And finally the 20V tool PCB for the 20/40V battery pack system. This shares the same complex power management system as the others for ultra low standby current.

It’s quite perplexing. I think two of the inputs are analogue for voltage monitoring.

An unexpected feature of this module is that it doesn’t control the tool directly, but just sits between it and the battery. When the tool is used this module detects the load, wakes up and switches on the MOSFETs to allow the tool to be powered fully. The bulk of the circuitry is to allow the module to sleep when not needed.

Saksalainen Bosch vahvistaa pienkoneidensa akkuallianssia nostamalla osakeomistuksensa ruotsalaisen Husqvarnasta 12 prosenttiin. Husqvarna-konserniin sisältyy myös tytäryhtiö Gardena ja sen Flymo-brändi, jotka ovat mukana Boschin Power for All -allianssissa.

When it comes to cordless power tools, color is an important brand selection criterion. There’s Milwaukee red, for the rich people, the black and yellow of DeWalt, and Makita has a sort of teal thing going on. But when you see that painful shade of fluorescent green, you know you’ve got one of the wide range of bargain tools and accessories that only Ryobi can offer.

Like many of us, Redditor [Grunthos503] had a few junked Ryobi tools lying about, and managed to cobble together this battery-powered inverter for light-duty applications. The build started with a broken Ryobi charger, whose main feature was a fairly large case once relieved of its defunct guts, plus an existing socket for 18-volt battery packs. Added to that was a small Ryobi inverter, which normally plugs into the Ryobi battery pack and converts the 18 VDC to 120 VAC. Sadly, though, the inverter fan is loud

I’m knocking together a gadget to run 12V devices off of 18V Ryobi One+ battery packs (of which I have a few). I found a sufficiently beefy buck converter a while back that knocks 18V (nominal) down to 12.6V, but there’s nothing in it to keep the battery from being discharged too much. This circuit will cut off its output at around 14.28V…2.86V per cell for Li-ion, 952 mV for NiCd (since I still have some of those).

Ruotsalainen Husqvarna liittyy tiukemmin Boschin alulle panemaan Power for All -akkuallianssiin, jossa yksi sama 18 voltin akkupaketti käy useiden eri valmistajien pienlaitteisiin. Allianssissa ovat mukana Boschin ja Husqvarnan lisäksi Gardena, Bosch, Flymo, Gloria, Steinel, Rapid, Wagner, Perfect Pro ja Kûbler Workwear.

Akkukäyttöiset pienkoneet ovat yleistyneet nopeasti, joten akkuja alkaa olla jo varsin montaa sorttia. Yleensä ne eivät ole yhteensopivia muiden valmistajien kanssa. Kaksi vuotta sitten Bosch lähti hakemaan laajempaa yhteensopivuutta 18 voltin Power for All -yhteenliittymällä. Ja sai samalla lisää bisnestä akkutuotantoonsa, koska allianssiyritysten kaikki akut tulevat Boschilta.

Most of us own at least one battery-operated power tool, including a charger. What if we could use their batteries also for our electronics projects? Let’s have a closer look!

Viewer comments:

I believe Ryobi brand 18V batteries have undervoltage projection built into the battery. It’s pretty uncommon in other brands though.

Thank you for the info. Others mentioned that Makita batteries are also protected. Mine are not, but Lidl replaced mine

Rob is right here. Ryobi batteries are expensive because they got their protection built-in, that’s why the tools are cheaper, too.

They are protected and even showing the battery level,

Milwaukee has built in protection as well, they even have a temp sensor, and without it it’s charger will not charge them.. Ask how I know

For Makita (at least LXT) the protection comes from the tool . There is also a board inside but it does not disconnect – or + .. those go directly to accus

Ryobi indeed does, and it sucks. if you pull the juice really quick it will not clamp fast enough and they will cut out and won’t take a change. you have to dissemble the battery and bypass the controller and spoon feed it.

Makita batteries (at least the ones I[ve had apart) do not have undervoltage protection – this would require a 100A capable switchiung device in the battery – there is no point in them including this as the power tool itself has switching for speed control.

From what I’ve heard (never owned or taken apart a lithium makita battery), some do and some don’t depending on age and capacity.

Dad uses the AEG (rigid in America) ecosystem primarily because at least as far as we know, they always have had some for of protection in the battery. From attemping to fix a water damaged one and reading online, the batteries don’t have cell balancing, but do have individual cell monitoring and over temperature cutoff. Power switching is two large mosfets in reverse in series so the battery can also be isolated if overcharged and when flat. There is definitely no protection in some of the tools we have – one rattlegun that blew up consisted of a 555 timer as the speed control and a small microcontroller that did nothing else except turn the led light on and fade it out. The battery protection circuit definitely gets a workout and automatically resets as devices like angle grinders and chainsaws will routinely overheat and rapidly discharge batteries.

The overall main components and approach seems to be fairly similar to a moderately recent big clive video of a teardown of a no name battery.

I believe einhell has some built in protection and doesn’t break the bank either

@Andreas Spiess are you aware of any over discharge protection modules that could be used in home made ‘accessories’? The normal 5S BMS modules all seem to require direct connections to the individual cells of the pack.

You can buy adjustable Relay and/or Mosfet based under-voltage modules from the usual online places. I have one on my desk right now – model XY-CD60 – however there are literally hundreds of different options

@Dan Nuțu – any device or circuit that monitors a battery will drain the battery, just like the inbuilt BMS of a battery drains the battery. However the drain of a decent under-voltage cut-off circuit is absolutely TINY compared to the capacity if the battery itself.
Any such drain is irrelevant if you charge the battery after using it. However if you leave the battery fot 12 months after you have fully drained ot to the cutoff voltage, then it might cause an issue.
The Ryobi tool batteries are notorious for that because the BMS runs off the first cell only. So if you store a Ryobi battery in a discharged state for a long period, the first cell(s) in the pack gets destroyed, which makes the whole pack unusable.

New power tool battery technology
One of the most recent developments to the market is DeWALT’s new FLEXVOLT battery. The batteries are fully compatible with existing DeWALT 18V XR tools and when fitted to the new DeWALT XR FLEXVOLT tools the voltage then surges to an unparalleled 54V. FLEXVOLT is a world first with this new 18/54V battery platform and the aim as DeWALT state is to give you: “the power of corded, freedom of cordless.”

Dewalt battery in a Makita, Makita in a Milwaukee, Milwaukee in a Dewalt, Dewalt in a Ryobi, Porter Cable in a Makita………………… The possibilities are endless with battery adapters.