Ultralife, Accutronics & SWE Blog

Are you still using SLA batteries?

Written by Rob Brown | 01-Feb-2021 14:11:00

Did you know that the lead acid battery is over 160 years old?  Since its invention there have been many improved variations, including the first sealed, or maintenance-free, lead acid (SLA) that was introduced in the mid-1970s.  However, in 1996, an alternative chemistry – Lithium Iron Phosphate (LiFePO4) – was introduced that can serve the same applications with significant advantages.

Lower Cost

When total cost of ownership (TCO) is considered, Sealed Lead Acid batteries have a much higher TCO than Lithium Iron Phosphate.  The main expense with SLA is the frequent need for maintenance and a high self-discharge rate that causes the need for trickle charging.  With LiFePO4 batteries, maintenance charging only needs to be performed once every four to six months, which also saves energy.

Additional cost savings can be had with LiFePO4 batteries thanks to their extended service life.  Where SLA may need replacing on a yearly or even bi-yearly basis, in applications such as security and alarm panels, Lithium Iron Phosphate can last for up to 7 years.  Yet the advantages go even further, as runtime is also 40% longer than current SLA batteries in medical carts, powered scooters, small motives and UPS lead acid markets.  Not only can cycling reduce to 100% depth of discharge but cycle life can exceed 1,500 cycles (compared to just 300-500 for the best ‘cyclic’ lead acid batteries).

 

Easier Device Integration

In addition to cost, time is a major factor in the product development lifecycle, with OEMs endeavouring to streamline the process from concept to launch.  Sourcing the right battery for the demands of the application can be time consuming, so ensuring the correct system voltage and/or capacity is critical.  LiFePO4 batteries simplify the process as they can be connected in a variety of series and parallel arrays to make different voltages and capacities available.  Take the URB121000 for example, up to five of these batteries can be connected in series and up to four in parallel.

(OEMs considering using multiple batteries should contact Ultralife for advice)


Once the battery has been selected, it also needs to be integrated safely into the product.  Ultralife LiFePO4 batteries contain built-in protection electronics to prevent over-charge, over discharge or over-temperature. This makes the battery self-dependent and robust enough for use in medical or government and defense equipment.

 

Weight Reduction

Lead acid is heavy and is less durable than nickel- and lithium-based systems when deep cycled.’ (British Battery Industry Federation)

Ultralife LiFePO4 Lead Acid Replacement batteries are three times lighter than lead acid batteries of the same energy. Replacing lead acid with Ultralife LiFePO4 will significantly reduce the weight of an existing system and have operational benefits in mobile/transportable equipment such as medical carts and robotics.

The table below shows Ultralife Corporation’s range of SLA replacement products that are suitable for such applications, their associated weights and other key specifications.

Model Number

Typical

Weight

Nominal Dimensions
(L x W x H)

Typical

Voltage

Typical Capacity

Typical

Energy

URB6450

0.36kg

(0.8lb)
70 x 48 x 100mm 6.4V 4.5Ah 29Wh

URB1270

1.10kg

(2.4lb)
152 x 65 x 92mm 12.8V 7.5Ah 96Wh

URB12200

2.85kg

(6.28lb)
181 x 76 x 165mm 12.8V 20.0Ah 256Wh

URB12350

4.60kg

(10.14lb)
195 x 127 x 165mm 12.8V 32.0Ah 410Wh

URB12550

7.85kg

(17.3lb)
256 x 132 x 200mm 12.8V 55.8Ah 714Wh

URB12550-22NF

7.50kg

(16.5lb)
228 x 138 x 208mm 12.8V 52.7Ah 675Wh

URB121000

13.90kg

(30.64lb)
340 x 170 x 210mm 12.8V 100.0Ah 1280Wh

URB12450-U1-SMB

5.46kg

(12.04lb)

209 x 136 x 182mm 12.8V 45.6Ah 584Wh

URB24200-U1-SMB
(Coming Soon)

5.46kg

(12.04lb)

209 x 136 x 182mm 25.6V 22.8Ah 584Wh

URB-X5

3.67kg

(8.09lb)

121 x 76 x 317mm 12.8V 21.6Ah 277Wh

URB0023

15.9kg

(35.05lb)

445 x 438 x 103mm 25.6V 54.0Ah 1382Wh

URB0016-SMB
(Coming Soon)

15.9kg

(35.05lb)

445 x 438 x 103mm 25.6V 54.0Ah 1382Wh

All of the above Lithium Iron Phosphate batteries offer the lower cost, easier device integration and weight reduction advantages; making them the perfect portable power option for original equipment manufacturers (OEMs) who are looking to replace sealed lead acid alternatives.