Let’s Boondock! Battery upgrade (to lithium)!

Have you ever seen a picture where there’s a camper in the middle of nowhere- no neighbors that you can see or hear? Usually it’s a beautiful picturesque location with mountains or a stream/river or maybe it’s on a beach where there are neighbors but you’re right there with the sounds of the ocean. After years of RV park camping with close neighbors, I wanted to cut the cord and break free from the need of water, electric, and sewer. I’ve been slowly making provisions- a sewer bladder for handling wastewater and a fresh water bladder for additional fresh water. But the biggest and most daunting task seemed like tackling power issues.

Current Setup – single 12v battery

My current setup was a Trojan 27TMH which is a simple 12v lead acid battery (I got an amazing price on it from Best Battery in Baltimore, MD). I bought it new in the winter of 2014 when we were planning on heading down to Key West from Maryland. We knew that on the way, we would want to Wallydock and would need to run the heater. It replaced the battery that came with the camper – which was the cheapest that the dealer could throw in.

BUT, IT HAD BEEN MURDERED.

Due to misuse and a complete and total lack of maintenance, I had murdered the battery by the time I replaced them back in September.

How do you misuse a battery, you ask? Overly discharging it mostly. The times that I did use it, we used it until the battery would barely give us light and certainly wouldn’t run our slides. We had to connect to the running truck in order to get by.

On lead batteries, you shouldn’t discharge them by more than 50%. More than that, significantly shortens their life.

Second to that, I almost never checked nor watered the batteries. A battery like this is supposed to be flooded- the lead plates are to be submerged in distilled water. I always meant to check them, but never did.

A dry battery is a dead battery.

Thus, the battery was completely shot by the time I replaced it. Murdered, even.

New Battery Selection

So now it was time to replace the battery, but with what? 12v, 6v, lead acid, AGM, lithium battery banks, lithium drop-ins… the options seemed endless! How do you pick?

First, Know Your Needs

First things first, you should get an idea of how much power you consume (or, just totally go overkill on batteries- but that gets expensive quick!). A little bit of research and time will teach you this. Technomadia did an excellent job of documenting how to perform an energy audit, so there’s no reason for me to reinvent the wheel.

Second, Define Your Requirements

What is most important to you? Cost? Weight? Speed of recharge? Are you like me and maintenance isn’t your strong suit?

Flooded lead acid batteries are the cheapest option out there. Make sure you get a true deep cycle marine battery- you do not want anything that has “cold cranking amps” or says “hybrid”. But, they also require regular maintenance with checking and maintaining water levels; not doing so is a recipe for throwing money out the window.

AGM batteries are the next cheapest and there are a ton of options out there for these. These are typically sealed and don’t require the same level of maintenance as flooded lead batteries. Again, make sure you’re getting a true deep cycle battery. It seems that most people are opting for 6v batteries and wiring 2 in series to combine them to 12v. If they get multiple batteries, they’ll wire the pairs of 12v batteries in parallel to increase the size of their battery banks. The biggest downside to these is the weight of them- they’re heavy!

Lithium batteries are the cat’s meow of batteries. They’re light, take a deep discharge (80% or more), can take high loads quite well, and can be recharged quickly. But, they thrive in moderate temperatures – high temperatures (100F) reduce their life and they can’t be charged below freezing (32F). The biggest downside is the cost.

It’s cheaper to build a DIY battery bank, but that comes at the cost of your time and it requires a quality battery monitoring system (BMS) or you’ll ruin your batteries in short order.

The 12v drop-ins are higher priced but more simple- you can often take out your old battery and drop in the new one. The drop-in batteries come with a built-in BMS. But depending on your charger, you likely won’t get the full benefit of lithium batteries. It’s often a good idea to upgrade that at the same time, fortunately that’s not too expensive.

A big con to lithium drop-ins in general is the lack of proven track record. There are folks out there with all other battery types (including DIY lithium builds) that have been around for 5+ years. But lithium drop-ins are new.

Note: to preemptively talk about “fire danger” of lithium batteries. When many people think lithium- they instantly think of laptop batteries from the late 90s to cell phone batteries of recent years and even an airplane incident where lithium batteries were used. The chemistry of these batteries is different from what is used in device batteries (and apparently a Boeing airplane) that have been known to spontaneously combust.

My Choice

I ultimately decided upon lithium drop-ins from Battle Born Batteries for a few reasons:

1. The weight of the batteries was my biggest concern; being fulltime- I’m running my rig maxed out as it stands already.
2. The speed of recharging; I wanted to be able to be able to mash as much juice as possible back into the batteries when boondocking to minimize generator time or maximize output from solar panels.
3. The depth of discharge; I liked getting 80Ah of usage out of my 100Ah battery vs. just 50Ah out of lead batteries.
4. No penalty for high-use appliances; lead batteries are impacted by something called Peukert’s Law (aka Peukert Effect). Basically, as the rate of discharge increases, the battery’s available capacity decreases. Lithium batteries don’t have this.

I honestly wanted to build a lithium battery bank but decided that my time and level of skill just weren’t there. I am not wholly comfortable with electricity in the first place and planning/designing a battery upgrade was about the limit of where I wanted to go.

My communications before and after the sale with Battle Born were fantastic. Questions were answered quickly. They also had the best pricing on lithium drop-ins that I could find. (Note, I did get a discount for writing about them- but pricing before that was still better than other brands.) You can get a discount through Brian Boone’s (a solar installer) blog.

The batteries are assembled at their shop in Reno, NV. In my travels, I’m hoping to stop in and visit them one day. Shipping to me in California was very quick- I think I received the batteries the next day (I say I think- I was thick in the middle of emergency camper repairs and not at the campground I had them sent to!).

Pros

The build quality on the batteries is great. They’re sturdy but still remarkably lightweight at less than 30 lbs. each. Based on the Trojan 27TMH that I removed- they’re a hair less than half of its weight.

Each battery was packaged well for shipping. I’d have no fear having these sent anywhere in the US.

But really, they’re batteries- I’m not sure what else to say for “Pros”. (grunt) They good. (grunt)

Cons

After publishing this article, Battle Born commented on my Facebook post that they now include hardware for all batteries. Other than the very expensive price, I’ve lost my only con. (smile)

I do have one minor “Con”… the batteries come with “flag terminals” which is essentially a post with a hole in it sticking up. At AutoZone, the closest comparison that I could find to this was for mower batteries and the like.

Being technically inept and knowing that I was about to hookup 400Ah of batteries to a 1000W inverter (and down the road, a 3000W inverter), I stressed on what best to use for nuts + bolts. In fact, I posted on a big boondocking Facebook Group and the responses were as varied as you’d expect- from use stainless steel bolts and to never use stainless steel bolts. Clear as mud, no?

I contacted Battle Born and asked for guidance, and here’s what they replied with:

The nut/bolt combo that we use is a ¾ inch 3/8 stainless steel bolt, a 3/8 nylon nut, and two 3/8 copper washers.

The problem was, I had a devil of a time finding copper washers. Fortunately, Battle Born also offered to throw in a few with my order. Unfortunately, they sent me 4 nut/bolt combos for 4 batteries (1/2 of what I needed). A quick email and they got another set in the mail and I got a mea culpa call from one of their managers who was embarrassed at the mistake.

That all said- for $900 batteries, Battle Born- you should throw these in with every order. You never know when you have ME on the other end stressing about nuts and bolts. Remember, I’m the guy who chants “righty tighty, lefty loosey” every time I go to screw or unscrew something!

What Else Is Needed?

Monitoring

As I said, I opted for lithium batteries. Regardless of what battery I went with, if I am investing the money in an upgrade, I need information and data to properly use the batteries and to extend their lives (murder is bad, mmm’k?).

For that, I look to either the Victron BMV-702 + Bluetooth dongle or the BMV-712 which has Bluetooth capabilities built-in. The Bluetooth connector isn’t needed and each comes with a display that you can mount in the RV. But, the app that these connect to is really handy. (And, in fact- is needed to properly program the BMV for the lithium drop-ins.)

Seriously, the app is sweet.

Charging

Again, for lithium- a lithium-charger is needed to take full advantage of your new batteries but for all battery types, upgrading your charger isn’t a bad idea. You’ll get quicker charges and likely able to have the charger’s settings specific to your battery type (lead vs. AGM vs. litium).

For many of us, we have a converter in our rig that doubles as the battery charger. This device takes 120v electric and converts it to 12v for when you’re hooked up to shore power. It also handles charging your battery at the same time. In these cases, I’d look at Progressive Dynamics chargers from bestconverter.com for replacements. I upgraded to the PD9180AL.

On the other side, there are a handful of rigs that come with inverter/chargers. These devices do the opposite of converters and make 120v electric from 12v. This is something that you may want to also look at with an eye towards boondocking; being able to put the TV on or run a curling iron or hair dryer are all nice conveniences that make boondock camping a lot more like camping with hookups. Anyway, for those- you might be able to have your inverter/charger reprogrammed for the battery type that you upgrade to. If I were purchasing something new, I would be looking at Magnum Energy products. These can run the gamut from simple and inexpensive to holy-amazing-Batman fancy (with a price tag to go with it). It goes back to your requirements from above. For instance, I was looking at the MSH3012M with an eye towards being able to augment my power when on less than 50amp hookups.

Installation

Lastly, you’ll need supplies for installing the batteries. In my case, I was installing 4 batteries, an inverter, and a battery monitor. I worked out a list of supplies for my total installation (which I’ll document sometime!).

But, at a minimum- you’ll want a quality battery disconnect so that you can isolate the batteries for storage (parasitic draws will run batteries flat quicker than you can imagine!) and working on them.

And you may need battery cables in various lengths depending on where things are being installed. Check the list of supplies for links to different lengths and gauges of cable.