Common questions and answers about LiFePo4 lithium batteries:

IS THE LiFePo4 BATTERY SAFE?

Lithium batteries with LiFePo4 composition are extremely safe today, at least on a par with normal lead-acid, provided they are used with due care, just as any accumulator should be used. Even a normal lead accumulator can create very serious problems if used incorrectly, without fuses and in risky conditions.

Modern LiFePo4 batteries incorporate a BMS (Battery Management System) mandatory for this type of battery: it governs the charge and discharge, regulating voltages and currents, protects against short circuits, checks the operating temperature, automatically balances the charges and discharges of the various cells.

I HAVE HEARD ABOUT HOME MADE LiFePo4 BATTERIES.

Today it is possible to buy the various components and build a high-performance battery, spending less than a well-known brand.
Choosing a battery to compose, i.e. without its dedicated BMS, may perhaps be a cheaper choice, but certainly less safe especially if you do not have the appropriate knowledge: the currents involved are very high and installation in a camper represents an additional source of risk. For this we recommend buying LiFePo4 batteries with integrated BMS, like this one, but if you have the necessary skills, it can be a valid alternative.
Perhaps, first compare the final prices, because often the difference is very small.

WHAT ARE THE REAL ADVANTAGES OF THESE BATTERIES?

Using a LiFePo4 can change the experience of "electric" life on the Camper.
First of all, their low internal resistance allows them to be charged with very strong currents.
If you have an energy source, such as an alternator with a 100A Battery to Battery Charger, for example, you could charge the LiFePo4 from scratch in just one hour of travel (if it is a LiFePo4 with a 100A BMS charge), or in thirty minutes if you had already charged it to 50%. A huge plus.
Conversely, the usable capacity: it is possible to request the same current from the battery, without problems of voltage sag, almost up to 100% discharge.
This means that you can use a power inverter without any problems (air conditioner, coffee machine, hair dryer, etc.)
Another huge advantage, the life cycles. a normal AGM after 500 cycles begins to show signs of "fatigue", while LiFePo4 last up to 10 times as much (5000 cycles with 50% depth of discharge)
To all this, we must add the weight, a good 100Ah AGM weighs about 30 kg, a LiFePo4 about 11/13 kg.

CAN I CHANGE MY LEAD BATTERY WITH THIS, WITHOUT MAKING MODIFICATIONS?

Theoretically, the answer is yes, but only theoretically.

The charging voltage must be between 13.6 and 14.6 and in the absence of a suitable Battery to Battery charger (DC/DC Charger), the charge may not complete, depending on the vehicle's charging voltage.
Or worse, with the alternator's constant fixed voltage (generally over 14V) once the charge is reached, the alternator continues to supply voltage and current, with the risk of ruining it. The integrated BMS could protect the battery by disconnecting it, with the related problems that could happen: PV regulator without the buffer effect of the battery, "spikes" that are sent to the 12V system.
Suitable devices to complete the system can be VICTRON (the most common) or Sterling, or Votronic or in any case a good DC/DC charger.

As a precaution, it is not advisable to connect a LiFePo4 directly to the alternator also due to the risk of damage to the vehicle's electrical system caused by the "spikes" which can be generated in the event of intervention by the BMS, as indicated above.

The choice will also be calibrated on the current we want to use from the alternator.
If your alternator is rated at 90A, for example, we recommend using a maximum 30/60A DC/DC charger.
Obviously it is possible to use DC/DC Chargers with lower power, simply the charging time will lengthen proportionally:

Examples:
100A DC/DC: 100% charge of a 100Ah LiFePo4 with BMS with 100A charge capacity in 1 hour
50A DC/DC: in 2 hours it charges a 100Ah LiFePo4 to 100%
25A DC/DC: in 4 hours it charges a 100Ah LiFePo4 to 100%

Using a CD/DC Charger with power that is not suitable for the alternator could overload the latter with consequent damage to it. It is recommended not to exceed 50/60% of the alternator power (100A alternator, maximum 60A DC/DC Charger)

HOW CAN I RECHARGE THIS BATTERY?

LifePo4s are charged with essentially the same sources as normal lead-acid batteries, but with different parameters.
For this, the solar regulator must have the preset configuration for LiFePo4 lithium batteries, or the correct parameters must be entered manually in the solar regulator.

Same speech for the 220V charger, it must have the setting for this type of battery.
If the LiFePo4 (Lithium) setting is not available the old charger CANNOT BE USED.

These are the typical values to be set on the solar controller manually, if there is no automatic configuration for LiFePo4:
Absorption voltage: 14.2 Volts
Absorption time: as little as possible, zero is better
Equalization: if possible, delete this function, if not possible, set 14.4V
Bulk voltage: 14.0-14.6V.
Float voltage: 13.5V (in case of prolonged stop with recharging, lower to 13.3/13.4)
High Voltage Disconnect: 14.8V
Functions such as desulphation and temperature compensation will then be eliminated.

CAN I CONNECT THE BATTERIES IN PARALLEL?

These batteries are designed to be connected directly in parallel with each other (only with batteries of the same type and series), with the maximum number indicated in the specifications. PARALLERATORS, SWITCHES OR THE LIKE SHOULD NOT BE USED.
The parallel is possible only with batteries purchased together and connected at the same time because over time the characteristics of the accumulator change causing a passage of current from the newer battery to the older one.
It is not recommended to exceed the limit of batteries in parallel indicated in the specifications.

WHAT ELSE SHOULD I KNOW?

All LiFePo4 batteries deliver current up to the maximum allowed by its BMS.
So in the case of use with an inverter, if the limit is 100A, approximately 1100/1200 Watts can be absorbed by the inverter.

LiFePo4 batteries do not need chargers / maintainers: if it is not used it is always a good idea to disconnect it with a battery switch and avoid it being left completely discharged for long periods.

You must not use desulphators, devices designed only for lead-acid batteries

It is not advisable to keep them always 100% charged for long periods, unlike lead batteries, this conduct can damage them.

One of the characteristics of LiFePo4 is that it always delivers the same energy both at 100% and at 30% of its charge: therefore having them always fully charged does not always make sense, they have to charge and discharge.

Absolutely, do not use parallel controllers (Imanager, BDS180, etc.) not dedicated to LiFePo4 batteries and absolutely not connected in parallel batteries of this type with others of a different nature.

IN SUMMARY, WHAT IS NEEDED AT A MINIMUM TO REPLACE MY AGM/LEAD WITH A LiFePo4?

To make the "jump" you will need at least:
- A DC-DC charger, i.e. the device that takes the current from the alternator and "adapts" it in voltage and current to the LiFePo4
- A 230V battery charger with setting for LiFePo4
- A solar controller with setting for LiFePo4
- Fuses to be mounted on the battery
Depending on the Camper system, relays may be required to manage the charge with the engine running
(The DS300 control unit, mounted on many Campers for example, requires a relay to leave the system, when running, only the charge from the alternator excluding the battery which would otherwise be connected to the alternator by skipping the DC-DC)

Optional:
An ENERGY METER to check the charge and discharge of the system