PEAK VOLTAGE

[lee82gx]

I using a Trinity Real Time 2.5 tray at the track as well.
But storage i use a Robitronics 1A,0.8V cut-off tray. Superb in taking the charge out, but very slow (3-4hrs).

[4z]

whatever it is always keeps your batt in cold condition.....charging or discharging u must keep it cool ...there is where your batt lifespan depends

[TRC]

True indeed...fellow racers also tell me to leave it 1-2 hours after the bulbs off....too long will reversed the celll and hurt the cell....anyway what discharger u r using now..??

[lee82gx]

3nity tray is not power enough, unless you leave it on for 1-2hrs AFTER the lights go out. But beware, you might reach deadshort levels, and I won't pay if you kill any cell hehehe.

[TRC]

what charge current are you using?
Were the cells trayed before charge?
How much charge do they take @9.5-9.8?

Yup all my cells a trayed b4 charging using the trinity d/charger..i usualy charge my cells at 4-5amps..peak at the track @7amps..
seems only my Lrp and smc is in good conditon..peaks at 9.3+ @ 4amps charging

Reedy and Trinity still pumping in 31++ but the peak is like i say above 9.5 charging at 4amps..

Hey i have read bout your intellect batts..impressive!!

[lee82gx]

Extremely important point that i just remembered:

My cells peak that low because i use 3mV delta peak/pack.
I think they would peak at closer to 9.3V if i use 15-30mV/delta

[lee82gx]

what charge current are you using?
Were the cells trayed before charge?
How much charge do they take @9.5-9.8?

There are better ways to determine whether the packs are too old,
namely a discharge cycle. Whatever the condition, if your cells can give out 3000-3200 they are still considered good enough.

[TRC]

Thanks for ur fast reply and infos.....seeing from your peak numbers, than i can compare with mine..anyway MOST my match packs peaks at 9.5>9.8 so what is the conslusion we can make.?? : (   does it means my batts maybe have suffer high IR..? Is pack still useable for racing purpose?
I think the time have come laa for my packs...

[lee82gx]

Oh, by the way, that simple experiment is not accurate because it assumes a constant voltage drop. Whereas 99% of batteries do not give a linear voltage drop when loaded.

You can also use certain chargers which can give the IR during charge and or discharge. They can be used to compare between cells and also to check the deterioration of a particular pack over time.

[lee82gx]

the peak voltage will also depend on your charge current,the amount of charge already in the cell b4 you charge it, the starting and ending temperature(if you've cooled it long enough or not, or cool it during charging or not) and many other factors which i can't remember off hand.

If i remember correctly, my best packs peak at 9.05-9.10 @4.5-5.0A(trayed b4 charge)
These would correspond to matched IR values of around 2.3-2.8mOhm on the cell labels. (matched GP3300)
I've some new sanyo 3300HV(unmatched) which peak at 9.5V-9.9V.
I've some unmatched GP3300 which peak at 9.3V thereabouts.

To check the IR you would need to graph the discharge of a cell (voltage vs current at 0 load)

The circuit for measuring the internal resistance is given below.



The current is set to some convenient value, such as 10 mA, or 50 mA, and the "voltage drop" is calculated. (The difference between open circuit voltage and the voltage at the specified load current.) This is used to find the internal resistance, IR = voltage drop/ current.

[TRC]

Peak Voltage

Peak Voltage is the point that you pack will no longer be able to accept a charge, it has reached the "peak" voltage value and the voltage will now begin to lower, signaling that the pack is fully charge. If you packs have a high peak charge value, then you packs are suffering from Internal Resistance (IR). With a lower the Peak Voltage, you will have a stronger pack.

My question is..what is the usual/normal peak voltage value for a matched/normal pack??
and how to know measure IR in our packs.??