Ragz

I have recently purchased 4 packs of sanyo cadnica 6v batteries. Each is 1700mA. I have given a forming charge to 2 packs with 0.1A charge rate. Both packs went upto 2100mA. Is this ok? I am worried about them taking extra 400mA...please let me know if there is a problem here.

I must add that the charger is the Orbit Pocket lader where we dont input the battery pack size in terms of mAh...so maybe the peak delta settings are making the packs go to higher than normal...what shld be the peak delta settings for forming?

rajul

My Feedback: (58)

Hi Ragz,

Forming charge can be done at C/10 or 170mA in your case. Most new battery packs, whether NiCd or NiMH may not respond well to peak detection circuits, so it is advisable to do the formation charge ( and perhaps the first few charges) based on 15-16 hours charge at C/10. This is a safety precaution to prevent from overcharging and overheating, which of course will damage the battery, especially NiMH. Normally the peak detection (and capacity) will improve after several cycles of charge and discharge.

On your measurement for the pack capacity, most manufacturer's base it on a discharge rate of C/5, or about 340mA in your case. A lower discharge current may lead to a higher than rated capacity, and vice versa. What discharge rate did you use?

richrd

This is s common concern the first time you experience this. Try to separate the two form charge from plain charging. Form we overcharge some 40% to 60% over at 10% mAH 14 to 16 hrs to make sure all cells are fully charged and balanced. In forming no delta peak should occur try to get charger to miss the peak set delta as high as you can on charger or other tricks on different chargers. Charging is best done using a peak detection charger and closer you get to detecting true peak the more accurate the capacity in is equal the stored capacity. Most batteries have a better peak near the fast charge rate of 50% to 100% mAH charge current at about 2mV to 10mV setting.
Hope this helps
Rich.

Rodney

The charging is not 100% efficient, you must always put in more than you take out. When charging at 0.1C (170 ma in your case) you will not damage the batteries even if you would leave the charger on longer than 16 hours. When you are charging at 100 ma as you stated, a forming charge should last 1700/100 * 1.6 or about 27 hours or you will input about 2700mah.

JNorton

My Feedback: (2)

Every body has given you good advice but I don't think your question was answered directly. You are fine.