Switching from AGM to lithium: What do you need?

Short answer

Often more than the battery. Check three things: that your charger has a LiFePO4 program, that you charge from the vehicle through a DC-DC charger, and that the battery can deliver enough current for your biggest loads. The checklist shows what you need and what it costs in total.

Updated 27.10.2026
6 min read
Sources
Checklist ↓

Checklist in this article Get your list and total price Figures from datasheets and our product data. Formulas and sources are shown with the result. Open the checklist →

The charger: does it have a LiFePO4 program?

Today I have a 240v charger that charges both starter and leisure, but it doesn't have lithium charging

User on the Dansk Bavaria Klub forum

A lead-acid charger charges to a higher voltage than lithium should get, and some have a "recondition" stage that goes even higher.

14.4–14.7 VLead-acid programs on a Victron Blue Smart charger 3

15.8–16.5 VRecondition stage for lead-acid on CTEK and Victron chargers 5 3

14.6 VThe most that four LiFePO4 cells can tolerate: 4 × 3.65 V 6

14.2 VVictron's recommendation for their 12.8 V lithium – without temperature compensation 1

If the charger has a lithium or LiFePO4 program, keep it and select that program. If it only has lead-acid programs, replace it. Our 12V 100Ah is charged at 14.6 V 15.

Charging while driving: use a DC-DC charger

where lifepo4 100ah can take 100a and that will burn out my alternator

User on the Dansk Bavaria Klub forum

The concern is valid. Lithium has very low internal resistance and draws far more current than lead-acid. Victron writes that you must take care not to overload the alternator 1. The result can be an overheated alternator 10.

Newer vehicles make it harder. In Euro 6 vehicles, the vehicle controls the alternator itself, and the voltage varies between approx. 12.5 and 15 V. The leisure battery can then end up undercharged 8. The D+ signal is also often missing in Euro 6 vehicles 9.

The solution is a DC-DC charger. It limits the current so the alternator isn't overloaded, and it detects by itself when the engine is running 9 8.

Can the battery power your largest loads?

Our batteries have a built-in BMS that limits how much current they can deliver 15. Compare this with your largest loads:

Device	Current	Source
Mover, Truma Mover XT	25 A on average · 150 A max.	Truma 11
Bow thruster, Vetus BOW3512E	220 A	Retailer data 12
Inverter	watts ÷ 12 V	e.g. 2,400 W = 200 A 13
LithiumPro 12V 100Ah	150 A continuous · 200 A peak	Our product data 15

How long a battery can sustain its peak current is not stated. If you are close to the limit, ask us.

Charging in frost?

The limits differ: Victron's lithium may only be charged from +5 °C 2. EVE's cell may be charged down to −10 °C, but with greatly reduced current – and not at all at −10 °C 6. Victron's Blue Smart charger states: do not charge lithium below 0 °C 4.

If the battery needs to be charged in winter, our batteries are available with intelligent heating control. It only heats at sub-zero temperatures, and only while the battery is charging 16.

Fuses and cables

The fuse goes in the positive cable, and there must be a main fuse. Lithium can deliver a very high short-circuit current, so at least one fuse must be able to break it 13. The cable must be thick enough for the current – Victron recommends no more than 2.5% voltage drop 13.

How much charge is left?

Our batteries have a Bluetooth BMS, so you can monitor them in the app 15. If you want to see it on a display or with a battery monitor, a shunt measures the current in and out. All loads and chargers must be connected after the shunt 14. If you already have a battery monitor, switch it to lithium: Victron recommends Peukert 1.01 and a charge efficiency of 98% 14.

Checklist and total price

Answer the questions. The list shows what you need, what you can keep – and the price of what you choose.

The checklist requires JavaScript. In short: a charger with a LiFePO4 program, a DC-DC charger if you charge while driving, a fuse in the positive cable and a battery that can deliver enough current.

What you can often keep

A charger with a lithium program. Select the program – e.g. Li-ion on Victron's Blue Smart 3.
A solar charge controller that can be set to LiFePO4. This applies to all charging sources 7.
Your battery monitor – once it has been switched to lithium 14.

Conclusion

Replace the battery – and check three things

The charger must have a LiFePO4 program. If you charge while driving, you need a DC-DC charger. And the battery must be able to deliver enough current for your largest loads. If you are unsure about your vehicle or boat, ask us before you buy.

Ask us Calculate how many Ah

Sources

Victron Energy: Manual – Lithium Battery Smart – charging voltage 14.2 V and 13.5 V float, no temperature compensation, low internal resistance and risk of overloading the alternator, fuse on the positive side, no built-in state-of-charge measurement.
Victron Energy: Datasheet – Lithium Battery Smart 12.8 V and 25.6 V – 2,500 / 3,000 / 5,000 cycles at 80 / 70 / 50% depth of discharge to at least 80% capacity, 12.8 V nominal voltage, charging from +5 °C, capacity in the cold and requirement for an external BMS.
Victron Energy: Manual – Blue Smart IP65 charger – charging programs: lead-acid 14.4–14.7 V and recondition 16.2–16.5 V; the Li-ion program 14.2 V without recondition.
Victron Energy: Manual – Blue Smart IP65 charger, features – Li-ion program for LiFePO4; do not charge lithium if the battery is below 0 °C.
CTEK: Manual – CT5 Powersport Lithium – the lead-acid program is "Only for lead-acid batteries"; the recond stage goes up to 15.8 V; separate program for LiFePO4 at 14.2 V.
EVE Energy: Specification LF105, version E (2023) – cell: 4,000 cycles at 25 °C and 2,000 at 45 °C to 80% SOH; max. 3.65 V; charging from −10 to 65 °C with greatly reduced current in the cold; at least 85% capacity at 0 °C and 75% at −20 °C; storage at 15–40%. The document is hosted by a retailer.
Büttner Elektronik: Basiswissen – Lithium-Ionen-Batterien – all charging sources (charger, booster, solar charge controller) must be configurable for LiFePO4; many AGM batteries are charged to 14.7 V.
Victron Energy: Manual – Orion-Tr Smart DC-DC charger – Euro 6 vehicles have a smart alternator; the voltage varies between approx. 12.5 and 15 V; risk of an undercharged leisure battery.
Victron Energy: Manual – Orion XS DC-DC charger – controlled charging protects the alternator from overload with lithium; current limiting; the D+ signal is often missing in Euro 6 vehicles.
Victron Energy (2019): Careful alternator charging of lithium – risk of an overheated alternator and damaged diodes when a BMS disconnects.
Truma: Mover XT – technical data – average current draw 25 A and maximum 150 A.
Defender (retailer): Vetus BOW3512E – current draw 220 A at 12 V. Retailer's data – Vetus' own manual could not be retrieved.
Victron Energy: Wiring Unlimited – current = power ÷ voltage; fuse in the positive cable and a main fuse; at least one fuse must be able to break the lithium battery's short-circuit current; no more than 2.5% voltage drop.
Victron Energy: Manual – SmartShunt – measures the current in and out; all loads must be connected after the shunt; for lithium: Peukert 1.01 and charge efficiency 98%.
LithiumPro: Product data for our batteries (e.g. 12V 100Ah) – Ah, max. continuous and peak current, charging current, charging voltage 14.6 V, Bluetooth and warranty are listed on each product page.
LithiumPro: Intelligent heating control – only heats at sub-zero temperatures when the BMS detects charging; not suitable for the 12V 50Ah "world's smallest".