Battery pack for Rigol DS1054Z

[usagi]

bypass the internal ps and find out what real voltage it consumes internally. unlikely it is 48vdc. drill a hole and put a barrel connector.

And what supplies the LCD backlight?
Not DC.

not DC? how the heck do you think laptops work? AC batteries maybe? 

[tautech]

bypass the internal ps and find out what real voltage it consumes internally. unlikely it is 48vdc. drill a hole and put a barrel connector.

And what supplies the LCD backlight?
Not DC.

I have never seen a CCFL backlight that's run from a main PSU board in anything other than a TV or monitor - there is always a separate inverter running off one of the DC supplies, most commonly 12V.

Inside DSO's where space is at a premium, it's not uncommon. Sure the backlight supply is derived from DC, and from/on the main PSU PCB.
Tek TDS2000 series used this format too.

usagi implied the DSO could be powered from a single DC supply, this I doubt very much. 

I would not call the service manual from Siglent a real service manual. There is a lot of useful information, but no schematics and no parts list.

You can do a board level fault diagnosis with this info though.
Which manufacturers supply a full schematic with equipment these days?

Parts lists hopefully will soon be available, it's something I've asked for and Jade has said they're in translation. 

[pickle9000]

It's actually a little surprising that there isn't a 1054z schematic, hand made of course. Dave did a bit on the front end and there is certainly enough interest.

[Mark]

I've just done a bit of experimenting with this set for 12Vout and this set for 60Vout and a battery pack of 8 x NiMH rechargeables (2500mAH) to power it all.  It works!  It is possible to power up and run the Rigol DS1054Z on AA batteries
No use to me at the moment so I won't be doing any more, but it is possible. 

[Fungus]

I've just done a bit of experimenting with this set for 12Vout and this set for 60Vout

You mean two boosters in series, one feeding the other?

[Mark]

Yes, in series.  For a more permanent solution I'd recommend a SLA and just the second booster from12 to 60V, cheap as chips and it stays cool. 

[pascal_sweden]

It would be cool, if you can cram this into the original internal PSU space, and make an external charging connector available.

This way you would have the world's cheapest usable portable oscilloscope (counting out Owon).

Unfortunately the 4 channels are not fully isolated from each other (common negative reference).

[Terry Lingle]

most of us have a favorite cordless tool set  and most of them are 18 -20 volt  why not use  these batteries
It would be easy to cobble up a plug in banking circuit.  you then have  about say 60 volts  with three batteries  spare batteries  easily available and chargers already on hand.

[ez24]

how the heck do you think laptops work? AC batteries maybe?

What I would like to know, would the Batterizer work on AC batteries?  If so maybe they could be used for this project.

[McBryce]

Just checked Indigogo and even the nuts there haven't "invented" an AC battery yet. Maybe we should start a campaign, but it would need to have a 50/60Hz switch so that it works in all regions! 

McBryce.

[Terry Lingle]

It need a knob that goes from DC to 400 hz  For those obsolete 25 HZ systems and for aircraft   

[Eheran]

So... are there any updates on powering it with (>40V) DC through the internal PSU?

Edit:
Any ideas how to get the Math function to calculate current? Got R=7,29Ohm (so no even 10-base..) but there is no option to calculate A/B with anything but the Channels as the two inputs...? Why is there no option for a fixed value? 

[John at the Falls]

CORRECTION, April 7:
The mA reading from the analogue meter is wrong. The actual reading with a better meter is between 470 and 500 mA. I posted more information in another post below.

I just finished building a 48 Volt 2.4 AH battery back for my new DS1054Z.

The pack consists of 12 18650 Lithium batteries in series. I built a holder using 18650 battery holders from eBay.

The battery holders were hot glued to a 5mm piece of plywood and mounting tabs were also glued to the base. The battery holders provide slots for ribbon to help remove the batteries.  The batteries are near impossible to remove without the ribbon and are susceptible to damage using tools like a screwdriver.

There is no way to charge the whole pack at once. It will take three salvos in my four slot battery charger to do the job. Not a problem for me because I do not expect daily use on battery power. I will use it for trouble shooting CNC equipment and would like to have the scope isolated from Mains Power.

The batteries are 2400mAh as measured on my battery charger. They are labeled as 4200 mAh but they are about $20USD for 12. They are also labeled as "Protected" for what that may be worth. I would like to fuse protect the pack just in case.

I am using modified (screwdriver and hammer) female spade lug connectors to attach to the mains input. They are not bump proof so will look for a cord to scavenge for a proper connector.

Here are the power stats: Current draw from the battery pack is 225 mA  at 48 volts. Thats only 11 Watts.
During boot up it drew only 190 mA. I will probably never run this more than 2 hours at a time with the batteries.


So the concept works. This blog was the final factor that sold me on this scope as I was also considering a hand held for Mains isolation but those would not be optimal for other projects and courses I am working on. 48 Volts straight into the AC power input simple beautiful.

Photos are attached.

The original intent for mounting was to use heavy wire hooked around the handle hinge pins but found that it requires some drilling which I am not ready for at this point so am just using string for the time being. Please, no one suggest peel and stick Velcro because the Velcro is generally stronger than the glue which fails and makes a mess.

If anyone sees anything dangerous going on here please let me know. I have a great deal of respect for the energy density of these batteries.

[mikeselectricstuff]

Where is your fuse ?

Also, I don't recall if the Rigol has a real mains switch - if so, it is probably not rated for DC operation, so there may be arcing issues.
You should probably also do a thermal test on the PSU, as the primary-side switch, and filter components may not be rated for the higher primary current operating on DC. 

[GeorgeOfTheJungle]

Now you're feeding a continuous current (previously it was half wave) of about 3..4x more amps through just one half of the bridge rectifier, iow there are 2 diodes working 100% of the time doing ~6..8x more work than before and the other 2 diodes doing nothing. It all depends on the rating of that bridge so perhaps that's something worth investigating.

[John at the Falls]

Now you're feeding a continuous current (previously it was half wave) of about 3..4x more amps through just one half of the bridge rectifier, iow there are 2 diodes working 100% of the time doing ~6..8x more work than before and the other 2 diodes doing nothing. It all depends on the rating of that bridge so perhaps that's something worth investigating.

  I just checked AC current draw with a Kill O Watt meter. It is drawing 290mA on 118AC Volts. That is in the same ballpark if not more than the straight DC battery pack draw of 225mA. The KOW meter also indicates a whopping 36 Volt Amps but only 22Watts Power. Again, the calculated DC power draw is 11 Watts.

Watching Daves teardown video, starting at 11:15
https://youtu.be/kb9P1Am9aFU?list=PLvOlSehNtuHsy89OdSxBajult8e5srVLA

all the components look beefy enough to handle much larger currents and the bridge rectifier looks like it could handle 2 to 3 Amps or at least 500mA per diode.  It all looks fairly simple with just step down, rectify and filter then regulate. Aside from the bridge rectifier, there are only 3 active components to deliver output voltages. But what are the opto couplers used for in a PSU? There is the circuit in the top left section of the Hot End; a diode coming off the first stage regulator, a filter cap then the opto couplers and a single transistor. Does this supply a reference voltage to the Cold end regulators?

When the batteries drop to 36 Volts, which is when the scope will shut down, the Amp draw will be 300mA.
After getting some facts, I am not worried at all about damaging the scope.

I am worried about burning my house down though with the battery pack.
My real concern is doing something unseen and stupid with the Lithium batteries that I am not aware of. Each battery is supposed to be current protected and I confirmed that once by accidentally inserting it in the battery charger backwards and it now no longer works. But I do not mind wearing suspenders and a belt when it involves the possibility of burning my house down.

[GeorgeOfTheJungle]

When it's plugged into 118Vac the capacitor after the bridge was at ~168V, now it's at ~48V  about 3.5x times less volts ergo the current must be 3.5x more amps, and it's all going through the same 2 diodes always when before only half of the time (half a cycle). So 3.5x times higher current * twice the time.

Put it another way: 118V*0,25A is not = to 48V*0,25A, so something is wrong there because it draws the watts it draws (and that's a constant regardless of V).

[Housedad]

Where is your fuse ?

Also, I don't recall if the Rigol has a real mains switch - if so, it is probably not rated for DC operation, so there may be arcing issues.
You should probably also do a thermal test on the PSU, as the primary-side switch, and filter components may not be rated for the higher primary current operating on DC.

Dave's tear-down video of the ds1054z shows that it has a hardwired main power switch that throws the 120v.  No soft switch.

[StillTrying]

When it's plugged into 118Vac the capacitor after the bridge was at ~168V, now it's at ~48V  about 3.5x times less volts ergo the current must be 3.5x more amps, and it's all going through the same 2 diodes always

I estim guestimate that when it's run from 118Vac the bridge conducts only about 1/5 of the time(1/10 of the time each pair of diodes), giving a peak of current and volt across each diode to keep the 160Vdc topped up.
I guestimate the average dissipation in each diode always less than 200mW, even when only 2 are being used with DC input.

[GeorgeOfTheJungle]

the bridge conducts only about 1/5 of the time

You're right, 100% right, my bad.

[John at the Falls]

After using this battery pack a few times and watching how many Amp hours it took to recharge, my current reading with the analogue meter did not make sense.
I found a cheap digital meter that would handle the current. My Fluke 16 only reads up to9.9 UA.
The bottom line is that it is using about 470 to 500 mA  between 54 to 50 Volts input.

I am not going to worry about the rating on the switch or the bridge rectifier. The bridge rectifier looks beefy enough and both the bridge and switch should be cheap and easy to replace even if I have to use generics.

I get at least 2 hours run time off the battery which is more than I need for troubleshooting CNC equipment.

Recharging the batteries is a small bother but I am use 18650 batteries for everything I can and am building battery packs for other equipment that uses 9 volts and LED lights that use 3 AAA batteries.

[Diosol]

Here's my setup. Rigol runs just perfectly from four 18 V tool batteries. The background noise is nonexistent and makes real joy of scoping. I also have new Fluke Scopemeter but this time I needed clearer screenshots and better data.

Would I recommend this? Nope, if you are 200 pound gorilla like AvE says it. But at this job Rigol made the difference between solving problem or not. Mining industry is really hard on equipment and I was surprised how Rigol even survived. For future I'm real keen on waterproofing this scope. It's so much better than other handheld scopes we have.

[bitseeker]

Wow, that's quite an environment for it. It'll be interesting to see how you go about waterproofing it.

[tautech]

Wow, that's quite an environment for it. It'll be interesting to see how you go about waterproofing it.

Seal the fan opening ?   

[bitseeker]

Liquid cooling.