In this article we are going to go over the differences between Lithium batteries and Sealed lead acid batteries to explain why Lithium is the better choice as well as the cheaper choice over the lifetime of your battery.
Before we begin, it’s true that for some situations sealed lead acid batteries are perfectly fine, maybe even preferable actually. If you will only need to discharge your battery around 10-20% then an AGM battery is perfect for you. If, for instance, have an RV or Van that you do not live in full time then a sealed lead acid battery can be a smart decision. If your power requirements are minimal maybe only needing to power a few lights, a USB charger and a laptop then some sealed lead acid batteries will work perfectly and the upfront cost will be much lower than lithium. However, if you rely on your solar system heavily or you live full time in your RV, Skoolie, van and plan on doing so for extended periods of time, then Lithium batteries are the smarter choice.
- Below we have outlined the 6 main reasons why Lithium batteries are the best choice in any off-grid situation.
1st benefit: Cycle life
The first and possible biggest benefit to lithium batteries are their significantly larger cycle life. This refers to how many times you can discharge it and recharge it back up again. In a sealed lead acid you can maybe get 500-800 cycles before replacing them. With a lithium battery your cycle life is somewhere in the range of 2000-5000. Some batteries like the Simpliphi boast a cycle life of 10000+. For example, in our best selling portable solar generator, the Inergy Apex you can get around 2000 cycles or around 10+ years of use from it. After the 2000 cycles, your battery still works perfectly, it just operates at 80% of what it was capable of.
2nd benefit: Depth of discharge
With most sealed lead acid batteries your discharge rate is somewhere between 70-80%. This means that you can only discharge the battery down around 30% before you need to recharge it because you will damage the battery. Therefore, in a 100aH sealed lead acid battery, you essentially only have 30aH available. Lithium batteries by comparison can discharge all the way down to 0% while keeping the same voltage and with no damage to the battery itself. Also, since you can discharge Lithium batteries down, you are getting significantly more real world use meaning that you dont need as physically large a battery bank in order to get the same amount of useable power.
3rd benefit: Efficiency
The efficiency of a lithium battery is also significantly greater than their flooded lead acid counter parts. When you put electricity into a FLA or AGM battery and take it back out, you will lose around 10 - 15%. If the battery is older or damaged you can lose even more than that. Lithium batteries on the other hand have about 99% efficiency meaning that whatever you put into the battery, you will be able to take out and use.
4th benefit: Weight
A great real world benefit for lithium batteries is their overall weight and size. Lithium batteries are much lighter than FLA or AGM batteries. In fact they are about 30% lighter in general which is of huge significance if you want a battery for any type of mobile function like RV’s, Van’s or Skoolies. If you will be driving around or want the ability to drive around, the lighter the weight of your battery bank the better. Not to mention that since they are 30% of the weight they are also smaller in size which means they are more beneficial for mobile situation again.
5th benefit: Constant voltage
In SLA or AGM batteries, when you lower the capacity the voltage drops. In a lithium battery the voltage stays constant right up until the point where it is completely dead. You’ll really notice this if you’re running any type of larger load because performance drops when the voltage lowers and you’ll have a constant voltage with your lithium battery bank.
6th benefit: Maintenance
The last benefit is one of simple practicality. Lithium battery require almost zero maintenance and also won’t give off any toxic fumes. You can essentially install your lithium batteries and forget about it. With a FLA battery bank, there is constant upkeep and work to be done to keep them functioning. Lithium batteries are the modern day plug and play battery option. A lithium battery with a BMS (battery management system) will cut off power if the battery is too low in capacity. This means that once the battery is at 0% capacity, the BMS will cut off the power to the appliances. It also cuts off the power when the battery is fully charged preventing over charging. The only way to damage a lithium battery is basically to damage the battery itself. Rupturing one of the cells or over discharging it too quickly; or if you short circuited it for a prolonged time the cells could puff up. However, for most applications if you have a file on the battery or a BMS that has a circuit breaker installed you dont need to worry about this. Contrast that with a AGM, FLA or SLA battery where is you discharge it past 50% even one time you will cause permanent damage.
In closing, a lithium battery will be:
- You have higher discharge capabilities for the size
- Much higher cycle life
- Ability to sustain higher voltages while discharging leading to higher performance
- Easier to use
- Easy maintenance
Lithium batteries are more expensive upfront so this leads many people to purchase FLA or AGM batteries because of the cost factor. However, over the lifetime of the battery the cost of Lithium is SIGNIFICANTLY less. Your Lithium batteries will last up to 10x as long as be more efficient as well. If you plan on using your batteries in any type of consistent way, we strongly suggest Lithium.