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towerofpower256 / davidmac.pro

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posts/2021-12-20-portable-battery-box/ #19

Open utterances-bot opened 2 years ago

utterances-bot commented 2 years ago

DIY Portable Battery Box for camping with a CPAP

Here's an easy and portable DIY battery box I made to go camping with my medical CPAP machine. It's also much cheaper than the official battery pack, and I can charge my phone from it too.

https://davidmac.pro/posts/2021-12-20-portable-battery-box/

Skovtrolden70 commented 2 years ago

Hi David, Looks great, but my Resmed runs on 24V, and I thought they all did, but I don't see any step-up Converter in your box, so do you have a 12V version, or do you use a separate step-up converter? Cheers Peter

towerofpower256 commented 2 years ago

Hi David, Looks great, but my Resmed runs on 24V, and I thought they all did, but I don't see any step-up Converter in your box, so do you have a 12V version, or do you use a separate step-up converter? Cheers Peter

Hi Peter, I've got a Resmed 12v power supply that can use power from a 12v camp / car battery. It looks like this, and usually costs around $110-$120 AUD. image

I did look into making my own 12v power supply for it using spare parts, but there's a little pin in the middle of the power plug that needs to be 3.3v and a specific resistance. If that pin isn't there and correct, the machine will boot loop, rebooting over and over again, sort of like a physical DRM that wants you to use a genuine Resmed power supply.

That said, the CPAP machines are sensitive and have very low tolerances for power, so you're probably better off using a genuine power supply anyway.

There are some guides & discussions on it here:

Skovtrolden70 commented 2 years ago

Hi Davis, OK I also got one of those 12 to 24V converters from ResMed, but as you didn't mention it, I assumed you didn't use one, the best information about the centerpin I found, was in the youtube video you link to in your reply. But is is way easier with their own converter. I still need to check other 2 links, thanks :-) Cheers Peter

buzzerdbait commented 1 year ago

Hi David. Outstanding idea. How do you charge the battery? I’m assuming you plug a cord into the cigarette liter socket?

towerofpower256 commented 1 year ago

Hi David. Outstanding idea. How do you charge the battery? I’m assuming you plug a cord into the cigarette liter socket?

I've got one of these 12v 4-stage SLA battery chargers from Jaycar. It goes great with all sorts of sealed lead acid batteries, like this one. I just attach the clips straight to the battery and leave it go in my garage.

https://www.jaycar.com.au/4-stage-6-12v-4a-battery-charger-with-lcd-display/p/MB3611