The weight of the battery is also something to look at - if one battery rated at 220 amp-hours weighs 60 pounds, and another weighs 68 pounds, that is a pretty good indication that something was skimped on in the lighter battery.Ī note here on 'free' batteries - they are usually worth about what you pay for them. Price is a fair indicator of the overall expected life when used in a particular application, with the exception of the Concorde AGM's, which are a special purpose sealed battery. In general battery types run (from cheapest to most expensive): generic golf car (such as those sold at various discount stores), 'regular' deep cycle, such as the Trojan's, heavy duty or premium deep cycle, such as the Rolls-Surrette, and then the sealed AGM by Concorde & Deka, and the industrial batteries, such as the Crown forklift batteries. There is a lot of hype about batteries, especially those being sold outside the solar industry - that 'deep cycle' marine battery on sale for $39 might seem like a good deal - until you find out that it will probably only last about 2 years. Batteries are the component that is most often skimped on but can make or break a system. A 12 volt 105 AH battery can supply (under perfect conditions and to 100% discharge) 12 x 105, or 1260 Watt-hours (1.26 kWh). How many Watt-Hours in a battery?: Watts are pretty simple - it is just battery voltage times amp-hours. UPS and backup power systems are the same, except that the times are often in hours instead of days. If you want to keep running for 4 days of bad weather with no sun, multiply that times 4, which gives you about 850 AH total capacity. Since you do not want to discharge the battery more than 50% in most cases, you would need 210 AH. For example, if you use 5 kWh (kilowatt-hours) per day, and have a 48-volt system, then dividing 5000 by 48 gives you 105 AH. To figure how many amp-hours of storage you need, take your average daily usage in watts and divide by the battery voltage. If you are in a good wind area and have a wind generator, you can probably cut this down a day, but wind turbine output can be highly variable in many areas.įor backup power systems (UPS), the total capacity should be enough to cover about twice the longest anticipated outage. 3 days is usually sufficient in most of the Sunbelt states, 4 in most of the Midwest, in the East and Northwest, 4 to 5 days is better. As a rough rule for home solar systems, the total battery capacity (in amp-hours) should be three to five times your daily usage. How much storage, in amp-hours, do you need? This will vary with the application and what part of the country you are in. There are many things to consider: System Storage Requirements: The 'Best' battery for a particular system is not always the most expensive, but it is seldom the cheapest either.

Trojan deep cycle solar batteries (RE series)įollow this link to see our entire selection of deep cycle batteries. Surrette Canada (Rolls) - All solar batteries. We do not stock all sizes from all companies.Ĭrown - Flooded, industrial (forklift type) and standard deep cycle. We stock batteries from these companies (among others). For the off-grid full-time home, capacity, life, and long-term cost would probably be the most important. If the batteries are in a remote communications site, low maintenance might be the most important feature. There is no one best battery for all applications. On the other hand, you probably would not want to store a flooded battery in your computer room. For example, based only on cost, the Concorde AGM's do not look so good. There is more to comparing batteries than just cost or amp-hour ratings. Pump Installation Equipment & Accessories.Solar Pump Installation Equipment & Accessories.Solar Pump Controllers & Current Boosters.C&I Multi-Mode Inverters (Off-Grid Capable).

Deep cycle batteries