Charge Dyson with boost converter

Thread Starter

Lexdon

Joined May 10, 2021
9
Hi all,

I need to replace my Dyson V6 charger which is rated at 26.1v @780mA. Rather than buying a new charger I've contemplated buying a $2 MT3608 DC boost converter to achieve a stable 26v from a 12v DC supply which I have tons of. I'm not certain what the output current would be but to be safe I could use a 12v 1A supply which after boost to 26v will drop the current down substantially. In theory I can even use an old 5v 1A phone charger.

My presumption is that output current shouldn't matter too much as the Dyson should regulate the charge current to the battery if it's too high, or, if the current is below 780mA it will just take longer to charge which I don't mind.

Would this work? Any thoughts?
Thanks
 

jiggermole

Joined Jul 29, 2016
53
Sounds like a solid plan to me. If the old charger was just a wall wart and only provided power to the dyson. You may want to double check. For a big company like dyson with dyson branded chargers, it may make sense for the company to offload the charge control to the wall wart to save board space inside the product. Caution would be my advice, but again it does sound like a solid plan. A watt is a watt is a watt. 26.1V @ .78A is 20.4w. for the 12v (assuming 100% efficiency) would be 1.7A. so the 12v 1A power supply would only give you a charging current of 0.46A. So yeah it will take longer to charge but not by much.
 

Thread Starter

Lexdon

Joined May 10, 2021
9
Thanks.
Does anyone know if the Dyson chargers are simply DC supplies or contain charge circuitry?
By the look of it I think they are just a DC supply. This is because the wall wart doesn't have any lights to indicate charger, the stick vac has those indicators on it. Also, these days with lithium cells a BMS/charge circuit is built-in to the pack for safety.
 

Thread Starter

Lexdon

Joined May 10, 2021
9
After stuffing around with the MT3608 DC boost converter I gave up.
  1. If I fed it with a 12v 1.5A switch mode power supply it reached 60c and smelt like it was going to melt, way too hot to touch.
  2. If I fed it with a 12v 500mA transformer the transformer got so hot I feared it was going to catch fire. It hissed when I removed it from the wall and smelt like it had melted plastic inside. I thought that the battery would just draw what it was able to. Maybe my understanding of supply and load is wrong.
  3. If I fed it with a 22v 350mA power supply from my cheap 18v tools the output voltage went haywire and would never stabilise.
  4. If I fed it with a 5v 500mA phone charger it seemed stable and the temperature around 37c but the lights on the Dyson would stop charging after a little while and never fully charge. This setup also somehow killed the MT3608 which is strange as it ran much hotter and survived previously.
  5. When I bought a cheap aftermarket charger from eBay - it worked!

I really thought it would be easier than that. Happy to hear where I may have gone wrong. If I have time I'll try a new suggestion.
 
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