Why no DC-DC charger and how did I pick the batteries?

Here's a question I got on YouTube.

Question:
 "Great set up.  I'm wondering your battery selection, and I guess it all depends on what you run for gear.  I am planning on a 31M for the aux and a 34m For the starter.  I don't think the alternator can fully charge the 31M, so likely a dc-dc charger to toss in.  I love the RedArc products I see.  Just that if I'm doing dual batteries, i want one for quick starting, and another for the slow drain...Great video."


I just kept typing and here was my response.  I thought this might help someone running into the same questions.

Answer:

Thanks man!

My selection of batteries was purely due to the battery trays and space available.  I went with the slee off-road trays since they were very nice and I didn't want to fabricate.  That said the start is a 31 and the aux is a 75/86.  Ideally these would be the other way around since the 31 has twice the amp hours. I intend to eventually wire them the other way.  

As for charging and dc-dc vs. a relay here is what I believe and trust me this could be debated by someone more knowledgeable than I.  

Many people especially in Australia use dc-dc chargers for a couple reasons.  

First, since many alternators on newer vehicles are "smart" they do not provide sufficient voltage to fully charge an AGM battery.  The alternator on my land cruiser consistently puts out 14.1-14.3v which I thought would be pretty good, below 14v would not be so good.  

Second big reason, even though having the higher voltage can get you fully charged or close to it, for the best battery life when frequently draining your batteries low you need to have a phased charge profile.  DC-DC chargers generally have the phases required by a battery like an AGM but some only provide higher voltage.  

Back when I planned the system the only DC-DC charger available in the US was the CTEK and it did not enable you to link the batteries in an emergency start situation or in high amp draw situations where having linked batteries can be helpful, like winching. Not sure how much I care since I don't have a winch yet but at the time it seemed important.  I also noticed many people operate with Tmax, IBS, national luna, or blue sea setups that are all simple relays with no problem.  I also considered the additional cost of the dc-dc chargers and some are a pretty significant investment. I also intend to add solar so this was part of the consideration.

I think if you are going to be on expedition with no shore power for many many days, frequently completely draining the battery, and potentially have a lower voltage alternator then a dc-dc charger is going to be preferred, or a must, but if your travel is more like a couple days here and there and your alternator is higher voltage (not smart) and you can always top off / condition your batteries with a good ac-dc charger and be fine. I am looking at adding an on-board Powermainia dual bank agm ac-dc charger so in campsites with power or when home I can plug in the cruiser and keep the batteries strong.  

Here's the charger:

Ultimately a group 31 battery with the load of my planned accessories, the cruiser's decent alternator output, a solor panel, occasional ac-dc charging and the fact that I don't think I will be completely draining the battery often all lead to me thinking the dc-dc charger is not 100% necessary. These opinions are based on research but I will be putting my system to the test this summer. I realize that at some point I may want to shift to dc-dc charging. I have heard from others that the REDARC products are now available in the USA so I will be checking those out at some point. Man that was longer than I though but it is a great question and I hope this helps. I am going to post this over on my bradyadventures.com blog since I know many people have these questions and it is not at all straight forward. Let me know if this makes sense and if you have any follow up questions or if you disagree. Thanks Chuck.

The Land Cruiser's Overland Blue Sea Auxiliary Power Distribution is in!

The Land Cruiser's auxiliary battery is now ready to distribute that power to some cool overland gear.  We got the blue sea systems 285 series circuit breaker and fuse block wired up and ready for our next big project.

Check out the video below and here are links to the products we installed in the video:
   

Dual Battery Auxiliary Wire Run

This is our first time using the hydraulic crimper. We chose the wire route, crimped the main eyelets, and ran the 2 gauge auxiliary wire to the rear.  We considered running the wire on the frame rail outside the vehicle but in the end went with running the wire along the door sills.  We chose 2 gauge wire since it was more than enough to provide power to the 100 gauge blue sea fuse block as well as another major electrical load, like an inverter, air pump, etc.

Here are links to the crimper, wire (although we got 30' not 100') and eyelets we used in the video.
   

Check out the National Luna Dual Battery Monitor Install

In this video we install the National Luna dual battery monitor. Not much to the installation.  You need to add a fuse to each positive lead and the supplied wire only got us to one battery but not a big deal.

I really love this thing, it has a certain 80's car gadget charm with the old skool LEDs.

We choose this one because it was one of very few available in the US and many that are available are number read outs that can be hard to read at a glance.  The LEDs and colors make it easy to know where you stand.  This particular one can be used with any dual battery system.  Many nicer monitors are also controllers and can only be used with the full system that they were intended for.

Blue Sea ML-ACR in cab switch install in the Land Cruiser 100 Series

We installed the ml-acr in cab switch and ran the wires through the dash and firewall to the future location of the relay.  It was a fairly simple process.  We needed to remove the panel under the steering wheel, the head unit, and the glove box to route the wire.  We also needed to hone out our chosen switch location in the switch blank by the mirror controls.  This actually went much smoother than expected.

The switch comes with the ml-acr below and we think it is one of the best options for an overland dual battery system.

Land Cruiser 100 Series DIY Tailgate Cover

The Toyota Land Cruisers tailgate is a signature item that every Land Cruiser owner loves.  There is one problem, when deciding on materials for the tailgate Toyota failed miserably.  The tailgate cover on the 100 series is made of a fiber cardboard type backing with carpet on top.  The tailgate cover pretty nasty over the years and creating something that can withstand the punishment of overlanding is a great DIY project.   Mine was very nasty and the commercially available ones like TrekBoxx are $200+.  WIth a little bit of elbow grease and very little money you can build your own.

This thing only cost less than $50 in materials maybe a little more with the monstaliner but I had plenty of extra from the drawer build. The only thing I would change is would have hunted down some 1/2" birch so it would have had a more uniform finish.

Check out our video on our DIY Tailgate cover.

The only hard to find item are the well nuts and you can find the exact ones we used at the following link.

Punching a hole in the Land Cruisers Firewall

We spent a fair amount of time behind the dash trying to make sure we weren't going to drill through anything and got some great pointers on ih8mud.com.  Just before we got started we realized that the grommet and drill bit we intended for the job were not going to be sufficient.  We ordered up a daystar firewall boot and a neiko drill bit and once those were in we were ready for action.

Here are the items we got for the job.

Here is a little video of the work and in our next post we will be running all our wires through the dash and up through the firewall as we make progress on our 100 series land cruisers overland expedition dual battery system.

Thanks

Slee Off-Road Battery Trays for the Land Cruiser Dual Battery System

If you have a 100 series land cruiser there is really only one off the shelf option in the US for easily installing a second battery.  Slee Off-Road makes and auxiliary tray as well as an upgrade tray for the primary battery.  The aux tray is unique in that you can mount a single or dual arb air compressor along side the battery.  There is one downfall of the Slee aux tray and that is the fact the space for the battery itself is quit small only allowing for a 75/86 group battery.  We hope to overcome this challenge in the future by wiring the 31 group in the stock start position as the aux and utilizing the aux for starting.  This will give us double the capacity for accessories when the vehicle is off.

Slee also has battery trays for other vehicles, a whole bunch of off road accessories, and if you are in or near Colorado they will do the work for you.

In these two videos we get both of these trays installed and the batteries in the vehicle.

Keep and eye out for the upcoming videos and posts where we wire everything up and get ready for our future overland projects.

Please feel free to ask us any questions that you might have and thanks for stopping by.

The Dual Battery Gear is In!

Hey everyone all the dual battery gear is in and I wanted to give you an overview and links to all the products we are using. We will be posting videos twice a week on the progress and updating the blog as well. Check out this video giving you an overview of the gear we have so far. I also describe and provide links for most of the gear below. Please send us any questions via email or feel free to leave comments in our videos and thanks for stopping by.

Blue Sea ML-ACR is the heart of the system and controls whether the batteries are connected while running and disconnected when off. It also offers manual controls on the unit and via an in cab switch. Below are two videos that show the switch and explain why we selected it over other options.




We chose Odyssey batteries are here is a video of us receiving the batteries and how we chose odysseys over the other options. We got the batteries from batterymart.com


We mounted the batteries using slee offroad battery trays here is the unboxing video for those.



The wire between the batteries and the ML-ACR and between the auxiliary battery and the accessory fuse block must be fused by the batteries. We decided to use blue sea 5187 and 5190 terminal fuse blocks for this purpose. Blue Sea Fuse 5187 and 5191. We are using 300 amp fuses between the batteries and 1/0 gauge wire and a 200 amp fuse to the accessory fuse block with 2 gauge wire.



We selected these mil spec terminals and covers for the main connections to the auxiliary battery.



From the auxiliary battery we used 2 gauge wire to a Blue Sea 12 Circuit Fuse Block protected by a 120 amp blue sea 187 breaker.


We used a number of different sizes of Seltrem Marine Tinned Eyelets for the various wire sizes and terminal connection sizes. Most of these will require a hydraulic crimper we chose an inexpensive one that should do the job.



We chose this firewall boot and will be running the 2 gauge wire, wiring to the battery monitor, and wiring to the ml-acr in cab switch. We picked up an assortment of 6 gauge wire for the ml-acr switch and this should be good for future switching projects.