step up DC DC cheap and powerful

[plusmartin]

Greetings

I am in need of a great boost converter that enables me to generate at least 2 or 3 Amps at aprox 28V from a 12V source.

this was recommended to me: You can use MC34167. It can step down and also it can step up. Look at the circuit named "step-up/down converter" in the datasheet.
https://pdf1.alldatasheet.com/datashe...I/MC34167.html

I intend to use this for a very one of a kind battery balancer.

-Battery A (0V to 12V)
-Battery B (12V to 24V) (yes, they are connected in series)
-both are lead acid for solar applications
-i am using 24V loads but also 12V loads from battery B (12 to 24)
-unbalancing batteries is bad, therefore i need to return the energy to B, from A.
-i use the DC DC boost to take amps from battery A and deliver them to B.
-when the voltages are equal on both batteries i turn the DCDC system off until next time.
-if i use this exatly the opposite way (to charge A from B) i could have a 2way battery charge balancer

is this IC a good idea? any other models out there?
i have space restriction on my pcb.


thanks

 

[ahsan_i_h]

It is better not to connect 12v load to one of the 12v battery.
It is better to connect 12v loads to the output of a 24v/12v step down DC/DC converter. Then supply 24v battery voltage to the step down converter.
Then you will do not need to balance charge between batteries.

---------- Post added at 21:58 ---------- Previous post was at 21:28 ----------

Is it possible for you not to connect 12v loads to one of the 12v batteries?

 

[plusmartin]

I agree completely on avoiding the unbalancing loads, the problem is that I will be needing 12V @ 5 or 10A. Perhaps sometimes 1 or 2 amps but i dont know if there are not so costly 10A step down converters

 

[plusmartin]

hi

i`ve come up with this idea

My question is:
1. will this work?
I mean, extracting energy from one battery and delivering to another that is connected in series with the first one will actually charge it?

2.what DCDC step up converters do you recommend that are small, cheap and deliver about 2A @ 28V?

greetings

 

[Tahmid]

hi

i`ve come up with this idea View attachment 75404

My question is:
1. will this work?
I mean, extracting energy from one battery and delivering to another that is connected in series with the first one will actually charge it?

2.what DCDC step up converters do you recommend that are small, cheap and deliver about 2A @ 28V?

greetings

1) Not too well. The conversion isn't 100% efficient. So, you'd get less energy for charging than you take from one battery. Also, to charge the 2 batteries, you'd need twice the energy to charge one battery. But you don't have twice the energy - in reality, you have less than half required.

So, in the end, there is an overall energy decrease.

Hope this helps.
Tahmid.

 

[plusmartin]

thanks tahmid

I will charge both batteries with another circuit, not shown on my drawing, probably with 24V solar cells.

Im aware that the DCDC is not 100% efficient, but maybe 80% or 90% is good enough.

does anyone have experience building a boost DCDC from scratch instead of using an IC? could that be a better idea?

- - - Updated - - -

thanks tahmid

I will charge both batteries with another circuit, not shown on my drawing, probably with 24V solar cells.

Im aware that the DCDC is not 100% efficient, but maybe 80% or 90% is good enough.

does anyone have experience building a boost DCDC from scratch instead of using an IC? could that be a better idea?