Ninelitetrip
Well-known member
Hi Shawn,
The OHMMU 156Ah battery https://www.ohmmu.com/product-page/gen2group31 seems like a good battery, but I've not been able to find any tear down videos to see in the inside/construction, so hard to compare to the Battleborn or SOK that have been torn down and tested hard. OHMMU reports they use the Gen2 Tesla cells so that gave it a bit more energy density than the first gen. 156Ah is great for a group 31 footprint. It's dimensions are standard Group 31 so 12.75 x 6.875 x 9 (L x W xH) which is identical to the stock group 31 AGM and to the 100Ah Battleborn but it is 56 more Ah than the Battleborn. It also allows for 200amp max discharge where the BB and SOK allow 100amp max discharge. It does not list any internal heating elements as an option and it lists for $999 on their website with standard 48 month warranty and $1,098 with 120 month (10 year) warranty). Battleborn comes with a 120month (10 year) warranty. From a cost perspective, the SOK are the most economical, but won't fit. The Battleborn and OHMMU are the same dimensions but the OHMMU has 50% more capacity making it the most Ah per dollar. Battleborn is $900 / 100ah = $9 per Ah. OHMMU is $999 / 156Ah = $6.40 per Ah (plus the option of pulling 2x max amps and the enjoyment of having the extra 50% capacity). Seems like a reasonable choice. You'll have to work out with them the cost difference.
Now will be a good time to decide if you want to add a switched, external heating element. It can be added later, but would be easier now. Only you will know your winter use cases, but for consideration... Will you be in a situation where the battery is below freezing and you need to charge? I would think 150Ah would last you several days without charging, though that would vary greatly with how much power you draw (like if you add the Truma 12v winter kit to you water heater, etc.). In the cold, the fridge won't run much and no vent fans, but the heater fan runs more. Would you keep it at 70F or 50F? Lots of variables on power consumption.
If your trip will last long enough that you must charge during the trip (via solar, shore power, or truck), would the battery be above freezing during that time period because of how you are using the camper? If you have the heat on inside the camper, even at a very low setting, that should keep the battery warm enough to charge as long as you've plugged the battery box vents. If you are driving, leaving the furnace on isn't recommended. I suppose if it is a rare enough occasion, one could even put some chemical hand warmers around the base of the battery if need be. Hope some of that helps.
No internal heating, but also there is no internal BMS for the OHMMU?
Lithionics has some interesting stuff. Not just assembled but made in the USA. No listed price, have to contact them.
12V 130AH G31 Battery | Lithionics Battery
lithionicsbattery.com
I believe this will be available in the Base Camp model? GTX12V315A-E2107-CS200.
12V 315AH E2107 GTX Battery Consumer Model | Lithionics Battery
lithionicsbattery.com
and now this. VPR 4EVER Platinum Custom 360
VPR 4EVER Platinum 360 Lithium Battery
The custom 360 battery packs a punch with an incredible capacity of 360Ah. Charge faster, stay longer and go further with the ultimate RV/Marine power upgrade.
www.expion360.com