Lithium Rechargeable battery mod

[earlynerd]

I've been working on a retrofit to the steam controller that adds rechargeable lithium ion batteries! It will not require any permanent modification to the controller itself, aside from possibly a new backplate/cover. The batteries themselves will install just like the stock AA batteries, but connect to a small circuit to handle charging them safely and regulating them down to the 3V the controller requires. The capacity will be less than stock AA cells, possibly around 20 hours or so, but I have not gotten to a point where I can test that claim just yet. Currently building prototypes, I will update with progress if there's interest!
Here's what I've got so far [imgur.com]

[ugafan]

how would these batteries be better than rechargeable ni-mh batteries currently available?

[Vepar]

That's cool what you did. But that's a lot of work for essentially just charging them directly from a controller and not needing to take out the batteries to recharge them...

You also can't take them out from what i read on your post? It's a permanent modification?

If so, you removed the possibility to just swap out batteries and continue playing wirelessly when the batteries die. Now you need a cable to charge them when they're low or dead...

I don't know, for me i'd rather just swap the rechargeable AA's and in a few seconds i'm playing wirelessly again. With your mod i'd have to sit somewhere where i can plug a wire to charge.

But kudos on the great mod! SC was designed with modding in mind so it's great to see people doing it. If li-ion batteries are your thing, go for it, i hope you make this mod successful!

[cammelspit]

This interests me in as much as I find it arousing my technical side. How are you planning on handling the positive terminals? I can think of two ways to do this. Which option are you planning?

1. You can open the controller and solder your own connection for the circuit
   
2. You can use springs and contacts to connect with the original positive terminals in the handles

If you have to replace the battery cover anyways, I assume you are going to add it's own second USB port on the cover for charging the battery?

[earlynerd]

Originally posted by Vepar:

That's cool what you did. But that's a lot of work for essentially just charging them directly from a controller and not needing to take out the batteries to recharge them...

You also can't take them out from what i read on your post? It's a permanent modification?

it is a lot of work just for that I suppose, but it bothers me to have a device that either has to use AA primary cells or charge its batteries externally in 2017. Plugging in a cable to continue using is how almost every other device currently works including almost every cell phone, so I don't see that as a big deal personally. My end goal is to make a wireless charge station of some type (magnet contacts, qi, etc) so that simply placing it back on its stand will keep the thing always topped off, and you never even have to think about the batteries again or even remove the rear cover. The firstone will probably just tap into the usb port for charging, and should be able to charge and play simultaneously.

It won't be a permanent mod or require soldering, my plan is to stick the little board to the center rear of the controller, and the lithium cells will actually be housed inside AA shaped cases. pop them in, plug them to the board, snap on a new rear cover to accommodate the extra thickness of the board (and possibly a secondary USB port, or qi receiver, or magnetic contacts) and you are set to go without soldering or voiding the warranty. pop out the battery pods, peel off the board, and replace the stock cover and it is back to factory condition.

[earlynerd]

Originally posted by cammelspit:

Which option are you planning?

1. You can open the controller and solder your own connection for the circuit
   
2. You can use springs and contacts to connect with the original positive terminals in the handles

If you have to replace the battery cover anyways, I assume you are going to add it's own second USB port on the cover for charging the battery?

The second one, but with the idea that the lithium batteries will actually be in an AA battery shaped housing which doubles as the connection to the controller battery terminals. the lithium cell inside wont contact directly, but will connect to the charger/regulator board which will feed 3.0V back to the controller terminals. The chip i selected has extremely low quiescent current draw, so while the regulator will be running all the time it will have excellent standby time.

I am thinking of a secondary USB, since tapping into the existing one requires soldering and warranty voiding, and also the controller acts strangely when plugged into a 5V source that is not the computer it is interfacing with. Even better would be a Qi wireless charge receiver and dock.

[cammelspit]

That's a good idea. I would have likely chosen the second one too. The only thing I would have wanted to do with the first option is also making room for two 18650s but I doubt there is THAT much space in the controller where making those fit would be practical. I was also thinking if you don't already have one, get one of those battery backs with the spot for the receiver. That should have plenty of room for the secondary USB port right there unless you are planning on 3D printing something custom that is. Yeah, this will be fun to follow. :)

[earlynerd]

There's definitely space for larger lithium cells, the grips are mostly empty. If you removed the AA holders and cut some plastic out you could get hundreds of hours of runtime and built in recharging easily. 18650 may fit, but you could certainly find some lithium ion polymer pouch cells that would fit. I was just shooting for minimally invasive changes so that if i decided to sell them anyone would be able to easily install it. Plus, intact warranty is a selling point too. I am planning to 3D print a custom back cover!

I may mod my personal controller with the huge battery though :)

[Vepar]

Originally posted by earlynerd:

Originally posted by Vepar:

That's cool what you did. But that's a lot of work for essentially just charging them directly from a controller and not needing to take out the batteries to recharge them...

You also can't take them out from what i read on your post? It's a permanent modification?

it is a lot of work just for that I suppose, but it bothers me to have a device that either has to use AA primary cells or charge its batteries externally in 2017. Plugging in a cable to continue using is how almost every other device currently works including almost every cell phone, so I don't see that as a big deal personally. My end goal is to make a wireless charge station of some type (magnet contacts, qi, etc) so that simply placing it back on its stand will keep the thing always topped off, and you never even have to think about the batteries again or even remove the rear cover. The firstone will probably just tap into the usb port for charging, and should be able to charge and play simultaneously.

It won't be a permanent mod or require soldering, my plan is to stick the little board to the center rear of the controller, and the lithium cells will actually be housed inside AA shaped cases. pop them in, plug them to the board, snap on a new rear cover to accommodate the extra thickness of the board (and possibly a secondary USB port, or qi receiver, or magnetic contacts) and you are set to go without soldering or voiding the warranty. pop out the battery pods, peel off the board, and replace the stock cover and it is back to factory condition.

Well, personally using AA's instead of fixed Li-Ion is a good thing for me, but only because it's a controller and it's easy to buy rechargeable AA's whereas with other devices such as phones, you can't just buy a cheap phone batter and swap it when your current one dies.

But my main gripe with this was because of the Dualshock 4 and its 4 hour battery life... Once me and my friend borrowed a PS4 to play Bloodborne and Diablo III and those controllers could barely hold a charge, always requiring us to plug them in mid game. In longer gaming sessions this becomes irritating. But with your 20 hr battery life, this becomes less of an issue because you can just charge it overnight, and a wireless charging station is a good design choice for this. As you said, just put it on there and it's ready for the next day!

I also like the backplate idea! This would be great if i can just switch the backplate and have a different power system. Having the batteries in the existing slots is great!

How thick would the modified backplate be though? I'm curious how you thought about the design and the ergonomics of it. I don't know how thick the board that controls all this is, so i'm just wondering.

All in all, i don't mind the AA's in SC, i actually like that better than the built in DS4 battery, but if there's a way to do this with just switching the backplates, i'm hella interested!

Keep us posted and good luck!

[earlynerd]

Originally posted by Vepar:

I also like the backplate idea! This would be great if i can just switch the backplate and have a different power system. Having the batteries in the existing slots is great!

How thick would the modified backplate be though? I'm curious how you thought about the design and the ergonomics of it. I don't know how thick the board that controls all this is, so i'm just wondering.

I think it would not need to be much thicker, the little charger/regulator board is only about 3mm thick. the slight additional thickness would be in the center, as far from the rear grip buttons as possible, shouldn't even be able to feel it when in use.

I'll definitely keep updates posted!

[SprayRate]

Have you thought about having one cell and a dummy on one side so you don't have to step down the voltage? Two cells may add capacity, but you're also losing efficiency because the controller has a boost regulator.

The controller can take up to 6.5V as an input voltage: http://www.ti.com/lit/ds/symlink/tps61029.pdf

Also a nice alternative to wireless charging (if you want something quick and easy) is something like this:
https://www.amazon.com/Charging-Magnetic-Generation-Spherecalls-Android/dp/B01FI53RK6/ref=pd_sim_0_5?_encoding=UTF8&pd_rd_i=B01FI53RK6&pd_rd_r=74K6JJ1YEC9G83CNZYZV&pd_rd_w=CSbVW&pd_rd_wg=PV6UU&psc=1&refRID=74K6JJ1YEC9G83CNZYZV

[earlynerd]

Originally posted by SprayRate.WorldStar:

Have you thought about having one cell and a dummy on one side so you don't have to step down the voltage? Two cells may add capacity, but you're also losing efficiency because the controller has a boost regulator.

The controller can take up to 6.5V as an input voltage: http://www.ti.com/lit/ds/symlink/tps61029.pdf

Also a nice alternative to wireless charging (if you want something quick and easy) is something like this:
https://www.amazon.com/Charging-Magnetic-Generation-Spherecalls-Android/dp/B01FI53RK6/ref=pd_sim_0_5?_encoding=UTF8&pd_rd_i=B01FI53RK6&pd_rd_r=74K6JJ1YEC9G83CNZYZV&pd_rd_w=CSbVW&pd_rd_wg=PV6UU&psc=1&refRID=74K6JJ1YEC9G83CNZYZV

The two lithium cells are in parallel, so they add capacity not voltage. There's no boost going on here, when they're full they are 4.2V and empty around 3.0V. the steam controller expects 3.0V down to 2.0V or so. The charger IC contains an ultra low quiescent current low dropout linear regulator to bring the lithium battery voltage down to 3.0V. Linear regulators are generally inefficient by nature, but the power loss here is low because it is only regulating down 1.2V at most and much less when the lithium cells are not 100% full. ~70% efficient at full charge to around 96% when almost empty. I can live with that.

I have been thinking about a magnetic contact charger dock as an alternative to wireless, would simplify things a bit.

[SprayRate]

The controller can take up to 6.5V across the battery terminals as per the power supply's datasheet.. There is no reason to step down the battery voltage. The batteries internally are connected to a boost regulator. The combination of the switching regulator + the power draw of the haptics is pretty high, so your low quiescent current LDO may not be up to the task. I'd also make sure to use batteries w/ built in protection circuits and not raw cells.

EDIT: might not be a good idea to put in more than 5.5V that USB would output.

[earlynerd]

Originally posted by SprayRate.WorldStar:

The controller can take up to 6.5V across the battery terminals as per the power supply's datasheet.. There is no reason to step down the battery voltage. The batteries internally are connected to a boost regulator. The combination of the switching regulator + the power draw of the haptics is pretty high, so your low quiescent current LDO may not be up to the task. I'd also make sure to use batteries w/ built in protection circuits and not raw cells.

EDIT: might not be a good idea to put in more than 5.5V that USB would output.

There's a low voltage cutoff, the batteries are protected. The average current is quite low even with the haptics, and I have sufficient capacitance that I dont believe it to be a problem. If you're more familiar with the input voltage limitations of the steam controller I'd be interested to hear, I wasn't able to determine some of the part numbers. It would be nice not to have to step down the batteries! I've got a spare controller minus the touchpads I can destructively test >;)

[earlynerd]

Update: it works! I've updated the album [imgur.com] with new pics. Its ugly for now, but wont be after i get a new back cover printed. I'm looking into the onboard boost converter inside the controller, but you may be right about not having to regulate down to 3V. Thanks for ID'ing it as a tps61029, I'm going to see what voltage its boosting to, and whether 4.2V is sufficiently below that for it to work properly.

[ryu]

Maybe enhance battery life by making a replacable back cover WITH a battery built in - So u can have the built in LiPo batteries and like an attached battery pack. This obviously requires some 3d printing and soldering as there'd have to be terminals for the back cover to touch on the controller itself.