March Solar – Battery Options
The majority of March Solar Power Systems store energy in batteries so that you are able to run your loads when the PV System may not be producing enough to meet demand at that moment.
Generally when you choose the size of your DEEP CYCLE BATTERY BANK you never
expect to use more than half of what it can hold. This basically means you
are limited to a 50% Depth of Discharge. This 50% D.O.D. will increase the
life expectancy of the batteries compared with a 80% D.O.D. You will also
like to have room for a couple of days storage in the event of inclement
weather or unexpected guests. As a very general rule we suggest 200 amp hours
of storage per Solar Panel.
Specifically, here is how to size your battery requirements:
1. Decide on how many days storage you require.
For a 3 day weekend at the cottage you need 3.
2. Multiply # Days of Storage by your watt hour load per day
3. Divide by 0.5 (D.O.D.) The result is your required storage.
4. Determine the watt hour capacity of your selected battery
by multiplying the amp hour capacity by its voltage.
e.g.:6 volt x 220 ah golf cart = 1320 watt hours
| Battery Bank Sizes: | Type | Watt Hours |
| 12 Volt 100 Amp Hours | Gelcell | 1200 |
| 12 Volt 220 Amp Hours | wet | 2640 |
| 24 Volt 220 Amp Hours | wet | 5280 |
| 12 Volt 427 Amp Hours | wet | 5124 |
| 24 Volt 427 Amp Hours | wet | 10248 |
| 12 Volt 1025 Amp Hours | wet | 12300 |
| 24 Volt 1025 Amp Hours | wet | 24600 |
Battery Bank Building Blocks:
| Model: | Amp Hours |
| 6 Volt 3 Cell GC 2200 | 220 ah |
| 6 Volt 3 Cell 6 CS 25 PS | 1025 ah |
| 8 Volt 4 Cell 8 HHG 31 PS | 430 ah |
| 12 Volt 6 Cell 12 CS 11 PS | 427 ah |
- Optional Bolt on Connections available
Your Battery bank sizing is critical because it dictates how much energy is available for the inverter to use.
Typically, a cottage that is used just on weekends requires a proportionately larger battery bank and fewer solar panels because you "deposit" into your battery bank all week but only "withdraw" from it over a short weekend. In a cottage that is operating with occupants all week long we require a larger proportion of solar panels and a modest battery bank.
At March Solar we are happy to assist you in selecting the proper size of battery bank for your application.
Location: Your batteries should be located somewhere warm and dry. Safety is important when working with batteries, they should always be in a separate, locked room or container that is vented to the outside. When purchasing our batteries be sure to ask for our battery safety checklist.
WHAT ABOUT WINTER? . . . WILL THEY FREEZE?
No the batteries will not freeze provided the system is allowed to continue operating. In the winter the panels still produce electricity and the controller continues to keep the batteries fully charged. Fully charged batteries freeze only at extremely low temperatures.