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Old 11-19-2009, 05:31 PM   #1 (permalink)
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Join Date: Oct 2009
Location: Jyvaskyla, Finland
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Golfwagen - '89 Volkswagen Golf mk2
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PCB design for led bargraph battery monitor

Hello everybody.

I've been reading these forums a bit and I thought I could share something with you.

I noticed cool monitoring system in Forkenswift project and decided to build one. The original led bargraph battery monitor story was posted on in two parts. Link to first part here and second one here.

Original design is very simple and functioning. It was build on a stripboard which I didn't like much. I asked one of the commenters for a pcb he had designed and got it, but it was faulty. One of comments included design for 12V but there was no pcb design for it. Emailing others for design sounds a hassle. I made a pcb design and that's what I'm willing to share.

You can find it in .pdf format from
Index of /huski/paskoo/led_bargraph_battery_monitor_12V

Voltage range for this design is from 10.3V to 14.7V. Lowest led lights up at 10.3V and highest at 14.7V and stays lit if more voltage is applied. I'm not electrician or designer but could do pcb drawing. I made four of these myself and tried one straight out of car 12V battery. Voltage sagged to ~10.5V while igniting and jumped right to ~14.5V when motor started running. This design works at least.

I made also sleek design like the original was. I haven't built it yet but I will do so tomorrow. It is as tall as led bar so should be easy to glue led bars together. I'll post pictures and a video when done with testing.

I was going to post this as a reply in original page but didn't figure out how. Forums are easier, hehe.

Last edited by mora; 11-21-2009 at 10:13 AM..
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