Best LiFePO4 batteries for ham radio
Flat voltage under load is the whole reason, not the weight saving.
The short answer
A 20 Ah LiFePO4 battery runs a 100 W HF radio for a full afternoon at normal duty cycles, and 100 Ah covers a field weekend or an outage. The real advantage over lead acid is not weight: it is that LiFePO4 holds voltage nearly flat as it discharges, so the radio makes full power until the battery is genuinely empty.
- Portable size
- 20 Ah
- Base backup
- 100 Ah
- Usable capacity
- Near 100 percent
- Lead acid usable
- About 50 percent
- Cycle life
- 2000 plus
- Needs
- LiFePO4 charger
The reason LiFePO4 took over portable amateur radio is not the weight, although a third of the weight of lead acid is welcome. It is the discharge curve. A lead acid battery sags steadily as it empties, so a 100 W radio starts making less power well before the battery is flat. LiFePO4 holds close to 13 V for most of its capacity and then drops quickly at the end.
That changes the arithmetic. A 20 Ah lead acid battery gives you perhaps 10 Ah you would actually want to use before voltage sag hurts your transmit power. A 20 Ah LiFePO4 gives you close to 20 Ah, which is why a smaller LiFePO4 replaces a much larger lead acid battery.
Everything here is researched from published specifications and verified owner reports rather than from testing we have not done. Work out your own runtime with the battery runtime calculator.
How long a battery actually lasts
The number that matters is average current, not transmit current, because you spend most of any operating session receiving. On SSB with normal back and forth you might transmit a quarter of the time, and on FT8 rather more with a lower peak.
Rough runtime for a 100 W HF station, researched from published draw figures
| Battery | Casual SSB | Steady SSB | FT8 / digital |
|---|---|---|---|
| 12 Ah LiFePO4 | 4 to 5 hours | 2 to 3 hours | 2 hours |
| 20 Ah LiFePO4 | 7 to 9 hours | 4 to 5 hours | 3 to 4 hours |
| 50 Ah LiFePO4 | 18 to 22 hours | 10 to 12 hours | 8 to 9 hours |
| 100 Ah LiFePO4 | Multi-day | 20 to 24 hours | 16 to 18 hours |
Casual assumes about 20 percent transmit time, steady about 40 percent. Digital modes have a lower peak but a much higher duty cycle, which is why they are harder on a battery than the peak figure suggests.
What LiFePO4 needs that lead acid did not
- A LiFePO4-specific charger, or a charger with a LiFePO4 mode. A lead acid charger uses the wrong voltage profile and will not charge it properly.
- Respect for the built-in battery management system. It protects against over-discharge and over-current by disconnecting, so a battery that appears dead may simply have tripped.
- Cold weather care. LiFePO4 should not be charged below freezing, and many BMS units will refuse. Discharging in the cold is fine.
- Fusing, exactly as with any battery. A LiFePO4 cell can deliver enormous short-circuit current.
- It does not need the float charging discipline lead acid needed, and it does not degrade from being stored partly charged.
Three tiers
Two sizes that cover most amateur use
Portable operating and station backup are genuinely different problems.
Parks, summits, field days and a go-bag
GOLDENMATE
GOLDENMATE 12V 20Ah LiFePO4 battery, 2 pack
Light enough to carry with the radio and big enough for a real activation. As a two pack it also solves the charge rotation problem, which is the practical annoyance of single-battery portable operating.
- Capacity 20 Ah
- Use Portable
Tradeoff
Not enough for extended base station backup. If the goal is running the shack through an outage, this is the wrong size.
Running a base station through an outage, or a full field weekend
SUPER EMPOWER
SUPER EMPOWER 12V 100Ah LiFePO4 deep cycle battery
Group 24 case and 100 Ah, which is enough to keep a station on the air for a day of solid operating or several days of casual listening. This is the battery that makes an emergency station real rather than theoretical.
- Capacity 100 Ah
- Case Group 24
Tradeoff
Heavy and expensive relative to the portable option. Overkill for anything you intend to carry.
Common questions
Questions people ask about this
Why is LiFePO4 better than lead acid for radio?
Because it holds its voltage nearly flat under load. A lead acid battery sags as it discharges, so a 100 W radio starts producing less power long before the battery is empty, and you can only safely use about half the rated capacity anyway. LiFePO4 gives you almost all of its rated capacity at close to full voltage, so a 20 Ah LiFePO4 replaces a much larger lead acid battery.
What size battery do I need for a 100 watt radio?
20 Ah for an afternoon of casual operating, and 50 to 100 Ah if you want a full day of steady operating or backup for an outage. Digital modes are harder on a battery than voice despite the lower peak power, because the duty cycle is so much higher.
Can I charge LiFePO4 with my lead acid charger?
No. The charge profiles are different and a lead acid charger will not charge it correctly, and depending on the charger may damage it. Use a LiFePO4 charger or one with a selectable LiFePO4 mode. Many solar charge controllers also have a LiFePO4 setting.
Is it safe to leave a LiFePO4 battery connected to the radio?
Yes, with proper fusing. LiFePO4 is the most thermally stable of the common lithium chemistries, which is exactly why it took over from lithium-ion in this application. Fuse it close to the battery regardless, because the short-circuit current available from any healthy battery is enormous.
Do these work in cold weather?
Discharging in the cold is fine, with somewhat reduced capacity. Charging below freezing is not, and most batteries with a built-in BMS will refuse to do it, which is a protection rather than a fault. For winter field operating, charge indoors and take the battery out already full.
Keep going
Related on this site
- Battery runtime calculator Runtime from your own draw and duty cycle
- LiFePO4 against lead acid The full comparison
- Portable power guide Putting a field power system together
- Portable field kit build A complete kit with the battery in it
- Home backup battery sizing The same arithmetic for a house rather than a field station
Keeping your own cut lengths, SWR sweeps and exposure record? The Station Build & Antenna Planner is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.
Disclaimer Researched guidance for planning purposes, not professional engineering, electrical or legal advice. Antenna work, RF exposure, mast and tower work, grounding and battery handling all carry real risk that depends on your specific site and installation. Verify anything safety-critical against current FCC rules, the National Electrical Code and the manufacturer's own documentation, and hire a professional where the job calls for one. We research equipment from published specifications, regulatory documents and verified owner reviews rather than claiming hands-on testing we have not done.