Batteries 101
Important Safety Information

ALWAYS wear protective glasses when working around batteries!
Batteries produce explosive gases. Keep sparks, flames and cigarettes away from batteries at all times. Protect your eyes at all times. Never lean over battery when jump starting or performing other maintenance.
Be careful of the sulfuric acid in the battery. It can burn eyes, clothing and damage paint and electronic equipment. FLUSH EYES IMMEDIATELY WITH LARGE QUANTITIES OF COOL WATER. GET MEDICAL HELP FAST.
How to Safely Jumpstart Your Vehicle
Connect positive (+) booster cable to positive (+) terminal of discharged battery.
Connect other end of positive (+) cable to positive (+) terminal of assisting battery.
Connect negative (-) cable to negative (-) terminal of assisting battery.
MAKE FINAL CONNECTION OF NEGATIVE (-) CABLE TO ENGINE BLOCK OF STALLED VEHICLE, AWAY FROM BATTERY.
Start vehicle and remove cable in REVERSE order of connections.
Source: Battery Council International

The Importance of Having Your Battery Tested on a Regular Basis
A battery’s condition and performance deteriorates with age, particularly when used under severe service conditions. The average life of an automotive battery in Canada is 4.5 to 5 years.
Contrary to popular belief, it’s excess heat, rather than cold, that damages batteries. Hot summer days and high under hood operating temperatures both contribute to eventual battery failure.
Although it’s heat that damages batteries, cold temperatures limit the amount of power a battery can generate. That’s why the colder the temperature, the harder it can be to start your vehicle. On a marginal battery, even a small drop in temperature could easily cause the battery to fail and leave you stranded in a potentially dangerous situation. Therefore, it is important to have your battery tested regularly, and especially during your pre-winter service before the cold weather begins.
Peterborough Battery can quickly perform a complete electrical system check, which includes the battery, and give you a complete report on your battery’s state of health.
It is important to compare the battery’s actual CCA (cold cranking amps) with the public rated CCA printed on the battery. Once the actual CCA falls below the public rated CCA, it’s time to consider a battery replacement.
Choosing the Right Battery for the Right Application
Function of an SLI (Starting, Lighting, Ignition) Battery
In engine starting applications, a battery performs the following functions:
- Supplies power to the starter and ignition system so the engine can be cranked and started.
- Intermittently supplies current for lights, radio, heater, and other accessories when electrical demands exceed alternator output.
- Acts as a voltage stabilizer. The battery smooths out or reduces high voltages (transient voltages) which occur in the vehicle’s electrical system. These excessively high voltages would damage other components in the electrical system if it were not for the protection provided by the battery.
- Supplies electrical energy for the accessories when the engine is not running.
Function of a Deep Cycle/Dual Purpose Battery
In some applications, the battery could perform two functions:
- Vehicle starting (i.e. SLI functions)
- owering of “key-off” auxiliary loads such as house power (lights, radios, TVs, fridges and other “home comfort” appliances), hydraulic lifts, winches, on-board electronics/communications equipment, high end stereo systems, etc.
Regular automotive starting batteries are designed to give short bursts of full power to start an engine. These batteries have low internal resistance so that power moves quickly through the battery. They are designed for cranking and minimal cycling where the battery power is not drained very much before the alternator recharges it back up again. They have not been designed for and will not hold up under deep discharge/recharge cycles; constant deep cycling (i.e. delivering lower amounts of current over longer periods of time as required by auxiliary loads) will literally tear the battery apart on the inside.
Peterborough Battery’s dual purpose batteries provide a combination of starting and cycling power – the best of both worlds. They are constructed very similarly to a true deep cycle battery, yet also have a high enough CCA rating for ample starting power. Thus they are ideal in RV and some marine applications.
Maximizing Battery Cycle Life
The life of a deep cycle battery will be determined not only by the number of cycles (a discharge and a recharge) it receives, but also by the depth (amount of power removed) of each cycle. A deep discharge does more damage to the plate.
To obtain maximum service life, a deep cycle battery should be fully charged every day it is used even if it is only discharged 25%. Do not completely discharge any deep cycle battery if it can be avoided. As noted above, the deeper the discharge, the less life you will obtain from your battery.
Battery Service Tips
Always wear safety glasses when working around batteries. Batteries can explode. Protect your eyes!
- Perform a visual inspection. Inspect for defective or cracked case and cover, and loose or damaged terminal posts or cables. Replace battery and/or cables immediately if any damage is found.
- Look for loose connections or hold-downs. Tighten snugly if appropriate. TO AVOID BATTERY DAMAGE, DO NOT OVER-TIGHTEN!
- Keep the batteries and battery compartment clean and corrosion free. Dirty, corroded batteries can self-discharge, which will affect performance and life. Clean corrosion with a paste made from baking soda and water. Apply liberally. Any corrosion is neutralized when the solution stops bubbling. Wash off with large quantities of water to avoid environmental damage.
- Shine lead posts and terminal ends with a wire brush or steel wool to clean corrosion and assure a low resistance connection. Reassemble and coat lead parts with petroleum jelly or a terminal protection spray. Repaint hold-down, tray and surrounding parts if necessary.
While you will never need to add water to your Peterborough Battery starting battery, our deep cycle and dual purpose batteries should be inspected regularly to ensure fluid levels never drop below the tops of the plates or the exposed portion will become permanently inactive. NEVER open the vent caps on your battery if it feels hot to the touch – the change in pressure could cause battery acid to spew from the vents. Therefore, NEVER lean over your battery when opening the vent caps.
- Before charging, add distilled water to just above level of plates.
- After charging, top up fluid to just below bottom of filler tube.
- Adding too much water before charging will result in overflow.
Battery Charging Tips
Always leave filler caps in place, tight and secure to reduce the risk of battery explosion and serious injury! Always wear safety glasses when working around batteries. Batteries can explode! Protect your eyes. Do not charge batteries without proper instruction.
Batteries should be charged if hydrometer reading is below 1.225 specific gravity, or open circuit voltage is below 12.4 volts, or if a load test is below 9.6 volts.
The following chart gives you the state of charge at various specific gravities (specific gravity measures the concentration level of the acid in the acid/water solution), corrected to 80℉. (26.7℃).
Percent of Charge
100%
75%
50%
25%
Discharged
Specific Gravity
1.265
1.225
1.190
1.155
1.120
To fully recharge a battery, you must replace the ampere-hours removed from it plus an extra 20% charge. This is because a lead acid battery is not 100% efficient on recharging. Do not charge your battery beyond the fully charged state as this also shortens the service life.
Never allow the fluid level in your battery to drop below the tops of the plates because the exposed portion of the plate will become permanently inactive due to sulfation. Check your fluid levels before charging and add distilled water to just above the level of the plates. After the battery is near full charge, recheck the levels and top up to just below the bottom of the filler tube. Over filling before charging will result in an overflow of electrolyte due to expansion.
Use a charger that has a voltage regulated charge rate to avoid excessive terminal voltage while on charge. If your battery is a sealed type, the charging method is critical to battery life so check with your Peterborough Battery battery specialist for advice.
Carefully read and follow the instructions that came with the charger to avoid serious injury, property damage and/or battery damage.
Unplug the charger before connecting or disconnecting a battery to avoid dangerous sparks which can cause a battery to explode.
Do not leave a battery on charge for more than 48 hours to avoid damaging the battery by over-charging. If gassing or spewing of electrolyte occurs, or the battery case feels hot, reduce or temporarily halt charging to avoid damaging the battery.
NEVER attempt to charge a frozen battery. To avoid explosion and serious injury, allow it to warm to 60℉ (16℃) before charging.
NEVER leave a battery on a trickle charger longer than 48 hours. Serious damage to the battery WILL occur.
NOTE: Above charging times are approximate and depend upon battery condition, age and design, the efficiency of the charger, line voltage and other factors.
Off Season Storage
Batteries that are not in use during the off-season must be cared for as follows to extend battery life and reliability:
Disconnect the batteries to avoid self-discharge due to parasitic loads such as clocks, ground faults, etc.
Put batteries into storage fully charged and keep them above 75% state-of-charge. Check state-of-charge every 90 days and recharge if necessary.
Store batteries in a cool, dry place with temperatures not below 32℉ (0℃) or above 80℉ (27℃). Typically, batteries will self-discharge at faster rates at higher temperatures. For example:
TEMPERATURE SELF-DISCHARGE RATE
100℉ (38℃) . . . . . . 3 Pts. Specific Gravity per day
80℉ (27℃) . . . . . . . 2 Pts. Specific Gravity per day
50℉ (10℃) . . . . . . . 1/2 Pt. Specific Gravity per day
30℉ (-1℃) . . . . . . . .1/10 Pt. Specific Gravity per day
Note that this is only an example. Self-discharge may be higher or lower depending on battery chemistry, lead alloys, age and other factors.
Location- -
Peterborough Battery
612 Water Street
Peterborough, Ontario
K9H 3N1
Hours of Operation:
Monday - Friday: 8am - 5pm
Saturday: 8am - 12pm
Sunday and Statutory Holidays: Closed