Battery Break-in Questions

mlanierjr

When using your break in method how long do you let the cart "rest" or sit before you take the voltage? I purchased your voltmeter, I like the aluminum template to cut the hole and it covers any mistakes. I measured the voltage drop between the pack and key switch to be .8v rather than .5v at my key switch. YMMV. I've ran it between 4 and 6 miles to discharge the batteries and and am on my fourth charge cycle with my DPI charger. I have noticed an improvement in range and acceleration between the 1st and 4th charge.

BGW

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Swan

average is 12 hours of rest .

mlanierjr

errr no. Perhaps I was unclear. I trying Scottyb's break in procedure taking the batteries down to 75% and then charging the first 10 to 20 times. I know you don't read the voltage of the pack under load, but how long do you let the cart sit before you determine what the correct voltage is to stop driving and start charging?

ThreeCW

From experience with my 5 year old, 48 volt battery pack (8 pieces x 6 volts each), it will take my pack approximately 30 minutes to stabilize to within 0.2 volts of the final stabilized voltage. My pack will then typically slowly creep up another 0.2 volts over then next hour or so to reach a stabilized voltage.

Now I suspect that my "old" pack will be different than your "new" pack. I also "suspect" that my batteries at 35 deg F may react different than your batteries at 70 deg F. I also "suspect" that the time to stabilize will be a function of how far (depth of discharge) you draw your pack down and how fast (amperage rate) you draw them down.

The best thing that you can do is to test the build up rate on your own battery pack. Draw your batteries down to your target voltage (about 75% or a little more depth of discharge in your case). Stop your cart and record the initial voltage. Record pack voltage readings every 5 minutes (this is where a dash mounted digital gauge comes in handy) until you record 3 voltage readings in a row that are the same. Go for a coffee / beer and come back in an hour and check the voltage again. That should give you a pretty good idea of what the build up rate is of "your" pack and of the stabilized voltage. You will be able to use this information to better estimate where you are with respect to the State of Charge on future draw downs (ScottyB's chart is attached below for reference).

Please share your findings with us on BGW as it will be an interesting exercise that the rest of us can learn from. Also let us know what your battery temperature is (for the record). Good luck with your new pack ... it looks like you are starting them off right

Attached Images

Carts Unlimited State of Charge Chart.JPG (71.0 KB, 0 views)