A little basic help please

[browningbuck]

well Audio, judging by the name, you may be able to help me.

im runing a lm4881n, and all the sudden its sounding very digital and distorted, lack of sound on some areas.... should i just get a new amp and see if i may have shorted a wire while putting all this together? or do you have another idea?
**broken link removed**

 

[audioguru]

The LM4881 has a very low output power of only 0.2W per channel into 8 ohms. A cheap clock radio has more than double the power.
Try replacing the IC if you want.

 

[browningbuck]

Output wasn't the goal on this, not to mention this amp is more my level ... Anyway I'll try and replace and see if it fixes anything.

 

[summitville]

browningbuck,
Precision 15V 1W +/-1% Zener may be available here ...
American Micro Semiconductor — Semiconductor Tutorials
Part # 1N4744D (The "D" means 1% precision)

Or you can replace the 15V Zener with a LM431 here ...
**broken link removed**
I think R1 = 10K & R2 = 1K would work
Adjust R1 to limit the Fully Charged A123 to 14.4 V when in Full Sunlight

I like the LM431 better since you can simply adjust R1 to tune the "Fully Charged Cut-Off Voltage" to whatever works best for your A123 Battery.

Prototype and let us now what happens.

 

[browningbuck]

EDIT: read before i type

and this seems like a REALLY simple design, EXACTLY what i was looking for. will get the thing built tonight. project was put on hold over the weekend due to the crappy amp out put. hopfully i can bring her back to life again

testing of the solar panel on another set of A123 cells has produced better than thought results, this above discribed circuit will be required i think

 

[browningbuck]

okay a bit more research and i am not sure if the LM431 by its self would do what we need? it has no dump mosfet .

anyway i am getting kinda close on my dead line (box has to be complete by tomorrow)

sooo i guess i may go manual control over the charging system since i dont think ill be able to figure out the requirments (ill pick up a 431 today, so that i am ready if some explains to me that this would work) just so you understand what i dont understand( i dont see where the circuit openes to stop charging once Ref is reached)

**broken link removed**

 

[browningbuck]

this seems like, it would dump the energy, but man i dont think i can do all the cals on what i need in there by tomorrow

**broken link removed**

 

[browningbuck]

ohhh maybe i can do this??
this would do 14V

D1 1N4007
R1, R2 3.3K
ZD1, ZD2 5.1V
RX 100K
R3 51K
R4 130 ohms
R5 8.1K or 8.2K
ZM ZM33064
N-fet 2N7000
P-fet BSS92

but not sure what C is ?


ehhh i just dont think im going to be able to do it

 

[spindrah]

WTF :0

**broken link removed**[/QUOTE]

 

[browningbuck]

basically it dumps the charge off the panel on to the Nfet rather than over charging the battery

 

[browningbuck]

wait i think this is the application Summit was thinking of witht he LM431
**broken link removed**

not really sure what NPN or what the unlabled resistors or cap would be?

 

[summitville]

browningbuck, Just substitute the LM431, R1 and R2 for the 15V Zener component. I am tying to keep this as simple as possible. Unless you have upgraded your 34ma Solar Panel why do you need a Dump Mosfet for 34ma? The LM431 is rate 3/4W which is cutting it very close. But, I doubt you will even get 34ma at 15 volts from your 12v Solar Panel.

Down the road if you really need to shunt more amps then you can use something similar to (but not exactly like) the ShuntRegLM431 diagram.

OK ?

 

[summitville]

browngbuck, Attached is an outline of a "Cell Balancing" Circuit for the 4S A123 Battery Pack. After you get your Solar Charger completed and you use it for a while you may find that one cell is "lazy". You cannot fix this problem (as discussed earlier) with a Series Charger. This circuit will re-balance all of the cells to within 1/100 of Volt !!! You could even attach the Balancer while your Solar Cell is charging the 4S A123 Pack. The Balancer circuit needs to be removed when the A123 Cells are balanced since the Op-Amps will continuously drain power from the batteries. A123's have low leakage (long shelf life) when disconnected.

 

[spindrah]

BB just to help you on something else, when you draw a schimatic don't draw little bridges over wires, to indicate "no connection", like you have, instead draw a little circle. also draw the circle at your T's

 

[browningbuck]

sorry spindrah, i cant take credit for those drawings.... they were copied off websites


okay guys here is what i finished up last night, my plane leave tomorrow and this is a gift for my dad who is the guy who has everything, it is very much into energy and i thought this was kinda right up his road . like i said its a man toy and it will most likely sit on a desk, so the charging system is wired in to the Power switch and then cell monitoring is on the voltage switch that cycles through with the first number being the cell and the next three being the cells voltage. i know im gunna get flamed for the HHO system, but its just a toy and HHO has some good potential energy(the generator still has all the acrylic protection film on it ) thats why it looks brown. was able to fix the little amp, that powers two speakers. anyway thanks for all your help, i WILL be building the Shunt and adding it in on my next visit in June (but due to time, i will not be able to finish it at the moment, but hes smart enough to run the system where it wont hit critical voltages

 

[Oznog]

Here is a 3 component 3v-12v boost converter really simple. https://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1042,C1031,C1060,P1272,D1661

This will not work.
For one, 12v is not enough voltage to charge 4x A123 cells. 3V per cell is almost dead.
But the real problem here is the that any boost converter like this designed for a fixed-voltage input will fail on a variable-current-output supply like a solar panel. It will easily fall into an effect where it draws too much current and lowers the panel voltage below the MPP, then to try to generate 12V out from a lower Vin it will increase the current, dropping the Vin lower. It will latch into a state where Vin is very low and produce no significant output.