How to select your lead-acid batteries

The first and most important step to configure your battery back is to know your system’s voltage. Small systems used in RVs and boats are usually 12V. It is recommended to use 24V or 48V for medium sized energy systems and always 48V for large systems. Some systems can even go up to 60V, however, 12V, 24V and 48V are the standard in solar and renewable energy systems. Whatever your system voltage is, keep that number in mind since it will be consistent across your system design; changing your system voltage down the road could be a costly alternative.

Another factor is to know the space available for the batteries, this is especially true for mobile applications and systems with a designated battery enclosures. These type of enclosures are usually designed for a certain type and number of batteries, for example, four L-16 batteries.

Knowing the type of battery you want is also part of the selection process. You only want to use deep-cycle batteries in renewable energy systems. Lead acid batteries are the most common, they can be flooded or sealed. Flooded batteries require periodic maintenance such as refilling water levels while sealed or VRLA batteries are considered maintenance free. Flooded batteries are seen in most renewable energy systems mainly because of their lower cost. Applications in remote locations with difficult access call for sealed batteries that do not require constant human supervision. Both batteries, flooded and sealed, are comparable in terms of performance; the determining factors are the application and cost.

A factor that requires careful consideration is your energy needs which ultimately will determine the size of your battery bank. Technically speaking, the larger the battery bank, the better. A large battery bank will reduce the depth of discharge of each cycle, thus extending the life of the batteries. Realistically, not everybody has the budget for an oversized battery bank.

Once the above factors have been figured out, the rest is relatively easy. The number of batteries in the bank will be determined by the voltage, if you have a 48V system you will need eight 6V batteries or twelve 4V batteries.

Wired and sized battery enclosure
Wired and sized battery enclosure

Your energy requirements will determine the capacity, or the total amount of energy stored in the battery bank. It is usually measured in charge / discharge cycles. This part can get highly technical so we are going to simplify it for the purpose of this article. The capacity of your storage is measured in Ampere-Hour or Ah per cycle. To extend the life of the batteries it is recommended to discharge your batteries less than fifty percent per cycle (50% depth of discharge or DOD). So if you know that you need 350Ah to power all your loads on daily basis, you should consider a 700Ah battery bank for a healthy life cycle. In the same scenario, a 900-1000Ah battery bank won’t hurt, it will provide additional energy on the days when it is needed and will also help extend the life of the batteries by reducing the depth of discharge of each cycle. Needless to say it will also cost more money.

Note: As a rule of thumb, the larger the size of the battery bank, the lower the nominal voltage of each battery. For example, 12V batteries are only recommended in small systems with one or two batteries. 6V batteries are ideal for medium size banks and are widely used in renewable energy systems. 4V and 2V are high capacity batteries reserved for large energy systems.

The following table shows a complete list of all the deep cycle lead-acid batteries available through Webo Solar. The table shows which batteries are flooded and which ones are sealed; it also indicates some basic specs such as voltage, capacity, dimensions and weight. Prices are approximate.

ManufacturerTypePart No.VoltsAh @ 20 hrAh @ 100 hrLength (in)Width (in)Height (in)Weight (lbs)Price
Surrette RollsFloodedS-4806 Volt37548612-1/47-1/816-3/4117$317
Surrette RollsFloodedS-5506 Volt42855412-1/47-1/816-3/4127$349
Surrette RollsFloodedS-6206 Volt48262412-1/47-1/816-3/4131$407
Surrette RollsFloodedS-14502 Volt1050138012-1/27-1/816-3/4115$362
Surrette RollsFloodedS-16602 Volt1200159012-1/27-1/816-3/4121$413
Surrette RollsFloodedS-18602 Volt1300172912-1/27-1/816-3/4125$471
Surrette RollsFloodedS-1400EX2 Volt1000140812/1/27-1/816-3/4114$443
Surrette RollsFlooded2-KS-33PS2 Volt1766249113-3/48-5/1624-13/16208$874
Surrette RollsFlooded2-YS-31PS2 Volt2430343515-1/29-1/431-5/8285$1,218
Surrette RollsFlooded4-CS-17PS4 Volt54677014-3/88-1/418-1/4128$627
Surrette RollsFlooded4-KS-21PS4 Volt1104155715-3/49-3/824-3/4267$1,094
Surrette RollsFlooded4-KS-25PS4 Volt1350190015-3/410-5/824-3/4315$1,370
Surrette RollsFlooded6-CS-17PS6 Volt54677022-1/48-1/418-1/4221$892
Surrette RollsFlooded6-CS-21PS6 Volt68396322-1/48-1/418-1/4271$1,066
Surrette RollsFlooded6-CS-25PS6 Volt820115622-1/48-1/418-1/4318$1,229
Surrette RollsFlooded8-CS-17PS8 Volt54677028-1/48-1/418-1/4294$1,181
Surrette RollsFlooded8-CS-25PS8 Volt820115628-1/411-1/418-1/4424$1,632
Surrette RollsFlooded12-CS-11PS12 Volt35750322-1/411-1/418-1/4272$1,089
Surrette RollsSealedS-275AGM6 Volt25027510-1/47-1/810-3/477$366
Surrette RollsSealedS-460AGM6 Volt41546011-3/47-1/816-3/4272$600
Surrette RollsSealedS2-5902 Volt5505909-1/26-3/414-1/271$425
Surrette RollsSealedS2-9452 Volt88094516-1/46-7/814-1/2118$695
Surrette RollsSealedS2-11802 Volt1100118018-3/46-7/814-1/2142$851
Surrette RollsSealedS2-1275 (L16)2 Volt11501275382943963016-3/4123$611
Surrette RollsSealedS2-18952 Volt1750189515-3/413-5/814-3/4229$1,373
Surrette RollsSealedS2-23752 Volt2200237519-1/413-3/415-1/8287$1,729
Surrette RollsSealedS2-35602 Volt3300356027-7/813-7/815-1/8431$2,524
TrojanFloodedT-6056 Volt21023310-3/87-1/810-7/858$130
TrojanFloodedT-1056 Volt22525010-3/87-1/810-7/862$153
TrojanFloodedT-1256 Volt24026610-3/87-1/810-7/866$171
TrojanFloodedT-1456 Volt26028610-3/87-1/811-5/872$203
TrojanFloodedL16P-AC/LT6 Volt42043311-5/87-1/816-3/4113$319
TrojanFloodedL16H-AC/LT6 Volt43546611-5/87-1/816-3/4121$353
TrojanFloodedT-105-RE6 Volt22525010-3/87-1/810-7/867$165
TrojanFloodedL16RE-2V2 Volt1110123511-5/87-1/817-11/16119$353
TrojanFloodedL16RE-A6 Volt32536011-5/87-1/817-11/16115$305
TrojanFloodedL16RE-B6 Volt37041011-5/87-1/817-11/16118$348
TrojanFlooded24TMX12 Volt85n/a11-1/46-3/49-3/441$151
TrojanFlooded27TMX12 Volt105n/a12-3/46-3/49-3/453$165
TrojanFloodedSCS15012 Volt100n/a11-1/46-3/49-3/450$165
TrojanFloodedSCS20012 Volt115n/a12-3/46-3/49-3/460$189
TrojanFloodedSCS22512 Volt130n/a13-15/166-3/49-3/466$201
TrojanFloodedIND9-6V6 Volt44554515-3/810-1/424-1/4220$780
TrojanFloodedIND13-6V6 Volt67382022-3/810-1/424-1/4315$993
TrojanFloodedIND17-6V6 Volt897109026-11/1610-1/424-1/4415$1,125
TrojanFloodedIND23-4V4 Volt1233150022-3/810-1/424-1/4370$1,057
TrojanFloodedIND29-4V4 Volt1570191026-11/1610-1/424-1/4465$1,276
US BatteryFloodedUS20006 Volt216n/a10-1/47-1/811-1/459$116
US BatteryFloodedUS22006 Volt232n/a10-1/47-1/811-1/463$128
US BatteryFloodedUS1256 Volt242n/a10-1/47-1/811-1/467$150
US BatteryFloodedUS1456 Volt251n/a10-1/47-1/811-7/870$173
US BatteryFloodedUSL166 Volt380n/a11-7/87-1/816-3/4111$263
US BatteryFloodedUSL16HCL6 Volt415n/a11-7/87-1/816-3/4117$293
US BatteryFloodedUSL16HCL6 Volt415n/a11-7/87-1/816-3/4117$289
US BatteryFloodedUSRE-L16XC6 Volt428n/a11-7/87-1/816-3/4124$373
Full RiverSealedDC224-66 Volt224n/a10-1/47-1/89-3/466$261
Full RiverSealedDC250-66 Volt250n/a10-3/87-1/810-3/877$304
Full RiverSealedDC400-66 Volt400n/a11-5/87-1/816-3/4123$486
Full RiverSealedDC85-1212 Volt85n/a10-1/46-3/48-1/255$222
Full RiverSealedDC105-1212 Volt105n/a12-1/46-3/48-1/267$259
Full RiverSealedDC115-1212 Volt115n/a12-7/86-3/48-1/272$274