I've run 2.0 AWG wire from my battery to the rear storage area (behind the rear seats

[MagicMtnDan]

2014 Jeep Wrangler JK Unlimited Rubicon

I've run 2.0 AWG wire from my battery to the rear storage area (behind the rear seats) to a Blue Sea 12 circuit fuse block.

I now want to connect a 2nd battery (and AGM battery?) located in the rear and use it as a 2nd (dual) battery. It will move weight to the rear, save me hundreds over the Genesis Dual Battery kit and give me peace of mind having a 2nd battery.

Questions:

1. Is this a good plan? I'll secure the battery so it's not loose.

2. Is an AGM battery the way to go? Is there anything I need to know about using an AGM battery in regard to maintenance, etc?

3. What is the best product to use to combine batteries during charging and isolate the batteries when discharging? I found two options - which of these is best or is there a better option?

https://powerwerx.com/blue-sea-7611-batterylink-charging-relay
or
https://powerwerx.com/blue-sea-7622-auxiliary-battery-separator-500amps

I'm OK with electrical but understand the risks and want to do this right.

Thanks in advance for your input.

 

[MagicMtnDan]

Moderator: please delete this thread - double post

http://www.expeditionportal.com/for...-as-dual-battery-system?p=2184609#post2184609

 

[verdesardog]

Sounds good, but would get two new identical batteries to start with. Combo deep cycle/starting batteries would probably be best for your use.

 

[mmaattppoo]

I did something like this in my JKU Wrangler using 4 gauge cable runs between my Northstar Group 34/78 AGM starting battery and a 76 Ah Northstar deep cycle AGM battery. Alternator based smart charging, battery separation, and solar MPPT charge controller duty is handled by a CTEK D250s Dual.

The selection of wire gauge will depend on your application. The more current you plan to draw, and the distance of your cable run, the smaller the gauge cable you will need to consider to avoid an excessive voltage drop avoid the your load.

I choose 4 gauge cable since my one way circuit distance is about 15 ft and maximum anticipate load will be 50 amps resulting in just north of a 3% calculate voltage drop...good for my application. The D250s charges ay just over 20 amps so I have approximately 30 amps spare capacity.

The CTEK D250S Dual (or other DC to DC charger) is something you may want to add to your system to ensure your house battery is charged to 100%. Just connecting a house battery to your vehicle's charging system will not achieve 100% SOC (state of charge) and may result in a reduced life span for you house battery.

The D250S Dual boosts voltage from your alternator (at the expense of drawing slightly more current) and ensures that the house battery is charged according to the charging profile of the D250S Dual. The D250S Dual is best placed close to the battery it is charging so that the charging voltage output from the D250S Dual to the house battery does not experience any drop.

Here's a photo of the completed setup (including meters to monitor charging input and loads):

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[4x4junkie]

2014 Jeep Wrangler JK Unlimited Rubicon

I've run 2.0 AWG wire from my battery to the rear storage area (behind the rear seats) to a Blue Sea 12 circuit fuse block.

I now want to connect a 2nd battery (and AGM battery?) located in the rear and use it as a 2nd (dual) battery. It will move weight to the rear, save me hundreds over the Genesis Dual Battery kit and give me peace of mind having a 2nd battery.

Questions:

1. Is this a good plan? I'll secure the battery so it's not loose.

2. Is an AGM battery the way to go? Is there anything I need to know about using an AGM battery in regard to maintenance, etc?

3. What is the best product to use to combine batteries during charging and isolate the batteries when discharging? I found two options - which of these is best or is there a better option?

https://powerwerx.com/blue-sea-7611-batterylink-charging-relay
or
https://powerwerx.com/blue-sea-7622-auxiliary-battery-separator-500amps

I'm OK with electrical but understand the risks and want to do this right.

Thanks in advance for your input.

#1.
Yep, that'll work. Don't forget about your ground (your post isn't real clear)... Either another 2 AWG back to the underhood battery, or with proper preparation you should be able to use the vehicle frame as your ground (involves bonding the frame & battery (-) together under the hood using similar-sized wire as your positive feed).

#2.
AGM batteries in my opinion are way overhyped in the 4WD world. This is not to say they don't have advantages over standard FLA batteries (they certainly do), but far & wide those advantages aren't utilized to a significant enough degree in a typical (non-competition) application to make their double-triple cost worthwhile, especially in multiple-battery configurations where current duties are shared among two or more batteries. A good quality FLA starting (SLI) battery together with a "maintenance free" deep-cycle battery for your house loads provides every bit of energy as their (far more costly) AGM counterparts will.
I stress 'maintenance-free' because these have lead-calcium plates which have exceptionally low hydrogen gas production and very rarely (if ever) require any additional water, making them acceptable to put in the interior of a vehicle (virtually all SLI batteries are maintenance free, but there still is a small number of deep-cycle types available that are "low-maintenance", which consume more water and emit more gas).
Deka makes good batteries, though the best value anywhere in batteries is probably at Costco (their Kirkland/Interstate units). The Deka Marine Master is a bit over $100 at Lowe's (the home improvement place), though Costco's deep-cycle unit (#27) is a mere $80, and with proper care (occasional overnight charging) should last 5 years or longer (if you don't have a Costco card, then go with Deka).


#3.
Hard to beat this setup for value:
http://www.expeditionportal.com/for...ke-a-cheap-isolated-dual-battery-setup-for-50

If the batteries are isolated when the key is off, it is not imperative that the batteries match. Only if they are hard-wired in parallel do they need to be the same.

 

[MagicMtnDan]

Thank you for your input!

I asked about AGM battery because I'm concerned about using a standard battery and venting it inside the Jeep.

Seeing the pics of the gauges/panels is intimidating because I don't know what they are or what I need (hence my questions).

I need some specific electrical advice as to how to wire this system. I'll look at that great thread - thanks for the link - I forgot about that thread.

 

[DiploStrat]

#1…
#2...
#3...
Hard to beat this setup for value:
http://www.expeditionportal.com/for...ke-a-cheap-isolated-dual-battery-setup-for-50

If the batteries are isolated when the key is off, it is not imperative that the batteries match. Only if they are hard-wired in parallel do they need to be the same.

Agree with all points. If you really want to geek this stuff, look under "Documents" on my website. You will find background studies and the slides of my presentations at Overland EXPO. These slides include a discussion of when a DC to DC charger will and will not help you. Also a discussion of when an automatic relay may offer advantages over a key controlled relay.

 

[MagicMtnDan]

Thanks!

 

[MagicMtnDan]

So here's my plan so far:

Purchase Blue Sea Systems ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A #7622 (product number)
https://www.bluesea.com/products/76...rging_Relay_with_Manual_Control_-_12V_DC_500A

Use this wiring diagram (disregarding brown, green and orange wires):

I'll use my Blue Sea Systems Fuse Panel to power accessories off the House battery.

This will give me a true dual battery system that will enable me to (1) charge both batteries, (2) isolate both batteries and (3) jump the Main Starting Battery from the House Battery if/when necessary.

I understand a solenoid will do some of this but this is a better, more complete solution as the solenoid doesn't disconnect the batteries.

Thoughts?

 

[DiploStrat]

So here's my plan so far:

Purchase Blue Sea Systems ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A #7622 (product number)
https://www.bluesea.com/products/76...rging_Relay_with_Manual_Control_-_12V_DC_500A

You can save a little bit of money by buying the model without the mechanical override - the dash switch is really all you need. https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

...
I understand a solenoid will do some of this but this is a better, more complete solution as the solenoid doesn't disconnect the batteries.

For the purposes of this discussion, a solenoid and a relay are the same thing. The Blue Sea uses a solenoid to move the switch and then holds it in position with a permanent magnet to save electricity.

Parthian Shot: Don't forget to fuse the whole mess - at both ends.

 

[4x4junkie]

Thank you for your input!

I asked about AGM battery because I'm concerned about using a standard battery and venting it inside the Jeep.

As long as it's a maintenance-free type, it should be fine. Just don't seal it inside an airtight enclosure (a battery box is fine as long as it doesn't have rubber seals on the lid & wire exits, etc.). It's not a good idea to put AGM batteries in airtight boxes either, since they too can emit hydrogen under some adverse conditions.

 

[MagicMtnDan]

Thanks for your input about the battery box.

On the WranglerForum someone suggested this one which does appear to be sealed but it has a vent tube...

https://m.summitracing.com/parts/mor-74051

 

[Mo4130]

So here's my plan so far:

Purchase Blue Sea Systems ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A #7622 (product number)
https://www.bluesea.com/products/76...rging_Relay_with_Manual_Control_-_12V_DC_500A

Use this wiring diagram (disregarding brown, green and orange wires):

I'll use my Blue Sea Systems Fuse Panel to power accessories off the House battery.

This will give me a true dual battery system that will enable me to (1) charge both batteries, (2) isolate both batteries and (3) jump the Main Starting Battery from the House Battery if/when necessary.

I understand a solenoid will do some of this but this is a better, more complete solution as the solenoid doesn't disconnect the batteries.

Thoughts?

I have that same setup and I absolutely love it. The peace of mind is more that worth it. Like my friends and I say you can't put a price on peace of mind.

 

[MagicMtnDan]

I have that same setup and I absolutely love it. The peace of mind is more that worth it. Like my friends and I say you can't put a price on peace of mind.

Thanks. Of course I agree.

What can you tell me about your installation? Where's your House battery - in a sealed box in back or ?

 

[Mo4130]

Thanks. Of course I agree.

What can you tell me about your installation? Where's your House battery - in a sealed box in back or ?

I have a leer cap so it's in an enclosure I made in the back. Check out my build thread a couple pages back in the Nissan forum. Installation was straight forward and has been super effective and confidence inspiring.


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