Lithium-Ion Batteries for Electric Vehicles: Page 4 of 4

Is the Investment Worth It?

When I decided to go with LFP batteries, I dug into EV discussion forum (evdl.org) archives, and researched large-format Li-ion vendors. I settled on a set of 48, 200 Ah, 3.2 V cells manufactured by Winston (formerly Thundersky, now Sinopoly) of China, and sold by Manzanita Micro, for $15,000 (with BMS).

The price comparison table compares the cost of a properly maintained FLA system and an LFP system using two reference batteries that are the most economical options available in both categories. It shows the lifetime price per kWh for the two battery types. Note that the up-front price per unit of storage (Wh) of LFPs is nearly four times higher than FLAs. But the LFP lifetime energy capacity (usable energy multiplied by cycle life) is much higher than the FLA. Thus, even with the additional cost of a BMS (ranging from $15 to $50 per cell) the total lifetime price per kWh for LFPs is very close when using a 70% depth of discharge, and somewhat worse than FLA when using an 80% depth of discharge.

The long cycle life of LFPs potentially prevents the ability to use the full mileage capability of those batteries within the 10-year expected battery longevity. With my vehicle’s 400 Wh per mile, this can yield 153,000 miles. With an average annual driving distance of 7,500 miles, that’s about 20 years. However, the true longevity of LFPs is unknown since this type of battery was first put into use only 12 years ago.

The real comparison comes by looking at your particular vehicle’s performance, local energy costs, and the distances you intend to travel. The good lifetime price per kWh of LFPs, combined with the reduced energy cost per mile, is where the rubber meets the road. The cost comparisons table shows the projected total cost of my two battery systems (pre- and post-upgrade), plus the electrical energy used to charge them over a 10-year period, with my particular EV, using my electrical rate of $0.09 per kWh, an average commute of 25 miles, and my average annual driving distance of 7,500 miles. Even without using the full kWh lifetime capacity of my LFP batteries, the 10-year total cost is nearly $3,800 less, or 82% of the cost of FLAs.

I’ve been driving my LFP-upgraded GMC Sonoma EV conversion for about a year and have put about 7,500 miles and 200 cycles on the LFP batteries. Compared to using FLAs, LFPs give about twice the range (with very little range reduction in cold weather), much better acceleration, and zero maintenance. Compared to FLAs, they only use about half the energy per mile, and this is with LFPs that have 77% of my original FLAs’ energy storage capacity (200 Ah vs. 260 Ah). The advantages gained were well worth the higher up front cost. What next? The new batteries are now capable of supplying more power than my 9-inch DC motor can consistently take, so I am preparing my EV for a higher-power AC motor, which will be more efficient and provide regenerative braking, promising to extend the EV’s range even farther.

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After earning his electrical engineering degree, Randy Richmond went to work for the telecom industry. In 1999, Randy founded RightHand Engineering LLC, which makes products for monitoring RE systems. He is a professional engineer and offers design, test, educational, and consulting services for Li-ion-based power systems.

Large-Format LFP Manufacturers:

CALB • calibpower.com

FluxPower • fluxpwr.com

GBS • gbsystem.com

Headway • headwaybatteryandcable.com

RealForce • en.realforce.com.cn

Sinopoly • sinopolybattery.com

BMS Manufacturers:

Clean Power Auto • cleanpowerauto.com

Elithion • elithion.com

Manzanita Micro • manzanitamicro.com

Pacific EV • pacificev.com

U.S. Dealers/Distributors:

EV America • evamerica.com

EVolve Electrics • evolveelectrics.com

EV Propulsion • ev-propulsion.com

EV Source • evsource.com

Lithium Storage • lithiumstorage.com

Manzanita Micro • manzanitamicro.com