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REC Active BMS

REC Active BMS

Regular price $329.95 USD
Regular price Sale price $329.95 USD
Sale Sold out
Shipping calculated at checkout.

The REC Active BMS is designed for 12V systems, providing advanced battery management with 2A active cell balancing. It's compatible with Victron, WS500, and supports a variety of Lithium-Ion chemistries. Key features include IP65 enclosure, precision measuring, temperature sensors, shunt current measurement, and extensive communication options including RS-485 and CAN.

14 in stock

REC BMS Product Line Overview

Store Reviews

Great customer service

Rated 5 out of 5 April 5, 2022

Rick was wonderful setting me up with parts for a project for a film studio. He was able to provide quick advice for a part that wasn’t functioning as expected and recommended a replacement part quickly. I’m happy they are carrying the REC BMS and have them in stock! It’s a very solid system that’s easy to interface with!

Avatar for Jeff Jeff

Response from Off Grid & Marine Energy Systems

Thanks for your kind words! I am glad we were able to help get you fixed up and running.

Easy to use website

Rated 5 out of 5 March 25, 2022

Fair prices for what I needed and easy to make sure I got all the accessories I needed due to the format of the product page.

Avatar for Brian Brian

Response from Off Grid & Marine Energy Systems

Thanks Brian, we are working now to make it easier to find the right product for your application.

Great customer service!

Rated 5 out of 5 January 10, 2022

OGSS was there to answer all of my pre-order questions and their communication response time is top notch. Great people to work with and I’ll be ordering from them again in the future.

Avatar for Matt Digan Matt Digan

Response from Off Grid & Marine Energy Systems

Thanks Matt!

REC-Wifi unit inoperable

Rated 3 out of 5 November 3, 2021

I purchased the rec-wifi on the advice of and the REC website. I could not log into the wifi unit referencing the product manual. I found many individuals were having the same problem through a web search. In the end, I purchased the pc software which allowed for me to change the parameters associated with my specific system. My understanding is that one cannot do what with the wifi system. The touch pad also just displays information, it does not allow one to alter the bms parameters.

Avatar for Tom McDonagh Tom McDonagh

Response from Off Grid & Marine Energy Systems

Hi Tom, sorry you had issues with the WiFi module. Early versions did have some issues but not recently and your situation seemed unusual. Hopefully Tine at REC was able to get your WiFi working for you in the end. The WiFi module, when working, will actually provide all needed functionality but you are correct, the LCD screen is for viewing only.

Excellent Service and quick delivery!

Rated 5 out of 5 September 27, 2021

Had to clarify a few things before we placed the order, Rick was very responsive and helpful. Will definitely buy again in the future.

Avatar for Kilroy Bus Kilroy Bus

Response from Off Grid & Marine Energy Systems

Thanks and glad we could help. After a few hiccups our new warehouse and shipping team is really coming together!

Definitely buy all of your gear from Rick

Rated 5 out of 5 September 17, 2021

Five stars all the way. Rick was very helpful throughout the process, and I’m already telling people to get their gear from him and OGSS. You can’t go wrong!

Avatar for Van Gogh (van build name) Van Gogh (van build name)

Response from Off Grid & Marine Energy Systems

Thanks for the kind words! Glad we got you sorted and thanks for your testing and feedback!

Efficient and prompt

Rated 5 out of 5 May 5, 2021

Recently purchased wakespeed alternator and was impressed with the prompt service and order fulfillment. The unit was well packaged and using USPS for delivery here in Western Canada saved me the typical huge customs brokerage fees that ups and fedex charge.

Avatar for Phil clatk Phil clatk

Great Support

Rated 5 out of 5 April 3, 2021

Purchased REC 16s BMS from Off Grid Marine Energy systems and did not purchase the current sensor wiring harness, I emailed asking if it was meant to be included and they threw it in for free. When I had questions about shipment they were answered in a timely and polite manner.

Avatar for Zak Crawford Zak Crawford

Great service and support!

Rated 5 out of 5 March 29, 2021

Trying to get an SMA SI to talk with a BMS has been a Challenge. Rick was a great help in getting me there.

Avatar for Bob Bob

extremely fast delivery

Rated 5 out of 5 March 17, 2021

Outstanding fast service – in answering questions as well as in shipping to Europe – very impressive indeed!

Avatar for Robin Robin

Awesome service and support !

Rated 5 out of 5 March 1, 2021

Rick gave us just the best possible service while setting up our LiFePO4 system with the WS500.
Thank you

Avatar for Fred Fred


Rated 5 out of 5 February 8, 2021

Recommended seller. Great pre AND POST sales service. Thank you Rick and everybody on your team. Cheers Chris

Avatar for Christian Christian

Great Service

Rated 5 out of 5 October 10, 2020

I am on a cruising boat currently in Aruba, and hoped to upgrade our charging system here due to favourable customs duties on imports. My purchase went awry when informed me they couldn’t deliver the alternator I ordered. I couldn’t find a replacement at this time so I had to cancel my order for a WS500 from Off Grid (I had placed the order right after ordering the alternator). Rick was very helpful in trying to find another source for the alternator, and providing information on what I would need to install it. When the only option turned out to be a size up in amperage (that I couldn’t use) and $$$ I balked. Rick refunded my money without hesitation. I will eventually get a WS500 from Off Grid, when Balmar restocks and when I know where I will be in a months time.

Avatar for Robin S/V Toboggan Robin S/V Toboggan

Response from Off Grid & Marine Energy Systems

Thanks for your kind words Robin, I am just sorry we couldn’t pull it together for you. We will keep a watch out for availability and hopefully we will get you fixed up in a few months.

A big shout out

Rated 5 out of 5 March 30, 2020

A big shout out for Rick Bell of
His knowledge and patience helping a novice install and commission a Wake Speed WS500 after a lightening strike wiped out the old charging system (alternators, Balmars, wiring the lot) has been refreshing in this day and age.
I am very grateful to him (especially during this Covid-19 shutdown)and the other technicians from offgridsoftwaresolutions for helping me problem solve a charging issue caused by a declined magnetic core.
A simple fix if you know what you are doing but I clearly don’t so very frustrating for him but thank you from me.

Avatar for Richard s/v Por Dos Richard s/v Por Dos

Response from Off Grid & Marine Energy Systems

Richard, we are just glad you got everything working. It can be hard to remotely troubleshoot, but your detailed testing and pictures really helped the process!

Love my new WS500's

Rated 5 out of 5 January 22, 2020

I’ve used the WS500 Configuration tool to setup my dual WS-500 regulators and to tune and monitor things the first few months. I love being able to see the alternator temperature along with the output all on a graph. This software also helps a ton in configuring the WS-500 which has a wealth of options, but can be overwhelming to configure at the command line. The WS500 Configuration software makes that much easier. You can read all about it in my full review at

Avatar for Steve Steve

Response from Off Grid & Marine Energy Systems

Steve, thanks for your support and the detailed review in SeaBits. This should help others make an informed decision!

View full details

Build your system as a kit and save!  Active BMS Kit Builder

Active BMS for 12V Systems. Victron and WS500 compatible. Be sure to include the custom wiring harness with cell & relay wires, CAN and RS485 cables, temp. sensor wires (2), and remote ON/OFF switch, unless you are just replacing a unit or doing a custom installation.

Designed to provide unsurpassed battery management in 12 volt systems, the REC Active BMS delivers 2A cell equalizing with active balancing and synchronous flyback bidirectional energy transfer from cell to pack and pack to cell.


  • Li-PO, LiFePO4, LiFeYPO4, LiCoO2, LiMnNiCo and LiMnO4 Lithium-Ion chemistry
  • 4 series connected cells per unit
  • high efficiency 2 A bi-directional active balancing (pack to cell and cell to pack)
  • IP65 protection enclosure, AMP 35 pin water resistant connector
  • 2 – 5 V measuring range, 2 mV accuracy
  • up to 2 digital temperature sensors
  • shunt current measurement
  • robust and small design
  • galvanically isolated RS-485 and CAN communication protocol
  • two programmable fused relay output
  • two programmable fused digital output
  • ON/OFF switch
  • LED and buzzer status indication
  • bootloader
  • error LED + buzzer indicator
  • PC user interface for changing settings, data-logging and firmware update
  • compatible with REC LCD touch display for monitoring
  • compatible with Victron inverters for solar applications
  • Seamless CANbus integration with Wakespeed’s WS500 Advanced
    Alternator Regulator


  • low power microcontroller RTC
  • custom made software with bootloader for remote firmware update
  • 60 mW self power consumption with disabled CAN and all outputs

RS - 485 communication:

  • galvanically isolated RS-485 communication
  • Slave configuration
  • RS-485 driver primary side supply is activated with Master connection to save energy consumption
  • fully compatible with REC LCD touch display and PC user interface BMS Master control

Active Balancing:

  • 2A cell equalizing with active balancing with synchronous flyback bi-directional energy transfer: cell to pack and pack to cell
  • top side and bottom side balancing prolong the cycle duration due to the weakest cell


  • two fused relay outputs with NO and NC pins
  • two fused galvanically isolated/non-isolated digital outputs with PWM option

Galvanically Isolated CAN:

  • galvanically isolated CAN
  • 100, 125, 250, 500, 1 MHz bit-rate selection
  • message programming
  • disable option

Complete wiring of ABMS connector:

  • 5 cells wires (l = 1m)
  • relays, digital output wires (l = 0.5m)
  • RS485 cable (l = 0.5m)
  • CAN cable (l = 0.5m)
  • remote ON/OFF switch (l = 1m)