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 need. There is a Volthium battery for all your needs!
The Volthium 12.8-050-G21Y is part of their Aventura series of batteries, with 12 Volt 50 Ah (0.64 kWh of stored energy). Physically this is a group 21 battery, very compact and at 14 lbs easily carried.
This battery has cold charge protection, UL1642 certified cells, and the best BMS on the market (powered by Texas Instruments), designed and programmed by Volthium. 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 = 14.2 – 14.6 Volt, with 14.4 Volt ideal
- Absorb time = about two hours, not critical
- Float = not needed, set to 13.6 Volt or less
- No equalize, or set to 14.4 Volt if it can’t be disabled
- No temperature compensation, set to 0
- Charge rate of 5 – 15 Amp is preferred for longevity, though up to 60 Amp is possible
- Charging works from 0C (32F), discharge works fine up to -20C (-4F)
The maximum discharge rate is 60 Amp continuous, 100 Amp for 180 seconds, and 200 Amp for 3 ms.
The Volthium 12.8-050-G21Y batteries can be connected in series and parallel to increase the bank Voltage and Ah rating. Series connection of up to 4 units is allowed, making for a 48 Volt 50 Ah system. Up to 4 batteries can be connected in parallel, making for a 12 Volt 200 Ah system. Series and parallel connections cannot be mixed! So it is either a single string of batteries to make a 24/36/48V system at 50 Ah, or parallel connection for a 12V system at 100/150/200 Ah. Parallel strings of batteries will increase the charge and discharge rates (i.e. 120A 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 21 battery, M8 terminals
- Much lighter vs. lead-acid, just 14 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 up to 1 year
- Can be mounted in any orientation, zero off-gassing, no dangerous acid
- 12 Volt, 50 Amp-hour @ 20-hour discharge rate (0.64 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