Series Parallel Cells Update

Guido.

Member
Hello,

As I said in my last post 1 and 2 cells are in series to 3 and 4 are in parallel. # 3 + is soldered to #2 -, making 1 2 3 cells in series. What got my attention was that from 1+ to 4+ I got the same voltage as I did from 1 to 2. The + on #4 acting as a -?
Any how. I duplicated the circuit with old cells. DO NOT TRY TO DO THIS TEST!!! You will see why in a minute. I used a 1 Ohm 10 watts 1% power resistor. All the cells were about 4 volts each before the test. As the picture shows the amp draw was a little over 4 amps. I quickly checked voltages on each cell, as the current draw was going down quickly, down to 1.5 amps, at the end of the test, then I unhooked the load. 1 2 3 cells, all in series, had the same voltages, showing 3.12 volts. The surprise was #4 cell. With the negative and positive leads on the meter matching the cell's polarity the voltage quickly climbed to + 5. 4 volts! It did not get hot as I quickly removed the load. But #4 cell appears to being charged when in the circuit that way? Its a new one on me!

Guido.
a197206.jpg
 
Unless cells 3 and 4 are also connected at the positive end they are not in parallel but in series with one cell offsetting the voltage from the other one. That is why you have the same voltage across cells 1 and 2 as you do across 1 to 4. Voltage from cell 1 is added to cell 2 and then added to cell 3 but cell 4 subtracts its voltage from the total of the others.

If cells 3 and 4 are connected on both ends to put them in parallel, you will still get the same voltage across 1 and 2 as you do across 1 to 4 because cells 3 and 4 will not be in then circuit they way you are testing it.
 
Hello jake2,

I was putting the cells in series to make a 5 cell drill pack. When I checked the voltage across 1 to 4 I noticed the 2 right cells were not in series, but in parallel. So the cell voltage was not 16 but 8. I was curious, so I asked the question on my previous thread. I got no answer to what would happen if I put a load test on the cells. Now I know,

Guido.
 
Hello Owen Aaland,

You are right,3 and 4 are not tied on the plus side. Voltage between 1 and 2 is 8 volts.
Voltage between 1 and 4 is the same as 1 and 2. Putting a strap across 3 and 4 should
have no effect on the voltage. I'll do just that and see what happens.

Guido.
 
Owen is correct - you don't have cells 3 and 4 in parallel - you just have cell #4 hooked up backwards, so iif it was of similar charge condition as cell #3 it would just be removing the voltage effect of that cell #3. You have cells #1 and #2 in series and then a mess hooked up to it in series
 
(quoted from post at 17:55:00 07/29/15) Hello jake2,

I was putting the cells in series to make a 5 cell drill pack. When I checked the voltage across 1 to 4 I noticed the 2 right cells were not in series, but in parallel. So the cell voltage was not 16 but 8. I was curious, so I asked the question on my previous thread. I got no answer to what would happen if I put a load test on the cells. Now I know,

Guido.

When I was still working we had an emergency power plant with strings of 1.5 volt batteries that put out 24 and 48 volts dc and in one if not all of them there was one cell called cemf(counter electromotive force) that would kick in under certain conditions. I'm not sure what the conditions were as I never worked power plant. It was hooked up backwards to the rest of the 4' tall wet cells. I think you had to push a button to initiate the process. Some type of voltage regulation?
 
Hello,


I tied 3 and 4 on the plus side.The plus side of 4 is now tied to 3 and 2.
I had left this connection off between 3 and 4 for because it was the only way that I could put 4 in the circuit from 1. Now from 1 to 3 the circuit is 12volts (3 cells in series).
4 is now not in the circuit. It can only be load tested by itself, or put in series with the other 3 cells to make a 16 volt total. One more cell will finish the pack that I started to do in the first place. Actually the cells are rated at 3.7 V, they will charge to 4.2 volts,

Guido.
 

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