"Volts mean nothing. Amps mean everything!" - Your Hybrid Battery

isn't the best way with tech stream while driving?

 

Seems like people have been talking amp-hours since the earliest battery-reconditioning posts I ever saw around here.

 

Step one: there's ten thousand posts on this topic that you could catch up on........

 

The first question when testing for Ah is the load the testing should be. No point in the lead acid high load test, depending on the chemistry, NiMh in this case, the load current can be huge, enough to destroy the testing machine, so the load in amps over a given time will determine the C value, C is the capacity, the number after the C is the number of hrs this battery should be able to provide a current (amps) before dropping below a given voltage .....

This sort of testing is done at cell level generally, can't do that with a Prius module, because each module is made up of 6 cells, it only requires a single cell to be weak to condemn all 6 cells, so a high C value could destroy a cell that simply needs to be balance charged and most likely, all 6 cells need to be topped up, they refer to it as rehydrating on this forum, so try looking up that topic to get more information regarding that topic, along with forcing the pressure relief valve free so the electrolyte no longer leaks out of the terminal seals ......

To find the C value, you need the cells to be in their best condition first, so all those steps must be completed first, then we can talk about C values, the cell capacity is only 6 Ah in as new condition, so a C1 test would be possible with 6 cells in good condition, so, get that part sorted first ....

T1 Terry

 

The terminology is one of the first things to make sure you get right, and that helps everything else be less confusing.

'Cell' is the smallest unit. It's a standard term. One cell has an anode and a cathode and an electrolyte between them, and the chemistry of the anode and cathode and electrolyte determine its characteristic voltage. For one NiMH cell, that's 1.2 volts, nominal. (Doesn't depend on who built the cell or how big it is or what it looks like, but only on the chemistry.)

'Modules' are the smallest things you can take the Prius battery apart into. Each module is long and flat and contains six cells. So the voltage of one module is 7.2 volts, nominal.

'Blocks' are pairs of modules. Because the modules have terminals on both ends and are all wired in series, and all the ECU's voltage sense wires attach to the terminals along one side of the battery, each pair of those adjacent terminals will measure the combined voltage of two adjacent modules, otherwise known as one block. So the nominal voltage of a block is 14.4.

 

It looks like one of the parameters used to trigger a P0A80 is the Delta SOC.

But how does the computer know the SOC of each block? As I see it, the computer can only monitor the voltage (or change of voltage) of each block (amp is the same for every block). Therefore, the voltage is the cricual parameter used by the computer to report the Delta SOC afterall, and therefore the P0A80.

Maybe C is the root cause, V (or change in V) is the symptom. They are related.

Of course, maybe I understand it wrong.

 

This post for sure tells us that dr Prius app is useless. It has voltage fan blade, voltage delta and packs voltage difference and other voltage data. We need amperage of each battery packs, amperage differences and delta instead.

 

Dr. Prius app shows us the amp flow when charging or discharging.

The car looks at the battery as one piece and not as modules so the amps would be totaled from all modules as one.

Nothing wrong the Dr. Prius app.

 

PriusII&C got this part right:

The battery is wired as one series string, so the current flowing through the whole thing is the exact current flowing through every block, every module, every cell. There's nothing about the current that needs to be 'totaled'. The single current sensor is all that's needed, along with the multiple per-block voltage sensors.

 

Amazing information!!!!

So toyota could have used less modules or did they have to add more modules to get the right total of volts?

 

Have you ever noticed that the voltage of a series string is the sum of all the individual voltages, while the current through a series string is the same current all the way through?

You get the reverse if you connect a bunch of cells in parallel. You would then add up all the current capacities to get the total, but the voltage of the whole parallel arrangement is just the same as each cell's.

Either way, you have just one measure (voltage or current) that gets summed, and the other does not.

You can easily remember that by thinking about what happens to the total available power from the collection of cells. Power is voltage times current. The power of N cells has to be N times the power of one cell.

If one cell is rated at V volts and I amps, then the N-cell series string has NV volts and I amps, giving power (NV)(I) = N(VI), N times the power for one cell. And the N-cell parallel arrangement has V volts and NI amps, giving power V(NI) = N(VI), again N times the power for one cell.

If you ever think you have invented a way to connect N cells so you get N times the voltage and N times the current, you can catch your mistake by realizing that battery would have N² times the power of one cell alone,

 

You really don't understand the difference between a series and parallel circuit....maybe electrons aren't your thing...

 

I thought this was going to be about the 12 volt battery, where Cold Cranking Amps testing is more telling than volts. Maybe append the word "battery" in the title, to be "hybrid battery"?

(Request sent to moderator)

 

Depending on what you think "IMPORTANT" is. From the point of view of Prius operation, the voltage differences among the blocks of the battery pack is more important. I think it is these differences that determine if a P0A80 code will be triggered. The computer doesn't see the difference between the two modules in each block.