NTE Electronics “NTE5251K” Zener Diode 9.1V @ 50W Do-5.5% Want to build a 9.1 output from a 9.6 lipo4 battery pack

[sam_sam_sam]

I have bought this Zener Diode for this project what size and wattage resistor value do I need to use to get near 50 watt output
I bought this from an eBay seller but unfortunately they only had one

I bought three from Vetco Electronics these are Sylvania ECG5185A 9.1@10w A to Stud what size and watt resistor do I need to use to get near 10 watt output
I bought three of from them to also make battery packs with this output power limit in mind

I want to use this battery pack and turn it into a 9.1 output battery pack output to eliminate using 9 volt battery cells that do not have much running time and do not want to use a switching power supply for this purpose which is powered on all time even when not being used

The BMS board that is on there right now might not be the one I use for the 10 watt version but going to use on the 50 watt version instead but I going to build a much bigger battery pack for this project for this purpose

The battery pack that was used for testing purposes is going to used on the 10 watt power supply output for small current devices for this size battery pack

I will be using a switch to turn off the power supply to the Zener Diode circuit board for longer running time because it is not necessary to leaving powered on when not in use

The reason for this particular post is because I not very good figuring out Ohm law so that is the reason for posting this question

It also been many years ago that I played around with Zener diode so this is the other reason for this post as well

[eccerr0r]

normally these high wattage zeners are not for regulation, rather they are for OV protection...

[CapLeaker]

Yep. What eccerr0r said. These are not to regulate as such.

[eccerr0r]

if you're insisting on using the zener diode to regulate, resistor depends on how much current your device uses. Without knowing the device, it's impossible to tell what resistor is needed.

If using as a OVP device, you don't need a resistor, making usage easier.

[sam_sam_sam]

If I wanted to over voltage protection how would I do this the most efficient solution possible

If want use it as a voltage regulator controller situation which voltage do I use to calculate the resistor 9.8 volts or 9.1 volts as the voltage used in the voltage calculator

[eccerr0r]

OVP, just shunt the output with the diode... Heatsink not required.

As a regulator, take the highest amount of current your circuit can possibly draw and select R with V=IR where V=(lowest expected source voltage - zener diode voltage). If you get a negative resistance, the circuit is impossible. Then you have to make sure that the wattage of the resistor is at least (highest expected source voltage-zener diode voltage)^2/R and the zener diode wattage is higher than ((highest expected voltage - zener voltage)/R)*(zener voltage) which should be less than 10 since you have 10 watt zeners. Heatsink is required most likely depending on the R that you find you need.

You probably will find this resistor to be quite silly (usually less than 10 ohms) and it along with the zener will tend to get quite hot, hence this is why this circuit isn't used as a regulator directly without an amplifier. It of course is a linear shunt regulator, and worst case would just be an OVP.

[stj]

what are you powering?
if noise is not an issue, remove one cell and use a boost convertor to 9v.
if noise matters then boost to 10v and then drop down to 9v with a linear regulator afterwards.

[stj]

btw, stop talking about 9.6v
it's a cell-pack, it has a minimum and maximum range not a fixed output

[eccerr0r]

Batteries still have a nominal voltage.

Yes looks like this thread seems like a "I must use this" solution to a problem despite there being more efficient solutions out there. Using a zener diode in this fashion is really dumb, alas, if all you have is a hammer...

[sam_sam_sam]

I want to stay away from boost and buck converter
I was looking for a simple solution to make a 9.0 volt battery power supply

[CapLeaker]

I want to stay away from boost and buck converter
I was looking for a simple solution to make a 9.0 volt battery power supply

For what do you need exactly 9.0V for?

[eccerr0r]

The reason why using a zener this way this is dumb because it actually is even worse than a linear regulator. Using a linear regulator with a transistor is actually more efficient - because a zener shunt regulator, whenever it's on it will consume full wattage whether you're actually using your device or not. At least a linear regulator, it will waste energy only when you're using your device.

[sam_sam_sam]

Don't you have have at least two volts above the linear regulator output of the regulator rating if I remember correctly otherwise you might have low voltage output

[CapLeaker]

Don't you have have at least two volts above the linear regulator output of the regulator rating if I remember correctly otherwise you might have low voltage output

Right! But why bother regulating a battery? A regular 9V battery doesn't have 9.0V either when new. A non rechargeable lithium AA battery has like 1.8V! I don't get it.

[eccerr0r]

You can also use an LDO, but knowing the load would be better, many can take the voltage swings from fresh to dead just fine and thus not need a regulator at all.

[sam_sam_sam]

I use to Alkaline battery cells that 1.65 new X 6 = 9.9 volts that dose not last very long at that voltage and stays 9.3 to 9.5 volts until falls below 9.0 volts and dies fairly fast at this point

Yes I might have fixated at 9.6 but real issue is when this battery pack is fully charged at 3.5 X 3 =10.5 which I not sure if the Blue Capacitor tester can handle this kind of voltage when the pack is fully charged now if it has a 5 voltage regulator in which I do not recall if it does or not but if it does then it does not matter if runs a little high I do remember however you can modify it to run at 5 volts but you have make a couple of changes for it to be able to run at this voltage

Zener diode do not come in all voltage flavors I know that 9.1 is one that would work but weather or not you find a higher voltage one is another story

But does this hold true for 9 volt multi meters can you run it at a voltage when the battery pack is fully charged this is the question

Dose this hold true for all 9 volt devices how much more voltage can you put to them before you start destroying them

[eccerr0r]

You can undercharge the cells too... that's another option? I think if it has a 7805 it's quite possible a higher voltage is just fine.

Oddly enough I was looking at ICL7106 and apparently it can deal with higher than 9V just fine...

[sam_sam_sam]

You can undercharge the cells too... that's another option? I think if it has a 7805 it's quite possible a higher voltage is just fine.

Oddly enough I was looking at ICL7106 and apparently it can deal with higher than 9V just fine...

The Maximum voltage of ICL7106 is 15 volts assuming that it uses this ic chip or something similar in nature would work

Dose under charging Lipo 4 to 10.2 volts how drastic would be the running time be I will have to test this and see if this is a good idea or not if I only lose a little bit of running time it might be worth it but now it time to take out my 12 volt switching power supply and see if I can make it go from 12 volts down to basically 11 volts is this switching power supply going to complain if I do this ( because some switching power supplies do not like working on lower voltage output if it is too low ) because I will need to put a diode on the switching power supply to keep the battery pack from back feeding the switching power supply if the switching power supply happens not being turned on for some reason

[sam_sam_sam]

btw, stop talking about 9.6v
it's a cell-pack, it has a minimum and maximum range not a fixed output

This is some what true however it working voltage is 9.6 to around 9.3 volts before the voltage start rolling out and this what I consider a non working voltage range because it does not last very long at this voltage level and above 9.6 volts it rapidly dropping down until it levels out to the working voltage output depends upon the current level that you are using I am basing this on a one amp load on these battery cells that I for this particular project granted the current draw would not necessarily be this high in every situation but I planning on using this battery pack on different types of devices so I have to go by some parameters in determining what is feasible and what is not feasible

[CapLeaker]

I think the blue ESR meter should handle that lithium ion battery pack just fine. Keep it simple, you said. Well this is as simple as it can get!

Put 6 Lithium AA's at 1.85V per cell =11.1v! Puts that 10.5v from the rechargeable pack to shame, Open that meter up and check the voltage regulator(s), but this should be within tolerance no problem.