ORCHID ISLE SOLAR 808-345-0660 719-330-2597 or John@orchidislesolar.com
CROWN BATTERY has been around for a very long time-- since the 1920s. they are an American Company located in Ohio and have been designing and making quality batteries for all types of applications for decades.
Through word of mouth between installers and end users, CROWN has gained a reputation for an outstanding Solar Battery at a very affordable price.
Thicker plates: mean longer life and reliabilty.
Outstanding Warranty: Among the best in the industry.
Outstanding life Cycle performance: longer life and more deep cycle tolerance than other brands make CROWN an outstanding choice.
We are an authorized dealer for BLUE ION and CROWN Batteries on the Big Island.
We offer the following battery types:
FLOODED, AGM, GEL, NANOCARBON, LI-ION LFP
Outback, BLUE ION, Simpliphi, CROWN, Interstate, Leoch
A little about Batteries:
- Batteries are the heart of your off grid system. They act as your "energy storage". Batteries are all about current (they store and distribute electrical charge) and as such they are very misunderstood and often neglected in off grid systems.
Flooded Vented Lead Acid: These venerable workhorses have been around for over 150 years and are the least expensive "up front" but the most expensive over time.
-Most affordable "up front" per AH of capacity - Needs the most maintenance of all battery types -Good entry level battery type for most applications - Outgases Hydrogen when charging
-Allows for larger storage systems on a budget - Somewhat messy to service
-Easy to replace when the time comes - Needs routine attention; cannot be ignored
- Can be charged properly with almost any charge controller - Can be damaged by over or undercharging
AGM: Glass matt and Gel batteries offer an alternative to Flooded Lead Acid batteries; no maintenance required which is a definite plus. However, these battery types are usually 30% or more expensive than Lead Acid. Also, when compared to well maintained Flooded Lead Acid Batteries, the Flooded Lead Acid Batteries generally have longer life cycles.
LI-ION: Best Value over the life of your system. Expensive up front. We recommend BLUE ION.
There are numerous battery chemistries available for Solar applications; Lead- Acid, Nickel- Iron, Lithium Ion, to name a few. While many of these battery chemistries have many advantages over traditional Lead Acid, there are advantages to Lead Acid which still make it the most specified battery chemistry in the Solar Industry:
1. Lead Acid batteries still deliver the most initial capacity per dollar spent "up front", but are most expensive over time.
2. Many alternative Chemistries are not supported by the available charge controllers. (Which can be a warranty issue.)
3. The Capacity size required for the typical off grid system makes the cost for the battery bank one of the most costly portions of the off grid system. Other chemistries tend to make the battery bank component so expensive that an off grid system of the appropriate size for the loads becomes unaffordable.
WHAT SIZE BATTERY SHOULD I PURCHASE? (System Design process)
The design process for an off grid system always starts with the loads that need to be powered. If you have an accurate and thorough understanding of your off grid loads, then you will be giving yourself the best possible chance to end up with a quality and functional system.
Let's assume that you have the following loads to be powered:
Load Watts: Hours/day Kilowatt hours (KWH)
Refrigerator 840watts 3.5 hr 2.940 kwh
Lighting 180watts 4.0 hr .720 kwh
water tank pump 500watts 1.5 hr .750 kwh
freezer 720watts 3.5 hr 2.520kwh
Microwave 1200watts .5 hr 1.200kwh
fan (3) 150watts 4 hr .600kwh
TV 100watts 3 hr .300kwh
PC 50 watts 4 hr .200kwh
printer 100watts .5 hr .050kwh
Total: 3850 watts 9.280kwh
This load list indicates that in a typical day you would need to generate 9.280kwh in energy if you wanted to supply all your energy needs for the day. This means that we need to size the battery bank (energy storage) appropriately to store the energy and supply sufficient solar panels to generate the energy.
Battery Bank Sizing:
We need to size the battery bank so that the bank has about a 3 day autonomy (meaning that the battery bank can source energy for the loads for three days without input. We also want to make sure that the Daily Depth of Discharge of the battery bank is not greater than 20% to 30% for long battery life. Additionally we need to select the battery bank voltage. The selection of the voltage is an important decision; the larger the battery bank voltage the smaller the current that the battery bank must source for the same wattage of load. This means that the larger battery bank voltage gives the battery system larger capacity for the same class of battery since the amount of current the battery bank must source will go down.
For a 96watt DC load, a 48volt battery bank will need to source 2 amps of current (2 amps*48volts = 96 watts) while a 24 volt battery bank will need to source 4 amps-- twice the current. Since the battery used has a fixed Amp - Hour capacity, the 48 vdc selection of battery bank voltage will effectively double the size of the bank because the current required for a given load is half as big.
As a rule of thumb, a 24vdc battery bank will be suitable for loads up to about 12 kwh per day. Above that a 48vdc battery bank is a better selection. While a smaller battery voltage can be configured to deliver larger capacity, this can only be done by paralleling more strings of batteries which is not a good design practice. Battery strings should not be paralleled above 3 strings unless there is no other option.
Assuming a 24vdc battery voltage for this example:
9820 wh/24 volts = 409.16 AH. To have a 3 day autonomy, we would need 409.16/.33 = 1239 AH. If we selected a CR-390 6 volt battery (390 AH at a C20 discharge) we would need 3 strings of 4 batteries for a total of 12 batteries. Four 6vdc batteries in series would give 24vdc for the bank voltage times 3 strings in parallel would give a capacity of 390*3 = 1170 AH. This would give a daily depth of discharge with no solar input for the day of (409/1170)*100 = 34.9% which is a little higher than we would like to see but this is a viable choice.
Assuming a 48vdc battery voltage for this example:
9820 wh/48 volts = 204.58 AH. To have a 3 day autonomy, we would need 204.58/.33 = 619.95 AH of capacity. If we use the same battery, the CR-390, we would need 2 strings of 8 batteries for a total of 780 AH of capacity. This would give a daily depth of discharge of (204.58/780)*100 = 26.22% which is better than the 24vdc selection. The downside of this configuration is that it takes 16 batteries not just 12 as with the 24vdc configuration which is a higher initial cost. However, the 48vdc configuration, while more expensive initially, will have a longer battery life due to its lower daily depth of discharge.