Ultralife URB0003 - Manual (Page 9)

MKM Multi-Kilowatt Module User Manual
Newark, New York | 315-332-7100 | Fax: 315-331-7800
©2013 Ultralife Corporation • www.ultralifecorp.com • All information is subject to change without notice.
The information contained herein is for reference only and does not constitute a warranty of performance. • 25 FEB 13 UBI-05342 Rev: -
Page 9 of 7
2.2 Discharging
The MKM products can be discharged repeatedly to 100% depth of discharge during use.
The MKM products have an extremely low internal resistance which allows high utilization
of internal battery energy with little loss due to heat. In system design, care should be
taken to limit capacitance to less than 2mF on the target device, as this can lead to high
inrush currents and nuisance tripping of the protection electronics over current protection.
If a highly capacitive load is attached; a pre-charge circuit should be implemented.
If there are extended times between fully discharging and recharging, care should be
taken to leave some reserve energy in the MKM during discharge. It is highly
recommended to never discharge the battery to “cutoff,” when the battery turns off the
output voltage. The system should be designed in such a way to prevent discharge to
cutoff.
2.3 Charging
The MKM products have been designed to be utilized with advanced Sealed Lead Acid
chargers, Power supplies, and Lithium Ion chargers. Please consult factory to verify the
applicability of a proposed charging solution. The MKM products can be charged rapidly
utilizing a 1-2 hour charge rate depending on model. It is suggested the MKM modules be
charged at constant current followed by constant voltage, a standard Lithium Ion type
charge. If long charge times (>10 hour) are used in system design, a constant current
charge to a cutoff voltage can be used.
The MKM products can be float charged, but it is suggested to conserve energy and
maximize life that charge be terminated when full, and then reinitiated when a noticeable
voltage drop occurs (approximately 1V).
Due to the low internal resistance of the MKM products, it is suggested that recharge be
preformed within 24 hours of a complete discharge. If there are extended times between
fully discharging and recharging, care should be taken to leave some reserve energy in
the MKM during discharge.
2.4 Parallel Connections
Factory suggests limiting number of MKMs in parallel to less than 10. This will result in a
very low resistance battery, so the user is cautioned as high capacitive loads will create
large current spikes which will/can lead to nuisance tripping of protection electronics. It is
suggested that all batteries be connected to a high current bus with as short wires as
possible.