Group 41 is the largest biggest standard flooded lead acid battery that can fit in the stock Vanagon battery tray without modification. The group 41 battery is the DC power station sitting under the passenger seat of most Vanagons. The battery features a lot of cold cranking amps and hefty size. Some Group 41 batteries claim higher Cold Cranking Amps than others so it pays to do some research.
The Group 41 battery isn’t always an easy battery to find. Only a couple places we tried carried it, and only one had it in stock. The battery is for an aging line of vehicles and isn’t going to likely be more readily available. Sears quit making the Group 41 around 2005 in its Diehard lineup.
Interstates Group 41 battery, the MT-41, isn’t available for truck delivery here in Seattle, making finding one in-store somewhere quite difficult. Interstate batteries can often be ordered online and the delivery truck will bring it to you for a fee.
Luckily NAPA auto parts carries them here in the Seattle area. They offer two NAPA batteries made by Johnson Controls, a major battery maker, in two different warranty options. NAPA also takes the AAA card for a 10 percent discount on parts at most stores.
A very important aspect to look at is the highest CCA (cold cranking amps) combined with the highest residual capacity (how long a battery lasts when it is not being recharged, such as a failed alternator). The higher the residual capacity is, the longer the charge should last. The more CCA it has the more likely it is to start on a cold winter morning.
Some owners have used two Group 41s of the same battery. One for starting and one for auxiliary items like the fridge or the sink faucet. Having two batteries that are the same, and the same age, helps add to their life span. Being the same make and battery it also helps with the charging. The Group 41 isnt a deep cycle battery but it will work well to power your fridge while driving and will keep charging while you are driving.
When camping running your fridge on LP will help save precious battery power for things like the sink and extra lights. To run your fridge while camping by battery you need an auxiliary battery to ensure your starting battery isn’t drained dead.
When working on your electrical system always take the ground off first. If you touch the body with your wrench while on the ground it does no harm unless its the positive terminal you hit. Once the ground is off, the positive wont arc if you touch the body (unless you hit the actual battery terminal). Also when changing batteries check that your battery tray doesnt short anything out beforehand.
Remember to take care of your battery with regular maintenance. The alternator charges up to around 80 percent pretty well. Topping off the charge is what takes the longest. When using the battery a lot it wouldnt hurt to put it on a charger to bring it up to 100 percent charge. This will help with its life. A long drive can charge up to 80 percent quickly but short drives do little to top off the charge.