Battery Equivalents and Replacements

Weize Group 34M Dual Purpose AGM Battery

Weize Group 34M is a dual-purpose, lead-acid battery intended for marine and automotive applications.

Dual-type terminals, good performances, and acceptable price make the Weize Group 34M battery one of the most popular batteries in its class.

Published: November 6, 2023.

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Weize Group 34M AGM Battery Features and Specifications

As its label suggests, the Weize Group 34M battery belongs to the battery group 34 and is based on lead-acid Absorbent Glass Mat (AGM) chemistry, ensuring great vibration resistance, more charging/discharging cycles, and less maintenance.

The physical dimensions of the battery are (L x W x H) 10.86 x 6.1 x 6.89/8.11 inches (~27.6 x 15.5 x 17.5/20.5 cm) and it weighs 42.6 lbs (~19.3 kg).

Note: Group 34 batteries maximum dimensions should be 10.25 x 6.8125 x 7.875 inches (10 1/4 x 6 13/16 x 7 7/8 inches, 26 x 17.3 x 20 cm), which means that the Weize Group 34M AGM battery is slightly longer and narrower than standard group 34 battery dimensions.

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The Weize Group 34M AGM battery features a nominal (20h) capacity of 55Ah, nominal voltage of 12V, and reserve capacity of 120 minutes.

As a starting battery, it is able to provide 650 CCA and 780 MCA, allowing the battery to crank smaller and medium-sized marine and automotive gas and diesel engines.

As a group 34 battery, the Weize Group 34M AGM battery features a positive terminal on the left side of the battery.

As a marine battery, the Weize Group 34M AGM battery comes with two sets of terminals, SAE studs, and M8 threaded posts, ensuring firm connection between the battery and the external loads, regardless of application.

According to the manufacturer, when being stored, thanks to its very low self-discharge rate, a fully charged Weize Group 34M AGM battery can be stored for up to 6 months without recharging.

Personally, AGM batteries can have a low self-discharge rate, but when being stored for months, especially when the temperatures are above 68-77°F (20-25°C), one should connect a good battery charger/maintainer that will keep them fully or at least almost fully charged.

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How To Charge Weize Group 34M AGM Battery

When the Weize Group 34M AGM battery is connected to a vehicle or boat that features an onboard battery charger (alternator + charging controller, for example), the onboard charger should keep the battery charged.

However, when the battery is charged using a dedicated battery charger, an advanced AGM battery charger is recommended.

According to the manufacturer, the maximum charging voltage should be 14.4±0.1V, and the maximum charging current should be 11 Amps (0.2C).

To avoid overstressing the battery, a good 5 Amps AGM battery charger will do the job well, especially when the battery is not discharged below 50% DoD.

When looking for a 5-10 Amps AGM battery charger, go for an advanced model that analyzes the battery first, and then, after recharging it, the battery charger automatically switches to the maintenance mode.

Also, having desulfation and equalization modes combined with temperature compensation is highly recommended.

Weize Group 34M AGM Battery vs. Optima D34M BlueTop AGM Battery

optima d34m

Weize Group 34M AGM battery and Optima D34M BlueTop AGM battery are some of the most popular group 34 marine dual-purpose AGM batteries, being similar in many details but also differing in some very important ones.


Weize Group 34M battery is slightly larger than the standard Group 34 battery should be, while the Optima D34M battery fits easily: 10.86 x 6.1 x 6.89/8.11 inches vs. 10 x 6.875 x 7.81 inches.

Weize 34M battery is slightly lighter: 42.6 vs 43.5 pounds (~19.3 vs. 19.7 kg).

Capacity and Reserve Capacity

Both batteries feature the same 20h capacity of 55Ah and Reserve Capacity of 120 minutes.

Cranking Amps

Thanks to its wound cells, Optima D34M is a slightly better starting battery: 750 vs. 650 CCA and 870 vs. 780 MCA.


Weize 34M battery comes with a 2-year limited warranty, while Optima D34M battery warranty depends on the battery use (personal/commercial, etc.).

Battery Price

While Optima D34M tends to be a better-starting battery and is generally a little bit tougher, when the battery prices are taken into account, it's clear who is the winner here.

If you really don't mind paying extra money, then consider the Optima D34M over the Weize 34M battery.

Long Story Short: Weize Group 34M AGM battery is a very popular group 34 marine battery thanks to its performances and, obviously, very acceptable price.

Although the manufacturer claims a very low self-discharge rate, do yourself a favor and, when storing the battery for longer than one month, connect it to a good battery maintainer.

Other than that, this is a good, reliable battery that has already been tested by numerous users in many real-life situations.

For more reviews and recommendations, feel free to check the Weize Group 34M AGM Battery Amazon link (the link opens in the new window).