The short version: Measure the battery tray or box, then buy the lithium battery that fits it. In LiTime’s range, a Group 24 case holds 100Ah, a Group 27 holds 100Ah with Bluetooth, and a Group 31 case holds up to 165Ah. If nothing standard fits, the Xtra-Mini is a Group 22NF case.
What a group size actually is
BCI group numbers describe a battery’s case: its length, width, height and terminal layout. They were set for lead-acid, where a bigger case meant more plates and more amp-hours. With lithium iron phosphate that link breaks. LiTime makes a 100Ah battery in a Group 31 case and a 165Ah battery in the same Group 31 footprint, so the group size tells you what fits, not how much it stores.
The LiTime cases we carry, measured
| Battery | Case | L × W × H (in) | Weight | Energy |
|---|---|---|---|---|
| 12V 100Ah Xtra-Mini | Group 22NF | 9.02 × 5.43 × 8.19 | 19.13 lb | 1,280Wh |
| 12V 100Ah Group 24 Bluetooth | Group 24 | 10.24 × 6.61 × 8.30 | 21.87 lb | 1,280Wh |
| 12V 100Ah Group 27 Bluetooth | Group 27 | not stated by LiTime | — | 1,200Wh usable |
| 12V 100Ah Group 31 | Group 31 | 13 × 6.77 × 8.43 | 24.25 lb | 1,280Wh |
| 12V 165Ah Bluetooth | Group 31 | 13 × 6.77 × 8.5 | — | 2,112Wh |
| 24V 100Ah Group 31 Bluetooth | Group 31 footprint | 13.11 × 6.93 × 9.45 | — | 2,560Wh |
Dimensions and weights are LiTime’s published figures; a dash means LiTime does not state it.
How to measure your box
- Measure the inside of the tray or box: length, width, and the height up to the lid or the underside of whatever sits above it.
- Leave room for the cable lugs on top. Lithium terminals take the same lugs, but the cable has to bend down to them.
- Check orientation rules. LiTime says not to mount its Group 27 battery with the top or back side down, and not to stand the 200Ah or 230Ah models on their top or front side. The Xtra-Mini is the exception: LiTime says it can be mounted on its front, side or bottom.
- For a sealed plastic battery box, measure the box, not the tray. LiTime warns that standard sealed Group 31 boxes may not take its 24V Group 31 battery, which is taller than the 12V ones.
Which to choose
Group 24 tray (most travel trailers): the Group 24 Bluetooth is a direct swap. Two in parallel give 200Ah if the box takes two.
Group 27 tray: the Group 27 Bluetooth. LiTime names the Brinkley Z 2900, Four Winds 22E and Forest River Forester among the RVs built with Group 27 compartments. The 200Ah Travel Trailer Lithium Swap Kit uses two of these with a 40A DC-DC charger, shunt and fusing.
Group 31 tray: you have the most choice. The Group 31 100Ah is the budget drop-in; the 165Ah puts 65% more energy in the same box, with a 165A BMS; the LiHeat 165Ah adds self-heating for winter use.
No standard tray, or a tight locker: the Xtra-Mini is the smallest and lightest LiTime 100Ah.
FAQ
Is a Group 31 lithium battery more powerful than a Group 24?
Not necessarily. LiTime’s Group 24 and Group 31 100Ah batteries both store 1,280Wh. Only the 165Ah model uses the bigger case for more capacity.
Can I use one of these to start an engine?
No. LiTime states these are not starting batteries. The only dual-purpose model in its range we carry is the 1200 CCA marine battery, which is built for outboards.
LiTime batteries we list ship free from our warehouse in Upland, California to the lower 48 states (not Hawaii, Alaska or Puerto Rico), with LiTime’s 5-year battery warranty handled by LiTime. Not sure what size you need? The RV solar and battery calculator sizes the bank from what you run and now shows a LiTime option, or talk to a parts person before you order. See the whole LiTime range.