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Boost Converter to run my laptop from my RV batteries.
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Hi all,
I have a Lenovo laptop that currently uses an AC power supply (135W).? I think the output is aprox 20V.
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I'd like to be able to run it from the RV batteries (typically 12 to 13V) without the need for an inverter.
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I think the major issue is the current draw.? 135W at 20V can draw 6.75A so a 12V boost converter would probably draw 11.25+ Amps.
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Any thoughts on how best to achieve this?
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Luke
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On Sat, Apr 19, 2025 at 07:20 PM, Luke Vogel wrote:
So, the question you need to answer is:? Can you correctly power the circuits inside the laptop that normally need 20 V, from just a 12 - 13 V power source and no inverter? ?
My first answer is "no!"? Not without an inverter to boost it up to 20 V.? But to correctly answer it, you would need to know exactly what inside the laptop gets driven by that DC input voltage, and whether or not it can accommodate such a low voltage.? If it goes directly into an internal DC-DC converter (and nothing else) and if that converter is compliant enough to accept 12 V without a hiccup, then OK.? But do you have access to the schematic and internal parts list for this laptop?
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Without that, I think the best you can say is that it is highly unlikely to work without an inverter.
I think that is incorrect.? Electronic circuits need certain voltages to work properly, and if 12 V is too little compared to the 20 V that it needs, then either it won't work with only 12 V, or it could let out the "magic smoke", or do something else bad.
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Yes, that is a reasonable estimate - if you can use a high efficiency inverter. ?
Note that your RV's battery might be as much as 15 V when charging.
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Also make sure that the laptop actually needs 20 V.? How did you determine that?? If you measured its AC-DC power supply without the laptop connected, it might not be the normal in-circuit voltage, as you probably know.
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Are we at odds over use of the word "inverter"?? You spoke of a "boost converter", but isn't that an inverter?
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Andy
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Maybe experiment with something like this from ebay. Read the description, looks like it may work for your use.
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Dave On 4/19/2025 4:08 PM, Luke Vogel via groups.io wrote:
Hi all, |
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An excellent solution is to buy a Lenovo 65W USB-C DC Travel Adapter. See . With that unit, you would have one that you can trust to safely power your laptop and save the time an expense to experiment with building your own device.
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You can also find third party adapters at cheaper prices but then you would need to evaluate user reviews for the one you buy. |
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On Saturday 19 April 2025 07:42:44 pm Andy via groups.io wrote:
Are we at odds over use of the word "inverter"?? You spoke of a "boost converter", but isn't that an inverter?No. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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Hi TJTomPhillips,
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No, this wont work as it cannot deliver the current needed.
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Hi Andy,
a DC-DC boost converter is not an inverter.? I was hoping to avoid the use of the inverter I already have because there is additional overhead on that device that will draw more current from my RV batteries.? I'm aiming for a reasonably efficient solution.
Hi Dave, Yes, this looks like it may do the job.? The description of the product recommends additional cooling if the current draw exceeds 8A.? This may not be a problem though because I believe full current draw would only be necessary if charging an almost flat battery.? As the battery state of charge improves the bulk charge current would reduce. ?
I'll investigate this option further.?
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Thank-you all for your replies.
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Luke
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and who your friends are! Donald. On 4/19/25 20:31, Dave via groups.io
wrote:
Maybe experiment with something like this from ebay. Read the description, looks like it may work for your use. Dave On 4/19/2025 4:08 PM, Luke Vogel via groups.io wrote:Hi all, I have a Lenovo laptop that currently uses an AC power supply (135W).? I think the output is aprox 20V. I'd like to be able to run it from the RV batteries (typically 12 to 13V) without the need for an inverter. I think the major issue is the current draw.? 135W at 20V can draw 6.75A so a 12V boost converter would probably draw 11.25+ Amps. Any thoughts on how best to achieve this? Luke |
开云体育Apologies for replying to myself - you can also (for both bitly and tinyurl) as a '+' after the tinyurl or bitly link to find out where it REALLY goes, then clip the "?....." stuff away from the link you find and see if it works. I don't like giving the internet lords the power to track my browsing habits and my friend connections. Donald. On 4/20/25 18:01, dhlocker wrote:
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if the tracking info is eliminated early in the process. Donald. On 4/20/25 18:04, dhlocker wrote:
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Luke Vogel