Battery Replacements
Here is some info on possible battery replacements.
The first place to check for a better battery was
CR's Car Battery Ratings. CR does expert and exhaustive tests on automotive batteries, far more than any other source. For Group 35 batteries which is the proper size for the Ascent, the
EverStart MAXX-35N (North) came out on top with excellent scores for:
Life
Life test measures how a battery endures repeated charge-and-discharge cycles at hot-climate engine-compartment temperatures. The more cycles endured while maintaining a higher voltage, the higher the score.
Reserve capacity
Reserve capacity estimates how long batteries can run a car if the charging system fails. It also estimates how long the battery will last using lights and accessories with the engine off. This is where the OEM Ascent battery appears especially weak so pay special attention to this rating.
CCA
CCA performance reflects voltage at a load of half the average claimed CCA for each group size after cranking for 15 seconds at 0º F.
The EverStart battery is sold exclusively at Walmart which makes purchasing it convenient for almost everyone. Walmart may sell a lot of lower priced items, but their auto department is actually quite good. The
Sears DieHardGold 50835 (North) battery also did well. The EverStart or the Die Hard may work appreciably better than the OEM battery. Both of these batteries are reasonably priced.
Specs for the
EverStart MAXX-35N (North):
Model: MAXX-35N
C20 Capacity: 42 Ah
CCA: 640 Amps
Width: 6.90 in
Length: 9.10 in
Height: 8.90 in
Warranty: 36 months
Specs for the
Sears DieHardGold 50835 (North)
Model: 50835
Weight: 33.5 lb
C20 Capacity: 37.5 Ah
CCA: 625 Amps
Width: 6.90 in
Length: 9.80 in
Height: 8.90 in
Warranty: 36 months
Here are some other batteries which I trust but were not tested by CR:
NAPA Legend Premium
Model: BAT 8435
Weight: 35.0 lb
C20 Capacity: 39.6 Ah
CCA: 640 Amps
Width: 6.90 in
Length: 9.75 in
Height: 8.88 in
Warranty: 84 months
Bosch High Performance AGM™ Battery
Model: S6
Weight: na
C20 Capacity: 50 Ah
CCA: 680 Amps
Width: na
Length: na
Height: na
Warranty: 48 months
Next, are the super premium batteries. These are considerably more expensive but have excellent specs and purported high performance.
Optima YELLOWTOP® D35
The Optima Yellow Top Absorbent Glass Mat (AGM) batteries are designed to provide excellent starting (CCA) and deep cycling capability (AH reserve capacity). They are expensive at around $255. Optima does not list a battery for the Ascent but they do sell a Group 35 battery which should fit. If you're interested in this battery then try to find a local Optima dealer to ensure the fit in the Ascent. You can order one online, but if it didn't fit it would be expensive to return.
Model: D35
Weight: 36.4 lb
C20 Capacity: 48 Ah
Post Type: SAE Post
CCA: 620 Amps
Width: 6.75 in
Length: 9.38 in
Height: 7.69 in
Warranty: 12 months
Odyssey 35-PC1400T
If you thought the Optima was expensive the Odyssey tops it at around $305, but it has one of the best overall specs I've yet seen for a Group 35 battery. If money is no object then this is one of the best Group 35 batteries you can buy.
Model: 35-PC1400T
Weight: 50 lb
C20 Capacity: 65 Ah
Post Type: SAE Post
CCA: 620 Amps
Width: 6.84 in
Length: 9.46 in
Height: 8.69 in
Warranty: 48 months
Again be careful about the fitment. It's very close to the size of the OEM battery but not exact.
Are the super premium batteries worth 2-3 times the cost of a standard battery? Hard to say, some people swear by them others swear at them. I personally wouldn't spring for one unless I had a very critical use.
So these batteries are some examples of replacements for the OEM battery. I think I'll give the EverStart a shot. I've used EverStarts before and I've generally had good luck with them. When I didn't, Walmart gave me no problem returning them for a full replacement within the warranty period, so be sure to save your receipt. Sears is on the way out so I wouldn't recommend the Die Hard battery, but you may be able to find them on closeout at Sears stores which are closing.
All of these batteries will probably be a superior replacement to the OEM Ascent battery. But before you buy a replacement also consider a Battery Jump Starter. If your OEM battery ever is too weak to start the car, one of these will get you going again. I just picked up a
Duracell Powerpack Pro 1100 from Costco for only $89. Not only is it a battery jump starter, but it also has dual 120VAC outlets, dual USB outlets, an air compressor, and an LED light.