See what you think of this line of reasoning....
My battery choice in 2019 was a single 12v 100Ah Battle Born (with 4x100watt panels). It has worked just as excellently as you'd expect from any well-executed lithium application. But with our new travel trailer we're gearing up for multi-month travel and want the option to occasionally run our 15k BTU AC unit for 1 to 3 hours in a 24-hour period. Doing this at Battle Born pricing makes that out of the question for our budget.
Enter the EG4. The rack mount was incidental. What I saw when looking at the EG4 was a power dense form factor with 5.12kW capacity from 16 A grade cells weighing 101.4 pounds for $1500.
I am looking at the 24v option to escape the trappings of high-amperage 12v operation. https://www.signaturesolar.com/products/24v-200ah-lifepower4-battery-by-eg4
Here's the (approximate) numbers that have my attention when comparing EG4 and SOK against my Battle Born. A single EG4 is compared against 2 SOK and 4 Battle Born in order to get roughly equivalent capacity:
Battery Options 1 of EG4 24v 200Ah 2 of SOK 12v 206Ah 4 of Battle Born 12v 100Ah Capacity 5.1 kWh 4.9 kWh 4.8 kWh Storage Volume 1931 cu. in. 2087 cu. in. 3153 cu. in. Weight 101.4 ibs 106.4 lbs 124 lbs. Cost 1,499 2,058 3,196 (the old, non-heated)
Even against the excellent SOK option, the EG4 holds a strong position. For me, the EG4 pricing means the difference between sizing a system to include AC or excluding AC completely. In such a case I'd either just run a single SOK and be done with it or buy a second Battle Born. Either would easily fill our electrical needs without including AC. When choosing between these three options there are many other factors to consider I know but these foundational comparison points have started to build a compelling case!
I am also looking at using the EG4 24v 200Ah batteries in my fifth-wheel; however, while everybody seems to be focused on their large capacity (5.1 kWh), it seems like a lot of people are overlooking their maximum continuous power output ratings which is 24v x 100 amps = 2400W.
I don't think that 2400W from one EG4 is enough to drive a 3000VA/2400W inverter (which has 95% conversion efficiency) plus the other 12v loads in the RV without tripping the overcurrent protection inside the EG4, so I think you would need to have at least two EG4 batteries which would give you a total of 4800W output. (Similarly, you would need four of the SOK 12v 206Ah batteries to get 4800W output.)
Here's the comparison chart after switching to 2 EG4s and 4 SOKs:
Battery Options | 2 of EG4 24v 200Ah | 4 of SOK 12v 206Ah | 4 of Battle Born 12v 100Ah |
Capacity | 10.2 kWh | 9.8 kWh | 4.8 kWh |
Storage Volume | 3862 cu. in. | 4174 cu. in. | 3153 cu. in. |
Weight | 202.8 lbs | 212.8 lbs | 124 lbs. |
Cost | $2,998 | $4,116 | $3,196 (the old, non-heated) |
Max continuous output amps per battery | 100 amps | 100 amps | 100 amps |
Max continuous output watts per battery | 2400W | 1200W | 1200W |
Total battery bank watts output | 4800W | 4800W | 4800W |
I still think the EG4 batteries look like a great choice since we get double the capacity for the same cost, but we need to pay attention to how many we need to get the needed power output.