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BMS4S out of stock again! Orders can be taken, but no deliveries until sometimes September-October.


All prices are excluding VAT. For orders within EU a VAT of 25% will be added. Here is what we can deliver:


The basic kit:

The basic package contains:

1: a BMS4S circuit board and a box to mount it in.

In addition to this, you may also need

2: a Bluetooth radio for communication with BMS4S,

3: an adapter for USB to serial connection to BMS4S,

4: a 12 V LED for low SoC early warning,

5: a buzzer/alarm,

6: or a buzzer/alarm for panel mounting,

7: a pushbutton for temporary charge level setting,

8: one or more temperature sensors.


Product Price USD
base package 200
temp sensor 12
push-button 10
12 V LED 10
Bluetooth adapter 17
USB adapter 17
buzzer 15

This is how you order:

1 you send a mail to order<at> and list the items you want. Example: I want one basic kits and one item of each: 4, 5, 6 and 7. My delivery adress is: Andrew...

2 if you describe what equipment you have etc. we can supply you with a shopping list proposal of what LFP cells, relays and other equipment you need for your installation, this is of course not necessary.

3 when we know how much the shipping will be (normally around US $ 30) and an estimated delivery time (normally 3-7 days)  we will send an invoice of the total amount to your mail

4 if you then pay we will send an order confirmation

5 you will get your goods


Beside these items you will need LiFePO4 cells, terminal connectors, chargers, relays and wires. We recommend that you buy these from a source that guarantees top quality products. We have good experience from here:

Other sources we have heard good things about, but have no own experience from is: and

There are of course a lot of other good sources out there, but there are also a lot of bad ones. So if you find LiFePO4 cells to a price that is "too good to be true", think twice before you place your order...


Below is an example of what you need to replace a house bank of 3 90 Ah LA batteries and where you can get the equipment. Since you can use almost all of the capacity in LFP cells, and that LA batteries looses capacity fast and shall never be discharged below 50% SoC, it is normally enough to install around half the installed LA capacity when switching over to LFP.

Amount Item Supplier USD/item USD
4 WB-LYP130AHA LiFeYPO4 (3.2V/130Ah) 165 660
3 Terminal Connectors for LYP130AHA 6 18
1 DC Power Latching Relay 100A, Coil 12V 12 12
1 Charger 3.6V/5A for LiFePO4 cells 30 30
1 BMS4S 200 200
1 temperature sensor 10 10
1 push-button 10 10
1 12 V LED 10 10
1 bluetooth 17 17
1 USB-adapter 17 17
1 buzzer 15 15
1 Wires, terminals etc  local dealer 100 100
Total USD:     1099