LiFePO4, AGM, or GEL — the short answer
If you need a battery for a hybrid inverter or solar system — get LiFePO4. Period. AGM and GEL make sense only in two cases: a very tight budget (under 10,000 UAH) or a system that is rarely used (emergency power 2-3 times per year).
This article is for those who need the numbers. We compare three technologies across 8 parameters and show why LiFePO4 is cheaper long-term, even when the entry price is higher.
How the three technologies work
LiFePO4 (lithium iron phosphate)
Iron phosphate cathode, graphite anode, lithium electrolyte. Cell voltage 3.2 V. Home batteries use 16 cells in series (51.2 V). Built-in BMS monitors each cell individually.
AGM (Absorbent Glass Mat)
Lead plates, fiberglass separator, absorbed sulfuric acid electrolyte. Cell voltage 2 V. Sealed, maintenance-free. But still lead with all its limitations.
GEL
Same lead, but electrolyte is gelled. Slightly better at handling deep discharge than AGM. Fundamentally — the same lead-acid chemistry.
Comparison table
| Parameter | LiFePO4 | AGM | GEL |
|---|---|---|---|
| Cycle life | 4,000-6,000 | 400-600 | 500-800 |
| Depth of discharge | 80-90% | 50% | 60% |
| Weight (5 kWh equiv.) | 40-50 kg | 140-160 kg | 140-160 kg |
| Charge time (0→100%) | 2-4 hrs | 6-10 hrs | 8-12 hrs |
| Lifespan (daily cycling) | 10-15 years | 1.5-2 years | 2-3 years |
| Self-discharge/month | 1-2% | 3-5% | 2-4% |
| Price per 5 kWh | 18-28K UAH | 12-18K UAH | 14-20K UAH |
Total cost of ownership: where LiFePO4 wins
AGM is cheaper to buy. But after 2 years you buy another. And another after that. Over 10 years — 5 sets of AGM.
- LiFePO4: 25,000 UAH x 1 = 25,000 UAH over 10 years
- AGM: 14,000 UAH x 5 = 70,000 UAH over 10 years
- GEL: 16,000 UAH x 3-4 = 48-64K UAH over 10 years
LiFePO4 is 2-3x cheaper in the long run.
When AGM or GEL make sense
- Budget under 10,000 UAH: you cannot buy LiFePO4 for that money. AGM 100 Ah — you can
- Rare use: 5-10 times per year, AGM cycle life lasts 5-8 years
- 12V/24V systems: old inverters, but better to upgrade the inverter
Safety
LiFePO4 is the safest lithium chemistry. Thermally stable up to 270°C. Do not confuse with NMC/NCA from phones — those burn, LiFePO4 does not.
AGM and GEL do not burn but release hydrogen when overcharged. Ventilation required.
Our experience: warranty claims 2024-2025
- LiFePO4: 2 claims on 350+ sold
- AGM: 18 claims on 120 sold
- GEL: 6 claims on 40 sold
We recommend LiFePO4 batteries as the primary option.
Selection algorithm
- Budget over 15,000 UAH? → LiFePO4
- Battery needed daily? → LiFePO4 only
- Budget under 10,000 and rare use? → AGM
More on selection in our battery selection guide for inverters.
Frequently Asked Questions
Is it true that LiFePO4 catches fire?
No. LiFePO4 is thermally stable and does not burn. Other lithium chemistries (NMC, NCA) do. Do not confuse them.
AGM is cheaper — is it good enough?
Cheaper to buy, more expensive to use. With daily cycling AGM lasts 1.5-2 years. Over 10 years LiFePO4 wins by 2-3x.
Can I replace AGM with LiFePO4 in an existing system?
Yes, reconfigure the inverter — change battery type and voltage thresholds.
Is GEL better than AGM?
Slightly. 500-800 cycles vs 400-600. But the difference is 20-30%, not orders of magnitude. Both lose to LiFePO4.
What warranty comes with LiFePO4?
5 to 10 years depending on brand. Actual service life is 10-15 years.
Bottom line
LiFePO4 costs more upfront and less over time. For daily use — LiFePO4 only. For rare emergency backup on a minimal budget — AGM. See the LiFePO4 battery catalog.
