Flooded battery balancing - soul

http://www.nabble.com/new-battery-break-in-td13294226ef25542.html#a13301565

but from other posts, this Roland bloke does some strange stuff!




Re: new battery break-in
Click to flag this post

by Roland Wiench Oct 20, 2007; 02:22am :: Rate this Message: - Use ratings to moderate (?)

Reply | Reply to Author | Print | View Threaded | Show Only this Message
200 amps! That's ok for motor amps, but not battery amps. I been now
driving with my latest battery pack for six years now and the average
battery amps is about 50 amps mostly at city driving at about 30 mph at 5000
rpm at a gear ratio of 13.5:1.

The 200 amps would be my motor amperes that may range from 100 to 400 amps.

The minimum ampere while parking may below 10 amps and accelerating normally
may be 75 amps and accelerating up a slight incline is about 125 amps. Only
one time, I took the battery amps to 250 amps after the battery was broke in
after about 2 years of driving, to see how much shrink back I had at the
post which was about 5 in.lbs.

To break in my batteries, I first torque all the battery connections to 75
in.lbs. Check the electrolyte level to make sure the electrolyte is above
the plates. Do not add water at this time if it looks low. Electrolyte
will be low in a discharge battery and will rise in a charge battery.

Charge the batteries to 1.250 S.G. which is about 90% state of charge.
Check the electrolyte level again. If its not up to the bottom of the fill
well, than add distill water to that level and than continue to charge the
battery to 1.275 S.G. or to 100% S.O.C.

Record the voltages of each battery and record the battery pack voltage
about 12 hours later after rest and record that voltage.

I then pull a 50 amp load for 1 mile and record the battery pack volt drop,
repeat that for 4 more miles and check specific gravity of the batteries,
which tells me how much S.G. per mile I am using. I then re-torque the
battery connections which will lose about 5 in.lbs in the first 5 miles.
This is common for new connections to lose this much torque where that the
surface of the lead is not completely compress.

During these test, it is best to not drop the State of Charge (SOC) of the
battery below 75%. Re-charge the battery at no more the 10 percent of the
rated Ampere Hour of the battery and repeat the test, except check the
battery S.G. after 5 miles and re-torque at 10 miles.

Checking the battery connections at 5, 10, 20, 40, etc. miles, you will find
that the torque lost may be only 1-2 in.lbs per month of driving.

Check the electrolyte level after about one week which will tell you how
often you will have to add distill water. Remember never add water when the
battery is low while it is discharge.

If a battery is setting for a while, it is normal for the battery acid
(H2SO4) will settle to the bottom of the cell, making the bottom read a
higher specific gravity reading while the top portion will read weaker.
Always charge first, add water when need at the 90% charge and finish
charging, which makes this added water mix better.

Another thing to watch out for, which happen to me, is that I had a group of
batteries, that was only partially fill by the factory with 1.275
electrolyte which was still about 3/8 inch below the fill well. Adding
water at a 1.275 S.G. reading only make the electrolyte weaker and trying to
charge the battery, boil off the water anyway. It is best at that time, is
to finish adding 1.275 S.G. electrolyte which you can get at some battery
shops.

After running the EV for a month, checking the electrolyte S.G. and level,
torque, load testing, and voltage, there is a battery conductance leakage
test and battery current shunt test that could be perform.

The conductance leakage test, is the voltage of a battery terminal that is
conducting across the plastic battery tops to either the other post of the
battery or batteries and/or to vehicle ground while charging and not
charging the batteries.

To do this battery current leakage test during charging, apply all the
safety cautions. I use a insulated electrical blankets, that I draped over
any metal portion of the vehicle. Turn the charger on and connect one test
lead to a battery post and the other lead to the battery top starting next
to that same post and slide it to the edge of the battery top, off the
battery case and on to the battery racks or enclosure. If you see any
voltage reading it is time to clean the batteries.

In stead of re-torque of the connections every month or so. I use a battery
connection shunt current test. While the battery charger is on, connect
your volt meter in the milliamp scale and connect in parallel with the
battery links. Do not connect it to the links itself, rather connect it to
the battery post.

Lets say it reads. 0.005 amps at a torque connection of 75 in.lbs. it may
read 0.009 amps at a lower torque reading and may read 0.001 amps at a
higher torque reading. Use that higher torque reading as a reference and
check the shunt current of every link and adjust the higher shunt amp
reading to match the lowest shunt amp readings. In this way you do not have
to run the torque wrench over every battery connection.

You also can sweep a infer-red temperature scanner over the batteries and
battery connections to a quick test. A good meter will have a heat sensor
to do this type of test.

If you can stand to do all these battery maintenance checks, which I now
been doing for 34 years now. You can a very long life out of your batteries.

Roland