Any electronics hobbiests want a project?

[Rednecktek]

I'm wondering if someone on here who plays with electronics should start building & selling battery-waker-uppers. Maybe something using an 18650 or two with an adjustable/programmable boost converter with settings/marks for 14.2v, 24.4v, and 48.8v with a momentary contact button. Connect a couple alligator clips, set your battery voltage, push the button. Power from the battery gets upconverted to $n voltage, BMS sees a charge voltage and wakes up.

Bonus points if it's USB rechargable and can be user changed between voltages for those of us with multiple voltage systems (i.e. I could wake up my 12v battery then turn a dial and wake up the 48v battery) easily.

Yes/no? Way more complicated than I think? Doesn't come in blue?

 

[DIYrich]

Car battery jumper/starter.

 

[meetyg]

Car battery jumper/starter.

Most of those are only for 12v batteries, maybe 24v too.

For 48v his idea is good.

@Rednecktek : it's a simple little project. Just use any 12v battery, connect to a DC-DC Boost converter (step-up) and apply to the dead battery.
The problem is most of the cheap Boost converters have POTS (those little blue screw type) for adjusting voltage, which is somewhat inconvenient.

 

[Rednecktek]

I'm sure I could kludge something together like that, but I'm no professional. It would be a great tool if:

It was USB rechargable, because that's easy

It had a knob or 3-way switch and a voltage display to verify you've got the right setting

It was handheld and small enough you could throw it in a tool box/parts bin

It had a professional looking 3d printed/molded rubberized case.

It used standard bananna clips or the like so you could get/make replacement wire leads.

Think anyone would bite if I offered to pay $100 for it as a bounty?

 

[Luk88]

I invested in buttons for all my Heltec BMS'es, so no need to jump start anymore. I can also switch off without having my phone on me. But I imagine not every BMS and battery has that capability.

So, for me an ideal device like this would not use an 18650, but a single AA battery (I'd use a Li-FeS2 AA 1.5V battery) and I'd like it last ages (at least 100 uses and 5 years sitting on a shelf).

Why no 18650? Because I'd use it twice per year and every time that battery would be discharged... With these new lithium AAs I'd expect it to just work when you need it.

I'm talking about proper 1.5V Li-FeS2 primary battery that can last 10 years in a drawer, not the down regulated higher voltage Lithium. They are non rechargable, but they have good amount of energy and marvellosly low self discharge rate (just do your research about avoiding crappy brands).

These requirements would actually make it an interesting and somewhat challenging project. The first question is: How much current and for how long "jump starting" a BMS requires?

 

[efficientPV]

I think about car jump starters and think maybe some people shouldn't have batteries. Like why even get into that situation.

 

[SparkyJJO]

Some kind of safety check would be good that you can't accidentally shove 48V onto your 12V battery....

 

[Rednecktek]

Because batteries die before payday?

Because off grid cabins sit untouched in bad weather and parasitic draws are a thing?

Because weather likes to fsck with your math?

Because the solar paywall is real?

 

[zcskywire2]

I'm wondering if someone on here who plays with electronics should start building & selling battery-waker-uppers. Maybe something using an 18650 or two with an adjustable/programmable boost converter with settings/marks for 14.2v, 24.4v, and 48.8v with a momentary contact button. Connect a couple alligator clips, set your battery voltage, push the button. Power from the battery gets upconverted to $n voltage, BMS sees a charge voltage and wakes up.

Bonus points if it's USB rechargable and can be user changed between voltages for those of us with multiple voltage systems (i.e. I could wake up my 12v battery then turn a dial and wake up the 48v battery) easily.

Pretty challenging on a single cell but could be done decently well now with some of the new Bidirectional converters. TI LM5171 would work well if not overkill, use one channel for charging over USB-C. Use the other channel for output up to 80V or so. Add an MCU, A USB-C front end and some buttons and you'd be done.

 

[SparkyJJO]

I have scads of NiMH batteries around here (kids toys) maybe I'll just stack up 40 of them....

 

[efficientPV]

There are always ways.

I once started a car with a toaster. And it made breakfast at the same time. Today that would be a KICKSTARTER or GO FUND ME project.

 

[MakeMePower]

Some kind of safety check would be good that you can't accidentally shove 48V onto your 12V battery....

how would that work if the bms is in protect mode, there is no way to get a real voltage reading.

 

[MakeMePower]

This is a not a overly hard project, but i question how many people would actually need this, as it seems that most that are here would already have PSU's capable of doing it.

 

[Rednecktek]

This is a not a overly hard project, but i question how many people would actually need this, as it seems that most that are here would already have PSU's capable of doing it.

Judging by how many "is my battery dead?" threads, more than a few.

 

[MakeMePower]

Judging by how many "is my battery dead?" threads, more than a few.

and I would be scare to sell a device like this to people who ask those kind of questions

 

[DIYrich]

BTW: The JK BMS has a port where you can plug in a switch to turn the BMS on/off.

 

[MrSparkle]

battery-waker-uppers. Maybe something using an 18650 or two

Alternatively. Instead of building an electric device with batteries included, skip the batteries, focus on the device and feed it directly through an USB-connection? That opens up choices for end-user. One could feed the tool from a portable USB battery, or from a wall-socket-to-USB (Is there ANYONE that does not have one?), heck even from a laptop USB-port.

Well, ok. I bet there are folks that would prefer all inclusive, with the battery. Well, ok, build one that have room for x2 rechargeable AA, but the unit would be able to be powered directly through an USB cable.

EDIT:
I would possibly consider also 36V. I guess not widely spread, but those system exist too?

 

[Rednecktek]

Some kind of safety check would be good that you can't accidentally shove 48V onto your 12V battery....

If you press the Wake Up! button on a 12v battery when the screen on the device says 48v, then you did it to yourself.

Having to manually press a button should be enough of a safety catch.

Alternatively. Instead of building an electric device with batteries included, skip the batteries, focus on the device and feed it directly through an USB-connection? That opens up choices for end-user. One could feed the tool from a portable USB battery, or from a wall-socket-to-USB (Is there ANYONE that does not have one?), heck even from a laptop USB-port.

That would be a lllloooonnnngggg set of leads to get from the car to the utility room.

Well, ok. I bet there are folks that would prefer all inclusive, with the battery. Well, ok, build one that have room for x2 rechargeable AA, but the unit would be able to be powered directly through an USB cable.

Inclusive would be handier I think. Rechargable AA's would be an option.

EDIT:
I would possibly consider also 36V. I guess not widely spread, but those system exist too?

It's just a POT so why not?

BTW: The JK BMS has a port where you can plug in a switch to turn the BMS on/off.

Most BMS's do and they all suck. Plus I've never seen a teardown of a 12v or 24v battery with a switch built in.

And JK sucks, but that's just my experience.

Yeah, seems like a simple project on paper, and you could certainly kludge something together, but I'm no EE nor do I CAD so it's more than my current capabilities to make.

No takers on the bounty?

 

[zcskywire2]

Mabye if I feel like it, this project is right up my current alley as a learning project to build a schematic of. I have an good idea of what parts I would use, though that would be overkill and an expensive bom cost.

 

[42OhmsPA]

Would it be possible to wire power tool batteries in series to jump start a pack?

 

[zcskywire2]

Depends on the brand, some of the tools have BMS units in the battery pack and some have it in the tool. Samsung 40Ts can take a lot of abuse but I wouldn't want to dump them uncontrolled into a large LFP pack.


Edit, I wouldn't trust that most tool batteries are rated for series operation either, it almost never is used. Could rig a DeWalt flex volt pack with a buck converter tho

 

[SparkyJJO]

If you press the Wake Up! button on a 12v battery when the screen on the device says 48v, then you did it to yourself.

Having to manually press a button should be enough of a safety catch.

Oh for you and me and a number of others here sure, but if you wanted to market it to the general public ya gotta think of the lowest common denominator.

 

[Rednecktek]

Mabye if I feel like it, this project is right up my current alley as a learning project to build a schematic of. I have an good idea of what parts I would use, though that would be overkill and an expensive bom cost.

PM me some renders & sketches, I'll kick in some cash towards R&D.

 

[zcskywire2]

PM me some renders & sketches, I'll kick in some cash towards R&D.

I can only do the circuit part, also Easyeda is free. Therefore schematics and layout if I do one, will be free

 

[MakeMePower]

I can only do the circuit part, also Easyeda is free. Therefore schematics and layout if I do one, will be free

based on what I am seeing, you need at least 10v to get to 60v for a 48v pack. thats 4 li-ions in series to get there. Box would actually be kind of big...

the other issue I am having, is how exactly would you use this? you need a charger, and how long does this thing need to run to wake a bms up? and what amperage? considering this would need to be a universal unit, i think we need to know more about how long at the voltage and what amperage. you might need IMR cells, this could get expensive fast.