Help with automatic battery switching.

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ron roberts

New Member

• Mar 7, 2008

• #1

Can any one help me please with a schematic for the following? I need to switch between 2 12 volt battery’s.
I have 2 12 volt battery’s that run a 12 volt 2 amp motor, but only one battery can be connected at a time to run the motor. Now when battery 1 runs low I need it to automatically switch over to battery 2 at the same time switching battery 1 on to the charger and back again.
Simple with relays but I cannot use relays and don’t want to use mosfets. Some way of adjusting low voltage level would be nice.

 

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ravix

New Member

• Mar 7, 2008

• #2

can we see any schematic you have sofar?

Why don't you want to use relays or mosfets?

 

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mneary

New Member

• Mar 7, 2008

• #3

Without relays or mosfets, this leaves you with a toggle switch.

 

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Pommie

Well-Known Member

Most Helpful Member

• Mar 7, 2008

• #4

mneary said:

Without relays or mosfets, this leaves you with a toggle switch.

Click to expand...

Or valves.

Why not just wire the batteries in parallel.

Mike.

 

Bob Scott

New Member

• Mar 7, 2008

• #5

I had a power boat with two batteries. It used a specially built huge two way SPDT rotary battery selector switch that is available at most marinas.

Just use two chargers, one for each battery. Leave them both on so you don't have to switch chargers.

 

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ron roberts

New Member

• Mar 8, 2008

• #6

Thanks to you all for your help on this.
This is a diagram I put together; I don’t want to use a relay, as this will be on 50% of the time. I know it’s not a lot of current drain but it is one, so I would like to remove the relay completely. Now for the mosfets, I just don’t like mosfets. Well let’s say they don’t like me no matter how many precautions I take I just destroy them. Thanks from Ron.

**broken link removed**

 

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ron roberts

New Member

• Mar 8, 2008

• #7

Don’t know if I’m going mad has I’ve been on this for weeks. This is what I done up to date.
I need help with this like values of components. Resisters will be about 630 ohms transistors 2n3055 to drive motor and so on but need help with it my brain is starting to get fried with this now.


**broken link removed**

 

Last edited: Mar 9, 2008

blueroomelectronics

Well-Known Member

• Mar 8, 2008

• #8

How are you going to keep the 12V batteries charged on your solar tracker? Is it a large panel?

 

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ron roberts

New Member

• Mar 8, 2008

• #9

Large panel array well 4 85 watts + wind turbine.

 

blueroomelectronics

Well-Known Member

• Mar 8, 2008

• #10

Have you thought about a latching relay and a simple transistor? You'll only need the relay once a day anyway.

 

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ron roberts

New Member

• Mar 8, 2008

• #11

Thanks Bill but I cannot express how important it is to me not to use any mechanical relays of any type.
-------------------
Ron

 

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ron roberts

New Member

• Mar 8, 2008

• #12

By the way Bill it’s not running a solar tracker, it’s just an experimental unit I’m playing with.

 

Hero999

Banned

• Mar 10, 2008

• #13

What about using solid state relays then?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Mar 10, 2008

• #14

ron roberts said:

By the way Bill it’s not running a solar tracker, it’s just an experimental unit I’m playing with.

Click to expand...

As it's just an experiment, use a mechanical relay, it's probably the best option anyway - what do you have against relays?.

 

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ron roberts

New Member

• Mar 10, 2008

• #15

Well I think I will give up on this one now but thanks to you all.


Thanks Ron.