Quicker full charge:
The fastest way to fully charge the battery is to charge for 4.5 hrs, then switch the power supply off and on again, thus
Warning:
If the battery is getting warm, that would indicate that it is full, and the power supply should not be connected again - overcharging reduces the life of the battery.
Note:
After a recently fully charged battery is connected to the charger, it seems that it takes the MAX712 about 30 min to sense that the battery voltage stops changing, and go to trickle charge.
Examples:
Older
trickle charge (50mA): 4.5*0.4+10.5*0.05=2.325Ah=3.5Ah*0.66, which fills the battery to 66% of capacity (3.5Ah).
To fill the remaining 34% at 50mA takes 3.5*0.34/0.05=23.8hrs, +15hrs = 39hrs to 100%. Assuming 20% losses:
(3.5Ah*20%)/50mA=0.7Ah/0.05A=14hrs of trickle charge to cover losses, +39hrs=53hrs total.
In fact it needs ~9hrs * 0.4A = 3.6Ah to fill the battery from empty to 103% full capacity. Assuming 20% losses:
4.5hrs fast: 0.8A*4.5h=3.6Ah = 90% of 4.0Ah
Slow: 10%= 0.4Ah/0.1A = 4h, total 8.5h to 100%
with 20% losses: 0.8Ah/0.1A = 8h
Total time fast and slow: 16.5hrs to 120%.
Fast only: 4.0Ah/0.8A=5hrs, +20%=6hrs,
that needs 2 sessions: 4.5hrs + 1.5hrs to 120%.
Micronics Ltd
Knaves Beech Business Centre,
Davies Way, Loudwater, High Wycombe,
Bucks. HP10 9QR
U.K.
Telephone: +44 (0) 1628 810456
Fax: +44 (0) 1628 531540 www.micronicsltd.co.uk
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