18650 Li-Ion Battery HAT for Pi - Page 1
Forum section: electronics / projects

author: enutilenergy
author_rank: Newbie
timestamp: October 26, 2016, 03:17:12 am
content: A neat 18650 Li-Ion battery HAT for Raspberry Pi. Allows you to run your Raspberry Pi off Li-Ion battery along with charging. Battery voltage and status can be read by the Pi with a Python script.https://www.kickstarter.com/projects/722780906/pi18650-hat

author: LukeW
author_rank: Frequent Contributor
timestamp: November 03, 2016, 05:40:09 am
content: Are you making schematic or layout available?Does it do automatic load switching?What's the output current ? Will it work with 5V peripherals connected?If you're going to blatantly promote your kickstarter you should at least use the crowdfunding projects forum.

author: viperidae
author_rank: Frequent Contributor
timestamp: November 03, 2016, 05:44:06 am
content: $40 is a bit steep. That's more than the pi you're attaching it to. Plus the cost for a battery.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 03, 2016, 08:59:08 am
content: This seems lika a nice idea, but hopefully you are aware that 18650 cells are not designed to be replaced by the user at all, and these kind of 18650 holders are inherently dangerous and should never be used by the end user, if anyone at all. This should be clearly stated in your kickstarter so that the users know they are taking the risk and using a designed-to-be-dangerous product. The fact that "everyone else" is doing it as well is no excuse.To fix the issue, consider selling the product with the cell properly mounted (and terminals spot welded) in place. You could use maybe three in parallel to increase the runtime. In this case, you could also sell the users high-quality, safe cells instead of "UltraFire" crap they might use otherwise.

author: tszaboo
author_rank: Super Contributor
timestamp: November 03, 2016, 10:14:39 am
content: I'm sorry, but the layout is just wrong. Boost converter circuit should take as small area as possible. The loops should be much smaller, and the components should be placed for performance, not like this. EMC aware engineers are crying now. Sorry.

author: amyk
author_rank: Super Contributor
timestamp: November 03, 2016, 10:59:58 am
content: WTF is a HAT? None of the acronyms that come to mind make any sense.Quote from: Siwastaja on November 03, 2016, 08:59:08 amI completely disagree. 18650 is becoming as common as AAs and there hasn't been any correspondingly great increase in incidents that all the naysayers were predicting. Torches, vapes, powerbanks, etc. Protected cells are also very common. If anything it's the pouch cells which are scary....I thought you didn't work for the industry...?

author: StuUK
author_rank: Frequent Contributor
timestamp: November 03, 2016, 11:15:39 am
content: Quote from: amyk on November 03, 2016, 10:59:58 amHardware Attached on Top

author: Siwastaja
author_rank: Super Contributor
timestamp: November 03, 2016, 04:41:04 pm
content: Quote from: amyk on November 03, 2016, 10:59:58 amIt is totally irrelevant whether you agree or disagree with facts.I personally use 18650's like that, too, and use those holders in some of my hobby projects, but I'd never ever design them in a commercial consumer product. This specific holder has a real issue of the spring clip puncturing the plus side insulation after too many insertions, and while PTC protected cells are OKish when shorted, some poor cells widely available are not; in any case, melting this plastic holder is not fun, the spring clip is quite resistive. When using these holders, I always insert plus side first without sliding it in, then slide in the minus side.The typical flashlight design is much less susceptible - when the cell insulation fails, the light just fails on and deep discharges the cell (happened to me and almost everyone I know using these flashlights!) - but it doesn't short the cell.It's true there are not as many issues as some "naysayers" expected, and it's all fun and games as long as you know what you are doing, but dangerous misuse is still dangerous misuse, and it's totally not OK to do this without telling it to the customers."Protected cells" are a joke IMHO from the safety viewpoint. Their actual idea is just adding low voltage cutoff, and maybe the "MOSFET fuse".QuoteI'm self-employed, currently involved with li-ion test&measurement.

author: enutilenergy
author_rank: Newbie
timestamp: November 10, 2016, 08:32:54 pm
content: Hello, thank you all for the feedback.We are considering releasing the schematic after our campaign is complete.No there is no automatic load switch but the unit does not interrupt prior to power source plug in and removal.It provides up to 2.4A from the boost circuit. You can tap into the 5.1V off the 3-Pin header. We have also upgraded and added a power switch and 20V input regulator to allow various solar panels and power supplies to the used with the board.Yes some of the components are pricey and we cannot find them lower anywhere other than buying in large quantities. The battery interfaces we have seen or bought are either small or require lots of wires or hanging batteries.This is a development board and it works as we have designed several commercial grade products in the $2K range with Li-Ion integration. We are also integrating the low cost ESP8266 to allow remote monitoring and reboot of the Pi. We are providing Raspberry Pi owners with options.Thks!Mark

author: BurtyB
author_rank: Regular Contributor
timestamp: November 11, 2016, 08:40:46 am
content: Quote from: enutilenergy on October 26, 2016, 03:17:12 amIt doesn't look like it follows the HAT spec at all (wrong size, no EEPROM, HAT can't be stacked, etc) so I'd advise they call it an add-on or similar.

author: kripton2035
author_rank: Super Contributor
timestamp: November 12, 2016, 11:16:04 am
content: $40 is really too expensive ... example here :http://www.dx.com/p/geekworm-raspi-ups-hat-board-lithium-battery-for-raspberry-pi-451766