RELiON RB75 Lithium-ion battery, 12V deep cycle, 75Ah/20h, 4000+ cycles, 5 years warranty
RELiON is without a doubt the premium brand to turn to when quality and reliability are at the top of the list for lithium-ion batteries. Also see our Finding Happiness with Lithium-Ion article, explaining the care and feeding of these batteries.
With many times the life-span at a fraction of the weight & size of regular lead-acid, lithium-ion batteries are the future of off-grid power. They can be cycled deeper, more often, charged faster, and all with zero maintenance. Lithium-ion is also a great solution when weight and space matter, such as for RV applications.
RELiON lithium-ion batteries are true deep-cycle batteries, and they have 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, and automatic balancing of the cells.
Charge settings for RELiON batteries:
- Bulk/absorb = 14.2 – 14.6 Volt, with 14.4 Volt ideal
- Absorb time = about two hours, or until the current drops to 0.05C or less.
- Float = not needed, set to 13.6 Volt or less
- No equalize, or set to 14.4 – 14.6 Volt if it can’t be disabled
- No temperature compensation, disable or set to 0
- Charge rate of 0.5C or less is preferred for longevity, though up to 75A is possible
- Battery has to be warmer than 0 Centigrade (32F), or the BMS will not allow charging, discharge works fine up to -20C (-4F)
The maximum charge and discharge current is listed on the spec sheet for each battery size (for all the 100 Ah batteries and up this is 100 Amp, the smaller batteries have other values, see the spec sheet). When the battery temperature is below freezing (zero Centigrade) the charge current is limited to 0.1C or 10A, whichever is smaller.
Up to four RELiON batteries of the same type can be placed in series to increase the battery string Voltage, and up to 2 strings can be connected in parallel to increase the Amp-hour rating of the battery bank (more strings can be paralleled with certain limitations, contact us if you are planning to do that).
In case of parallel strings the maximum charge and discharge current is the sum of the individual batteries, minus 25% (so any imbalance doesn’t trip the BMS). For example, two 100 Ah batteries in parallel makes for 200A – 25% (or 50A) = 150A maximum charge/discharge current.
RELiON batteries us LiFePO4 chemistry (Lithium-Iron-Phosphate). This is very stable and is not sensitive to spontaneous combustion, in comparison to laptop and cell-phone lithium-ion batteries (which use Lithium-Cobalt-Phospate chemistry). The cells have build-in protection for over-pressure, over-temperature, contain a fire-retardant in the electrolyte, and have a stainless steel jacket. These are very safe batteries!
Because lithium-ion batteries can be discharged deeper, and this can be done for more cycles, a smaller battery bank can suffice vs. lead-acid.
- Zero maintenance!
- Long lifespan, true deep-cycle: 4000 cycles at 80% DOD, 6000 cycles at 50% DOD
- Wide -20 … +70C operating temperature range
- 12 Volt, 75 Amp hour @ 20 hr discharge rate
- Compatible with standard charge controllers
- Active cell management through included battery management system (BMS)
- Can be mounted in any orientation, zero off-gassing, no dangerous acid
- Light weight & small footprint!
- Very low self-discharge rate
- No memory effect
- 5 year warranty