PDA

View Full Version : MaHa set-up help.


lfisminiz
2007.04.13, 11:14 PM
I could use some basic help, with out getting to technical. Im using Sanyo 1000 aaa batts. I would like to know...
1. refreash and analyze mode - what rates should i set this at?
2. charging mode - what rate should i set this at? i ussually like to charge my batts for around 30 minutes.
3. IF i want to do a break in mode - what rates should i use?
Thanks for the help.I ussually dont get to hi-tech with chargers, but i want to take some advantages of this charger.

shuter
2007.04.13, 11:40 PM
Which Maha charger do you have?

lfisminiz
2007.04.14, 12:36 AM
Sorry, mhc9000 wizzard. :o

rharris
2007.04.14, 03:19 AM
There is a TON of stuff on this in the batterys forum.

Here's the short of it:

Cells charge best at 1c. 1c is calculated by deviding the total capacity by 10. So for a 1000mah 1c = 100mh.

But...

If you want punch, get them hot. I charge 1000mha cells at 1000ma. They won't last very long, and sometimes they will vent (ooze chemicals out of the top) but it's the best way to get punch.

I break in and test with the 9000 charger just like the manual says to. Select break in from the menu, then type in the rated capacity. Then wait a few days.

You can't really match cells without checking individual discharge rate and internal resistance, (featurs you don't have with the 9000)

but...

You can group them by capacity. You'll notice that not all cells have the same capacity.

Start with the above and go from there.

shuter
2007.04.14, 09:46 AM
The C9000 has some great features designed to get the most out of your batteries. The MOST IMPORTANT thing you can do for your batteries is to "FORM" them. Use the "break-in" feature a minimum of three times. You will see the capacity and to a lesser extent the voltage increase each time, even up to a half dozen times. The break in feature will fully activate and evenly distribute the electrolyte allowing the battery to reach its full potential. Each break in cycle takes about 36 hours so it is a time consuming process but it will pay dividends in battery performance. You can do a set or two each week between races. Once your batteries are fully formed you will not use that feature again unless you allow the batteries to sit for more than three months. I put a small lable on each battery and number it. When your batteries are fully "formed" they can be matched by capacity and voltage at this time.

Just use the charge feature to recharge your batteries. When you snap your batteries in the charger it will automatically default to the charge function and set the charge rate at 1000mA. A VERY COOL FEATURE! Frequent deep discharging (discharging to 1V) is not necessary or recommended. Each deep discharge shortens battery life a little. After about 30 charge cycles or three months just run the batteries through a refresh and analize cycle and your batteries will be good to go. Following these simple steps will keep your batteries healthy and powerful for a very long time.


C rate - Is an industry term describing how long it takes to charge/discharge to the batteries rated capacity. A 1000mAh battery charged at a rate of 1000mA for one hour is a charge rate of 1-C. A 1000mAh battery charged at 500mA takes takes two hours to reach the batteries 1000mAh rating and is a charge rate of .5C. In race day terms your batteries will only be depleted a fraction of their full capacity and will therefore reach a fully charged state much sooner than a fully depleted battery. The recommended charge rate is between .5C and 1C.

IMO high charge/discharge rates should be avoided as they can damage the seperators, cause high internal resistance or even a short. Once a battery has vented due to high rate charging the loss of electrolyte prevents that battery from ever reaching its full potential again and can not be repaired. The seal frequently does not reseat itself properly and future venting and performance loss becomes likely.

lfisminiz
2007.04.14, 03:07 PM
Thanks for the help. Do you guys trust leaving the charger on that long? Its hard to keep an eye on the charger for that long of a time and not worring about a electrical malfuction. Dont need to start a fire. :D

Sinister_Y
2007.04.14, 04:02 PM
I've left my 4 chargers running constantly (basically) for over 1 month now. the only break they get is when they're done doing whatever (usually break-in), then I load new cells in (immediately) and start the up again.

The only problem I had is what I described when 1st zapping the cells and then trying to cycle at 1amp. They blew the seals and I threw them away, i.e. they started to leak. Don't do that like me.

Otherwise, if you still to the manual and their procedures, everything should be cool.

lfisminiz
2007.04.14, 10:09 PM
Thanks. Maybe ill give it a shot.

lfisminiz
2007.04.17, 04:29 PM
If you charge your batts...at the end does it show the capacity of batts, or only on refreash mode? Thanks.

shuter
2007.04.17, 05:56 PM
The batteries true capacity can only be measured when discharged from a full charge. This happens in the "break-in", "refresh & analize", and "cycle" modes. Those three modes will also recharge your batteries.

lfisminiz
2007.04.17, 08:04 PM
Thanks again. Thats what i thought. Just wanted to confirm it.