MZ-RH1 DIY battery-pack

[MDfreak]

UPDATE: Dutch DIY-instructions can be found here:

http://www.mdcenter.nl/artikelen/mzrh1/batterypack.php

(hope for an English translation soon)

As promised in our RH1 review I would provide you with an alternative for the dry-battery-case we know from different MD-walkmans but that is absent with the MZ-RH1.

Today I got the final components for the prototype and it showed the battery-pack works as expected. Detailed plans on how to build one yourself will be available soon but for now I just want to show you that it is possible to make a simple alternative for the dry-battery-case.

Battery-pack "proof of concept".

WARNING! Directly connecting 4 non-rechargable AA's or fully charged Ni-MH batteries can produce a too high voltage on the RH1's USB port and can cause permanent damage to the RH1. But because we had to return the RH1 to Sony before finishing the final prototype we carefully tried if the concept works with almost empty Ni-MH batteries.

Battery-pack prototype.

As you see we added some extra electronics to make the batterypack more safe to use with the RH1 and it also makes it more userfriendly. Furthermore the RH1 is back to Sony so sadly we could not take a final picture of the RH1 connected to the prototype of the batterypack.

Estimated batterylife

Based upon calculations when using 2500 mAh Ni-MH batteries.

- around 33 hours of PCM recording

- around 125 hours of Hi-LP playback

- around 6,5 full charges of the Li-ION battery

Extra features

- voltage regulation to regulate battery-voltage.

- can be used without the need of a Li-ION in the RH1.

- can be used to charge the Li-ION.

- can be used to power the RH1 during normal operation (e.g. recording or playback).

- on/off switch to turn of the power to the electronics.

- power-LED indicating the batterypack is on.

- low battery LED indicating the batterypack is almost empty.

- adjustable low battery indication: by adjusting the variable resistor you can adjust on which moment the low battery LED will go on allowing you to adjust the time between the LED lighting up and the moment the batteries are fully empty.

- can also power other USB-devices that use USB-bus-power like e.g. mp3-players

Basically the RH1 will not see the difference between this batterypack and the supplied AC-adapter. So everything you would use your AC-adapter for you can use this battery-pack for.

P.s. as said before: detailed plans on how to build one yourself will follow soon. Please do not try to make a batterypack yourself without understanding how it works as it can damage your RH1 so that it will not work anymore.

Edited July 30, 2006 by MDfreak

[danielbb90]

Thats neat...

Could that be applyed to the MZ-NH1?

(You should add a resistor to the circit to prevent damage to the player - From the 6 volts of the AA's to the 5Volts of a USB port!)

Edited April 27, 2006 by danielbb90

[MDfreak]

Thats neat...

Could that be applyed to the MZ-NH1?

Probably not. I tested it with my RH10 and NH700 and they immediately go into "PC --> MD" modus after connecting the USB cable so normal operation is not possible after that. An alternative would be to adapt the batterypack in such a way it uses the normal DC-in. For the NH1 that would result in using another pin of the special connector.

So this specific design is for the RH1 because it uses it's the USB also as DC-in. For other models you will need a minor adjustment to the battery-pack to connect it to the normal DC-in and you will need an adjusted output-voltage (with most models 3V, with the NH1 6V)

Edited April 27, 2006 by MDfreak

[danielbb90]

Probably not. I tested it with my RH10 and NH700 and they immediately go into "PC --> MD" modus after connecting the USB cable so normal operation is not possible after that. An alternative would be to adapt the batterypack in such a way it uses the normal DC-in. For the NH1 that would result in using another pin of the special connector.

So this specific design is for the RH1 because it uses it's the USB also as DC-in. For other models you will need a minor adjustment to the battery-pack to connect it to the normal DC-in and you will need an adjusted output-voltage (with most models 3V, with the NH1 6V)

I was looking at this..

http://forester.uf.a.u-tokyo.ac.jp/~ishiken/e/ADAM/HiMD.html

If you just did this http://forester.uf.a.u-tokyo.ac.jp/~ishike...ersupply_07.JPG

With the USB cable and forgot about the rest of the steps, would this work? From chargeing through a USB port?

(I know its lower voltage...)

[MDfreak]

I was looking at this..

http://forester.uf.a.u-tokyo.ac.jp/~ishiken/e/ADAM/HiMD.html

If you just did this http://forester.uf.a.u-tokyo.ac.jp/~ishike...ersupply_07.JPG

With the USB cable and forgot about the rest of the steps, would this work? From chargeing through a USB port?

(I know its lower voltage...)

Yes, that is the same idea. What it does is putting the voltage of the battery-pack on pin 1 of the USB-connector which is the normal 6 Volt DC-in. So just like I said: instead of using the USB-power you use the DC-in (which in case of the NH1 is "hidden" in the special cable).

The only problem with those plans is that you destroy your dockingstation and it is not a very "compact" endresult. With a little different approach you would not have to destroy the dockingstation and you will end up with a design like mine except with the special USB-connector in stead of the normal one.

If I had to make a batterypack for the NH1 it would end up something like this except for minor changes in the electronics:

MZ-NH1 battery-pack "mockup"

Edited April 27, 2006 by MDfreak

[ozpeter]

Please do not try to make a batterypack yourself without understanding how it works as it can damage your RH1 so that it will not work anymore.

Thanks for the warning - I'll wait for further details before attempting to connect anything to mine.

I wish.....

[Stuge]

Nice work Mark ..

[bobt]

Just a thought, haven't tried it myself, but with several a/c adapters around, you could wire up your batteries for six volts, and feed it via plug into the cradle of the NH1. A little bulky, but might work, other alternative is to find the pinouts on the NH1 USB cable and feed into that.

TTFN,

Bob

[MDfreak]

Just a thought, haven't tried it myself, but with several a/c adapters around, you could wire up your batteries for six volts, and feed it via plug into the cradle of the NH1. A little bulky, but might work, other alternative is to find the pinouts on the NH1 USB cable and feed into that.

TTFN,

Bob

Yes, the only problem with directly feeding batteries to a DC-in is that batteries don't have a constant output-voltage. It depends on load and how full they are. A DC-in is designed to take a constant voltage so you have to be very careful not to damage it. The normal battery-supply is designed to handle batteries with changing voltage so that is no problem. Furthermore it may be nice to have some kind of reference to know how full your battery-pack is.

Example:

- Ni-MH batteries say they are about 1.2 or 1.25 Volt. This voltage is an average and it can range from about 1.5 till 1.0 volts untill fully drained. So if you use 4 batteries for the pack you have voltages ranging roughly between 4 and 6 Volts. With an USB-connection expecting 5 Volt you have to look out for overvoltage. With using a 6 V DC-in you may have the problem that MD stops working way before the batteries are empty.

- Normal alkaline AA's say they are 1.5 Volts. But this voltage can be about 2 Volts with a full battery so with that you have to be even more carefull because the voltage can get as high as 8 Volts when using 4 of them.

With that in mind we tried to find out the save ranges with which the RH1 still works fine and designed the batterypack in such a way the output voltage of the batterypack will be always in that range so that there is no risk of damaging the device. So it does not matter if you use full or empty batteries or rechargable or dry.

With the NH1 we also would have to do some tests to find out how much margin you have on the 6 Volt input before the NH1 stops working. And with the results of those tests you could design an appropriate battery-pack. The same for e.g. the RH10 or NH700 that have a 3 Volt DC-in.

Conclusion: you can better be safe than sorry. That's why our battery-pack has some electronics in it. To be on the safe side.

[MDfreak]

I'm still working on the DIY info for making this batterypack yourself but suddenly I had some additional ideas I want to try.

1) adding a more detailed battery-indication.

2) adding an improved version of the phantom-power circuit you find on our site so that it also works on the batterypack:

http://www.mdcenter.nl/artikelen/mics/portablephantom.php

I already ordered some sample-chips to step-up the voltage of the batterypack to about 25 volts (phantom power has to be between 12 and 48 volts). So plenty for most professional microphones that almost all need the minimum of 12 volts.

In this way you have not only longer batterylife for the RH1 but you can also connect professional microphones that need phantom power.

I think it is a nice idea to have one additional box with your RH1 that does it all. What do you people think of the idea?

p.s. some people complain about the mic-preamplifier in MD-equipement and therefore want to use their own external pre-amp to connect microphones to the line-in. Furthermore some people want to increase the power-output of the headphone out to power large headphones. Those two things also can be incorporated in the same box. Therefore I only need more info on good amplifier-chips for audio-use.

[Roamer]

The standard voltage for phantom power is normally 48V, but effectively some mics have a wider range of choice for voltage input. The voltage specification should be check with the mics to make sure it will work properly.

Otherwise this sounds like an interesting project.

[MDfreak]

The standard voltage for phantom power is normally 48V, but effectively some mics have a wider range of choice for voltage input. The voltage specification should be check with the mics to make sure it will work properly.

Otherwise this sounds like an interesting project.

Officially you have a 12V, 24V and 48V version. Most microphones I checked (Shure, Sennheiser e.t.c.) will work with voltages as low as 12V but I try to make it as close to the most used 48V. Therefore however I will have to do some more experimentation to get a nice and stable 48 volts out of 4 AA's.

[Stuge]

can you make battery pack for DH10P ?

[MDfreak]

can you make battery pack for DH10P ?

The DH10P has a 6 volt DC-in if I'm correct? If so and after testing what supply-voltages the RH1 accepts I would say the only thing you need to do is changing the type of USB-cable and connect the right pins.

[Odyssey]

UHM, instead of building all your electronics to curb voltage variances, have you considered just applying the 4volts to the battery terminals with a dummy battery for the plug?

This would allow the MZ-RH1 to use its own electronics and you are not going to accidentally damage this expensive recorder by feeding the wrong voltage in a USB port.

Just a thought.

O

[MDfreak]

UHM, instead of building all your electronics to curb voltage variances, have you considered just applying the 4volts to the battery terminals with a dummy battery for the plug?

This would allow the MZ-RH1 to use its own electronics and you are not going to accidentally damage this expensive recorder by feeding the wrong voltage in a USB port.

Just a thought.

O

Yes, also tried that but you still end up with variating batteryvoltages. Furthermore, most batterychargers charge batteries in pairs (2 or 4 of them) so to get about 4 volts you need 3 batteries. So if you have drain an additional 4th battery before you can charge the other 3.

[yoda_143]

UHM, instead of building all your electronics to curb voltage variances, have you considered just applying the 4volts to the battery terminals with a dummy battery for the plug?

This would allow the MZ-RH1 to use its own electronics and you are not going to accidentally damage this expensive recorder by feeding the wrong voltage in a USB port.

Just a thought.

O

You'd be surprised to know how unstable in terms of voltage most PC USB ports are. So I think any device built to be charged via USB will be protected against damage by varying voltages. At least that's how a good engineer would do it, but you never know with Sony, right ?

[MDfreak]

You'd be surprised to know how unstable in terms of voltage most PC USB ports are. So I think any device built to be charged via USB will be protected against damage by varying voltages. At least that's how a good engineer would do it, but you never know with Sony, right ?

From looking at some service-manuals of different NetMD/Hi-MD devices there is some protection but that is very limited. Furthermore a good engineer designs it's devices in such a way it complies with the standards used and does not rely on protections in other devices.

Also most USB-connectors will indeed output not exactly 5 volts. From the outputs I measures all were below 5 volt and none above. That is in line with the service-manuals I looked at where overvoltage-protection is very limited but it was not a real problem to let USB-devices work on lower voltages that 5 volt.

But as said before, to have a reliable batterypack without any strange behaviour in the pack and connected device I designed it in such a way that will output close to 5 volts as USB requires exept when the batteries get realy drained.

[MandoRod]

Dear MDFreak, Any progress to report on this project? Having just gotten an MZ-RH1, I would be very happy to acquire the item you've been describing in this thread. I'm not enough of a hardware guy to make one myself, but would pay genuine bucks for one if some enterprising person were to make one for me. It's really too bad that Sony didn't provide an add-on battery box for the RH1 for those recording situations where you need to record past the capacity of the Lion battery and you can't plug in your AC power adaptor to tide you over. RF

[MDfreak]

Dear MDFreak, Any progress to report on this project? Having just gotten an MZ-RH1, I would be very happy to acquire the item you've been describing in this thread. I'm not enough of a hardware guy to make one myself, but would pay genuine bucks for one if some enterprising person were to make one for me. It's really too bad that Sony didn't provide an add-on battery box for the RH1 for those recording situations where you need to record past the capacity of the Lion battery and you can't plug in your AC power adaptor to tide you over. RF

Currently very busy with other things but I will try to have the plans ready as soon as possible.

[bobt]

http://www.mdcenter.nl/artikelen/mzrh1/batterypack.php

Just got this link a couple of days ago from the dutch minidisc site, translation link didn't work, but babelfish did a credible job of translating. seems to have most of what has been said here, but thought I'd post it anyways.

TTFN

Bob

[Ferenc]

Hello!

Nice project... Just a question: what's the role of R5 between pins 2 and 3 of the USB connector?

[MDfreak]

Hello!

Nice project... Just a question: what's the role of R5 between pins 2 and 3 of the USB connector?

To let the RH1 know that a charger/powersupply is attached.

[Ferenc]

To let the RH1 know that a charger/powersupply is attached.

Thanks, MDfreak!

Does this resistor affect the use of the battery pack to other USB-powered devices?

Edited September 18, 2006 by Ferenc

[MDfreak]

Thanks, MDfreak!

Does this resistor affect the use of the battery pack to other USB-powered devices?

Not that I know of.

[Kain_]

Sorry to resurrect a such old thread but as several topics on battery packs have been lately posted of MDCF, I thought it could be a good idea to share what I have done using MDfreak diagrams from MDcenter.nl :

Note that it works perfectly to recharge my RH1

Edit : thanks to guitarfxr for checking my typo

Edited November 9, 2008 by Kain_

[Strungup]

" Not that it works " Possibly meaning " Note that it works "

looks neat Kain . nice wire twist and clean layout , good job dude!

[mat_skm]

Yes, that is the same idea. What it does is putting the voltage of the battery-pack on pin 1 of the USB-connector which is the normal 6 Volt DC-in. So just like I said: instead of using the USB-power you use the DC-in (which in case of the NH1 is "hidden" in the special cable).

The only problem with those plans is that you destroy your dockingstation and it is not a very "compact" endresult. With a little different approach you would not have to destroy the dockingstation and you will end up with a design like mine except with the special USB-connector in stead of the normal one.

If I had to make a batterypack for the NH1 it would end up something like this except for minor changes in the electronics:

MZ-NH1 battery-pack "mockup"

Hi All (MDfreak especially). Sorry to resurrect such an old thread, but I will soon be obtaining an NH1 without the charging cradle (but with the USB cable). I've been looking on the forums for a way to power the unit using the USB cable. I know it can't be done by the computer (multiple posts!)

I really like the project idea of this page and would like to adapt it to NH1. I will need a 6V voltage regulator. I'm planning on using a variable regulator. Also I want to use NiMH batteries, so will need about 8 of them (because the regulator will eat about 2V). I'm a bit concerned about over-discharging. So I'm trying to figure out how to add a protection mechanism to shut off the circuit if the voltage falls below a certain level. So far the best I've been able to come up with is the idea of wiring a second op-amp circuit tuned to a switching voltage a little below the first one. The output of this would trigger a latching relay to switch off the circuit (i.e., its default position would be to keep the circuit on). Would this work? It seems like there must be a more elegant solution to this...

Any suggestions appreciated!

[1kyle]

Nice ideas everone but there are some quite cheap "Portable USB chargers" around with either rechargeable or normal batteries in them. These are quite small and can also be used for some mobile phone charging as well such as Motorola Razr series etc.

These usb chargers have electronics in them --I' recommend these --cheap as well

I applaud all sorts of creativity --great stuff and there isn't enough of it around but in this case I thing the commercial products are probably better value at this time.

If you WANT to do it yourself here's a decent guide (illustrated)

http://www.instructables.com/id/MintyBoost...ed-USB-charger/

If you want to get a commercial device

"Rolls Royce" version (relatively expensive but brilliant)

http://www.ohgizmo.com/2008/01/21/powersti...le-usb-charger/

Cheaper

http://www.amazon.co.uk/LUPO-POWERSTICK-Po...0691&sr=8-1

Cheers

-K