How to make a cheap isolated dual-battery setup for $50
- Thread starter evldave
- Start date
dlichterman
Explorer
Is there a reason for the stinger to be all the way over there? Seems like if you could mount it on the drivers side it'd be a lot less wire going back and forth.
That is where the stock truck battery is, i guess i could shorten up the ignition fuse line a little but i would still need to bridge the power and ground lines so the cables would still need to run the full length regardless of where i place the stinger isolator, or am i missing something?
I am copying another build i have seen online for this truck.
I was also told you have to connect the negative posts on both batteries so the truck can "sense" the 2nd battery and charge it. With all the electronics in cars these days, it does not surprise me and i believe it. His setup seems to be working fine for an audio system pulling a ton of power so this should work fine for my needs, i'm just trying to keep a dometic cf-50 running while the truck is off.
I am copying another build i have seen online for this truck.
I was also told you have to connect the negative posts on both batteries so the truck can "sense" the 2nd battery and charge it. With all the electronics in cars these days, it does not surprise me and i believe it. His setup seems to be working fine for an audio system pulling a ton of power so this should work fine for my needs, i'm just trying to keep a dometic cf-50 running while the truck is off.
dlichterman
Explorer
Ohhhhh, so the 2nd battery is going on the passenger side? That makes a bit more sense. I did connect the grounds of mine too. Next you need to scope creep some solar....
dlichterman
Explorer
I have 2 of the Renogy panels - they work great. A proper deep cycle is on my wish list.
So I'm almost finished gathering parts for my isolator setup, and had a 2-3 questions.
I have a diesel E350, so it has two batteries from the factory, one under the hood and one on passenger side frame rail. I'll be adding additional house batteries. I want to make my connections to the rail battery. Should I connect positive to rail battery, negative to hood battery, or just make both to rail battery? I eventually plan on upgrading the factory wiring between the hood and rail battery, but don't know if I should do anything different until then.
I'll be putting a fuse as close to the battery as possible, any reason not to have the isolator in my house battery box instead of on the frame rail next to the battery? I figure the load will be the same in either spot, so it shouldn't make much of a difference.
Thanks!
I have a diesel E350, so it has two batteries from the factory, one under the hood and one on passenger side frame rail. I'll be adding additional house batteries. I want to make my connections to the rail battery. Should I connect positive to rail battery, negative to hood battery, or just make both to rail battery? I eventually plan on upgrading the factory wiring between the hood and rail battery, but don't know if I should do anything different until then.
I'll be putting a fuse as close to the battery as possible, any reason not to have the isolator in my house battery box instead of on the frame rail next to the battery? I figure the load will be the same in either spot, so it shouldn't make much of a difference.
Thanks!
DiploStrat
Expedition Leader
Scholars Differ
Some insist that you must have a dedicated ground wire from the camper battery back to the negative terminal of the starter battery. I don't. My starter battery is grounded to the frame and my camper battery is likewise grounded to the frame. You do have to use a cable that is at least as large as the positive cable and you do have to make sure that you are connecting directly to the same frame that is used by the starter battery, not some branch that may not have a good connection.
You need to fuse the positive cable as closely as possible to each battery's positive terminal. (I like terminal post fuses.) You can put the isolator relay wherever it is most convenient; makes no difference.
Some insist that you must have a dedicated ground wire from the camper battery back to the negative terminal of the starter battery. I don't. My starter battery is grounded to the frame and my camper battery is likewise grounded to the frame. You do have to use a cable that is at least as large as the positive cable and you do have to make sure that you are connecting directly to the same frame that is used by the starter battery, not some branch that may not have a good connection.
You need to fuse the positive cable as closely as possible to each battery's positive terminal. (I like terminal post fuses.) You can put the isolator relay wherever it is most convenient; makes no difference.
Wow! It's taken me 4 years to finally use this thread!!! I'm almost finished with my second battery setup.
Its cost more than $50. Let's blame it on Obama and inflation, shall we?
Hierotochan
New member
Long time stalker, first time poster.
Thanks to the OP, I'm really enjoying reading through this. It's great to have informed opinions.
I've asked about this sort of thing before in camper groups and everyone recommends one of the expensive kits.
I'm sure they're great, but less is more (less to go wrong at least)!
I'm about to do a 'big 3/4' swap and the diagrams are really helpful for the simple minded. 😉
My new battery is a different profile to the old one, hence needing to move the terminals anyway, so while I'm there I'm going to prep for the dual + solar setup.
I found the Rugged Ridge dual battery wiring kit and am glad I didn't go for it after reading/finding the thread, your solution is much cheaper!
I do like the rocker switch though, so might connect one of them...
Anyway, I'll post photos as I go. Out of interest anyone here completed this on a 4.0 Jeep?
Think I'm going to make myself a stepped battery tray...
Thanks to the OP, I'm really enjoying reading through this. It's great to have informed opinions.
I've asked about this sort of thing before in camper groups and everyone recommends one of the expensive kits.
I'm sure they're great, but less is more (less to go wrong at least)!
I'm about to do a 'big 3/4' swap and the diagrams are really helpful for the simple minded. 😉
My new battery is a different profile to the old one, hence needing to move the terminals anyway, so while I'm there I'm going to prep for the dual + solar setup.
I found the Rugged Ridge dual battery wiring kit and am glad I didn't go for it after reading/finding the thread, your solution is much cheaper!
I do like the rocker switch though, so might connect one of them...
Anyway, I'll post photos as I go. Out of interest anyone here completed this on a 4.0 Jeep?
Think I'm going to make myself a stepped battery tray...
Been reading on this thread ever since I got my 79 VW Bus.
So I plan on getting a dual- battery setup, but slowly as I can afford it.
I got my inverter last week (1100 watt with digital display).
This week I will be ordering my gear to hook up a second battery, after that I'll buy the battery, and lastly the solar kit.
My questions..
1. I found an isolator (Stinger SGP38 80-AMP Battery Isolator and Relay) on amazon that is cheaper(only $15 + free shipping) than the first 2 options in the original post and has better reviews as well.
Would it work the same and just as well? Any pros or cons?
2. As far as cables to connect the batteries, the cheapest (but still affective) way is to buy jumpstart cables(and cut em) and fuses, or would a wire kit be in my best interests? Theres a $28 wiring kit on amazing that has 10ft #4 black, 10ft #4 red, 8ft #8 green, heat shrink + terminals. The kit is called "Cobra CPI-A4000BC 4-AWG Heavy-Duty AC Power Inverter Cable Kit"
3. I really wanted to get 2 6volt golf cart batteries and hook them up in series as I heard this is the best way to go for my needs. I don't use that much power, mainly fans, lights, charging, music. Any suggestions on cheap but good batteries for me?
Hope this isn't a redundant post, just want to get some advice before I pull the trigger and drop some coin. Thanks for taking the time to read!
So I plan on getting a dual- battery setup, but slowly as I can afford it.
I got my inverter last week (1100 watt with digital display).
This week I will be ordering my gear to hook up a second battery, after that I'll buy the battery, and lastly the solar kit.
My questions..
1. I found an isolator (Stinger SGP38 80-AMP Battery Isolator and Relay) on amazon that is cheaper(only $15 + free shipping) than the first 2 options in the original post and has better reviews as well.
Would it work the same and just as well? Any pros or cons?
2. As far as cables to connect the batteries, the cheapest (but still affective) way is to buy jumpstart cables(and cut em) and fuses, or would a wire kit be in my best interests? Theres a $28 wiring kit on amazing that has 10ft #4 black, 10ft #4 red, 8ft #8 green, heat shrink + terminals. The kit is called "Cobra CPI-A4000BC 4-AWG Heavy-Duty AC Power Inverter Cable Kit"
3. I really wanted to get 2 6volt golf cart batteries and hook them up in series as I heard this is the best way to go for my needs. I don't use that much power, mainly fans, lights, charging, music. Any suggestions on cheap but good batteries for me?
Hope this isn't a redundant post, just want to get some advice before I pull the trigger and drop some coin. Thanks for taking the time to read!
patoz
Expedition Leader
Cheap jumper cables are cheap because they use cheap quality cable to build them with. Therefore your new system, which your life or well being may depend on at times, will be cheaply constructed using the same cheap cable. Spend the extra money and buy quality cable and connectors. Look at bulk welding cable to keep the price down some. Marine tinned cable is the best, but very expensive if you need much of it.
4-AWG is too small to connect the batteries with, but should be OK for that size inverter. Most automobiles use at least 2-AWG, and larger trucks use even bigger size cables. Also, the length of the cable dictates the larger sizes.
The electrical system on an off-road vehicle is the last place I would ever cut corners on. Even the modern fuel system won't function without a good working electrical system, not to mention the fire hazard that exist from undersized and poor quality components!
I agree on the wire. Generally jumper cables are made with inexpensive copper coated aluminum wire. Look for 100% copper conductors with temperature rated insulation. Welding cable can be very cost effective in bulk.
Generally 2 gauge is about right for connecting batteries.
I upsized all my winch cables to 1/0. (Warn supplies 2 ga for almost all winches)
Generally 2 gauge is about right for connecting batteries.
I upsized all my winch cables to 1/0. (Warn supplies 2 ga for almost all winches)
patoz
Expedition Leader
Hahaha, this would be true! I was just referring to the parameters available to us ordinary 'Po Folks', when it come to throwing money into said holes!
Being a retired DoD District Fire Chief, I've worked around military aircraft and had occasion to use some of 'the best stuff' or is that 'the right stuff', and now all I can do is just cry when I have to use the 'junk' that most stores sell now days.
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