Tomberlin's Tech Corner by Andy Johnson
Edition: November/December 2011
It’s that time of the year again and it is time to prepare your electric vehicle for winter.
The biggest threat by far for any lead acid based electric vehicle is freezing of the batteries. The good news is that if the batteries are properly maintained and charged there is very little chance if any of them freezing (It takes exposure to about -90 degrees Fahrenheit for a fully charged battery to freeze). Where a Delta-Q charger is used with the correct algorithm the charger will sense when the battery voltage is low and will come on and automatically charge the batteries as needed to assist in preventing freezing. Also, it is important to know that as temperatures become lower the amp hour capacity also decreases and your battery output is reduced. However, at the same time deterioration is also reduced but generally averages out with the higher temperatures of the summer months.
Note: Do not attempt to charge a battery that has been known to have been frozen. A frozen battery is potentially dangerous and should be handled with extreme care. Wear proper protection such as face shield, rubber gloves and a rubber apron when handling any batteries.
When preparing an EV or for any long term or extended storage period of 30 days or more use the following processes to insure that your vehicle will be ready when you are. Check the guidelines provided in your owner’s manual to insure you are following your manufacturer’s procedures for your particular vehicle:
1. Check the batteries and battery cables:
a. Clean the tops of the batteries if needed
with a mixture of baking soda and water (1 cup of baking soda to one gallon of water). If the tops of the batteries are wet it indicates they were overfilled and should be adjusted to the proper level.
b. Battery cables should be corrosion free and tight. If corrosion is present remove the cables and remove all of the corrosion with a wire brush and reinstall. If the battery cables are in poor condition have them replaced. Tighten the terminal nuts to 105-110 inch pounds (do not over tighten) and coat the exposed metal surfaces of the terminal and lug with a good quality battery terminal protective coating.
c. Safety Note: Only work in or around batteries in a well ventilated area. Only use insulated tools, wear protective eyewear and rubber gloves when working on with or around batteries.
2. Tow Switch:
a. Place the Run/Tow switch in the “Tow” position. This will help to prevent residual discharge of the batteries during the storage period.
3. Charge:
a. Fully charge the batteries and check the water level. Use distilled water only to replenish batteries.
b. Do not over fill and only add water after charging.
c. Make sure the battery caps are installed properly and sealed.
4. Perform an “Equalization Charge”
a. The equalization charge mixes up the electrolyte in the batteries and allows them provide peak performance and helps to balance the electrolyte in all the cells to a similar specific gravity level prior to storage.
b. To perform an “Equalization Charge” simply charge the batteries as normal. After the charge cycle completes disconnect the charger for about 20-30 minutes and then re-connect the charger and allow it to go through the charge cycle a second time.
5. Charger:
a. Leave your charger connected (for models other than Tomberlin please refer to your owner’s manual or contact the manufacturer of the vehicle). The Delta-Q charger will monitor the state of charge for the vehicles and will give the batteries a charge if they drop below a certain point during storage.
