Could i use step up dcdc converter to make 9V from li-ion battery

>>1017352
How would you be able to check your work?

>>1017357
What work? If meter is working properly?

>>1017357
Oh you ment how is stepup working, i got another junk meter. This isnt a problem

I'm not quite sure what you mean by big capacitor.

But you could indeed use a boost converter to supply a multimeter from a lower voltage battery..

What I recommend is that you figure out the current draw of the meter when operating at 9v from a battery.

Then you find a boost converter which has current specs a bit higher.
Then you add additional output filtering. Look at LCR filters. The R lower the Q of the filter, but helps it become stable at transients.

You might want to consider the physical placement of the boost converter, due to magnetic interference with the multimeter.
Shielding the converter in thin sheets of iron might help if you have EMI problems

>>1017413
k thanks, ill do. They say it's about 10mA drawing, so any booster should do.

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Neat idea op, while we are at it lets replace everything with lithium ion batteries. I wonder if /diy/ could reverse engineer teslas 10kW wall battery???

>>1018989
I'm sure it is actually a simple technology just overly built

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there was a site that talked about using a boost circuit to power a multimeter. just can't seem to find it anymore.

http://www.instructables.com/id/1st-9v-Battery-that-can-be-recharged-from-a-USB-Po/?ALLSTEPS

>>1017352
Couldn't you just use two cells in series?

>>1017352

You could. But what are your other limitations?
If you need to fit this into the space taken up by the original 9V, The space taken up by the converter won't leave you much room for the Li-ion battery. So not much capacity.

If you can handle a bigger footprint, then a couple of batteries in series will be simpler. 9V batteries are just 6 AAAA cells in a rectangular can.

That would add up to 8.4 in the best case.

>>1018999
The BMS for these things is never simple. After all, it protects the battery which makes up for more then 1/2 the final price of the car, so you never want to cheap out on it...

>>1019157
Voltage varies depending on charge level and amp draw.

Li-ion cells are more like 4.2v each when fully charged and 3.6v when discharged.

Alkaline cells are about 1.5v each when new and because they're disposable they can pretty much be run down to 0 without needing to worry, but the minimum useful voltage depends on the particular device you're using them with. A 9v battery is 6 cells in series for a total of 9v when new, but the voltage will drop significantly with usage, and most electronics will regulate voltage and be able to keep working with a much lower voltage than brand new cells provide, otherwise the cells would quickly become useless and need to be changed very often.

The important question is what is the minimum operating voltage for the meter. It might still function fine with a 7.2v supply (which is what you'd get from a 9v when the six cells drop to 1.2 volts each, which isn't even very low for alkalines. In that case, two Li-ion cells in series would be perfect. About 8.4v fully charged with a nice discharge down to 7.2v, and the meter would work perfectly.

One of the reasons why your meter is using batteries is that they offer great isolation from other circuits, so you can connect your probes to any circuit you like. Don't fuck with the meter's batteries because you're likely going to fuck things up.

>>1017352

Yes, but this isn't a very wise solution because it's a lot of trouble. If battery life on your meter is an issue, perhaps you should get meter that isn't shit.

If you are just doing this for fun, I would recommend doing something else because that isn't very fun.

>>1018989

> it's a big fuckin battery with charge control circuitry

What exactly do you hope to learn from that?

>>1020297
This. There's nothing actually exciting about Tesla Ir anything they make. The most exciting thing is their pr is good enough the company hasn't gone under yet for making insane products.

find a multimeter that uses 2AA batteries and you do not need a converter circuit.
be careful with boost converters they usually have a bad ripple current