Battery maintenance & trouble shooting

Presented by -  Mr. Shah Md. Sazzad Hossain

Sales & Marketing Manager ( IB & Solar Unit),  Rahimafrooz Batteries Ltd.

Address : 705, West Nakhalpara, Tejgaon, Dhaka -1215

Solar Home System Consists of:-

• Generation  System
• Storage System
• Load

Battery selection criterion

• Deep Cycle capability
• Charge acceptance efficiency
• Self discharge

(Fig: Solar Deep Cycle Battery)

Battery sizing depends on :-

• Loads & its operating hour
• Autonomy
• Self discharge of battery
• Depth of discharge (DOD)
• Self consumption of Charge Controller
• Cable loss
• Battery deterring factor
• Temperature effect on battery

 Battery maintenance : 

• Keep the battery dry & clean

• Place the battery in a clean & well ventilated place

• Put petroleum jelly in battery post every month to prevent from corrosion

• Never allow flame or cigarette near the battery

• Keep the electrolyte level above the “lower level” mark

• Keep electrolyte level of all the cells in the same level

• Never add electrolyte in to the cells. Always carry out topping with de - mineralized water

• Don’t allow electrolyte specific gravity to drop below 1.180

• Keep specific gravity of all the cells in the range of  0.05 (for example 1.250, 1.245, 1.250, 1.245, 1.245, 1.250)

• Ensure both the LVD & HVD of charge controller works properly

• Don’t keep battery in under charged condition. If we keep the battery under charged condition then battery plates would be sulfated.  If battery is undercharged we should charge the battery as per charging instruction

Fig: Sulfated plate

Don’t keep the battery in over charged condition. If the battery is kept over charged condition then battery plates would be hard and shaded 

Fig: Hard plate  

     Fig: Shaded Plate 

Indication of trouble

• High temperature
• Excess water consumption
• Low gravity or voltage

Double Sulphate Reaction

Symptoms of end of life: 

• The cell temperature runs appreciably higher than normal

• Water requirement usually increases

• Irregular gravity and voltage

 Battery Construction  

SOC & its Impacts on Charging 

SOC & its Impacts on Charging 

SOC & its Impacts on Charging : 

• 0% SOC to 84% SOC the average overall battery charging efficiency is 91%

• The incremental battery charging efficiency from 79% to 84% is only 55%

• The impact of low charge efficiency at high states of charge has the greatest potential impact on systems where high energy viability is needed.

Sulphation from lagging of Charges : 

Stratification

  Load management

• Load should not cross 10 Amps

• Load should not exceed generation from PV module

• Ensure load is connected with the SHS as per generation from the PV module      

 30 Wp                                    7.5           Ah

40 Wp                                    10            Ah

50 Wp                                    12.5         Ah

75 Wp                                    18.75 Ah               

Issues Identified

 Issues Identified

SOLAR DEEP CYCLE BATTERY TIPS !

The following are some consumer tips for deep cycle solar batteries:

• Wear glasses when working with a battery, because it might explode.

• Recharge your battery as soon as possible when the State-of-Charge drops below 60% or specific gravity below 1180. 80%-discharged batteries connecting with the Solar Panel don’t have any option to recover the charges by the connecting solar panel.

• Keep your battery away from salt water, cool, properly filled with de-ionized water, and the top clean. Do not allow battery electrolyte to mix with salt water. Even small quantities of this combination will produce chlorine gas that can KILL you! Whenever possible, please follow the manufacturer's instructions for installing, charging and equalizing batteries.

• Lower the average Depth-of-Discharge (DOD) and you will automatically increase the service life.

• Follow the battery manufacturers recommended Charge controller & Load. Permanent sulfation kills approximately 85% of all deep cycle batteries.

• When buying a replacement battery, be sure it matches your Solar Home System & ampere hour (Ah) requirements and is fresh. Heavier is better.

• Keep the battery cable mating surfaces and terminals/post clean. Use Petroleum Jelly or Vaseline to clean the terminal of the batteries.

• Avoid shallow discharges (less than 10%) or deep discharges (greater than 80%) on any battery. This could prematurely kill it.

• For longer battery life, do not add battery acid or additives, keep your battery securely fastened, and recommended by the battery manufacturer, equalize it.

• In case of deep discharged of the batteries use external chargers (or charger settings) that will recharge batteries over eight to ten hours.

• If the electrolyte levels are low in the batteries, allow the battery to cool and add only de-ionized water to the level indicated by the battery manufacturer or to between 1/8 to 1/4 inch (3 to 7 mm) below the bottom of the plastic filler tube (vent wells). The plates need to be covered at all times. Avoid overfilling, especially in hot climates, because heat will cause the electrolyte to expand and overflow.