DC to DC Converter Pair Connection Problem

To any expert out there;

I have a 3.7 Volts 2000 MAH battery to use for my Arduino Nano.
I need to feed 9 Volts to Arduino even though my battery discharged level is 1.0 to 1.5 Volts.
So I have a low voltage DC to DC boost converter and I verified the operation . 1.5 Volts input gets 4.96 Volts output. I verified the higher voltage DC to DC boost converter and not so good. The 6 volts input produces a higher peak voltage which declines down to like 1.5 Volts . I can adjust the output voltage with the available pot but the output changes but does not remain constant. it declines.
When I connect the lower voltage DC to DC boost converter to the higher voltage one it stops functioning as the led extinguishes and no output.
Disconnecting the lower voltage booster from the higher voltage booster and removing the battery + power lead resets the booster it looks like. Reconnecting +power lead causes the led to light up and I know I have 4.96 Volts output. Again connecting the output voltage to the higher voltage booster causes the lower voltage booster to stop operating. That is crazy!!
Any Ideas

Thank you.

If that is a Li battery, the battery voltage stays relatively constant until it is empty. 1.5 Volts would be essentially a dead battery, with only a fraction of a percent of battery capacity left. Why on earth would you continue to try to drain power from it? It sure is crazy!

Hi,

When I connect the lower voltage DC to DC boost converter to the higher voltage one it stops functioning as the led extinguishes and no output.

Can you draw a diagram of what you are doing please.
Tom… :slight_smile:

Thanks Tom for the reply;
I received the boost converters from China with no data sheets nor schematics.
connection is simple, the higher voltage. Booster is piggy back connected to the lower voltage booster. A diagram will not help but I will try to post pictures.
regards,
Pierre

We need a diagram. It sounds like you are trying to connect two 5v boosters in series to make a 10v power supply. There are ways to make this work but it sounds like what you have tried is the way which doesn't work.

I would recommend you buy a 10v booster and don't mess around with 5v ones.

What other components in the system require 9v? The Nano will work on 3v.

If everything can be powered by 5 V, there is no need to provide 9 V to the Arduino. Just use a boost converter to provide 5 V and feed that to the Arduino via the Vcc connection.

jremington:
If everything can be powered by 5 V, there is no need to provide 9 V to the Arduino. Just use a boost converter to provide 5 V and feed that to the Arduino via the Vcc connection.

?? The V-in of a 5volt Arduino needs to be at least ~6.5volt.
V-in is the input of the onboard 5volt regulator.

You can feed 5volt directly into the 5volt pin, but that could be dangerous for the onboard 5volt regulator.
So they say.
I like to live dangerously, so I always do that.
Safer to inject 5volt on the USB in with a hacked USB lead.

Maybe better for a beginner to adjust the Chinese regulator to 7.5volt, and feed that into the DC socket.
Leo..

salsiccia:
To any expert out there;

I have a 3.7 Volts 2000 MAH battery to use for my Arduino Nano.
I need to feed 9 Volts to Arduino even though my battery discharged level is 1.0 to 1.5 Volts.

If you discharge a LiPo to 1V it becomes a time bomb and must be disposed
of in a safe manner. It will swell and become unstable, and may catch fire
and explode if recharged.

As I suggested, the premise is completely wrong. It's like someone asking you for the best kind of rope to hang themselves.

Hi,
Just a hand drawn diagram with the dc-dc converters as boxes with input and output labellded and you show us how you have them wired to the battery.

Tom....... :slight_smile: