Battery Isolators...

[Cruiserdrew]

Riley, there is room to route wiring underneath the sheet metal in front of the top radiator tank. There is already factory wiring running through there. One consideration is that is an area that may crush in event of even a somewhat minor collision, which then raises the concern of a major short circuit. That risk in part motivates me to include high amp fuses for feeds from each battery as close to the battery as possible.

This is exactly the route I took when doing my dual battery install. I attached mine to the factory harness that rides in that space. Taking that assembly apart takes a fair amout of time and care but provides a secure and safe place to run the cable. Looking at my 60, it looks like there might be room in the same space to do the same thing. Mike- any reason you decided to leave the wire exposed and unsecured?

 

[Mike S]

Mike-You should ground that battery to the block as well. Having only a body ground probably isn't the best idea, maybe you did that and I missed it. I would also consider some plastic wrap or plastic conduit over the cable to provide some additional resistance to chafing. You should also fuse those big cables or you risk turning your 60 into a bonfire.

The cables are grounded to the block. I used very thick cable because it is resistant to chafing. If I think it needs it, I will put some split loom over the cables as well.

The only thing those cables are connected to is the ACR. I could put high AMP marine fuses into the lines, but I do not believe that they are required for a starting circuit. For a winch or other heavy draw accessory, they would be essential.

Mike- any reason you decided to leave the wire exposed and unsecured?

They wires are secured. Exposed? They're in the engine compartment. What did you have in mind?

M

 

[Cruiserdrew]

They wires are secured. Exposed? They're in the engine compartment. What did you have in mind?

M

I'm looking at the pic of the wire running in the groove between the radiator and body. It isn't tied down and isn't protected with split loom. I would fuse that wire at the battery, and try to see if you can find a protected location for it to run. You are right though, it likely makes no difference, but 1% of a fire is too much.

The picture is me at Dusy Ershim 2003.

 

[Rich]

Whether or not the parallel wiring is also part of a starting circuit doesn't make a difference as to the risk of a short circuit.

A difference between the factory starting circuit and the typical fzj80 dual battery system is that in the factory system there is one reasonably short unfused wire that runs directly from the battery down to the starter. It is not routed along the perimeter of the engine compartment. In the typical fzj80 dual battery system with batteries on opposite sides of the engine bay a relatively longer length of cable runs between the batteries and is located in right at the very front of the engine compartment. This cable has much greater exposure to shorting out due to chafing or collision than the factory system. That is why I plan to fuse both positive leads at both batteries.

Whenever the batteries are paralleled by whatever combining device is being used both of the cables joining the batteries will be hot. This means that the paralleling cable needs to be fused at both batteries in order for it to be protected. Fusing the paralleling cable at only one end does not provide short circuit protection when the batteries are paralleled.

 

[Rich]

Drew, how did you fare after the fire was out?

 

[Cruiserdrew]

Drew, how did you fare after the fire was out?

Suprisingly well! My battery had shifted and shorted against the braided steel air line for the front airlocker. The wire harness for the locker was burned, the horn relay was burned and the high tension coil wire burned through. About 1 hour of wiring, and I had everything going except the front airlocker. I drove for 2 more days on the trail and then drove home with no drama. The coil wire was the worst-my friend spliced the carbon fiber core together and wrapped it up with fuel line. It ran great. I now travel with 2 spare coil wires. THat trail is very remote and takes 3-4 days, my fire was on day 1. I felt fortunate to get through in one piece.

 

[siglo]

Has anyone tried TJM dual battery products?

I'm still not sure on how to approach my dual battery setup, already got the batteries (optima bluetop D34M) and a 380Amp marine switch. So far I couldn't find except a 100 amp solenoid (offered by ARB) but 100 amp doesn't seem enough. for wiring I think I'll go with a 2 guage wires. I'll try to get a Blue sea 9012 solenoid..

My main application would be winching and running a fridge/freezer overnight. I wanted a setup where the whole car would run from either battery 1 or 2 when the switch is set to 1 or 2 including the winch.. and the both position to be for extending winching or self jump start. reading this whole thread and seeing the various setups proposed has made me ever more confused

I was thinking of doing Slee's setup but my electrical background is very modest that is why I can't make up my mind. I'm open to suggestions..

 

[Mike S]

Calculate the maximum draw on the combined batteries (winching, lights and fridge running, starting, etc.) and the run (length) of the cables, and you can look up what size cables you need, or call BlueSea tech support. I think size #2 is way too small. size 1/0 would be better.

You probably want everything to run off the primary battery, with the second battery in reserve. This is what is usually recommended.

Mike S

 

[Rich]

Siglo, here is how I will accomplish for myself what you are proposing: https://forum.ih8mud.com/showthread.php?t=34725

 

[siglo]

@Mike
thanks for the info.. I'll try contacting Blue sea

@Rich
I've printed your diagram along with Slee's a while ago and have both laying somewhere in my car.. your diagram fits my requirements but is more confusing to me than Slee's (due to my limited electrical knowledge I'm sure).. I have a some questions though..

what kind of solenoid are you planning on installing?
also, why use a winch enablement switch?
what type of load distribution panel would you recommend?

btw.. when are you planning on installing your dual battery setup?
thanks

 

[Rich]

Siglo, I will answer your questions, but first I will say that if you don't have the knowledge to understand my diagram or slee's, then I would recommend that you not pursue installing a dual battery system until you obtain the knowledge to understand the what and how of designing and installing high amperage power circuits. I'm not being critical of you; nobody is born with this knowledge. But I don't think anybody should be blindly following advice regarding this work that somebody within unknown skills or knowledge has happened to post on the web, including what I have posted via my diagram. If you don't have the knowledge to verify what somebody is suggesting is correct, complete, and proper, then you will have no way to know that it will work for you and be safe. I have seen a number of dual battery systems posted on the web where what is pictured is unsafe, in ways that the installers may or may not be aware or appreciate.

I will likely go with the Blueseas solenoid based on its specs. They have two models. I will be using the non-automatic version. The automatic version has the concept of a primary and a secondary battery, which conflicts with my objective of enabling each battery to be fully redundent and either being capable of being the sole battery operating the entire electrical system.

The underhood winch enablement switch provides two principle benefits 1) when off and with truck locked it prevents anybody from operating the winch unless they are also willing to break into the truck and 2) provides the mechanism to enable automatically disabling the solenoid during winching. The solenoid needs to be disabled in order to winch off of only one battery when engine is running. Otherwise, with engine running, with the battery select switch to either battery, each battery would still be providing winch current, with half going through the solenoid. In my scheme the winch enablement switch is totally optional. The solenoid can be manually disabled by the "parallel charging control switch" in my diagram.

I expect that I will be using one of the Blueseas "powerposts" for handling the power distribution. It is compact and I expect will handle the connections I will need, which is one cable from battery switch, one cable from winch switch, and the existing factory cables going to the factory battery. http://www.bluesea.com/product.asp?Product_Id=30131&d_Id=7465&l1=7465&l2=.

Can't say when I will complete the install, I pursue the work from time to time as it floats to the top of my list of entertaining diversions. The vast majority of the effort is the time required to 1) select the appropriate components based on desired features and the need to be able to support the power draw of the winch (400 amps max) and 2) determine how and where to mount all the bits to fit underhood and be positioned where the risk of wire chafing and short circuits will be minimized. I will probably spend less the 20% of the total time actually installing wiring and components. The conceptual work of designing and planning the layout will consume the majority of the time spent on this project. I probably have already spent more time playing with Visio to do the diagram than I will spend installing the wiring.

 

[siglo]

Thanks Rich, I really appreciate your advise
I was never planning on installing the system myself, I'm planning to have a professional do it.. I am trying to educate myself in order to be able to better discuss and communicate my requirement with the electrician.. I don't like it when electricians or mechanics try to talk over my head that's another reason I'm trying to understand everything I can before proceeding with a dual battery setup..

btw, have you looked at TJM dual battery setups?

 

[Rich]

Today I looked at the sparse info TJM has published on their website. It's a totally different direction than I am taking. It doesn't appear to offer the features that I am looking for which is total redundancy between both batteries, total disconnect, and simple mechanical control of switching between off, either battery, or both batteries.

It appears to me that the BlueSea "Automatic" soleniod would provide the same basic functions as TJM's product.

 

[Mike S]

I'm looking at the pic of the wire running in the groove between the radiator and body. It isn't tied down and isn't protected with split loom. I would fuse that wire at the battery, and try to see if you can find a protected location for it to run...

Andrew, I took your advice, and the cable is now sheathed in split loom and secured to the radiator support with zip ties.

Whenever the batteries are paralleled by whatever combining device is being used both of the cables joining the batteries will be hot. This means that the paralleling cable needs to be fused at both batteries in order for it to be protected. Fusing the paralleling cable at only one end does not provide short circuit protection when the batteries are paralleled.

As for the marine grade, hi amp fuses, I used these when wiring by boat for dual DD marine batts for the trolling motor. I really don't see that they buy me much here in case of a collision. First, the cable (as you correctly point out) is only hot when the batteries are combined. In this system they are only combined when; 1.) I am starting with a low primary battery, or, 2.) when the B battery is being recharged - for perhaps a few mintues after it is used to start. Also, to add them 'close to the battery, I would need to install the fuse holder, and a short cable from the battery to the fuse holder. This is a lot of additional connections for dubious protection in a collision sitiuation. It can, of course, be retrofitted into the system if I decide to add it later.

Please post pictures of your manually operated system when you are done planning and actually have it installed. We all like to see stuff that is different.

As it is, this system is preforming flawlessly, and the BlueSea Contoura rocker with LED allows me to lock it open, closed, or leave it automatic. This was installed in the cutout in the dash next to the steering column and iginition key.

 

[Rich]

Mike, my understanding is when the relay you are using is set to automatic that both batteries will be combined whenever the starting battery is up to 13.6 volts, which means that long cable will always be hot when engine is running except for right after starting.

I appreciate the extra trouble fusing the main battery cables presents, but I do believe that that the long cable up front presents a significant short circuit hazard. Given the cable size and it's current carrying capability, a nick in the insulation contacting the body could be quite spectacular.

I spent a bit of time out in the sunshine on Saturday working out the layout and mounting for the main battery switch. I also have worked out a scheme where the solenoid can connect directly to the main battery cables going to the 4 way battery switch, which will eliminate the need for 2 of the 5 fuses I have in my current schematic.

 

[Mike S]

Rich

I think the open / closed scenario is academic, since the cable COULD be broken and it's 'live' whenever there is a accidental ground. Otherwise, not to worry, right?

They are connected when charging, as you point out. Again, academic.

The way I see it, the original battery starting cable was unfused. The ACR sits between the battery and the starter, and the original cable is in place (I may change it out later if it starts to have problems). BlueSea specifically states that no fuse is needed on the starting circuit. So the only fuse I could conceivably need is one to protect against accidental short in the main cable from the back-up battery (DS). IF I installed a MegFuse, the questions is - what fuse rating to use? Too small, and I could blow the fuse needlessly, too high and the protection wanes. If the max amps I need for cranking is 200 AMPs, I should use a 200 amp fuse. That MIGHT prevent any big problems in an accident, but it is still high enough to start a fire.

Or I could just buy a bigger bumper?

M

 

[Rich]

Mike, I'm not able to follow your meaning about academics. My point is that the parallel cable is generally going to be hot all of the time the engine is running, and therefore poses a short circuit hazard anytime the engine is running, and that the only way to provide over current protection to the paralleling circuit is to fuse it at both battery connections at each end of the circuit.

When Blueseas says fusing is not required in the main feed to a starter motor, they are referring to ABYC standards, which are engineering standards for marine vessels. In the past, small high amp DC fuses were not available, so the ABYC standards exempted the starter motor circuit from fusing. I don't believe that they are implying that starter circuits are safer than any other circuits and therefore should be left unfused.

The Toyota main feed to the starter motor is also unfused, as I expect is true for most or all automobiles. I also expect it is for the same reason: that, in the past, small inexpensive high amp DC fuses were not readily available.

It is worthwhile to compare the difference between the routing for the starter motor and your parallel cable. The starter motor feed (in a FZJ80, I haven't looked at a FJ60) runs pretty much directly from the battery down to the starter motor, away from the periphery of the engine compartment. In contrast your parallel cable runs exposed across the front of the engine compartment for its entire length. In my opinion this cable is much more exposed to chafing and damage than is the factory starter cable and is therefore at much higher risk of a short circuit. My cable will follow a similar route, but be somewhat more protected underneath the sheet metal and not in contact with the radiator tank. There will still be notable risk of short circuit, and this is what motivates me to fuse both battery feeds.

In your case, with 1/0 cable, 200 amp fuses at each end should protect the cable quite well. 200 amps is well within the ampacity of 1/0 cable, depending on the temp rating of the insulation. I would suggest taking steps to prevent direct contact between the cable and the radiator tank on general principles. But if your not going to run a winch, I don’t see you ever getting anywhere near impinging on the ampacity of your cable, other than a short circuit, which the fusing would address.

My task will be a bit more challenging, as I am intending to install a winch which will require me to deal with a max potential draw of around 400 amps intermittent.

Adding any additional wiring to our trucks adds additional risk. In my setup I will be taking all practical steps to recognize and minimize the risks involved to the best of my ability, while also striving to maintain a balance with weight, cost, and ability to route and mount the components and wiring.

 

[Mike S]

Rich:

I used the 'academic' line of reasoning simply because the cable - if accidentally grounded - would be hot regardless of whether the batteries are combined or not.

So the only risk is a breach in the cable, regardless of the state of the ACR.

the cable has very heavy insulation, is covered with split loom, and zip tied in place to the radiator supports. I COULD add the fuse (yeah, I know about ABYC sandards), but we are getting to the sub 1% level of security, where the economic laws of diminishing returns come into play.

Post pics when you have your project done.

M

 

[TOYOTADRUNK]

I just read the entire thread and must admit I am confused, arent there some books out there that I can read to better understand diffrent dual battery systems. The whole mobi-arc thing just threw me into a coma and I cant recover. Must read book!

 

[Mike S]

There are couple of modes or designs discussed here. One (Rich's) is for complete isolation of the winching and other loads, and others, mine included, are for the second battery as a back-up for starting.

Go to the Hellroaring site for additional discussion and diagrams for various configurations.

M