There are questions that customers repeatedly ask us. Maybe you have a similar question? That is why we have clearly written these frequently asked questions below on this page. The answer will be shown after clicking on a specific question.

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We have in stock ready most products to ship. However, there are cases when it is necessary to wait a few days or weeks for the order. This mainly applies to AkuSets and AkuBoxes that we assemble for you by ourselves.

In orders with a large number of products it is possible that it is necessary to wait for restocking. But you will find out everything by email or by phone, either based on your order or if you contact us at

ℹ️ You can also find out more information about the purchase on the page How to shop.

Payment by bank transfer - on invoice, is the most used payment method with us. When you choose it, we will start working on it immediately after receiving your order. You don't pay us anything until we have everything ready for you. We will send you an advance invoice only when the complete order is ready to be shipped.

ℹ️ You can find more information about payment options on the page Shipping and payment.

We do not offer cash on delivery above the limit of CZK 50,000. This is due to high fees of shipping companies with such large amounts. This would significantly increase the price of postage. Don't worry, even when paying on an invoice, which we recommend as an alternative to cash on delivery or payment by card, you don't pay anything in advance. You will receive the advance invoice only when we have your order completely ready for dispatch.

In short: yes and yes. Each lithium cell, which you can find in our e-shop, is brand new. From the manufacturer - straight to you. Nothing to add to that. The quality of our batteries is guaranteed by the manufacturer himself. Our suppliers (CATL, REPTCALB and others) are industry leaders and their products are purchased by companies such as Volkswagen, Apple, Tesla, etc. It is always about “Grade A” or “Grade B” batteries, i.e. the highest possible quality designation. They are for other diagnostic tests and quality controls, which we carry out ourselves.

All our goods are subject to legal requirements warranty period of 24 months. However, remember that regular use of batteries gradually reduces their lifespan, the so-called cyclic decline. Of course, this is not covered by the warranty. When you use a new battery, it doesn't have the life of a new battery after a year. That makes sense. :)

Please note that specifically lithium cells can be protective packaging different from the photo product. The packaging protects the cell from damage, so small scratches are possible on it. Likewise, the color of the packaging may be different.

Anyway, these cosmetic defects have no effect on functionality and safety, therefore they are not a reason to recognize the complaint. Of course, you have the right to make a claim if there was an error in the order you sent and you inadvertently received other goods. Likewise for damaged goods.

ℹ️ Read more here: about complaints.

We are focusing on lithium batteries because there are amazing developments in their technology. We liked lithium batteries for their high energy efficiency and at the same time their significant lower weight than lead-acid batteries.

LiFePO4 batteries has advantages in higher resistance, lifetime and safety operation. For example, they also have a larger operating temperature range. On the other hand, the benefits are that Li-Ion batteries have a higher energy density and lower weight. In numbers, you can see the difference at first glance, for example in the voltage when the accumulator Li-Ion has 3.7 V and LiFePO4 it has 3.2 V.

If you are going to assemble your own battery from individual lithium cells, you will need connection accessories. Choose a suitable number and type of jumpers, or and pads. These accessories are not included in the price of articles, as its selection is individual.

For concepts of BMS and balancer there is often confusion among customers. Probably because some BMS can - depending on the specific type - also contain a balancer. But the balancer is not a BMS.

Active balancers only provide equalization of energy in the battery assembly. BMS is a battery management system, so they provide information about the state of the battery, check and adjust its functions and protect, for example, against overvoltage, undercharging, short circuits, etc.

At the first – initialization charging– the battery is charging with a current of no more than 1C to a voltage level corresponding to the specification of a particular battery. Initialization must be done for all the cells needed to assemble the accumulator. These subsequently among themselves, in parallel connection, we balance for 24 hours.

About the first 5 cycles, prevent rapid discharge of the battery to minimum capacity, as well as rapid charging. In this way, you contribute to the long cycle life of the batteries. You can also extend this with batteries compliance with the operating voltage, which we recommend in the range of 3.15 V to 3.45 V.

Currently we do not provide battery reconditioning.

Service life LiFePO4 batteries can generally reach over 4000 cycles. With proper use, it can be expected that even during daily charging and discharging last at least 10 years (4000/365=10,96 let).

Here it depends on size, capacity and charging power. An example can be a 48V battery with a capacity of 100Ah, to which you have 20A the charger. 100/20=5 hours of charging.

On-grid - supplies to the network. Off-grid - does not supply to the network. Hybrid inverter supplies to the grid and works in off-grid mode. If you come across the term combined converter, then it is a connection between the inverter and the MPPT or PVN regulator.

It is an abbreviation of the English "maximum power point tracking". MPPT controller is tasked to continuously detect voltage and current of the PV panels in order to charge the batteries most efficiently.

The function of the MPPT charge controller is similar to the function of a gear lever in a car transmission. When the transmission is in the wrong gear, the car does not get maximum power.

This abbreviation stands for Ethylene-Tetrafluoroethylene, which is a polymer used to make quality semi-flexible solar panels. The benefits of ETFE are primarily his high resistance to corrosion, extreme resistance and durability in a wide range of temperatures. Which you cannot expect with cheap PV panels made of PET polymer.