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10v -14v input to 12v regulator circuit high current

bonsia

Sep 3, 2018
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please help I am new to electronics I have a voltage input from batteries that can be 10v to 14v I would like to have a clean regulated 12v output can anyone help with a circuit diagram that would do this job the current flow is quite high. kind regards in advance Bonsia
 

Bluejets

Oct 5, 2014
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For a regulator the input has to be higher than the output by at least 2 volts normally to allow for voltage drop on the regulator itself.
Quite high means nothing, you need to provide actual figures.
 

bonsia

Sep 3, 2018
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Hello!
Thank you for helping me I have 2 325w solar panels that go through a Vistron MPPT 100/30 solar controller that connects to 2 140ah 12v batteries but the controller does not have a regulated output like some smaller cheap solar controllers so i am forced to connect my load to the batteries and the voltage changes from the amount of sun, night it can drop to as low as 10.5v and middle of day when it's sunny it can reach 14v.
 

Bluejets

Oct 5, 2014
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Where are you taking your voltage readings?
How long are you discharging at 10A?
How much capacity is being fed into the battery before discharge?
How are the 2 * 12v batteries connected?
Sounds like you are not getting enough into the battery during the day for night consumption.
 

Externet

Aug 24, 2009
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To charge your batteries, 14V is what you need, not 12V. You did not expect a higher voltage at night, right ?
 

bonsia

Sep 3, 2018
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thank you, the power is required 24/7 everything works great and has done for 6 month the only issue is the output of the batteries changes when they are being charged and when they are not being charged but everything still works ok.

the 2 batteries are in parallel so we still get 12v but double capacity as we don't want our device attached to turn off.

our concern is that we would like a regulated 12v out can you help?
 

Bluejets

Oct 5, 2014
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To charge your batteries, 14V is what you need, not 12V.

I thought requirement originally was regulator on the output, seems like it now.

our concern is that we would like a regulated 12v out can you help
Again, you need more than 12v output to regulate to 12v as I explained above.
You cannot get 12v output through a regulator that is only supplied with 10.5v.
12v from 14v, marginally, yes, but not 12v from 10.5v input.

6 months seems like you were marginal at best with daytime charge and now entering a period of less daytime input.

If you need assistance, I suggest you answer the queries above.
 

bonsia

Sep 3, 2018
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answers

Where are you taking your voltage readings? from the batteries pos and neg terminal
How long are you discharging at 10A? all day
How much capacity is being fed into the battery before discharge? it feeds from the solar controller while the sun is shinning
How are the 2 * 12v batteries connected? in parallel
Sounds like you are not getting enough into the battery during the day for night consumption? well the voltage does not drop below 11.5v but i want to be covered as winter it may be lower!!
 

Bluejets

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Still sounds like you are not getting enough charge into the battery during the daytime.
Sadly for you, this is not the type of thing one can point a multimeter or your guesstimate finger at and get any useful final conclusions.
e.g.............

How long are you discharging at 10A? all day

Sounds like you are not getting enough into the battery during the day for night consumption? well the voltage does not drop below 11.5v but i want to be covered as winter it may be lower!!

Starting point for you to follow is.........energy out = energy in minus any losses.
Also look up your particular battery type characteristics, charging and discharging at batteryuniversity site.
 

bonsia

Sep 3, 2018
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so if I increase charge in and get 12v -14v as when charging in middle of day it can increase above 12v is there a way of regulating 12v - 14v to 12v?
 

kellys_eye

Jun 25, 2010
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As already mentioned you are not charging the batteries properly in the first place. You can't charge a 12V lead acid battery using 12V - you need (around) 14.4V to charge them properly.

What are you actually powering from them? Most 12V equipment will tolerate a 10% over voltage and some will take even more - is the actual voltage output THAT critical for the equipment in use?

If you have the correct charger/controller (a ViCtron, not a ViStron and they are a very reputable company for such equipment) then read the manuals for it. It charges and controls the battery PERFECTLY when installed correctly i.e. the default charge setting is 14.4V and the float voltage (the output when the batteries are in a fully charged state) is 13.8V.

If the equipment you are powering is suited for use in a vehicle then they won't need any additonal regulation to work properly. In fact, most 12V equipment has input regulating circuitry built-in that can readily use the 14.4V the maximum charge output might reach.
 

Bluejets

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You can't charge a 12V lead acid battery using 12V - you need (around) 14.4V to charge them properly

Doesn't appear the Op's input voltage level is a problem but rather ( as you say) the amount of energy being put in to the battery bank in the first place.

Request for a regulator was on the output (incorrectly) as I assume because he wanted to boost the 10.5v upwards along with his 14V down.
Hense the reference to do some reading on how things work.:):)
 

scmong

Jun 22, 2012
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Dear Bonsia, so far I understood, you need a ragelated 12v for particular load of 10A which will not be affected by the charging or battery voltage within 14v to 10v. Right?
If so, you have to use 'buck-boost' regulator or a double conversion (dc to ac and then ac to dc) converter-regulator.
 

(*steve*)

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To answer the question as posed, and without considering other aspects...

You could use an inverting regulator which could create -12V from a positive voltage from 10V to 14V.

Another alternative is a boost regulator followed by a buck regulator. The first converts there input voltage to (say) 15V, and the second reduces it to 12V.

If your load can handle input voltage variation (e.g. many low voltage LED bulbs) then it is more efficient to let them do it.
 

Bluejets

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No good if the battery is way down on charge, as quoted 10.5v.
 
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