Dual battery systems; making sense of the options (2 Viewers)

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Those military terminal adaptor plates are slick! Did you fab those up yourself or are they readily available for purchase somewhere?


Got mine from Slee.........
 
yep I have been using them for 30 years. Cheap, easy to remove the battery or install it. Dumb simple....the way I like it. :)
 
Suddenly those arent desirable at all. $100 cad for some terminals and adaptors...will stick to bolting my eyelets directly to the terminal. 6 of 1 half dozen of the other..... either american wages are better or the canadian dollar is terrible :rofl:
As others have said, they are from Slee. They are not cheap at $49 us. The mil spec terminals are easy to find cheap other places. I have not been able to find the extensions anywhere else.
 
Ideally with electrical install locations, you want it as clean, dry and cool as possible. The BCDC also wants to be mounted as close as possible to the auxiliary battery in order to reduce or eliminate voltage drop. in my testing and experimenting, I have mounted the BCDC in an 80 in 4 different locations with no charging issues. My personal one is behind the PS headlight and it stays very cool there. Others near and around the aux battery or the starting battery. Taking temps throughout the engine bay, I’ve found the hottest place to mount would be high up, closer to the firewall. I’m sure a bracket can be made to mount it in front of the radiator, but I’d prefer, at least on an FZJ80, not to block airflow thru the radiator. I wouldn’t be afraid to mount the BCDC 10’ away from the aux battery either. With the 25amp unit, I run 8awg, but if you have longer runs, Redarc suggests a 6awg cable.

I have a 200 series and there looks like there is a lot of room to mount this thing... to minimize wiring I think i will put a blue sea fuse box in the rear of the truck and wiring everything up to it...
 
hi everyone, can i just hard wire 2 lead acid batteries together as the cheapest option for extra led bar and a winch? if so, will 2004 LC100 alternator charge them in parallel? actually how many amps is lc100 2004 UZJ100 alternator ? thanks in advance
 
I installed a pretty basic dual battery system. I really wanted to isolate power used by accessories, like a fridge, when parked to a dedicated house battery. There are many possible routes to achieve a functional dual battery setup; this is how I did it.

Objective:
Install a simple and cost effective dual battery system

Goals:
System should operate automatically, manually or be switched off
Ability to self jump start
Keep it safe

I like to draw basic diagrams when doing electrical work, for home or vehicle. This helps keep me organized and greatly reduces the chance of me wiring in a short circuit or having and un-fused power source. Below is a basic diagram for this dual battery system.

Dual Bat Wire.png


This works as follows:

Voltmeters - I can view the battery voltage anytime. With the solenoid deactivated the voltmeters will show the resting voltage of each battery. With the solenoid active the voltmeters will display the voltage of the batteries combined. Obviously if the rig is running and the solenoid is active, the voltage displayed should be the charging voltage and the same.

Charge/Solenoid control
- AUTO, the solenoid is activated when it receives power from an ignition power source. This setting automatically ties the batteries together when the vehicle is running and isolates them when it is off.
- ON, the solenoid is activated when it receives power from the house battery. This allows a self jump start in case the starting battery has died.
- OFF, the solenoid will not activate and the batteries are isolated from each other.

The control center for the batteries is fitted to my overhead console. The primary switches replaced the useless sunroof controls in my 100 since the sunroof hasn't operated in years. The small digital voltmeters were cut into the console.

IMG_20190623_132519.jpg


The 2nd battery tray I am using is an old style Slee Offroad tray, which is designed for an Optima battery. Since I was trying to keep costs down, I found a Group47 AGM battery that fit the tray. As a bonus the terminals are recessed into the battery case.

IMG_20190420_162455.jpg


At both the starting battery and house battery, I installed Bussman fuse holders and 300A MEGA/AMG fuses to protect the vehicle and batteries from a massive short circuit in the event a cable breaks. I used 2AWG welding wire, tinned copper lugs, braided loom and adhesive backed heat shrink to build the battery cables.

00100dPORTRAIT_00100_BURST20190804124905909_COVER.jpg


I tucked the solenoid against the firewall directly in front of the driver's seat. The solenoid engages with a solid audible 'click'. I made sure to cover all positive terminals in the whole system.

00100dPORTRAIT_00100_BURST20190804124844090_COVER.jpg


I could easily add a solar charge controller + panel to the house battery if desired. With my current use of driving daily and only relying on the battery overnight, I have no problem maintaining a charge.
 
Help me with this situation please,
Since I have been forced to work from home my '94 80 series has more or less been sat on my drive. I noticed over the weekend that the fridge had stopped. For the past 18 months it has more or less run 24x7 and never skipped a beat.
I have a 75Ah flooded lead acid deep cycle battery which is connected to my starting battery via a Blue Sea ACR. I also have 2 x 100watt solar panels on the roof which are connected to an EPEVER Tracer solar controller. The only thing that runs in the vehicle when it is parked up is the fridge. I always assumed that the 2 solar panels should provide sufficient power to run the fridge but clearly that is not the case.
Any suggestions on where to start making improvements?
 
Is the fridge connected to the same battery that the solar is charging? Maybe just some small variables like fridge temp, outside temp, shade or battery condition made a difference? I run my half full 50qt ARB 24/7 with 100watt solar panel on my roof with no problems, but again environmental differences may be the factor.
 
Is the fridge connected to the same battery that the solar is charging? Maybe just some small variables like fridge temp, outside temp, shade or battery condition made a difference? I run my half full 50qt ARB 24/7 with 100watt solar panel on my roof with no problems, but again environmental differences may be the factor.
Yeah, the fridge is actually connected to the load output on the solar controller. When the solar output is insufficient the power is taken from the second battery.
Over the next few weeks I will get to keep a close eye on this. Might make for an interesting science project (that's how bored I expect to be ). I had been toying with the idea of removing the ACR and solar controller and fitting the Redarc BCDC unit. Not sure if it worth it though...
 
First step would be to measure voltages to see what is going on...

a) Battery connected to solar charged?
b) Solar panels working?
c) Solar actually outputting charge current to battery?
d) Connection between solar charge controller and fridge?
e) Fridge actually works?

Then you can spend money buying new toys :)

cheers,
george.
 
I am kind of worried about this happening to me. I have not gone solar yet but I plan to. I am about to add a house battery and I am looking into ways to switch it. I have an 80 series so no complicated alternator, but if my starting batteries are fully charged then I suppose it is possible that my house battery will not charge and I will be dead in the water or I won't be able to use my house battery because it is dead and won't charge. I plan on switching the house battery to isolate it when using it for extended periods and I have an ACR to charge, but that won't be of much use if the starting batteries are fully charged right? Is a Redarc about the only way to guarantee I get all my batteries charged to full capacity? I was going to ask if Irish Reiver's solar panels were before or after the ACR. Would there be enough amperage (or would it have to be a total wattage?) to open the ACR and charge the house battery? Just a thought.
 
IR, yes, I would also expect 200W to be enough this time of year if you don't have weird shading going on in your driveway. Something is off and perhaps manifested itself only now due to the lack of alternator charging.
No recent change in settings for the controller eh?
 
I am kind of worried about this happening to me. I have not gone solar yet but I plan to. I am about to add a house battery and I am looking into ways to switch it. I have an 80 series so no complicated alternator, but if my starting batteries are fully charged then I suppose it is possible that my house battery will not charge and I will be dead in the water or I won't be able to use my house battery because it is dead and won't charge. I plan on switching the house battery to isolate it when using it for extended periods and I have an ACR to charge, but that won't be of much use if the starting batteries are fully charged right? Is a Redarc about the only way to guarantee I get all my batteries charged to full capacity? I was going to ask if Irish Reiver's solar panels were before or after the ACR. Would there be enough amperage (or would it have to be a total wattage?) to open the ACR and charge the house battery? Just a thought.

Solar is enough to open the ACR and charge both batteries. The ACR works both ways in both directions, so it's pretty failsafe. I have been doing this for years with a 100w panel and it has always worked fine. IMHO, all this dual battery, solar, etc, gets way too overthought and over done too often. Its really just math. I have always preferred a KISS methodology to the electrical in my rig and with that I have had decades of trouble free usage and never yet stranded because of a dead battery. If I was to do it again, I would probably go to a 150ish watt solar panel just for a bit more peace of mind.

I am currently setup so that when driving my truck charges the main, secondary, and trailer battery and then when parked, the solar charges the trailer and both truck batteries. Basically, I am charging everything always regardless of if I am running or not and the ACR always protects my starting battery from draining from accessories, etc.
 
So the ACR DOES protect both ways? I was worried about that. I was going to add a switch so just the house battery was used for (house) power on extended stays and left the starter battery alone. That is one of my main goals. I have been trying hard to try and do the KISS method as much as possible, but I just found myself looking at a Redarc which I did not want to buy. My main worry is that once my starter batteries are fully charged, my house battery will not charge anymore. But I thought about using your idea of just simply adding a solar panel to the house (therefore all) batteries and it would take care of everything I need. But as long as my starter batteries are always charged and isolated from being used under house power, that is all I really want. If the ACR does that, then that is good news.
 

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