Cut off voltage lithium battery?

[spec]

This is awesome! I will definitely make and use this one for all projects including lithium batteries. Can't thank you enough for all help and fast feedback spec! And I can admit I'm a bit jealous of all your knowledge
I will try to update my moser list with components above and post it here.

No Probs Rorut.

I dare say you have skills that I would be jealous of : music, singing, dancing, art of any kind, advanced maths, physics, chemistry, are examples.

Oddly enough, this was the architecture I started out with but chose the other architecture because it was simpler and gave more voltage drive for the PMOSFET, which is the critical aspect.

spec

 

[Rorut]

Hi again, I have a question regarding my project that I think maybe is related to the circuit. If you look at my image (hope you can understand my drawings) and look where my arrow points between relay 3 and amp.

If I connect ac/dc and turn switch 1 on and then off and measure where arrow is pointing I get around 3v that slowly counts down. I think this is wierd? Shouldn't I get 0v after power off? Is there any current staying that leaks down to the capacitor in the LVC?
Same thing happens if amp is disconnected.

Relay 3 activates on ac/dc on. Its normally on/closed for battery use.

 

[spec]

Hi again, I have a question regarding my project that I think maybe is related to the circuit. If you look at my image (hope you can understand my drawings) and look where my arrow points between relay 3 and amp.

If I connect ac/dc and turn switch 1 on and then off and measure where arrow is pointing I get around 3v that slowly counts down. I think this is wierd? Shouldn't I get 0v after power off? Is there any current staying that leaks down to the capacitor in the LVC?
Same thing happens if amp is disconnected.

View attachment 99940

Nothing to worry about:

There is always stray capacitance around that will store electric charge and as your digital multimeter has a very high input impedance it will take a long time to discharge the charge.

The amplifier will certainly have some capacitors across the input lines which will store more charge, but the amplifier circuit will provide a discharge path in addition to the input resistance of the multimeter.

Put a 100K resistor or so across the input to the multimeter and measure again.

spec

PS: Some electronic products, especially hifi amplifiers, have massive capacitors across the supply lines and will continue to operate for a few seconds after the mains power has been switched off.

 

[Rorut]

Nothing to worry about:

There is always stray capacitance around that will store electric charge and as your digital multimeter has a very high input impedance it will take a long time to discharge the charge.

The amplifier will certainly have some capacitors across the input lines which will store more charge, but the amplifier circuit will provide a discharge path in addition to the input resistance of the multimeter.

Put a 100K resistor or so across the input to the multimeter and measure again.

spec

PS: Some electronic products, especially hifi amplifiers, have massive capacitors across the supply lines and will continue to operate for a few seconds after the mains power has been switched off.

Thank you very much Spec. Now I feel more relaxed about it . Next step maybe is to figure out how to change my three relays to mosfets

 

[spec]

No probs. Rorut

After looking at your schematic/block diagram, I hope you don't mind me saying this, but I suspect you have three relays too many. Can you post a truth table to show us what you would like to achieve?

spec

 

[Rorut]

No probs. Rorut

After looking at your schematic/block diagram, I hope you don't mind me saying this, but I suspect you have three relays too many. Can you post a truth table to show us what you would like to achieve?

spec

Thank you. No problem, appreciate it
Only reason I have two of thoose relays is because my switches is small and only handle 1A. Third relay is switching between ac/dc and battery. That is why Im using that third relay.

 

[spec]

Thank you. No problem, appreciate it
Only reason I have two of thoose relays is because my switches is small and only handle 1A. Third relay is switching between ac/dc and battery. That is why Im using that third relay.

Shall I have a look at simplifying your set up?

spec

 

[Rorut]

you are to kind!
This is how my mess looks at the moment. Dont know anything about how to do or draw schematics correct so it's possible things looks crazy. Sorry if it does not make sense! hope its not a problem going offtopic...


19.5v DC is now a 16v, 5A DC psu
4s BMS is a small balance charger

 

[spec]

No worry. I will have a go.

spec

 

[spec]

Work in Progress

(1) Switch two pole, triple throw
https://www.electrokit.com/en/toggle-switch-2p-ononon-solder-lugs.51157

 

[Rorut]

Work in Progress

(1) Switch two pole, triple throw
https://www.electrokit.com/en/toggle-switch-2p-ononon-solder-lugs.51157

That one would probably do it.
AC/DC and charger on one side and battery on other side. And one more switch for on/off charging? (When battery is full the charger beeps loud )

 

[spec]

That one would probably do it.
AC/DC and charger on one side and battery on other side. And one more switch for on/off charging? (When battery is full the charger beeps loud )

Yes, you have got it in one.
If you can ever remove a relay or switch, it is best to do it because they are troublesome things.

spec

 

[Rorut]

Just wanted to share my boombox i have been working on. It sounds great!!

 

[spec]

Just wanted to share my boombox i have been working on. It sounds great!!

View attachment 100187
View attachment 100188

Great work

spec

 

[Rorut]

Great work

spec

Thanks! Because of you I got last pieces together! Im very grateful