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| Powerbanks tested with DHO800/900 |
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| Houseman:
Ah, ok got it now. It is not just a cigar plug. How long does it last? |
| shapirus:
--- Quote from: Houseman on February 19, 2024, 11:14:44 am ---Ah, ok got it now. It is not just a cigar plug. --- End quote --- But it is. It's a plain automotive 12V USB power supply designed for the cigarette lighter socket, only of the fancier ones -- higher power and with support of PD, QC and all the type C paraphernalia. --- Quote from: Houseman on February 19, 2024, 11:14:44 am ---How long does it last? --- End quote --- Haven't measured. Will be equal to: battery energy capacity * DC/DC converter efficiency * wires and connectors loss factor / scope power. Very rougly, that's a 50 Wh battery, let's assume 80% conversion efficiency, then at 35 W consumption it's going to last 50 Wh * 0.8 / 35 W ~= 1.14 h. Speaking of min voltage, it seems to work fine at (currently) ~11V, and there's really no reason for it not to: there's a plain switching buck-boost converter inside, and they typically have a wide range of acceptable input voltages. I will test it later with a lab PSU to see how low a voltage it can accept on the input. |
| jsobell:
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. But, if two hours is sufficient, then this model works fine and is nice and cheap. I've also ordered a 40,000mAh unit to test, and I'll post if it works or not. It's a bit of a minefield choosing the packs, as some are only 5V, and many split their current over several ports, rather than a single one with 15V@3A as we require. |
| shapirus:
--- 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. |
| jsobell:
--- Quote from: Houseman on February 08, 2024, 08:43:42 pm ---I confirm that powerbank INIU BI-B63 clamed as PD 100W 25000mAh does not complete Rigol's boot. Fan goes on but after a while DHO shuts down. Asked for refund. --- End quote --- Interesting, I have the same one and have no issues running the scope. I can use it in either output socket (45W or 100W) and I get about 110mins out of a full charge. The pack is rated to 3A@15V, which meets the requirements. |
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