NEW – Redwing BMS for lithium battery modules
If you’re using more than 3 NMC lithium modules from repurposed Volt batteries (or Leaf or …), based on our actual experience and years of cumulative testing, we strongly recommend using a battery management system (BMS).
Why use a RedWing BMS?
Essentially the BMS will do two things. One; it will keep your cells in balance enhancing safety and pack life longevity. Two; it will add to peace of mind.
For those who with fewer modules who don’t mind checking their cell balances regularly you may not need a BMS. But if you are concerned about the ultimate in safety and battery pack longevity. We recommend using the RedWing.
Our results to date have shown the Volt cells to be impressively stable. However, we have had cells drift. One client called us when his cells went suddenly .3v out of balance. This is not safe. We quickly got him a RedWing and within a day his cells were back in “safe” range. By day 9 the cells were back within .009v. And this is the clear RedWing benefit. Keeping the cells in safe balance.
Remember, you’re going to have your pack 10 to 20 years. Amortized, the RedWing adds pennies/mo cost to your system.
Our RedWing 12S BMS for off grid Volt lithium battery packs is available for shipping now and features:
- active balancing (the best topology of 2018)
- low overhead balancing
- tested and proven (now at Version 3!)
- 10 years and more lifespan
- the best topology available 2018
- peace of mind
How does the RedWing work?
The RedWing utilizes an “active balancing” strategy. This means when a cell is too low or too high the BMS transfers energy from the high cell to the low cell. Most BMS solutions use “passive balancing.” This means they send high cell energy to a resistor which burns off the excess voltage. These can be highly wasteful. Your RedWing wins this round!
The RedWing balancers take time. There’s no need for rapid balancing in a solar energy system designed to last decades. So the RedWing transfers energy slowly. Keeping a gentle hand on the voltages. This allows for a level of natural fluctuation and reduces overhead strain and cost.
See our “Using your RedWing” post for more info.
How do I put it together?
Using our “YellowBird” harnesses, you can tie together up to 12 Volt modules. The RedWing then balances the paralleled cells. So whether you’re balancing one module at 2.125kwh, or 12 for an astounding 27kWh pack; all it takes is one RedWing to keep your pack balanced.
What about cost?
It took over one and half years for us to find the right balance on cost. Our system is not thousands of dollars. But we don’t provide cell voltage measurements, temperature, state of charge. The RedWing does the very best, most efficient, and reliable cell balancing. Period.
Our system does not cost next to nothing. There are many low cost “BMS” boards developed for the electric bike market. We tested a bunch. We researched many more. They’re called “battery murdering systems” for a reason. The lowest cost approach does not offer the reliability you need for a solar energy storage system designed to last for decades.
That’s how we came to our solution. Keep the feature list down to keep costs affordable. Keep quality as a priority.
The design comes with help from research and developers in Slovakia, Australia, Canada; with most of the work done in the USA. The chip comes from the electric bus market and was developed and built in China. Assembly is done in Ontario, Canada. BobolinkSolar would like to send a huge thank-you to all the folks who helped and supported our development process.
The modules are also available in 14S for Leaf based packs. 6S for 24v Volt systems. Contact Kelvin for ordering details. Other custom ranges are available (ie. 13S etc).
Bigger, better, stable: lithium pack technology
The new 12S RedWing allows you to actively balance Chevy Volt 48v 2.125kwh battery modules. This is as good as it gets for 2018.
A 14S model is also available for Nissan Leaf based packs. Contact your BobolinkSolar team member for pricing.