RV Batteries: Overview of Batteries for RV Usage

2017-07-06 • SEND FEEDBACK •
Related: Mercedes Sprinter

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I researched batteries extensively before tenatively deciding on the Lithionics lithium ion battery I also considered the Lifecycle (Concorde) 6V batteries in series for 12 volts and high amperage and charge rate, but lead acid batteries have big downsides in weight and size.

Things I considered for battery choice

Many considerations are involved in choosing the right battery system and it is not possible to simply compare on specifications for power (amps and watt-hours are apples and oranges for the two technologies). These were my considerations, below.

• At least 3000 watt hours, that is, 3000 usable watt hours so that I could run a 300 watt computing load for 8 hours (computer with large display and accessories) along with other miscellaneous loads. That load implies a nominal 3750 watt-hour capacity for 80% discharge, but a whopping 6000 watt hours of lead acid batteries if 50% discharge is assumed.
• Stretch goal of 5000+ watt hours, so that on cold morning I could run an electric heater to warm up the van, pop the microwave for hot water anytime desired, run an A/C fan on hot days, etc—all while computing with a workstation-class computer for 10 hours or more. The lead acid solution would work, but at least 2X the size and weight, at least.
• Enough power to use electric heating for two hours at 1200 watts without overly depleting the batteries.
• In general, ability to use battery power 'recklessly' (space heater, microwave, computers, etc) so that I could “set and forget” the batteries nearly all of the time.
• Long service life with at least 1000 charge cycles over 5 years in spite of 50% to 80% discharge rate. 1000+ charge cycles preferred (120 days per year for 7 years).
• Reasonable size and weight for optimizing battery placement, minimizing wiring length and avoiding listing of the van by having too much weight on one side.
• Preference for a single battery (dual 6V lead acid is better than one 12V, but that means dual batteries).
• I wanted to use power as much and as often as I’d like without having to fret over discharging more than 50%
• I do not want to have to charge batteries every day.

When I looked at these requirements, I found that at least 240 pounds of lead acid batteries would be needed. These would take up additional space, be difficult to fit where I preferred, and would add considerable weight to one side of the van (for simple wiring). That kind of weight where I wanted it (driver's side behind the seat), would start to make the van weight-lopsided as well.

In any discussion, distinguishing initial price from value is important: immediate cost versus lifespan and performance over time.

Accordingly, I turned my attention to lithium batteries. While lithium batteries are expensive, their cost is offset by the long service life and higher true power capabilities that offer considerably more value than the price and nominal power ratings would suggest—the price gap between military-grade lead acid AGM batteries and lithium narrows significantly when real power output is considered. That is, the value proposition is much stronger than the nominal numbers would suggest—an apples-to-oranges comparison.

• RV Batteries: Overview of lithium batteries for RVs
• RV Batteries: Lithionics Lithium Batteries
• RV Batteries: Overview of Lead Acid batteries for RVs

Lithionics GT 12V 525 Lithium Amp Hours 8D Case
6720 watt hours, 23.0 x 13.0 x 11.4, 135 pounds