Questions answered
Lithium battery questions, answered
The lithium questions we see most in forums and searches, each answered from the battery makers' own manuals and spec sheets.
Updated October 24, 2026. Every answer lists the sources we read it from. Prices are the makers' own, from the day we last checked.
Disclosure: We may earn a commission if you buy through these links. It never changes what we recommend or what the tools calculate. How we make money.
How long will a 100Ah lithium battery last?
Short answer
A 12.8 V 100Ah LiFePO4 battery stores 1,280 Wh, the figure both Redodo and LiTime list. Divide that by what you use per day: a fridge using 400 Wh a day would take a little over three days to empty it with no charging. For AC loads, divide the watts by the inverter's efficiency first; Redodo uses 85% in its own sizing example.
Redodo's inverter manual gives the method: energy (Wh) = load watts x hours / inverter efficiency, then amp-hours = energy / 12.8 V.
Its worked example: a 1,000 W load for 3 hours a day needs about 3,529 Wh, which is about 276Ah of 12.8 V lithium.
Our planner keeps 20% of the battery in reserve, so its runtimes come out shorter than the full 1,280 Wh would suggest. That reserve is our choice, not a maker requirement.
For your own rig: Runtime for your own list of loads (planner)
Redodo 12V 100Ah Group 31 Bluetooth
1,280 Wh with a 100 A BMS, phone app monitoring and a low-temperature charge cutoff. Cheaper than Redodo's basic 100Ah the day we checked.
$260.99$389.99
See at Redodo (opens in a new tab)LiTime 12V 100Ah
1,280 Wh with a 100 A BMS. LiTime's best-known battery; it cost more than Redodo's 100Ah the day we checked.
$335.99$359.99
See at LiTime (opens in a new tab)Is a 100Ah lithium battery the same as 200Ah of lead-acid?
Short answer
In usable energy, roughly yes. Battle Born says lithium can be discharged 100%, against a recommended 50% for lead-acid, and LiTime describes its 12V 100Ah as the same energy as a 12V 200Ah lead-acid battery at a fifth of the weight. So half the amp-hours of lithium does about the same job.
LiTime lists its 12V 100Ah at 24.25 lb.
Price check: the Redodo 12V 100Ah Group 31 Bluetooth was $260.99 on the maker's site the day we checked.
For your own rig: Lithium batteries compared by price per usable watt-hour
Can you charge a LiFePO4 battery below freezing?
Short answer
No. Redodo lists a charging range of 0°C to 50°C (32°F to 122°F), and its battery management system stops charging below 32°F and resumes above 41°F. Discharging is allowed down to -4°F. If you camp in the cold, keep the battery in the heated space or buy a self-heating battery.
A self-heating battery warms itself before it accepts a charge. On Redodo's self-heating 100Ah, the heater turns on below 32°F (0°C) and stops at 41°F (5°C), then charging resumes. It uses 100 W of heating pads.
Cost of the feature: the Redodo 12V 100Ah Self-Heating was $279.99 against $260.99 for the Redodo 12V 100Ah Group 31 Bluetooth, a difference of $19.00, on the day we checked.
Redodo 12V 100Ah Self-Heating
Warms itself before charging, so solar and the alternator can charge it on frosty mornings. 100 A BMS.
$279.99$559.99
See at Redodo (opens in a new tab)Can you mix lithium and lead-acid batteries?
Short answer
Not in the same bank. Battle Born says not to combine lithium and lead-acid batteries directly in series or parallel, because they sit at different voltages and need different charging. If you need both, such as a lead-acid starter battery and a lithium house bank, put a battery isolator or a DC-DC charger between them.
Battle Born's reason: when batteries are not at the same voltage or discharge at mismatched rates, power flows quickly between them.
Even lithium to lithium has rules. Redodo only allows identical batteries in one bank: same capacity and BMS, same brand, bought within about a month of each other.
For your own rig: Do I need a DC-DC charger?
Can I charge a lithium battery with a lead-acid charger?
Short answer
Use a charger with a LiFePO4 setting instead. Redodo specifies 14.4 V (plus or minus 0.2 V) for its 12 V batteries, while a lead-acid converter such as Progressive Dynamics' Charge Wizard holds 13.6 V in normal mode and only reaches 14.4 V in boost. Battle Born also notes that lithium needs different charging parameters than lead-acid.
Redodo recommends 20 A (0.2C) of charge current for its 12V 100Ah battery.
A plug-in lithium charger is the simple fix if your charger has no lithium mode. The Redodo 14.6V 20A LiFePO4 Charger was $82.99 the day we checked.
For your own rig: What else changes when you switch to lithium
Redodo 14.6V 20A LiFePO4 Charger
A simple plug-in lithium charger for campground or driveway power.
$82.99$119.99
See at Redodo (opens in a new tab)Should RV batteries be wired in series or parallel?
Short answer
Parallel keeps the voltage and adds capacity; series adds voltage. Two 12 V 100Ah batteries in parallel make a 12 V 200Ah bank, and in series a 24 V 100Ah bank. Redodo only allows identical batteries of the same brand and capacity, bought within about a month, and up to four in parallel and four in series.
Victron's wiring guide: in series the voltage increases, in parallel the capacity increases.
How you wire a parallel bank matters. Victron warns that if you connect the system to one end of the bank, most of the current runs through the nearest battery. The fix is to make the current path in and out of each battery equal, for example with bus bars.
For your own rig: Draw your battery bank (wiring tool)
Do I need a shunt or battery monitor for a lithium battery?
Short answer
You need one if you want an accurate fuel gauge. Redodo says resting voltage only gives a rough state of charge, and Battle Born notes that lithium's voltage stays flat through most of the discharge. A shunt measures the current going in and out, which is how a monitor works out what is left.
Victron's wiring guide: the shunt usually goes in the negative cable, as the last part before the battery or battery bus bar, with every load and charger connected after it. It must be rated for the most current the system can draw.
Some batteries measure this themselves. Victron notes that smart batteries that generate their own state of charge remove the need for a shunt, and Redodo's Bluetooth batteries report voltage, current and capacity in its app.
If yours doesn't, the Redodo 500A Battery Monitor with Shunt was $92.99 the day we checked.
Redodo 500A Battery Monitor with Shunt
Counts every amp in and out so the percentage you see is real, not a voltage guess.
$92.99$99.99
See at Redodo (opens in a new tab)How long does it take to charge a 100Ah lithium battery?
Short answer
About five hours from empty at the 20 A that Redodo recommends for its 100Ah battery (100Ah divided by 20 A). A bigger charger is faster: Redodo allows up to 100 A of continuous charge current on the same battery. It takes longer when the RV's loads are using part of the charger's output, a point Progressive Dynamics makes about its converters.
The same math works for any source: amp-hours to refill divided by charge amps. Solar and alternator charging vary through the day, so the planner works in watt-hours per day instead.
For your own rig: Charging time from solar, driving and shore power (planner)
Safety first
Fuse every positive wire as close to the battery or bus bar as you can, and use the wire and fuse sizes from a standard table, not a guess. Boats should follow ABYC E-11; anything that touches 120/240 V AC should follow the NEC. Have a qualified installer check any 120/240 V AC or shore power work.
Run the power planner
Battery, solar, charger, inverter, every wire and fuse, and a priced parts list.
Draw your wiring
Drag parts onto a diagram and get gauge and fuse labels on every run.
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