Weasels build

[sergon]

dear Tom,

i'm working together with stephan,but have a question to shoot we are now discharging the big battery each day while it's still on the load, we see some major progress to do so,do we heart the battery fisicly?(appearently not) but is it wise to take some discharges in rest stand?or switch each day of these tactic?

Kind regards, Serge and Stephan.

[Tom C]

you must do one or the other, it is 2 chemical process in the battery, do you want it to charge and desulphate or power a load? you cannot expect it to do both. look here at the electrochemistry section:
http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery

Tom C

[wild weasel]

hello tom

desulphation is happening during charge cycle
but each evening we do a hot discharge as well. meaning putting a load on it while its connected on the wheel basicly running it down and using the power of the wheel.
after this discharge its back on regular charge.

the reason is basicly that its a bit tricky having to tune it every time again after startup cause it wont come up to speed on this setting
and we have small diffrences every time in the result

regards
stephan and serge

[wild weasel]

hello folks

last 2 days something changed in our charging cycle
before it took aprox 20 hours to charge the battery

now without changes to the system it is charging to the same level (15.55 volt) in 12 hours
and still small increases in the discharge cycle ( its lasting now unhooked 1.45 hours at its c20 rate) to 12.40 volt
when discharging while on the wheel its 2.40 hours till 12.4 volt

just a question again on the discharge time.
running it down at c20 rate till 12.4 volt so to 80 percent how long should this take? is it 4 hours or less?

kind regards
stephan and serge

[Tom C]

ok you said this is a 12 volt 225 amp hour battery. 225AH/20 =11.25 amps as a discharge rate at C20, lets call it 10 amps it will put you a bit higher. discharge time depends upon battery capacity. a good battery of your size would take 18 hours+ to discharge to 80 percent in ideal conditions, as a rough estimate. your battery has less than 20 percent of it's capacity. and you just lost a bunch for some reason. either material is falling off the plates into the bottom, which reduces capacity, or because you are charging and discharging at the same time, you are growing sulphation and you have destroyed some of the surface area....

so you are destroying the battery. if you need to, put a variable resistor in series on your trigger, so you can get it up to speed and then switch to your fixed resistor. but stop discharging while you are charging. batteries do not like it.

Tom C

[sergon]

thx Tom, do you think we can make this battery still to good condition or do you think that we broke it completely?

Serge and Stephan.

[Tom C]

I do not know. do a few cycles the normal way and see what happens. your charge times should increase a lot, as the plates open up. and your discharge times should increase. there is no guarantee when it comes to restoring batteries, you do not know how they have been treated.

Tom C

[wild weasel]

hello tom

i have a problem with what you said. but i have some info here witch is verry diffrent than what you say

you say discharge on the c20 rate to 12.4 volts during 18 hours. but when i check the tables its 20 hours till 10.5 volt
so now im verry confused.
0 percent charge is a terminal standing voltage of 10.5 volt correct?
12.4 volt is 80 percent charge correct? but now i find some controverse... some say its 12.4 volts during discharge others say its 12.4 volts standing voltage

if its standing voltage then i need to drop below it to compensate for the recovery during standing idle and find out where to pull the plug

by the way this battery shows a constant increase in capacity so i dont think we do some damage.
in the beginning it lasted only seconds on a load of 55 watt and its now lasting 1.45 hours on a load of 130 watt till 12.4 volt during discharge

kind regards
stephan

[wild weasel]

ok first discharge completed off the wheel 1hour 42 minutes
stopped the wheel at 15.45 volt total charge time today 20 hours
standing voltage arround 13.3
discharge stopped at 12.40
lets see tomorrow if there is change

[guyzzemf]

rest the battery is a must for me /usually over night/ or till voltage settles down a couple of hours
A discharged bat rest till voltage settles down a couple of hours

[Tom C]

what does the manufacturer of your battery say? 12.4 is fine, but you can go lower on a deep cycle also . you have to run the battery in its own curve. it is the charging that is removing sulphation, the discharge is so that you can do another cycle. batteries are damaged when they are discharged at too high of a current, too low of a voltage, and not recharged immediately after discharged. 12.4 off the charger is fine. batteries always recover voltage after they are done discharging.

Tom C

[wild weasel]

hello tom and guy

report of the day
this morning battery was fully charged at 15.67 volt after 9 hour charge cycle
left it standing for 12 hours and voltage now is 13.30
discharge 1.2 hours till 12.40 under discharge

now the funny part
i have a same capacity battery here brand new only used a couple of times to power the machine
did the same test but only charged it with a regular charger yesterday
standing also the whole day and just did discharge till 12.4 and it lasted only 10 minutes standing voltage was 13.00 volt
this is weird at best

the idea was to have a reference on discharge time with a new battery but this is a big fail

kind regards
stephan ands serge

[Tom C]

just for clarity please tell us again the battery make, type and capacity. and what is the manufacturing date of the new battery.....


Tom C

[wild weasel]

the new battery is a varta promotive silver 225AH
build 2013

the one on the wheel is same size but no markings on it so brand and age unknown

[wild weasel]

ok after 1 hour rest the old bat came back to 12.86 volt after the discharge.

we put it back on charge now

kind regards
stephan and sege