Products > Test Equipment
Powerbanks tested with DHO800/900
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jsobell:

--- Quote from: shapirus on February 22, 2024, 11:11:50 am ---
--- Quote from: jsobell on February 22, 2024, 10:54:42 am ---I can confirm that the INIU 25000mAh unit works fine - https://www.amazon.com.au/dp/B08VDJP7WN
I timed it, and it gives almost exactly two hours out of a 100% charge.
That's not overly impressive, as at 3A draw it mathematically should be over 7 hours, and even allowing for losses it would be nice to have more than 25% of the power delivered.

--- End quote ---
No that's actually good enough. It's 25000 mAh at 3.7 V -- the usual disgusting trick of the powerbank manufacturers who don't specify capacity at the actual battery voltage, or, better, energy capacity. Always use energy -- measured in Wh -- to estimate the battery run time. This makes the battery 25 Ah * 3.7 V = ~92 Wh, and at 35 W power draw it theoretically means slightly over 2.6 hours. Apply the conversion losses and the chinese Ah derating, and 2 hours run time doesn't look bad at all.

--- End quote ---

That is interesting, and I see what you mean. I guess it's a tricky one to specify accurately, as you can only specify the battery capacity as it supports so many voltages. It is a bit disappointing though!

The good thing about this particular pack is that it also works in pass-through, so you can leave it connected and charge it (quite slowly) while running the scope.

I'm just running a test on a 40000mAh pack to see how that fares, but it doesn't support pass-through, so may not be worth the extra hassle. It reports 2.3-2.4A of current draw at 15V, so on that basis (40Ah * 3.7V = 148W) it's got over 4 hours of running.
I'll post up the actual running time once the scope dies :)

J.
shapirus:

--- Quote from: jsobell on February 23, 2024, 07:41:33 am ---I guess it's a tricky one to specify accurately, as you can only specify the battery capacity as it supports so many voltages. It is a bit disappointing though!
--- End quote ---
This is exactly the reason why specifying not charge, but energy capacity, in Watt-hours, and conversion efficiency at different output voltages, is the right and universal way of doing it. Having these two, the customer can adequately compare different powerbanks and estimate how long they are going to last in a particular scenario.


--- Quote from: jsobell on February 23, 2024, 07:41:33 am ---It reports 2.3-2.4A of current draw at 15V, so on that basis (40Ah * 3.7V = 148W)

--- End quote ---
Make sure you make no mistake in units calculation to avoid misunderstanding the concepts of power, current, charge, and energy. Multiplying Ah and Volts won't yield Watts:

1 A = 1 C / 1 s [current, aka charge over time]
1 W = 1 J/s [power, aka energy over time]
1 A * 1 V = 1W
1 A*h = 1 A * 1 h = 1 A * 3600 s = 3600 C [charge]
1 W*h = 1 A*h * 1 V = 1 W * 1 h = 1 W * 3600 s = 3600 W*s = 3600 J [energy]
LonnieU:
I purchased a Baseus Model BS-30KP365 for a USB Soldering Iron and for other general purpose usage awhile back.

https://www.amazon.com/s?k=B08JV4W4NY

Ran my DHO924 for an hour and 45 minutes today and it took the pack fully charged down to 56 percent. Negotiated for 15vdc and ran 2.1-2.2 amps.
jsobell:

--- Quote from: jsobell on February 23, 2024, 07:41:33 am ---I'm just running a test on a 40000mAh pack to see how that fares, but it doesn't support pass-through, so may not be worth the extra hassle. It reports 2.3-2.4A of current draw at 15V, so on that basis (40Ah * 3.7V = 148W) it's got over 4 hours of running.
I'll post up the actual running time once the scope dies :)

J.

--- End quote ---

Yes, I get almost exactly 4 hours of running from the ROMOSS 65W 40,000 mAh pack.
The only thing I'm not keen on is that it only has a single USB-C ports, so it doesn't support pass-through and you can't leave it connected to recharge when the scope is powered off.
jim_griff:
For those who are curious, you CAN indeed hook up your Rigol DHO800 directly to a battery. I've tested between 11V and 15V on the bench PSU connected to a USB-C cable and the scope powers up fine. It draws roughly between 3.1A and 2.8A depending on input voltage.

I haven't tested in-depth to see if there are any long-term issues when running at lower voltages, but the fact it powers up shows there is no USB PD negotiation going on, so no trigger board is necessary to "trick" it into working.

I'm going to build a 3S LiPo pack with in-line fuse and BMS protection to run mine when out and about. Don't see the point of inefficiencies in power banks, unless there is a solid requirement for it to constantly have 15V on the scope's USB-C power input. Maybe I'll figure out some issues later down the line! However, the scope has many Vregs inside it anyway which are serving all the necessary voltages, so I don't see any point regulating the input to 'precisely' 15V.
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