Most efficient way to get 1.5 volts from 3.7 volts or less?

I should proofread my posts better. 1.55 volts and 1.45 are indeed the correct voltages. Eric

Reply to
etpm
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Greetings George, I looked and found a couple with apprpriate specs except for the miniscule size and the location of the solder pads. I did see an evaluation board described though. I still need to see if one is available and cheap enough. I also need to figure out if the noise coming from a DC-DC converter will upset the electronics in my gauge. Not sure how to do that yet. Eric

Reply to
etpm

On Wednesday, September 27, 2017 at 12:01:40 PM UTC-4, snipped-for-privacy@whidbey.com wr ote:

te:

e=100

Does cost matter? (As long as less than ~$20 or something.) (It's going to take you at least an hour to f-around and get it working.)

I was looking at this murata one

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It looks like it wants to at least source 100 mA... or it gets noisier. You might want to measure the current draw of your device.

I don't suppose you can power your device from a wall wart?

Noise effecting operation. Right that's hard to know without something to work with, test. Say can you get into your gauge? I wonder if the source of the excess current draw is due to capacitors that have gone bad?

George H.

Reply to
George Herold

snipped-for-privacy@whidbey.com wrote on 9/27/2017 12:01 PM:

I was going to give you a link where you can buy a batteroo boost which should do all this for $2.50 each. But it seems they don't maintain the output voltage very well. There is something jiggy going on at the top end where the output voltage quickly drops with the input. This may be a pass through mode which seems to switch out a bit below 1.45 volts where it switches to boost mode. So it would drop below your 1.45 volt threshold for a bit. It then continues to maintain a voltage of 1.45 volts until the input reaches 1.3 volts below which the output drops below 1.45 volts again. Seems the lack of output regulation is likely by design so the Batteroo Boost will work with device gas gauges.

Not sure it will work for you or not. Might be worth a try though. If your device will get past the 1.45 volt switching point it will at least let the AA cell work down to 1.3 volts. It's only $10 plus shipping I suppose and no construction required other than hacking a AAA/AA cell holder to your device.

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Rick C 

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Reply to
rickman
[about DC/DC converters for battery adaptation]

Mainly, DC/DC converters aren't as energy-stingy as you'd want. For low quiescent drain, in the absence of a switch, the linear regulators win (and some have an 'enable' line, to take a switch).

If the threshold is "$20 or something", bear in mind that DigiKey sells fifty A76 cells (one of the LR44 variant labels, from Energizer) for $21.

If you could replace the 'takes four screws' fitting with a bayonet-mount, would that help?

If a solar cell could be cemented on, would normal shop lighting be enough to get readings?

Reply to
whit3rd

$20 is just my guess at a price point for a one of. I did get this new linear product catalog the other day. The LTC7800 claims an efficiency of >80% starting at abut 1 mA.

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(Eric, I'm not suggesting you use this part!)

George H.

Reply to
George Herold

Adding a different mounting system for the cover would not be very easy. I had thought about solar cells in the past but forgot about them. Can a solar cell be paralleled with a silver oxide button cell without causing the cell to leak? Or an LR44 alkaline cell? The whole reason for adding the voltage regulator and outside coin cell is to make battery changes less frequent and easier. And I can mount a coin cell holder to the back of the gauge housing easily. With a tiny reg and any associated circuitry soldered to the coin cell holder. Thanks, Eric

Reply to
etpm

If you put the regulator in the batt socket,and maybe a 5V Zener to keep the input in limits, you could snake out two wires and fit your choice of Li button cell or solar cell, or any variation with rechargeables or AA's. Or three wires, and a switch.

Ideal, for me, would be a few batteries in bayonet-mount housings, that I could detach at will. I'm currently doing the battery-remove-for-storage thing with a couple of cheapo calipers, and the loose parts are just TOO prone to damage or capture by gremlins.

Reply to
whit3rd

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