Best Wet/Flooded, Gel-Cell, AGM and Lithium 12V 100Ah Deep Cycle Batteries

Wet/flooded, gel-cell, AGM, and lithium 12V 100Ah deep cycle batteries are a very popular group of deep cycle and dual-purpose batteries, offering relatively large capacities (100+ Ah), a large amount of stored energy (1200+ Wh), and large discharge currents at acceptable price and weight.

Due to the maintenance requirements, wet/flooded batteries are used rarely, with the SLA Gel and AGM batteries being most common. Also, lithium 12V 100Ah batteries are getting more and more present on the market, offering huge weight savings.

Published: February 24, 2021.

12V 100Ah Batteries Features and Specifications

The most common 12V 100Ah batteries are BCI Group 27 batteries and BCI Group 31 batteries, but there are other sizes as well like 30H, 24, GC2, etc. but there are also batteries featuring non-standard sizes.

The most popular BCI Group 27 batteries are listed in the following comparison chart:

Note: Amazon affiliate links ('Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices.

The most popular 12V 100Ah batteries are listed in the following comparison chart:

Note: Amazon affiliate links ('Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices.

The most popular 12V 100Ah batteries are deep cycle models, with few dual-purpose models.

The main reason for not having starting 100Ah batteries is that even dual-purpose 100Ah batteries are able to easily provide 900-1000 CCA Amps and with some models going even well above 1000 CCA Amps.

For applications where extra-large starting currents (for example, 1500+ Amps) are required there are few possible solutions:

- Ultracapacitor based Engine Starting Modules (ESM) may easily provide 1500+ starting Amps,

- Connecting several smaller starting batteries in parallel in order to achieve 1500+ starting Amps,

- Using a single BCI Group 8D deep-cycle or dual-purpose battery as starting battery,

- Connecting two dual-purpose BCI Group 31 batteries in parallel in order to achieve 2000+ CCA Amps.

---

Wet/Flooded 12V 100Ah Batteries

Wet/flooded 12V 100Ah batteries are still present on the market, but since they are not maintenance-free and they are not spill-proof, we can't recommend them.

These batteries still have some advantages over Gel-Cell and AGM batteries, but all in all, for most applications Gel-Cell and AGM batteries are the way to go.

But, if You prefer/need flooded 12V 100Ah, there are several models that are good performers and that come at an acceptable price.

Typical example of flooded 12V 100Ah battery is Trojan SCS150 (photo on the right) featuring a nominal (20h) capacity of 100Ah and Reserve Capacity (RC) of 150 minutes (2.5 hours).

Although it is not designed as a starting or dual-purpose battery, Trojan SCS150 nonetheless features CCA rating of 530 Amps and MCA rating of 650 Amps - all that at an acceptable weight of only 50 lbs (~22.6 kg).

Gel-Cell vs. AGM 12V 100Ah Batteries

Gel-cell and AGM (Absorbent Glass Mat) SLA (Sealed Lead-Acid) batteries are almost maintenance-free, spill-proof batteries that are very vibration resistant and may operate in almost any position - some models may operate properly even when turned up-side-down.

We say that these batteries are 'almost' maintenance free - it is good practice to periodically check the battery if there are any signs of physical damage, corrosion, and similar.

Gel-cell batteries feature diluted sulfuric acid mixed with silica in the form of silica gel - hence the name.

AGM batteries feature diluted sulfuric acid suspended in a woven glass mat - hence the name.

These types of batteries are obviously different, but they operate in the same way as wet/flooded lead-acid batteries, except that ions move much more freely in the wet/flooded cells than in AGM and especially gel-cell batteries.

However, AGM and Gel-cell batteries may have plates packed more tightly, without increasing the danger of the cells short-circuiting due to the lead-phosphate crystals buildup, with ions having a shorter path to travel.

Generally, Gel-cell batteries are better deep cycle performers than AGM batteries, and AGM batteries are often able to crank larger currents than Gel-cell batteries. Also, Gel-cell batteries are able to withstand more charging/discharging cycles than AGM, although this may differ from the brand to the brand.

For example, the following comparison chart lists the most important features and specifications of Renogy 12V 100Ah AGM batteries:

Renogy AGM 12V 100Ah battery is a well balanced deep-cycle design that is also able to crank smaller internal combustion engines. Renogy Pure-Gel 12V 100Ah battery is just the opposite - it should not be charged nor discharged using strong currents. But, Pure-Gel can withstand a rather large number of charging/discharging cycles, has excellent standby life, and very low self-discharge rate.

The Hybrid-Gel model is a newer battery, and its performances are somewhere between the AGM and Pure-Gel batteries.

This example shows that these batteries are not just about 20h capacity, CCA/MCA currents, RC minutes, and the weight.

Best Lithium 12V 100Ah Batteries

Lithium batteries feature many advantages over lead-acid batteries, including:

- lightweight design: on average, lithium 12V 100Ah batteries weigh 2-3x less than lead-acid batteries.

- very constant capacity: when lead-acid batteries are discharged with stronger currents, for example, 1C, their effective capacity drops often down to 55%-65% of 20h capacity. When lithium batteries are discharged with 1C currents, their capacity remains almost unchanged, leading to even greater weight difference in high current applications.

- faster recharging: lithium batteries may commonly be recharged in 2-3 hours, while lead-acid batteries should be charged for longer periods of time - even fast charging AGMs should not be recharged in under 4 hours, at least not every time.

- large number of charging/discharging cycles: lithium batteries may easily withstand 3000-5000 cycles down to 80-100% DoD and often 10k+ cycles down to 30-50% DoD. That is approximately 10-15x more cycles than lead-acid batteries.

Lithium batteries also feature several issues, including:

- safety issues: lithium batteries are made using Lithium-Iron-Phosphate (LiFePO₄) chemistry which is practically the safest lithium battery chemistry, but nonetheless, such batteries are always transported semi-charged and in order to be safe, they MUST feature good Battery Management System (BMS).

- Battery Management System (BMS) protects the battery from unwanted conditions like short-circuit, over- and under-voltage, over-current, over- and under-temperature, etc. Also, BMS dictates if the battery is safe to be connected in parallel or series with other batteries and what kind of battery charger may be used to recharge the battery.

- charging issues: lithium batteries should be charged with battery chargers intended for lithium batteries or with smart AGM chargers that feature lithium-battery charging mode. Some 'drop-in' battery replacements may be charged even by common lead-acid battery chargers.

Note: proper charging of the lithium batteries is very important - it is so important that some of the manufacturers offer their batteries almost exclusively with the battery chargers (VMAXTANKS, for example) intended for such batteries. Such practice increases the price of the battery, but in the long run, it protects the battery and prolongs its operating life.

- connecting in series and parallel lithium batteries is much more complicated than connecting the lead-acid batteries. Every lithium battery model comes with different BMS, and thus with different options regarding connecting the same batteries in series and parallel.

Some models may be easily connected in parallel (Renogy lithium batteries, for example, but only as instructed by the manufacturer), allowing the user to create much larger battery packs.

Some models may be easily connected in both parallel and in series (Battle Born BB10012 model, for example, again, only as instructed by the manufacturer), creating battery packs of much larger capacity or voltage (24V, 36V, 48V).

The initial price of lithium batteries is high, but they last much longer than lead-acid batteries and in many applications weight savings also lead to lower costs - in the long run, they are even cheaper than lead-acid batteries.

 

Best Deep Cycle 12V 100Ah AGM Batteries

Deep cycle 12V 100Ah AGM batteries differ greatly in the number of charging/discharging they support, maximum allowed charging and discharging currents, nominal capacity (at least in our chart), weight, CCA/MCA/RC ratings, etc. Also, they differ greatly in price.

General purpose, budget-friendly deep cycle AGM batteries feature nominal 20h capacity of 100Ah, 1h capacity of ~56-65Ah, Reserve Capacity around 180 minutes and should not be used as cranking batteries. But, due to their size, they can easily crank smaller gas and even diesel engines not requiring more than a few hundred cranking Amps.

Most popular budget-friendly 12V 100Ah AGM batteries are commonly used as sump-pump batteries, off-the-grid batteries in solar and wind applications, in standby/float applications, medical/security systems, as trolling motor batteries and similar.

General purpose, high-capacity "12V 100Ah" batteries feature nominal capacity of 120-135 Ah and Reserve Capacity ratings between 230 and 265 minutes.

These batteries belong to the BCI Group 31 batteries and are intended for similar, but more demanding applications than deep-cycle budget-friendly batteries - sump-pump batteries, off-the-grid batteries in solar and wind applications, in standby/float applications, medical/security systems, as trolling motor batteries and similar.

Note that some of these batteries are intended only for deep cycle applications (for example, VMAXTANKS SLR125) and should not be used for anything but that - they can be used for cranking small gas engines used on power generators, but nothing more.

On the other hand, some batteries are labeled deep cycle batteries and they ARE deep cycle batteries, but they are also able to crank relatively large gas and diesel engines, like VMAXTANKS XTR31-135 or XS Power XP3000.

But, as the performances go up, so do the prices of these batteries.

Best Dual-Purpose 12V 100Ah Batteries

Dual-purpose 12V 100Ah AGM batteries are designed for industrial and other high-demanding applications where the battery is expected to power various loads for longer periods of time, but it also must be able to crank large gas and diesel engines.

Dual-purpose 12V 100Ah batteries feature a nominal capacity of ~100Ah except the Odyssey PC2250 battery, which features 126Ah capacity, but it is also the heaviest of them all.

Note: Exide XMC-31 AGM-200 is labeled as a deep-cycle battery, but it performs like a true dual-purpose battery.

Cold Cranking Amps (CCA) range from 925 to 1150 Amps, with Marine Cranking Amps (MCA) ranging from 1050 to 1550 Amps - and that is a lot of power.

Reserve Capacity of dual-purpose batteries is between 190 and 240 minutes and the weight between 68 and 86 pounds (31 and 39 kg).

As their performances go up, so do their prices.

12V 100Ah Batteries as Trolling Motor Batteries

With a maximum trolling motor current of 50-60 Amps, 12V 100Ah lead-acid batteries may power any 12V trolling motor for up to 1h, with some energy left for safety purposes.

Note: we must repeat this - nominal capacity of lead-acid batteries is given for the 20h discharge period down to 10.5 volts. When the lead-acid batteries are being discharged for 1h, their capacity drops down to 55-65% for budget-friendly models and down to 65-70% (or slightly more) for premium (read: expensive) batteries.

When the trolling motors are throttled down to, for example 25 Amps, most of these batteries may provide power under such load for almost 3 hours, with some models being able to provide power for more than 4 hours (VMAXTANKS XTR31-135).

For applications where the weight of the battery is very important, lithium 12V 100Ah batteries are the way to go - most of the 12V 100Ah models are able to provide 50 Amps for almost two hours and 25 Amps for 4 hours and at just fraction of the lead-acid battery weight.

Initially, lithium-ion batteries cost more, but for many reasons (weight savings, 10-15x larger number of charging/discharging cycles, etc.) they are actually cheaper in the long run.

---

Long Story Short: 12V 100Ah batteries are very popular batteries that come in a large number of sizes, shapes, chemistries, types, etc.

When choosing 'the best' one, be sure to choose according to your own needs and preferences - after all, what is good for us, don't have to be good for You and vice versa.

If You are new to trolling batteries and trolling motors, and You are not sure which battery to pick, go for the budget-friendly model and learn along having fun.

But, whatever You do, stay safe!