Also see our Finding Happiness with Lithium-Ion article, explaining the care and feeding of these batteries.
Quebec-based Volthium is working hard to bring lithium-ion batteries to the mainstream for battery banks. Not just for RVs and boats, but for for larger off-grid systems as well. They make various popular battery group sizes as a drop-in for lead-acid, and batteries for 19″ rackmount in a modular system that can be sized to fit any project. There is a Volthium battery for all your needs!
The Volthium 25.6-200-G8DY-CH20 is part of their Aventura series of batteries, with 24 Volt 200 Ah (5.12 kWh of stored energy). Physically this is a group 8D battery, weighing in at 104 lbs.
The 25.6-200-G8DY-CH20 is a heated battery, with an internal self-heating system and an advanced BMS that will never again make you fear our Canadian winters. The heater will automatically kick in and heat up the cells to 11 Centigrade before it starts to actually charge them, thus allowing charging even when the external temperatures are well below freezing.
These batteries have a button that, when activated, will allow charging-only. This is a great option for storage where solar charging should be enabled, while discharge by (parasitic) loads needs to be prevented.
The battery is equipped with two internal heating systems: The traditional intelligent system is activated when you charge the battery at below-freezing temperatures. The second system, called manual, is activated when you apply a voltage to the positive H+ connector (M6) of the battery. This manual heating system is not automated. If you connect the positive terminal of the battery (M8) to the H+ connector (M6) of the battery with a small piece of cable, it will start heating using the internal energy of the battery. Please note that this can drain the battery, and should be on a timer. It is meant for use in special/professional applications and works to -25C.
All Volthium batteries have UL1642 certified cells, and the best BMS on the market (powered by Texas Instruments), designed and programmed by Volthium in Quebec. This battery is designed to last!
Volthium lithium-ion batteries are true deep-cycle batteries, they can repeatedly be discharged a full 100% without damage. The battery has a build-in battery management system (BMS). The BMS allows them to be charged with regular solar PV charge controllers, with the same settings as for any other sealed battery (such as AGM batteries). The BMS also takes care of protecting the batteries from over- and under-charge, low Voltage disconnect, over-current, and automatic balancing of the cells.
Charge settings for Volthium batteries:
- Bulk/absorb = 28.4 – 29.2 Volt, with 28.8 Volt ideal
- Absorb time = about two hours, not critical
- Float = not needed, set to 27.2 Volt or less
- No equalize, or set to 28.8 Volt if it can’t be disabled
- No temperature compensation, set to 0
- Charge rate of 15 – 80 Amp is preferred for longevity, though up to 150 Amp is possible
- Charging works from -40C (-40F), discharge works fine up to -25C (-13F)
The maximum discharge rate is 150 Amp continuous, 200 Amp for 30 seconds, and 300 Amp for 1 second.
The Volthium 25.6-200-G8DY-CH20 batteries can be connected in series and parallel to increase the bank Voltage and Ah rating. Series connection of up to 2 units is allowed, making for a 48 Volt 200 Ah system. Up to 4 batteries can be connected in parallel, making for a 24 Volt 800 Ah system. Series and parallel connections cannot be mixed! So it is either a single string of batteries to make a 24/48V system at 200 Ah, or parallel connection for a 24V system at 400/600/800 Ah. Parallel strings of batteries will increase the charge and discharge rates (i.e. 300A for two parallel strings etc.). Ask us if you have any questions about properly sizing a battery bank.
Volthium batteries use LiFePO4 chemistry (Lithium-Iron-Phosphate) in prismatic cells. This is very stable and is not sensitive to spontaneous combustion, unlike laptop and cell-phone lithium-ion batteries. The cells have build-in protection for over-pressure, over-temperature, and contain a fire-retardant in the electrolyte and casing. These are very safe batteries!
Because lithium-ion batteries can be discharged to 100% DOD, and this can be done for more cycles, a smaller battery bank can suffice vs. lead-acid. Since there is no off-gassing these batteries can be mounted indoors, in any orientation.
- Zero maintenance!
- Quebec engineering
- Group 8D battery, M8 terminals
- Much lighter vs. lead-acid, just 104 lbs!
- Compatible with standard charge controllers
- No memory effect, can be left at any State-Of-Charge
- Can be discharged 100% repeatedly without damage!
- Very low self-discharge, can hold charge for at least 1 year
- Can be mounted in any orientation, zero off-gassing, no dangerous acid
- 24 Volt, 200 Amp-hour @ 20-hour discharge rate (5.12 kWh of stored energy)
- Active cell management through included battery management system (BMS)
- Long lifespan, true deep-cycle: 3000 cycles at 100% DOD, 4250 cycles at 80% DOD
- 4 years full warranty, plus 6 years pro-rated, for 10 years total