Whether or not you’re in search of an power storage resolution to pair with house photo voltaic panels or a technique to run your trolling motor, a deep cycle battery is the reply. These batteries are specifically designed to cost and discharge many instances throughout their helpful life, offering battery energy to units and home equipment for a few years.
There are vital issues to find out about deep cycle batteries, together with the assorted varieties, how they differ, and the functions for which every works properly. So let’s soar proper into the deep finish and get to it!
- Deep cycle batteries are supposed to be charged and discharged commonly, and supply a gentle stream of energy.
- The primary kinds of deep cycle battery are flooded lead acid, sealed lead acid, and lithium-ion.
- Lead acid batteries typically supply decrease prices however shorter lifespans, and lithium batteries typically have increased up-front prices and longer lifespans.
- Every sort of battery has its personal greatest makes use of, however most varieties could be designed to be used to retailer photo voltaic power in cell properties or stationary ones.
What’s a deep cycle battery?
A deep cycle battery is a battery that’s meant to be charged and discharged commonly and might supply a gentle stream of energy whereas it discharges. Though they arrive in lots of sizes, they largely seem like a normal 12-volt automobile battery, housed in heavy-duty rectangular packing containers with constructive and unfavorable terminals on the highest. Like automobile batteries, deep cycle batteries typically use lead-acid expertise, with lead plates linked to the terminals and suspended in an electrolyte resolution containing sulfuric acid, however lithium batteries are rising in popularity.
The distinction between deep cycle batteries and automobile batteries
Gasoline-powered automobiles use their 12-volt battery for 3 issues: offering energy to the ignition swap, activating and powering the starter motor, and operating the lights. That’s why a automobile battery can also be referred to as a beginning, lighting, and ignition (SLI) battery.
So as to present the very highly effective burst of power the starter motor wants, an SLI battery has to attract a lot of electrons from its electrolyte resolution. To do that, an SLI battery makes use of many skinny metallic plates linked to its terminals. This will increase the floor space that’s involved with the electrolyte, permitting the battery to attract a lot of electrical energy directly.
A few of Trojan’s deep cycle lead acid batteries for photo voltaic storage. Picture supply: Trojan
In distinction, a lead acid deep cycle battery has thicker metallic plates. This implies the battery can’t draw a really excessive present via its terminals just like the SLI battery, however as an alternative can present a gentle stream of energy, and its thicker plates assist it keep away from corrosion even when the battery is discharged. As well as, deep cycle lead acid batteries are available in many sizes, as a result of they don’t have to slot in the usual auto battery enclosure.
Lithium deep cycle batteries
All lithium batteries qualify as deep cycle batteries as a result of they are often totally discharged and recharged. Lithium batteries are constructed slightly in another way, although. They use cylindrical cells with the electrolyte between two electrodes that management the movement of electrons. Many of those cells are wired collectively to provide a battery pack, which is then encased in some kind of enclosure with constructive and unfavorable terminals on it. Except you’re shopping for uncooked cells to make your personal battery, lithium batteries virtually at all times include an onboard battery administration system (BMS).
A lithium battery pack earlier than being put in in an enclosure. Picture supply: AA Portable Power
Kinds of deep cycle batteries
As talked about above, there are two fundamental sorts of deep cycle batteries which are generally used as we speak: lead acid and lithium batteries. Lead acid batteries could be additional damaged down into the classes of flooded lead acid (FLA) batteries, which require common watering and upkeep, and sealed lead acid (SLA) batteries, that are maintenance-free. Inside the SLA sub-category, there are absorbent glass mat (AGM) and gel batteries. You may examine these differing types in our full article on lead acid deep cycle batteries.
Deep cycle Lithium-ion batteries are mostly very similar, but there are two specific types that differ in the materials used to make their cathodes (positive terminals). One type uses Nickel, Magnesium, and Cobalt, and is referred to as a lithium NMC battery, while the other uses lithium iron phosphate, with a chemical composition of LiFePO4. These are called LFP batteries for short. In general, they perform very similarly. LFP batteries have the advantage of being safer, less toxic, and more robust than NMC batteries, but also tend to be heavier and more expensive.
Things to know when choosing a deep cycle battery
There are a few important concepts to understand in order to be informed about the benefits of different types of battery technology. These are:
- Capacity (amp-hours)
- Depth of discharge (DoD)
- Battery life
Voltage is related to how much power the battery can push out at one time. Common voltages are 6V, 12V, and 24V. A 12V battery is often used by itself for mobile uses, while battery banks for home energy storage can be made of several low-voltage batteries wired in series to increase the total voltage to 24V or 48V.
Capacity, or amp-hours, tells you how much energy a battery can deliver. For deep cycle batteries, this discharge rate is measured over 20 hours. For example, a 100ah battery can discharge at a rate of 5 amps for 20 hours until it is no longer able to produce power.
Depth of discharge (DoD) describes the amount of capacity that can be safely used without potentially damaging the battery. Yes, it’s true that some batteries tease you with a larger capacity than you can safely use.
The guideline for FLA batteries is to discharge them to no more than 50% of their capacity for maximum lifespan. A very deep discharge of an FLA battery can cause irreparable damage to the plates inside. It’s recommended to never deplete these batteries below 20% of their capacity.
Gel and AGM batteries can be discharged to 100% of their rated capacity, but most experts still advise a DoD of no more than 50% for maximum battery life. As you know if you have a cell phone, lithium batteries can be fully discharged and fully charged back up (100% DoD), but an 80% DoD is often recommended by manufacturers to ensure they last as long as possible.
That brings us to battery life, which is measured in charge cycles. This is related to DoD, in that the number of discharge cycles the battery can handle goes down when DoD goes up. For example, a gel battery can survive for 1,000 cycles at 50% DoD, however solely 450 cycles at 100%. In distinction, an AGM battery can sometimes undergo 500 cycles at 50% DoD, however solely 200 at 100%.
It is vital to notice that the rated battery life doesn’t imply the battery is predicted to instantly turn out to be unusable afterward. As a substitute, a battery’s helpful life “ends” when it’s diminished to 80% of its authentic capability.
Right here’s a fast information to the completely different sorts of batteries and their cycle life and advisable DoD:
|Battery sort||Really useful DoD||Common Cycle life @ advisable DoD|
Makes use of for deep cycle batteries
The varied sorts of deep cycle batteries have their very own greatest makes use of.
Flooded lead acid batteries are greatest used for stationary functions. They’ve the benefit of being comparatively cheap and are straightforward to wire into battery banks for off-grid photo voltaic power storage and backup energy functions. Their disadvantages embody the necessity for normal upkeep and the truth that their electrolyte can spill except the batteries are held stationary.
AGM batteries are spill-proof and vibration-resistant, to allow them to be utilized in autos like golf carts, wheelchairs, and scooters. They’re additionally generally used as UPS backup batteries and in photo voltaic backup energy functions. They’re considerably costlier than FLA batteries, have to be charged rigorously to forestall overcharging, and don’t work in very chilly environments.
Gel cell batteries, as their identify implies, have their electrolyte suspended in a silica-based gel, This makes them very immune to shocks and really secure to be used for issues like bikes and trolling motors. As a result of the electrolyte is already a thick paste, they’re much less vulnerable to freezing in low temperatures. Cons of gel batteries embody comparatively sluggish charging speeds and excessive preliminary price.
Lithium batteries have been utilized in digital units like cell telephones for a very long time and are shortly changing into the only option for giant functions like automobiles, house photo voltaic backup, and moveable photo voltaic chargers. They are often discharged to 100% with out an excessive amount of injury, aren’t vulnerable to vibration shocks, and have lengthy cycle lives. The disadvantages of lithium batteries are their excessive preliminary price (though that’s coming down) and the potential of NMC batteries exhibiting thermal runaway (catching fireplace) after they’re broken. So far as ease of use, capability, and lifespan, they’re the only option for house photo voltaic backup.
Greatest deep cycle batteries and the place to purchase them
There isn’t any one “greatest” deep cycle battery. As a substitute, there are nice deep cycle batteries for a lot of completely different functions. For those who’re in search of the most cost effective possibility and might deal with the upkeep, get an FLA battery. For those who want a easy, vibration-resistant battery with medium up-front price, a gel or AGM battery would work greatest for you. If cash is not any possibility and also you need the simplest, strongest possibility, go lithium.
Right here’s a rundown of a few of the greatest batteries of every sort in the marketplace:
Greatest FLA deep cycle batteries
- Possibility 1: Trojan
- Possibility 2: Rolls
Trojan has been the #1 identify in flooded lead acid deep cycle batteries for photo voltaic power storage for a very long time. They’re so widespread, in truth, that they at present have a 4-5 month lead time on new orders. If you cannot wait that lengthy, batteries from Rolls and Crown are additionally superb, and at present accessible.
Greatest AGM deep cycle batteries
- Possibility 1: Concorde Solar Xtender
- Possibility 2: Weize
On the subject of stationary solar energy storage, Concorde Sun Xtender batteries are second to none. They could be a little heavy and hulking however are glorious, long-lasting batteries. For those who’re in search of one thing that may be put in in an RV for photo voltaic storage, the Weize 12V 100AH battery on Amazon is a more sensible choice.
Greatest Gel deep cycle battery
- Possibility 1: Mighty Max
- Possibility 2: Weize
Gel batteries will not be typically advisable for photo voltaic storage in residential functions. The batteries we’ve listed right here from Mighty Max and Weize are good for smaller functions the place fast recharge isn’t needed, resembling powering a trolling motor or mobility scooter.
Greatest lithium deep cycle batteries
- Possibility 1: SimpliPhi
- Possibility 2: Battle Born
- Possibility 3: Bluetti
For sturdy, sturdy house power storage, it is laborious to discover a higher battery than these made by SimpliPhi. Utilizing LiFePO4 chemistry and with a lifespan of as much as 10,000 cycles at 80% DoD, these batteries are constructed to carry out for a lot of, a few years. They are often fairly costly up-front, however that top cycle life and DoD means the last word price per kWh of throughput is way decrease than different batteries in the marketplace.
For extra moveable options like small storage in an RV, BattleBorn batteries obtain excessive marks from individuals within the DIY and off-grid communities. However for essentially the most half, these batteries are drop-in options for a longtime storage system. Within the case that you simply’d want the simplicity of an all-in-one resolution, Bluetti moveable photo voltaic battery banks are a wonderful alternative. Bluetti’s photo voltaic batteries all embody an MPPT photo voltaic cost controller, battery administration system, pure sine wave inverter, AC and DC retailers, and a number of methods to cost.
Lastly, for those who’re in search of app-enabled house power storage in a smooth bundle, we suggest the Tesla Powerwall, in addition to lots of its opponents, together with LG Chem, Enphase, and HomeGrid.
Deep cycle batteries: are they best for you?
Whether or not you reside a life on the go or want to remain house, deep cycle batteries are important if it’s worthwhile to retailer power for later use. They’re the right match for a house photo voltaic system, and even only a moveable photo voltaic panel. As our world turns into extra reliant on units powered by electrical energy, it will likely be important for individuals to have data of deep cycle batteries and all they will do.