TheSamba.com :: View topic - Adding a second battery..how to...with photos FAQ

Tue May 15, 2012 8:45 pm

After reading all the previous posts and talking to people who have done this I decided to use the German supply kit to add a second "Camping" battery to my 69 tintop. It was easier than I thought ;
What you will need, the kit and instructions,a battery hold down,a small fuse pannel , #8 wire and connectors :

Install the hold down and add battery,attach relay to grounded metal,run wires to terminals as directed,

Run long peice of kit harness up and across to original battery(coiled pigtail in photo)

Unplug green wire off alternator and plug it into clear Y connector;plug blue wire from clear Y connector onto the terminal you removed green wire from

At this point you have a second battery that will charge when the bus is runningand when you turn off the key you have an isolated "camping battery"
To add circuts you need to connect the positive terminal of the new battrery to thefuse block and start running your accessory circuts from there
Costs : Battery hold down kit (west marine ) $16 marine deep cycle 800cca battery $99, G.S. kit $39, Wire and connectors $8, Fuse block $12, ..=$ 174 + time = 2hours
If your rich substitute a $249 ultimate battery and a $139 blue sea three way switch;I just want to go campin several times a year,this will do for me 8) 8) Hopes this helps somebody else

Tue May 15, 2012 9:20 pm

Thanks for posting that, you make it look easy. Please forgive my ignorance but I'm not totally clear on how this would work. So the camping circuit is totally seperated to insure the 'drive' battery is not drained? Would it be necessary to have seperate set of 'camping' lights and other electrical accessories?

Tue May 15, 2012 9:35 pm

YES that is the idea...the "camping battery" runs everything you need for camping and does not draw down the STARTING battery...And at the end of the weekend when you start the engine to drive home your alternator/generator recharges your camping battery for the next trip...NOTE you have to be a little conservative with this setup,you can,t run AC units or large refridgerators but if you use LED lights and a small fan you can watch a movie on your computer that is pluged into a inverter and all that is plugged into your new two battery setup 8) 8) 8)

Wed May 16, 2012 5:21 am

stuco wrote: Would it be necessary to have seperate set of 'camping' lights and other electrical accessories?
No.........Anything you want to run off the Camping Battery gets connected to the new fuse block

Wed May 16, 2012 5:44 am

grandpa pete wrote: you can watch a movie on your computer that is pluged into a inverter and all that is plugged into your new two battery setup 8) 8) 8)

Well you can watch a movie that way but you should not .. Converting DC to AC then back to DC is terribly inefficient and many if not most DC/AC inverters don't provide current in a manner that the charger can use correctly.

There are a number of mobile laptop chargers like this
http://www.targus.com/us/productdetail.aspx?sku=APD80US
on the market that can run directly from a 12 volt DC source without the waste of multiple conversions.

Wed May 16, 2012 7:02 am

Great thread Grandpa Pete. I will put it to good use very soon. Camping battery on top of list of things I want.

Wed May 16, 2012 7:09 am

a-marshal : thanks for your input,I did not know about running computers direct :shock: ...I drove around U.S, for 1 1/2 years using an imverter to run a laptop for truck directions (before garmins)...why didn't you tell me this back then :lol: .thks 8)

Wed May 16, 2012 7:32 am

I run my laptop off of my yellow emergency jumpstart gadget with no proplems. But it does seem wierd and wasteful converting back and forth and back and forth from AC to DC to AC to DC.

Pete, you're on a roll. :wink: Keep it up 8)

Wed May 16, 2012 7:37 am

Nice writeup.

I still don't know what I'd use this for, however. When we camp we use the fluorescent light in the bus and that's about it. I could see hooking up a string of lights.

What do others use their dual batteries to power? Give me some ideas.

Wed May 16, 2012 7:44 am

Good job Pete except for the part about wiring the new fuse block. Your picture shows it mounted next to the "camping" battery. If it stays there then you would need to run several wires from it forward to under the dash to run power to your stereo, dome lights, etc.

I believe a better way is to run "one" large wire forward from the "camping" battery with a 30 amp inline fuse to up under the dash where it would power your "aux" fuse block. At that point it's pretty simple to just unplug the power wires for the dome lights and stereo, etc from the main fuse block and plug them onto the aux fuse block. That way you're using the existing original powers wires which have long ago been run throughout the bus.

Wed May 16, 2012 7:49 am

What do others use their dual batteries to power? Give me some ideas.

1) Power your interior lights (dome lights)
2) Power any cigarette/power recepticles you've installed (cell phone)
3) Power your stereo
4) power a heating system (Propex would be a good example)

The idea is to use power without running your engine and still have a fresh battery when you want to start up the bus and head for the house.

Wed May 16, 2012 8:00 am

So, if I wanted to run my stereo off the AUX battery, I'd have to wire it to the new rear fuse panel? Same with cigarette lighter?

When the bus is running you can still get power from the AUX battery, correct?

Wed May 16, 2012 8:03 am

aeromech wrote: What do others use their dual batteries to power? Give me some ideas.

1) Power your interior lights (dome lights)
2) Power any cigarette/power recepticles you've installed (cell phone)
3) Power your stereo
4) power a heating system (Propex would be a good example)

5) A fan
6) A low drain evaporative cooler

Wed May 16, 2012 8:19 am

I have my fuse panel under my jumper seat and may install another one up front so I don't have to run more wires.

My Aux run my fog lights, CDI, A/F gauge CB and dome light I have my stereo to the cars key on since it would drain the battery if I had it on all the time.
EDIT: electric car seat warmers and converter some times.

cigarette lighter is off the main I plug a solar panel in that one and I have a panel for the AUX I hook up while camping.

EDIT: electric car seat warmers and converter some times.

Wed May 16, 2012 8:35 am

Yondermtn wrote: So, if I wanted to run my stereo off the AUX battery, I'd have to wire it to the new rear fuse panel? Same with cigarette lighter?

When the bus is running you can still get power from the AUX battery, correct?

Best to mount the aux fuse block up under the dash. Run all your stuff from that.

When the bus is going down the road the aux battery still powers everything. The alternator (or generator) is supplying 13+ volts and the new relay sees that so it closes and both batteries receive the charge. When you shut off the engine the 13+ goes away (the relay opens) and you separate the batteries from each other. This is how you save your "start" battery from depleting.

Wed May 16, 2012 9:21 am

I took a factory bus fuse box and support frame twisted the center support tab the other direction and mounted it up front in the mirror position of the original fusebox.

Ran some fat wire from the new battery up to the fuse box and rewired the bus so anything that I would operate with out the motor running gets hooked up to the aux battery (interior lights, emergency 4way flashers, radio & amps, 12v cig power outlets, VDO clock, gas heater and future plans for external LED flood lights to assist setting up camp). Anything in the back of the bus such as engine room lighting can get run straight off the battery fused with the black twist fuse housings like the one for the reverse lights and blower fan. I think the only thing I can turn on without the motor running and draw down the primary battery are the parking lights. I'm sure I could find a way to even wire them up to the aux battery but I wanted to keep everything that was required to run a vehicle on the primary battery system even though you can pull the aux power wires off of an aux battery and connect to the main battery to run everything should the aux battery crap out. And vis-a-versa.

The second stock fuse box is more than you need so you can run some additional fat cable from the starter and use a portion of the aux fuse box for items you run would only use while driving (fog/driving lamps, cabin blower fans, seat warmers, etc)

Some tricks to save power:
-DC to DC power adapters are way better than invertors
-when you purchase electical devices always try and get them already with a 12v adapter
-wired my stereo so I can bypass the amps when I just need ambient music w/o bowel moving bass
-LED replacement bulbs

My favourite electrical addition is a 20amp power converter hooked up to my outdoor plug at one end and the aux battery at the other. Allows me to plug the bus into a 120v outlet and run all of my 12v stuff plus is an automatic battery charger. The converter cost a bit but it is designed to run even without a battery so it can handle a full load. Many battery chargers are not designed to run loads, only charge a battery.

Next month's project is to hook up a solar panel I've had sitting around as a trickle charger for the aux battery.

Wed May 16, 2012 9:22 am

If the set-up described above works fine, what is the advantage of adding a ACR to the mix?

Wed May 16, 2012 9:37 am

hiwaycallin wrote: If the set-up described above works fine, what is the advantage of adding a ACR to the mix?

A few things... the ACR allows any charging source on either battery to charge both batteries whereas the stock relay method only combines both batteries when the engine is running.

Also it allows for slightly faster charging since you can use bigger wires and the resistance is less.

Personally I spent the money and bought a really fancy ACR...this one which you can find for around $150 if you search.

This is the "ultimate" setup, fully automatic high amp charging in both directions, and also the capacity to manually combine or manually isolate with very simple wiring. The magnetic latch function also eliminates one of the main drawbacks of the other ACR, which is that the ACR draws about 350ma when it's combining. For my solar setup, this was not acceptable. the magnetic latch version draws only about 10ma or can be manually combined so the draw is zero.

Wed May 16, 2012 9:42 am

hiwaycallin wrote: If the set-up described above works fine, what is the advantage of adding a ACR to the mix?

The ACR is made by Blue Sea and is marine grade. The Bus Depot battery relay is pretty light duty (in my opinion) but costs a lot less. They both work pretty much the same way (I think). The ACR does have an LED light on it to tell you when the batteries are combined as well as a terminal on it you can run a wire to power a remote LED light. I did this once. Mounted a small LED in the dash so the driver could see that both Batts were being charged.

The Blue Sea "Add a Battery" kit comes with the ACR as well as a battery switch. Once you have the switch you'll appreciate being able to not only shut down all power from the batteries easily but also combine both batteries for emergency starting.

Wed May 16, 2012 11:30 am

Pete, thanks for the write up. Gary thanks for the additional input. The other ideas/gadgets are also great fodder. I'm holding on to this thread. :wink: