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Every battery the Megawatt calculator recommends is a Vatrer lithium pack. That’s a choice, not a verdict on AGM, and it helps to know what the calculator assumes before you buy either one.
How the calculator counts lithium
The watt-hour figures are printed right in the widget. A 12-volt 100Ah pack counts as 1,280 Wh, a 300Ah pack as 3,840 Wh, and so on up the list.
That’s 12.8 volts times amp-hours, a common nominal voltage for LiFePO4 (lithium iron phosphate). It isn’t a lab test Megawatt ran.
Where AGM differs
AGM is a sealed lead-acid battery. Owners usually plan on using a smaller slice of its rated amp-hours, because deep discharges shorten lead-acid life.
Our battery runtime calculator lets you set that usable fraction yourself. It doesn’t ship a default and pretend it was measured.
What we won’t quote
Cycle life, weight, and cold-weather charging limits belong on the maker’s spec sheet for the exact model. We don’t have lab numbers, so you won’t find any here.
One more honest gap: the 12-volt 100Ah short link from the old calculator didn’t resolve to a product page when the site was crawled on October 1, 2026. We kept it exactly as James published it.
Voltage follows your watts
The calculator picks system voltage from continuous watts. It stays at 12 volts up to 3,000 watts, moves to 24 volts through 5,000, and goes to 48 volts above that. Those cutoffs come from the published widget, not from an electrical code.
A higher-voltage bank means a different charger, a different inverter, and usually a professional install.
Vatrer 12V 300Ah lithium battery
3,840 Wh of 12-volt lithium. It's the battery in the Bounder solar starter kit.
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Vatrer 12V 460Ah lithium battery
5,888 Wh at 12 volts, for loads that have outgrown a 300Ah pack.
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Vatrer 24V 200Ah lithium battery
5,120 Wh at 24 volts. The calculator moves to 24 volts once continuous loads pass 3,000 watts.
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Check the converter before you swap
Match the pack to the calculator’s net storage number, then read the battery maker’s manual for charging voltages.
Fleetwood’s house electrical chapter says the coach electronics are voltage sensitive. A lithium swap that ignores the converter’s charge profile is how coaches end up with cooked circuit boards.
