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Which battery is best for my solar powered road sign?

This entry was posted on 23/01/2019 04:51:30 PM by Valen

Which battery should I install in my solar powered road sign

VMS signs, radar signs, arrow boards and portable traffic lights all rely on some form of a battery system, whether the battery is an AGM, Gel or Lithium battery. Often these battery systems are charged by solar panels, and in some cases, the charging only happens when the sign is back at base. 

Long service periods with no battery charging, plus other challenges such as solar drought, play a large part in limiting battery service life. However, when the correct battery technology is used, emergency maintenance and downtimes can be dramatically reduced.

In this blog, the team at Valen will explore the basics of different types of battery technologies and the associated advantages for their use in the solar road sign industry. 


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AGM (Absorbent Glass Mat) Batteries

Mainly designed for standby power applications, AGM (Absorbent Glass Mat) batteries are a low-cost VRLA (Valve Regulated Lead Acid) battery. The acid is immobilised in the separator, meaning they are maintenance-free and will not need topping up unlike conventional wet cell batteries. 

There are a few advantages to using AGM batteries in solar-powered road signs: 

  • Low cost,
  • Freedom from electrolyte maintenance, and
  • Vibration resistant. 

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AGM (Absorbent Glass Mat) Batteries with Tin

AGM batteries with added tin, such as the Valen X-CEL range, carry additional benefits compared to standard AGM batteries. 

Benefits include reduced internal impedance, reduced plate sulphation and in turn, increased design life.

Other advantages for solar-powered road signs are: 

  • Lower cost than Gel batteries,
  • Maintenance-free,
  • High purity virgin lead plates with tin,
  • Freedom from electrolyte maintenance, and
  • Vibration resistance.

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Hybrid Batteries

A hybrid battery, such as Valen Forte range, is based on the AGM technology but utilises a combination of AGM separators with liquid Gel Colloidal Silica electrolyte. 

Hybrid technology offers the best of both worlds - delivering the advantage of increased cyclic life similar to that of a Gel battery, with the lower cost advantage of an AGM battery. 

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Gel Batteries

A Gel battery uses polyethylene separators with a thixotropic Gel. The electrolyte is suspended within the Gel. While AGM batteries can provide an affordable and workable solution, Gel batteries are the recommended solution for solar-powered road signs.

  • Designed to handle constant cycling regularly without damaging the battery,
  • Ability to combat solar drought and cyclic pressure,
  • Thanks to the thixotropic Gel, the battery can be left in a partial state of charge (SOC) without damaging the battery,
  • Ability to cycle back from a low state of charge (SOC), and
  • Better vibration resistance compared to AGM batteries. 

Related: Why cyclic batteries are essential for solar powered road signs


Gel Batteries PLUS a Catalyst Life Extender

EXCLUSIVE TO VALEN - the Valen ENDUROGEL range features out Catalyst Life Extender and advanced Gel technology.

The Catalyst recombines the hydrogen and oxygen gasses which the battery creates whenever it charges and discharges. The Catalyst offers the following benefits: 

  • Extends service life by reducing cell failure due to sulphation, and
  • Maintains full design life when used at temperatures up to 30°C.

The Valen ENDUROGEL range is an ideal solution for your cyclic road signage equipment, such as VMS signs, due to its longevity and reliability in remote locations and higher operating temperatures.


Lithium Phosphate (LiFEPO4) Batteries

Lithium batteries are designed to be a direct replacement for similar Ah sized AGM or Gel batteries. While they are a more expensive option, they offer many advantages when used in solar-powered road signs: 

  • Easier installation and maintenance as they are more than 50% lighter than other AGM or Gel batteries,
  • No acid, therefore no mess if the sign or light is vandalised or knocked over,
  • Ability to endure higher temperatures, thereby minimising replacement time, costs and system downtime,
  • No corrosion inside enclosures as there is no gassing, unlike AGM or Gel batteries, 
  • Battery Management System (BMS) installed into each battery cell equalising and preventing over-discharge extending service life, 
  • Low environmental impact due to the long service life of the batteries, 
  • Integrated safety systems including short circuit, overvoltage and over-discharge protection, and
  • Flexible design ensures that a Lithium battery can be customised to fit into space restrictive areas, especially where Gel or AGM batteries would be unable to fit. 

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Need advice choosing the right battery for your solar powered road sign?
Just ask Valen!

We’re industry leaders in energy storage systems and have extensive experience in the road signs industry. If you have a current or upcoming road sign project, speak to us today. We can provide assistance with your battery needs as well system design so you can make that final decision with confidence.

Click here to get in touch.

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Written by Valen

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