As an engineer or procurement officer, the spec sheet says you need a 200Ah batterij, but the pressure is on. Under-spec and you risk costly failures; over-spec and you blow the budget. It’s a tough spot.
The question, “How long will a 200Ah battery last?” seems simple, but it’s one of the most critical we get. A miscalculation is a big deal—it could halt a production line or lose critical data.
With over 15 years designing these industrial power systems, I won’t just give you a single number. I’ll give you the framework to answer this for je specific application. We’ll cover the formula you really need, the critical factors that can swing your runtime by 50% or more, and finish with pro tips to maximize your investment.
12v 200ah lifepo4 accu
12v 200ah natrium-ion batterij
What to Expect from a 200Ah Battery
Alright, let’s just get right to it. For some quick back-of-the-napkin planning, here’s what you need to know:
A healthy 12V 200Ah lifepo4 battery gives you about 2400 Watt-hours of usable energy. That’s the key number. And it means you can power a 100-watt load—think an industrial monitoring system with a few sensors and a modem—for roughly 24 hours.
Now, compare that to a traditional 12V 200Ah lead-acid battery. You’ll get about half of that, maybe 12 hours if you’re lucky. Why the huge difference? Because with lead-acid, you can only safely use about 50% of its stated capacity without doing some serious, permanent damage to it. It’s just the nature of that chemistry.
But—and this is a big but—this is a perfect-world calculation. The true runtime you’ll actually see in the field is going to depend on a handful of other factors we need to go through.
How to Calculate Runtime Yourself in 4 Simple Steps
You don’t need an electrical engineering degree for this. I’ll walk you through the math. It’s pretty straightforward.
Step 1: Find Your Battery’s Usable Energy (in Watt-hours)
First thing’s first, we need to get from Amp-hours to Watt-hours. Amp-hours are fine, but Watt-hours tells you the total energy stored, which is just a much more practical metric for what we’re doing.
The formula is: Watt-hours = Voltage (V) x Amp-hours (Ah) x Depth of Discharge (DoD)
- Spanning (V): Your battery’s nominal voltage. Usually 12V, 24V, whatever it is.
- Amp-hours (Ah): The rated capacity from the label. So, 200Ah for us.
- Diepte van de lozing (DoD): This is the part that trips people up. It’s how much of the battery’s total capacity you can actually use without hurting it. For LiFePO4, that’s usually 90% or even 100%. For lead-acid, it’s a measly 50% if you want the battery to have a decent service life.
Step 2: Calculate Your Total Load (in Watts)
Next, you just add up the power consumption of everything the battery has to run. Check the data plate or the manual for each component. The wattage is usually printed right on there.
So let’s say a small control panel has:
- PLC Controller (15W)
- HMI Screen (25W)
- LED Indicator Lights (10W)
- Total Load = 50 Watts
Step 3: Account for Inverter Inefficiency (The Hidden Drain)
This is a step people forget all the time. If your DC battery is powering AC equipment through an inverter, you have to account for the energy the inverter itself burns off as heat. No inverter is 100% efficient. A good industrial-grade unit might be 85-90% efficient, and that’s about as good as it gets.
So to find out what the battery is actually dealing with, you just divide your load by that efficiency rating.
Voorbeeld: 50W AC load / 0.85 efficiency = ~59 Watts drawn from the battery. That extra 9 watts is just the “cost of conversion.” It’s a tax you have to pay to get AC power.
Step 4: The Final Calculation
Now, you just put it all together.
Runtime (in hours) = Total Usable Watt-hours / Final Load (in Watts)
Let’s run a side-by-side with our 59W load:
- 12V 200Ah LiFePO4 Battery:
- Usable Energy: 12V x 200Ah x 0.95 (DoD) = 2280 Wh
- Runtime: 2280 Wh / 59W = ~38.6 hours
- 12V 200Ah AGM Lead-Acid Battery:
- Usable Energy: 12V x 200Ah x 0.50 (DoD) = 1200 Wh
- Runtime: 1200 Wh / 59W = ~20.3 hours
The difference is stark, isn’t it? For the same capacity on the label, the lithium battery gives you almost double the uptime. It’s a huge factor in any system design.
The 5 Key Factors That Dramatically Affect Your Battery’s Runtime
The formula gives you a great starting point. But the real world always has other plans. What we see out in the field is that these five factors are where theoretical specs collide with reality.
1. Battery Chemistry: LiFePO4 vs. Lead-Acid (and a look at Sodium-Ion)
We just saw how usable capacity is the biggest differentiator. But the story doesn’t end there. Two other things come to mind: voltage sag and cycle life.
If you put a heavy load on a lead-acid battery, its voltage will “sag” quite a bit. That can cause sensitive electronics to shut down early, even when there’s still juice left in the tank. A LiFePO4 battery? It has a very flat discharge curve, so it maintains a stable voltage until it’s nearly empty. Then there’s cycle life. You can expect a LiFePO4 battery to last 3,000 to 6,000 cycles, sometimes more. An AGM battery might only give you 300-700 cycles at that 50% DoD. For any application that cycles daily, the Total Cost of Ownership for LiFePO4 is just so much lower it’s not even a fair fight.
And lately, we’re getting more questions about sodium-ion batteries. LiFePO4 is the mature, proven technology right now. It has a higher energy density, a solid supply chain… it’s the go-to. A sodium-ion battery pack, however, is a really compelling piece of emerging tech. Its main advantages are a potentially lower cost down the road and great performance in extreme temperatures, especially the cold. The trade-off is that its energy density is currently lower. So a 200Ah Na-ion pack will be bigger and heavier. It’s one to watch, for sure, especially for stationary energy storage where space isn’t as much of a premium.
2. Load Size & C-Rate (Peukert’s Law for Lead-Acid)
C-rate is just a way to measure how fast you’re draining the battery relative to its size. A 1C rate on a 200Ah battery means you’re drawing 200 amps. Simple.
The thing to remember is that for lead-acid batteries, a nasty little rule called Peukert’s Law comes into play. The faster you discharge it, the less total capacity you actually get out of it. I’m serious. A 200Ah lead-acid battery rated over 20 hours might only give you 130Ah of usable capacity if you drain it in one hour. LiFePO4 batteries are pretty much immune to this effect. They deliver nearly their full capacity even at a high 1C discharge rate. This is huge for applications with big inrush currents, like starting up motors.
Batteries are chemical devices. At the end of the day, their performance is tied to temperature. It’s just physics.
- Cold. In a cold storage facility or outdoors in the winter, a battery’s capacity can drop significantly. LiFePO4 performance dips in the cold, but lead-acid chemistry can basically come to a standstill. The good news is, many modern LiFePO4 batteries now have built-in heating elements that allow for reliable charging in sub-zero weather.
- Heat. On the other side of things, high ambient temperatures, like you’d find inside a non-ventilated box in the sun, will speed up battery degradation and permanently shorten its lifespan. The sweet spot for most chemistries is around 20-25°C (68-77°F).
4. Battery Age and Health (State of Health – SOH)
A battery is a consumable part, not a permanent one. Its State of Health (SOH) is its current capacity compared to when it was brand new. So a five-year-old battery with a 90% SOH is, for all practical purposes, now a 180Ah battery. You have to factor SOH into your maintenance and replacement planning if you want to ensure mission-critical reliability. It’s just a reality of using batteries.
5. System Inefficiencies (Wiring and Connections)
This one is a small but cumulative drain. Undersized cables, long wire runs, or even a slightly loose connection at a terminal all create electrical resistance. That resistance just turns your precious stored energy into useless heat, which of course cuts into your runtime. In a well-designed system this should be minimal, but in a messy one, it can be a surprising source of power loss. I can’t tell you how many times we’ve traced a “bad battery” problem back to a bad crimp or a loose nut on a terminal.
What Can a 200Ah Battery Actually Power?
The following example uses a common RV setup, but the principles of calculating a mixed-load energy budget are the same for any industrial application. You can use this exact method to spec out power for a security trailer, an off-grid pump jack, or whatever you’ve got.
Scenario: A Typical Weekend in an RV/Van Assumptions: Using a 12V 200Ah LiFePO4 battery (2400Wh usable).
| Toestel | Power (Watts) | Est. Daily Use (Hours) | Daily Energy (Wh) |
|---|
| LED Lights (x4) | 20W | 5 | 100 Wh |
| 12V Fridge/Cooler | 50W (cycling) | 8 (24h on, 33% duty) | 400 Wh |
| Laptop Charging | 65W | 3 | 195 Wh |
| Phone Charging (x2) | 15W | 2 | 30 Wh |
| Waterpomp | 40W | 0.5 | 20 Wh |
| MaxxAir Fan (low) | 25W | 10 | 250 Wh |
| Total Daily Demand | | | 995 Wh |
Based on this daily usage of around 995Wh, a 2400Wh 200Ah lithium battery would last about 2.4 days with no recharging. For an industrial job like a marine backup power system, you might have a VHF radio (25W), GPS (10W), and navigation lights (15W) running. That’s a 50W load, which our 2400Wh battery could keep running for a solid 48 hours.
How to Maximize Your 200Ah Battery’s Runtime and Lifespan
- Specify LiFePO4 for High-Cycle Apps. Look, the higher upfront cost is almost always worth it when you look at the total cost of ownership. It’s just simple math, thanks to the better usable capacity and a much longer cycle life.
- Demand a Quality BMS. The Battery Management System (BMS) is the brain of the whole operation. A good one protects the cells from everything… over-charge, over-discharge, short-circuits, you name it. For industrial systems, make sure the BMS can communicate (like CAN bus or RS485).
- Optimize Your Loads. Whenever you can, use high-efficiency DC equipment. You want to avoid the energy loss that comes with using an inverter if at all possible.
- Implement Correct Charging Profiles. Use a charger made specifically for your battery’s chemistry. If you chronically undercharge a lead-acid battery you’ll kill it, and using the wrong voltage can damage a lithium battery.
- Integrate a Shunt-Based Monitor. Don’t just rely on voltage to guess the state of charge. A smart shunt acts like a real fuel gauge, accurately tracking all the energy going in and out of the battery. Honestly, it’s a must-have for any serious system.
Is a 200Ah Battery Right for You?
- Who it’s perfect for: Low-to-moderate power applications. Think remote monitoring stations, backup power for telecom towers, small marine vessels, and fleets of smaller AGVs or utility carts.
- When you might need more (e.g., 400Ah+): When you’re powering larger motive loads like a Class 3 forklift battery, running high-draw commercial equipment, or designing a commercial Energy Storage System (ESS) that needs to provide autonomy for more than a day.
- When you can use less (e.g., 100Ah): For basic backup systems, powering individual sensors, or in applications where weight and space are the absolute top priorities.
FAQ
What kind of industrial equipment can a 200Ah battery reliably power?
A 12V 200Ah LiFePO4 battery, which gives you about 2400Wh, is a great fit for systems with a continuous draw somewhere in the 100-300 watt range. This covers things like multi-sensor environmental monitoring stations, security camera systems with a DVR, backup power for critical control panels, or the lighting and controls for an off-grid outbuilding.
How long does it take to fully charge a 200Ah battery?
That depends completely on your charger’s amperage. The formula is simply Hours = Amp-hours / Charger Amps. So, a depleted 200Ah battery is going to take about 5 hours to charge with a 40A industrial charger. With a 100A charger, you’re looking at just 2 hours. Just always make sure your charge rate is within the battery’s specified limits.
Can I connect two 100Ah batteries in parallel to get 200Ah?
Yep, you absolutely can. Connecting two 12V 100Ah batteries in parallel creates a single 12V 200Ah battery bank. The trick is, you have to use two identical batteries—same chemistry, brand, capacity, and age. If you mismatch them, you’ll get imbalanced charging and discharging, which reduces the performance and lifespan of the whole bank.
What if my application requires a higher voltage, like 24V or 48V?
No problem at all. You just connect batteries in series to increase voltage. For instance, two 12V 200Ah batteries in series creates a 24V 200Ah bank. Four of them in series makes a 48V 200Ah bank. The total energy stays the same (48V x 200Ah = 9600 Wh, same as four 12V 200Ah batteries), but the higher voltage is more efficient for bigger motors and lets you use smaller-gauge wiring.
Conclusie
So, how long will a 200Ah batterij last? At the end of the day, there’s no single number. The real answer is a dynamic calculation based on your battery’s chemistry, the exact load you’re running, and the overall health of your system.
The difference between a lead-acid battery lasting 20 hours and a LiFePO4 battery lasting nearly 40 under the same load isn’t trivial—it can be the difference between a successful project and a failed one. By using the framework and understanding the key factors we’ve talked about, you’re now in a much better position to look past the nameplate rating and specify the right power source for your critical applications.
Need to run the numbers for your next project? Onze kamada power team of application engineers is here to help you model your power requirements and specify the most cost-effective and reliable battery solution. Neem contact met ons op today for a technical consultation.