Solar

Pure Energy has recently introduced new Solar Charge rechargeable alkaline batteries that have been specifically designed for applications that utilize solar charging techniques.

There are several key features that make Pure Energy’s Solar Charge rechargeable alkaline batteries the ideal choice for products utilizing solar charging. These include:

• Industry leading charge retention and charge acceptance – 7 yr. shelf life. Manufactured in the fully charged state – ready to go without initial recharge.
• Excellent intermittent discharge/charge characteristics – 5000+ cycles possible.
• The higher nominal voltage of 1.5V of rechargeable alkaline batteries will provide greater brightness in solar lighting applications compared to 1.2V batteries.
• Simple charging circuitry – Solar chargers can be easily and economically made.
• Pure Energy’s rechargeable alkaline is considered the most environmentally responsible battery system in the world – it is the only battery system in North America to be awarded the “Eco Logo” in the Rechargeable Consumer Batteries Category.
• Pure Energy’s Solar Charge rechargeable alkaline is very cost effective – lower in price compared to most other rechargeable batteries.

Charge Retention

As shown Solar Charge has very low self discharge compared to Nickel-Cadmium and Nickel-Metal Hydride systems.

As the storage temperature increases the benefit of Solar Charge gets even more pronounced:

Capacity Loss	PE-XL	Rechargeable Alkaline	NiCd	NiMH
20°C/month	<1%	1%	20%	25%
45°C/month	<3%	5%	60%	80%
65°C/month	<10%	20%	100%	100%
Shelf Life (80% of rated Ah)	7 yrs	5 yrs	charge prior to use	charge prior to use

Intermittent Charging

The cycle life of Solar¤Charge batteries depends on the actual use conditions. The figure below demonstrates that Solar¤Charge can be cycled many hundred times when not all of the capacity is removed in each and every cycle. In this case the voltage under load at the end of discharge remains above the usual 0.9 volt cut-off, but gradually decreases or fades as cycling proceeds.

This mode of discharge/charge cycling is the most efficient mode, providing the greatest cumulative capacity or cell life. In this shallow discharge cycling example, cumulative performance over 300 cycles of Solar¤Charge will reach 60 times the performance of single-use alkaline cells, without the XL Solar batteries reaching their end-of-life criteria (0.9V).

Cycle Life of Solar Charge AA on a 4 Hour Daily Use Pattern
(10 ohm load, approx. 100-125mA)

If the discharge is even shallower than 30% depth of discharge, several thousand cycles have been demonstrated on the example of cordless phone testing. The figure below illustrates the excellent cycling performance in a simulated cordless phone application achieving up to 7000 cycles without reaching the cut-off criteria.

Performance of 3AAA Solar Charge Packs on shallow discharge cycling with frequent recharge simulating frequent phone usage (Sanyo (CLT30) Phone) with 5 or 15min talk time (low depth of discharge)

Charging

The excellent high temperature charge retention and charge acceptance of Solar Charge cells allow the effective use of solar energy for charging. Note that solar charging of Nickel-Cadmium and Nickel-Metal Hydride cells is not very successful due to the poor high temperature charge retention of these battery chemistries.

Two Shunt Regulators are used in parallel to
increase charge current to 300mA.

A solar panel can be considered a constant current source. Therefore, charge circuitry as outlined previously is needed to properly charge Solar Charge batteries. This figure gives the example of a 2-Cell Solar battery charger. Of note, this solar charger will work for Solar Charge as well as for NiMH, even though the NiMH cells are not very efficient at higher temperature charging, which is usually the case with solar applications.

For more information please contact Stephen Meldrum at 905 764 9457, ext. 254 or visit the OEM section of Pure Energy’s web site at pevi.ca.