I need to consider?Cheers.

author: Terry Bites
author_rank: Super Contributor
timestamp: April 21, 2023, 09:20:20 am
content: Looking at the DS for the XL6009 it has UVLO which gives some protection to the battery and shuts down the switching.It has thermal shutdown designed to protect the MOSFET switch.So at face value, self protecting.The most common failure mode is the converter's switching MOSFET (or other transistor type) going into meltdown.They usually fail short connecting the the battery to ground. That pops the input fuse.In that case your kit is safe. An input fuse is anabsolute mustfor battery protection.A Lipo battery can bloat, burst, explode and burn if shorted!You also have to make sure its not going to get crushed or punctured.PPTC fuses can be used, they trip in about 100mSYou could add an electonic over voltage and over current circuit to the output.Hot swap and some POE controllers are just the thing eg TI's eFuse among many others, from AD Onsemi, Microchip, ST....Typically less than $1 each.You could make a muti channel system with one controller per output without breaking the bank.

author: tunk
author_rank: Super Contributor
timestamp: April 21, 2023, 09:48:51 am
content: Check if the battery can provide the current:2A*12/6/0.85=4.7AA fully discharged battery is ~6V and assuming 85% efficiency.Also see if the XL6009 can handle this input current.

author: barshatriplee
author_rank: Regular Contributor
timestamp: April 21, 2023, 09:52:52 am
content: I think you can depend on XL-6009. I have no bad experience with the boost converter.

author: stiffman
author_rank: Contributor
timestamp: April 22, 2023, 12:00:55 am
content: Quote from: Terry Bites on April 21, 2023, 09:20:20 amThe batteries I'm using are camera batteries - originally for sony videocameras, but they have been adapted for a wide range of uses for video production. They are basically 18650s in a hard plastic case, so not too much of a crush or puncture issue (within reason, obviously)The batteries are internally protected, so will shut down with a short circuit, low voltage etc..., and stay off until you put them back on the charge, so that's something. Obviously it's not something to rely on though, so in the design I'm working on right now, I'm planning on putting a polyfuse on the input of the device.I'm also contemplating putting a crowbar overvoltage circuit on the output to limit any possible high voltage output in a failure mode. It can operate between 9 and 18v on the power input, so I'm not going to have issues if it goes a little above the 12v I'm planning on using, but is it possible for these boost converters to fail in a mode that causes them to generate a much higher voltage?I'll look into the eFuse, it sounds like a helpful component.Quote from: tunk on April 21, 2023, 09:48:51 amJust looking at the manual for the recorder I'll be powering, it drawers 15w, and will take an input between 9 and 18v. That puts the output current at 1.25A as opposed to the 2A that I quoted (the DC plugpack that it comes with is 12v 2A, for some headroom i guess), so that should be a little less taxing on the battery.I'll need to investigate what current the batteries can supplyCheers for the info, It's certainly given me some points to work on.

author: james_s
author_rank: Super Contributor
timestamp: April 22, 2023, 01:13:28 am
content: I've found the XL6009 to be a reliable part, I've also use the MT3608 which is a smaller lower power part. Boost converters are fairly safe, unlike buck converters which can fail such that the full input voltage ends up across the load, boost converters fail such that they stop boosting and/or burn up.

author: additiondakku01
author_rank: Newbie
timestamp: April 22, 2023, 10:41:04 am
content: Each time one LM2596 failed, I recheck and reconnect everything. I’m using a breadboard between my 12v battery and the LM2596, and cord with alligator clips when connecting non soldered parts.