AGM Battery vs Lithium: Which Is Better?

A camper may go to bed with a full battery and wake up to a dead fridge. It may be a 100Ah battery, the same size as in the neighbour’s RV. There is no indication on the label concerning how low the battery may be drained each and every day. Hence, the agm battery vs lithium debate continues for many, along with many questions.

That kind of information is what makes the AGM battery versus lithium choice. National Battery Supply has batteries for all sorts of various tasks. An engine needs a quick burst of power to get going. A fridge requires electricity constantly for hours.

How is AGM different from Lithium?

AGM stands for absorbent glass mat. It is a sealed lead-acid battery. The electrolyte is contained in fiberglass matting. No flooded batteries therefore no water fill ups required. Convenient when positioned beneath a seat or inside a boat compartment.

Lithium here means lithium iron phosphate (LiFePO4). Most packs have a battery management system (BMS) that can turn off power if the temperature or voltage go outside of safe limits. It safeguards the cells, even if a shutdown seems like a flat battery.

Both kinds may be made for deep cycle usage. The article on clarifies a frequent confusion about AGM deep cycle battery . Deep cycle is what the battery is supposed to perform, not what is within it.

Different Runtime, Same 100ah Label

A 100Ah AGM battery is often believed to have about 50Ah usable for everyday usage. Regular discharging it a much shorter its life. The 50% rule is a guideline, not a hard and fast law.

Depending on their specs several 100Ah LiFePO4 batteries may usually provide approximately 80Ah – 90Ah. Without connections, the disparity becomes evident by nite two. Even after an AGM has reached its normal recharging point the fridge and water pump may be powered.

AGM also loses some capacity with heavy loads. In general, lithium keeps its voltage more consistently during discharge. Neither difference is visible on the shelf.

Everyday Use Weight & Charging

If you need to replace a boat battery, it might involve lugging a hefty box past pipes in a cramped locker. A LiFePO4 unit of equivalent capacity will often weigh a lot less. Trailers benefit too, since weight cuts into cargo.

AGM charging slows down when the battery gets close to full. Lithium may tolerate greater current over a larger portion of the charging process, within the restrictions of the battery and charger.

A solar system could only receive a few good hours of sun. Clouds may wipe out an afternoon of charge. A brief generator run may also send more useable energy back into lithium than an AGM reaching a full charge. With deep cycle batteries, you want to be careful with the compatibility of the charger.

Need Fair Comparison of Lifespan & Price

AGM batteries are often cheaper. That matters if you’re talking about a backup unit that gets utilized twice a year. Thousands of potential cycles is meaningless if the battery seldom gets cycled.

Cycle life matters more every evening in a battery-powered cabin. LiFePO4 batteries may frequently last thousands of cycles if circumstances are right. Many AGM types hold much less, particularly if routinely profoundly discharged.

Heat, storage and charging practices still impact longevity. Cycle ratings might be based on various discharge depths. The warranty and its terms are not the same as a number of years provided.

Then you have the charger. If the old equipment can’t handle it, replacing the lithium might cost you more.

Cold Weather Is An Important Exception

An cold RV and a warm garage place very different demands on a battery. Cold weather will impact AGM performance, however many models are chargeable below freezing if the temperature parameters are modified. The manufacturer’s restrictions still apply.

LiFePO4 deserves more attention. Many models should not be charged at or below freezing temperatures unless the batteries are kept warm. The battery management system may not allow charging until the temperature increases. others batteries have built in heaters, others don’t.

On a bright winter morning, a lot of solar power may be generated even with the battery still ice cold. The panels may be operating well and not one amp would be getting into the battery. An RV kept outdoors all winter requires proper charging protection.

Can You Replace an AGM Battery With a Lithium One?

Or the old AGM compartment could only take a lithium battery. But how to properly charge it is another question.

Older lead acid converters may be set at the improper charging voltage. Solar controllers, alternator charging and battery monitoring may also need maintenance. LiFePO4 battery charging guide shows why you cannot estimate the charging profile.

Check cables, fuses and dimensions. A deep cycle lithium model is not to be used to start an engine unless approved for that use by both battery and vehicle manufacturer.

Which Battery Is Right For Which Situation?

Good choice for RV housing systems that get a lot of usage, yachts with long-running accessories and off-grid solar storage. Lithium. Lighter weight and longer duration benefit when charging possibilities are few and far between.

AGM still makes sense for infrequent journeys, standby duty and smaller costs. Its charging behavior may be simpler to cope with when it is chilly.

If you have batteries that are kept between journeys, monitoring the charge frequently is still important. A little alarm or monitor left on may silently consume electricity for weeks. What a nasty find the first go out in the spring.

Some normal questions a buyer still needs to know. How long does the fridge need to be running? How frequently do you charge the battery? Is it just going to sit there, unused, all winter? A comparison chart seldom provides you such answers.

Conclusion

Lithium usually offers more usable power and longer cycle life. AGM is still a sound choice for some lighter-duty setups. The charger and temperatures matter too. Comparing the specifications of LiFePO4 batteries against the existing equipment is a sensible way to decide.