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Inverter Battery Charger with Cut Off

Description

Comments

Transformer CT not connected to GND for voltage adjust.Is it tested circuit?

kishor

 

Hi, I am planning to make this circuit. My battery is 12V 7Ah SLA battery. And my Transformer is 22v 1A. (it has another output with 12v 1A). The value of R1 and R4 shows in this circuit is 1k and 100 R. And the result is 300mA. Is this current enough for my battery?. And do i need to regulate the input voltage from 22v to 15 ?.I hope you will answer these questions.

-vinod chandran

Hi, I build this circuit in breadboard . My powersupply is 27v 1A. And i didn't connect the battery to this circuit but i measured the output voltage. It shows me 10.4v when the 10k pot fully opened. And when i turned the pot to opposite side, the meter shows 8.4v . Interesting thing is, when the meter shows the 10.4v, all led 's are start to glowing. I think either my LM317T is damaged or the ZENER DIODE is below 8v. What is your opinion ?. How can i test a zener?, the zener which i use is 8.2v 1W.

-vinod chandran

Hi , I've changed the zener and now everything is ok except the charfull indicator. That LED always glowing eith this charger.

have you had any luck with this, or have used a diff circuit

Hi all,

 

I have tried out this circuit. Both the LED's glow upon operation.

 

I think this ciruit is just an idea... Its not tested.

 

 

The circuit is supposed to turn off the current when the battery reaches 13.5v.  But the "turn-off" circuit consists of an 8v2 zener, the base-emitter junction of T1 and the voltage drop across a red LED.  This is 8v2 + 0.7v + 1.7v = 10.6v    The zener needs to be 11v.            

"Hi, I build this circuit in breadboard . My powersupply is 27v 1A. And i didn't connect the battery to this circuit but i measured the output voltage. It shows me 10.4v when the 10k pot fully opened. And when i turned the pot to opposite side, the meter shows 8.4v . Interesting thing is, when the meter shows the 10.4v, all led 's are start to glowing."

The red LED is glowing and the transistor is pulling the output down.   The zener has to 11v or higher 

have you had any luck with this circuit???

I have made this circuit with no luck,

 

I have used a 18-0-18 1.5Amp Transformer and am charging a 12v 7.2Ah Artheon Battery

 

-- Both LED's glow when the circuit is powered on

-- Both LED's keep glowing when the circuit is disconnected from the mains and not the battery, means battery discharge goes on and on

-- Ideal voltage set by me is 14.7 volts

 

 

Please guide further

You cannot connect a zener to the base of a transistor as shown in the circuit. The zener leaks and the transistor is turned on at a much lower votlage.

Having played about with this circuit, a couple of things seem to not function too well. The zener is the wrong value and also connected the wrong side ot the 10 Ohm load resistor. As many have found, the circuit shuts off immediately.

The green LED is just an indicator that the circuit is on.

The red LED should come on only when the set cut-off volatge is reached BUT with the zener as only 8.2 volts, on a 12 volt battery it will shut down the charger even on a discharged battery. I have re-calculated the values here.

The voltage drop across the transistor and the red LED is around 1.88 volts, the combined voltage across R4(1K . there seem to be two R4 in the original?) and the zener diode needs to be 11.72 volts but as that is a rather odd value, the correct voltage is achieved by adding two series diodes to a 10 volt zener and making the resistor a variable 50K. This it becomes possible to adjust the cut-off point to a more useful level. At just 1K, it hardly has any effect at all due to the very small current flow.

As a zener in operation is electrically noisy, plus the base of the transistor is fairly sensitive, a 100nF capacitor has been added to dump any noise in the circuit.

To set this up, with no battery connected, remove the LINK and set the output volts to 14.1 (Max for a lead-acid battery) with VR1.

Reconnect the LINK and a battery then monitor the voltage as it charges. Set the cutoff voltage to 13.6 volts, which is the ideal voltage for full charge. The charger can now be left to charge a battery and it will automatically shut off at the correct voltage. Yes the red LEDwill stay lit as long as the battery is connected after charge but as the current for a small led is minute compared to the capacity of the battery, it is not going to affect the full charge status for a very long time.

I think the original circuit was based on the zener being 1 watt but in this circuit, it is not even nearly passing that level of current and thus the 1K resistor does not drop enough volts to give the correct cut-off point.

I have re-drawn the schematic here with the modifications that should make this work for you.

 

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This circuit too aint working the way it should, any other ideas

Bear with me, I'm going to stick this on the bench and tweak it!

I'm awaiting a new batch of zener diodes,.. for some reason I've run out because my stock sheet wasn't up to date. Oops!

Watch this space, I'll be back.

I have 5 KVA x6 Inverters parallel connected with DC batteries of 2.2 Volts 650 Amps .The inverters cut of setting around 43 VDC can any one pls calculate the backup time.

Hi

from an electronics engineer:

The secondry transformer winding need to have mid terminal leading to ground.

also, voltage regulator should not be used like this. it does not regulate the output.

 

I want circuit diagram of this 

plse mail me at sai.sundeep0@gmail.com

I need the circult can u pls send it to my mail box.bukolaolawusi15@gmail.com

where is the circuit diagram???

please mail it to sebinthankachan97@gmail.com

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