Can someone please look over my battery box circuit?

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
Hi,
Im kind of a newbie in the electronic world and need help with my battery box project.
What I'm doing is housing a box with two 12vdc lead sealed 8,5ah batteries.
The switch selects between 12vdc and 24vdc and leds indicate which is on.
I want the Output terminals to be hot until i plug in a cord that acts as a momentary trigger which will
only be hot when the button is pressed.
There is a shunt on the cord end that bridges the 12v/24v positive side that actuates a 12v relay.
the LED's i was thinking of using were red 12v ones with a resistor to protect it when it flips to 24vdc.
Does any of that make sense? Please let me know how i can improve upon this.
Also the charger just plugs into the wall and wont be used while using the battery power at the same time.
Thank you so much in advance for your time.
 

Attachments

Last edited:

LowQCab

Joined Nov 6, 2012
1,096
What are You trying to accomplish ?,
What is the end result You are looking for ?,
Why are You building this "Box" ?
Why do You need 2 different Voltages ?
How much Current will need to be delivered by this "Box", and what is the Load ?

We need a Schematic using conventional, standardized, symbols and layout.
I can't understand very much about your Drawing.
What is the rectangular box with 6-connections in the middle ?

It's probably a bad idea to use the same 2-terminals for 2 different Voltages.
.
.
.
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
What are You trying to accomplish ?,
What is the end result You are looking for ?,
Why are You building this "Box" ?
Why do You need 2 different Voltages ?
How much Current will need to be delivered by this "Box", and what is the Load ?

We need a Schematic using conventional, standardized, symbols and layout.
I can't understand very much about your Drawing.
What is the rectangular box with 6-connections in the middle ?

It's probably a bad idea to use the same 2-terminals for 2 different Voltages.
.
.
.
Hi LowQCab,
Sorry, i know that this "schematic" prob kills a real electronic guy, which i am not ha.
I appreciate you responding. I do not know conventional layout schematics.
I was drawing the parts i had and how i wired them.
Is there a program you could recommend that would help lay this out better?

What I'm trying to accomplish is to have a portable battery source that i can hookup
either a 12vdc or 24vdc device to right to the output terminals in the field.
I also want to, when the xlr plug/cord is plugged in, to switch the always "on" current
to the terminals to a "momentary on" when the button is pressed.

The end result is to have this work and learn more about circuits :)

The box is to make this portable.

I need to different voltages for two different devices that i commonly use...like to fire a solenoid for example.
Some are 12vdc, some are 24vdc.

I don't know the current, or the load. Its all low voltage devices i intend on using this for.
I am using two 12vdc lead acid sealed batteries that are 8.5ah each if that helps?

The rectangular box is a on-off-on switch (DPDT?)

I'll attach a different pic to help understand what I'm trying to accomplish.
 

Attachments

LesJones

Joined Jan 8, 2017
3,490
IF the rectangle in the middle of the picture in post #1 is a DPDT switch and the center two connections are the commons then I think your drawing is correct apart from the following. If you have the switch set to the 12 volt position (The two 12 volt batteries in parallel.) and you switch the 24 volt charger on you will be trying to charge the 12 volt batteries to 24 volts.

Les.
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
IF the rectangle in the middle of the picture in post #1 is a DPDT switch and the center two connections are the commons then I think your drawing is correct apart from the following. If you have the switch set to the 12 volt position (The two 12 volt batteries in parallel.) and you switch the 24 volt charger on you will be trying to charge the 12 volt batteries to 24 volts.

Les.
Hi Les, It is a DPDT on-off-on switch. You are correct, thank you! I'll try to fix that. I am googling in hopes to find some kind of smart charger that would sense the 12/24 difference.
 

LowQCab

Joined Nov 6, 2012
1,096
The Load is extremely important to the design of this Box.

I see that You have Fuses on the Batteries ........ good.
What size are the Fuses ?

You say it's for testing Solenoids "in the field" .......
Is this for Pneumatic-Rockets ? ( BTW, I have an excellent design for this )
Is this for Solid-Rocket-Motor-Igniters ?
Is this for large Air-Conditioning-System diagnosis ?
Is this for Irrigation-Valve-Testing ?

Why do You need 24-Volts ?

Why do You need such huge Batteries for testing "Solenoids" ?

I hope that You aren't thinking that this is going to be a "Jump-Start-Box" for Cars or Trucks.

24-Volt Chargers are generally quite a bit more expensive than 12-Volt-Chargers,
You may be better-off with 2- 12-Volt Chargers.

In any case, You need a "Charge" / OFF / "Operate" Switch.

You may be surprised to find out that a much simpler system,
or a system better suited to the exact job at hand,
can be lighter-weight, smaller, and more efficient, and possibly even automated.
.
.
.
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
The Load is extremely important to the design of this Box.

I see that You have Fuses on the Batteries ........ good.
What size are the Fuses ?

You say it's for testing Solenoids "in the field" .......
Is this for Pneumatic-Rockets ? ( BTW, I have an excellent design for this )
Is this for Solid-Rocket-Motor-Igniters ?
Is this for large Air-Conditioning-System diagnosis ?
Is this for Irrigation-Valve-Testing ?

Why do You need 24-Volts ?

Why do You need such huge Batteries for testing "Solenoids" ?

I hope that You aren't thinking that this is going to be a "Jump-Start-Box" for Cars or Trucks.

24-Volt Chargers are generally quite a bit more expensive than 12-Volt-Chargers,
You may be better-off with 2- 12-Volt Chargers.

In any case, You need a "Charge" / OFF / "Operate" Switch.

You may be surprised to find out that a much simpler system,
or a system better suited to the exact job at hand,
can be lighter-weight, smaller, and more efficient, and possibly even automated.
.
.
.

I was thinking of 10amp fuses?

As far as the load, I really don't know, does that mean the load of the device i want this box to run?
if so it would never operate a dc device more than 1 amp (more than likely much lower) i would imagine.

The solenoids are for air and water. Some of the 3 way air valves are 24vdc.
Sometimes the 12v will just be to run 12v devices like led strips or a 12v fan for a long period, which is why i wanted larger batteries. The system isnt that huge, it all fits into a small pelican case that keeps it all weatherized and contained.

this is definitely not for a jump pack.

Thank you, i will look into working out a charge-off-operate switch, and totally open to learn more about this much simpler system you speak of.
 

Yaakov

Joined Jan 27, 2019
3,489
I would strongly suggest ditching the XLR connector. It is generally not a good practice to put unexpected signals on a standard connector, and the XLR is expected to have audio level signals. (Yes, DMX may have screwed that up, but it's still true.)

I would suggest Andersen Powerpole connectors for actual power supply. They are purpose made, come in a variety of ampacities, interlock to form multpin configurations, and are clearly power connectors.

For higher level control signals, something like this: https://www.amazon.com/CNLINKO-Industrial-Connector-Receptacles-Waterproof/dp/B06XFM835T which is not going to be confused with an audio connector would be good. There are a lot of options in this area, but this connector seems to be affordable, rugged, and watertight.
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
I would strongly suggest ditching the XLR connector. It is generally not a good practice to put unexpected signals on a standard connector, and the XLR is expected to have audio level signals. (Yes, DMX may have screwed that up, but it's still true.)

I would suggest Andersen Powerpole connectors for actual power supply. They are purpose made, come in a variety of ampacities, interlock to form multpin configurations, and are clearly power connectors.

For higher level control signals, something like this: https://www.amazon.com/CNLINKO-Industrial-Connector-Receptacles-Waterproof/dp/B06XFM835T which is not going to be confused with an audio connector would be good. There are a lot of options in this area, but this connector seems to be affordable, rugged, and watertight.
Excellent suggestion!! Thank you Yaakov!! will change out the xlr to that exact connector you linked to, and love that it has a watertight cap.
 

LowQCab

Joined Nov 6, 2012
1,096
It's important not to insulate your Batteries with Foam while Charging.
This is not usually a problem if you are Charging at less than 1-Amp.

I would get 2- Automated "Battery-Maintainers",
which usually have a maximum Charging-Rate of around ~1-Amp,
and they will automatically shut-down on most faults.
They will usually completely Charge Your Batteries overnight, ( ~8 to ~12-Hours).
Walmart has them cheap.

Never leave your Batteries in a partially discharged state.
Connect the Maintainer(s) permanently when the Box is not in use.

Most Auto-Parts Stores have handy "Trailer-Lights-Harnesses" with Polarized-Plugs/Sockets.
They come in 4-Wire, and 2-Wire versions.
The Battery-Maintainers will probably come with the 2-Wire variety already attached.
This could be a viable alternative to needing a large Switch to take your Batteries
"Out-of-Circuit" while being Charged.
Very simply, you would have to pick which item to plug the Battery into,
either the Box-Circuit, or the Charger, you can't do both at the same time.
.
.
.
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
It's important not to insulate your Batteries with Foam while Charging.
This is not usually a problem if you are Charging at less than 1-Amp.

I would get 2- Automated "Battery-Maintainers",
which usually have a maximum Charging-Rate of around ~1-Amp,
and they will automatically shut-down on most faults.
They will usually completely Charge Your Batteries overnight, ( ~8 to ~12-Hours).
Walmart has them cheap.

Never leave your Batteries in a partially discharged state.
Connect the Maintainer(s) permanently when the Box is not in use.

Most Auto-Parts Stores have handy "Trailer-Lights-Harnesses" with Polarized-Plugs/Sockets.
They come in 4-Wire, and 2-Wire versions.
The Battery-Maintainers will probably come with the 2-Wire variety already attached.
This could be a viable alternative to needing a large Switch to take your Batteries
"Out-of-Circuit" while being Charged.
Very simply, you would have to pick which item to plug the Battery into,
either the Box-Circuit, or the Charger, you can't do both at the same time.
.
.
.
Thank you for your input. I like the idea of two chargers. I'm not sure if I'll have room for another charger in the case I have.
I suppose I could find a larger pelican case
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
I assume each charger gets hooked up to its own battery yes? Will that be a problem if the DPDT switch is in the 24v position (when it ties them to series) ?
I'm trying to think of a way with another 12v relay (Engages when there is power from charger) that breaks the batteries from the DPDT switch
and reroutes to only charge in series).
Does that make sense? or am i overthinking this?
 

LowQCab

Joined Nov 6, 2012
1,096
Will that be a problem if the DPDT switch is in the 24v position (when it ties them to series) ?
Yes, You must assume that it will be a problem.
Until PROVEN otherwise ...........
the Chargers cannot be assumed to have Transformer-Isolation from the Mains Power,
therefore they will probably short each other out if the
Batteries remain connected to each other in any way during Charging.

There are Battery-Maintainers that are very small, about the size of a small Laptop-Brick.


Here are the Battery Connectors that I would recommend .............
Get 6 of them so You can cut them up and choose the appropriate Colors and Genders.
.
F20022_-_W_1.jpg
.
.
Battery Box 12V 24V FLAT .png
 

Thread Starter

J_Dizzle

Joined Aug 1, 2021
10
Will that be a problem if the DPDT switch is in the 24v position (when it ties them to series) ?
Yes, You must assume that it will be a problem.
Until PROVEN otherwise ...........
the Chargers cannot be assumed to have Transformer-Isolation from the Mains Power,
therefore they will probably short each other out if the
Batteries remain connected to each other in any way during Charging.

There are Battery-Maintainers that are very small, about the size of a small Laptop-Brick.


Here are the Battery Connectors that I would recommend .............
Get 6 of them so You can cut them up and choose the appropriate Colors and Genders.
.
View attachment 244907
.
.
View attachment 244910
Thank you LowQCab! I just ordered them from amazon.
Is that my circuit drawn the way its supposed to be? if so, thats awesome! thank you for simplifying that.
I did download KiCad and am going to learn it so that my future schematics are not so elementary.
I appreciate all the help
 

LowQCab

Joined Nov 6, 2012
1,096
""Is that my circuit drawn the way its supposed to be?""
Not exactly,
I don't use a "conventional" Schematic Drawing Program,
I'm just pretty good at making a Schematic easy to understand.
I use an old Photo-Editing program to create them, ( Microsoft "Picture-It" ).
I haven't found a Schematic Program that I like,
so I've just stuck with Picture-It, since I use it for so many other things.
Check it out, Nothing about this Photo is original .......................
.
.

girls~418.png
 

jiggermole

Joined Jul 29, 2016
32
I built a similar device for troubleshooting out on the plant floor. I don't really have anything in particular to add about your design other than once you get everything working you can start working on version 2 which uses a little lithium ion battery vs the heavy lead acid. If its anything like the one I made you'll be SUPER glad you have one when you need it. Such a time saver vs having to dead bug a 120V to 24v ps out in the field with all the live terminals just exposed.
Probably a bunch safer too. The battery box is the way to go.
 
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