The 650GS battery location can result in it being subjected to higher temperatures than other battery locations and with the standard wet cell battery require more frequent top up of battery fluid levels. An indication of battery overheating or overcharging is that the inner cells of the battery require greater top up than the outer cells.
At least some 2010+ G650GS have a larger heat shield between the battery and oil tank with a shield between the battery holder and the engine rocker cover. The Part No is unchanged but the shield can be removed and replaced. In addition the 2010+ models have a shield over the top front of the battery. There does not appear to be a Part No to purchase it, it has an alloy outer coating and so does not seem to be a good idea near the battery terminals.
The battery is a considerable weight mounted high on the machine contributing to the top heavy feel.There are two solutions. The first is to fit a Lithium LifePO4 battery which reduces battery weight from 4 kgs to 1 kg or less, They are also much smaller leaving space for mounting electrical relays or HID ballasts in the battery box. The second is to relocate the battery to below the seat behind the engine. This is only possible on non ABS machines.
The 650GS STD battery is a Yuasa YB12AL unsealed lead acid battery. Size (LxWxH) is 134mm x 80mm x 160mm.
Not many other models use this size, most use the longer 148mm case. The Deka ETX15L AGM battery is about the best replacement conventional battery but the width at 90mm is a tight fit. Many Co's sell rebadged ETX15L.
The G650X STD battery is a Z10S which is 150mm L x 87 W x 93 H and a fairly tight fit in the battery holder.
A Voltage Regulator output of 14.4v is required. See the Voltage Regulator page.
Batteries with dual + and - terminals ease accessory connection but the additional exposed terminals can be a safety problem especially when working on the machine. It is best to ensure the terminals are covered
Lithium batteries were originally built packaged in shrink wrap to provide maximum cranking power & low ampere hour capacity for the race community. Conventionally packaged lower cost general purpose lithiums are now available. These batteries provide cranking power above a lead acid battery but lower ampere hour capacity.
The smaller size of the batteries gives new choices of battery capacity & manufacturers are packaging the batteries in either OEM case sizes or minimum size allowing more flexibility in battery location.
Many Mfrs offer Lithium batteries, most manufactured in China and rebadged for western markets. The traditional brands have been slow to move to the new technology. When selecting a lithium battery it can be better to select the largest capacity which physically fits in the battery holder rather than the battery recommended in supplier listings. Some of the better lithium batteries available are below.
Lower cost general purpose lithium suitable for the GS, IP 66 sealing
ETX12B 12v, 12Ah PbEq, CCA 135 A, Weight 0.6 kg, Max Charge Rate 5A
ETX18B 12v, 18Ah PbEq, CCA 230 A, Weight 1 kg, Max Charge Rate 5A
Dimensions ETX12B and ETX18B 135 mm L x 66 mm W x 105 mm H
The EarthX has internal cell balancing and protection circuitry
Small, sealed CCA optimised batteries suited for under seat mounting
AG0801 (8-cell), 9ah PbEq, CCA 240 A, weight 0.78 kgs, 108Lx57Wx95H mm
AG1201 (12-cell), 12ah PbEq, CCA 360 A, weight 1.0 kgs, 115Lx82Wx108H mm
AG1601 (16-cell), 16ah PbEq, CCA 480 A, weight 1.5 kgs, 115Lx82Wx133H mm
A sealed robust model line which has stood up well in testing
Lower cost general purpose Lithium suitable for the GS
LFX Lithium-Iron Powersports Battery Part No: LFX14L2-BS12
12v, 14Ah PbEq, CCA 210 A, Weight 0.73 kgs, Max Charge (A): 14
Dimensions (mm) 113 L x 58 W x 87.5 H
SSB LFP9Q-B, 9ah PbEq, CCA 180 A, weight 0.7 kgs, 134Lx75Wx133H mm
SSB LFP12Q-B, 12ah PbEq, CCA 240 A, weight 0.9 kgs, 134Lx75Wx133H mm
SSB LFP14AHQ-BS, 14ah PbEq, CCA 290 A, weight 1.1 kgs, 134Lx75Wx133H mm
A battery relocation thread was written up on advrider by Dwayne in Calgary, a pdf version is available below with permission from Dwayne. The points to note are that the later Dakars did not have the voltage regulator behind the engine so that element is not needed on all year models and the regulator is better mounted on the side of the engine. The second point is that the lithium batteries would ease space requirements under the seat