Dual battery systems for DIESEL Jeeps - the full story!

[Genesis Offroad]

Genesis Offroad now has dual battery systems in stock for the diesel Wrangler and Gladiator!

Below we have our overview videos and also our detailed installation videos that cover a lot of information.

To address the biggest topic of our new kits, yes, we have to put the extra battery under the back seat, not under the hood. We typically like to keep the batteries and all the wiring together under the hood, but the reality is that those days are over. The diesel engine bays are just too compact. When I got our diesel Gladiator, at first glance it seemed like we would be able to drop a couple Group 25 batteries in there, just like the gas JL. The first hurdle I ran into was getting the stock plastic battery tray out of the engine bay. It was obnoxiously, stupidly difficult to remove. It looks like the factory must have installed the battery tray before they installed the engine or anything else, because there was so much stuff in the way. The stock battery tray runs from the firewall all the way up to right behind the headlight, and there's an obscene number of wires in the way. After fighting with it for hours, I finally stood up on top of the engine, reached down and yanked the tray so hard I almost fell off. Once the tray was out, again at first glance it looked like the batteries would fit. The factory wire bundles along the fender were a problem, and they have no slack at all to move them anywhere. I ended up buying a 3d scanner to get a very detailed scan of the space we had available to try to design a battery tray in CAD that would fit precisely. I spent a huge amount of time trying to find a way to get 2 batteries to fit, but it was so tight that a Group 25 battery was bumping the fender side and the engine side. I looked at using a smaller battery, but any standard normally available battery that was any smaller had far less cold cranking amps and capacity than even the stock battery, so it just didn't make sense. Even if the batteries would fit, the first step of our installation instructions would be to move the engine over by one inch just to get the stock tray out.

Our design philosophy from the very beginning is to make the most complete and easiest to install dual battery systems on the market. So even if we found a battery with enough capacity that fit, it still would be WAY too difficult to install. So, after all that, it was time to abandon ship and come up with a new plan.

I looked all over the vehicle, front to back, top to bottom. I considered mounting an extra battery under the vehicle, maybe tucked up behind the rear wheel, or maybe bolted to the side of the frame, as I believe I've seen one or two guys on here doing a DIY job like that. Also thought about using the bed of the Gladiator, or the rear storage cubby in the rear floor of the Wrangler. However, again I kept coming back to the same issue - none of those would be easy to install. I know I personally do not want to lay on my back and lift a 50+ lb battery up to a bracket under the vehicle even once, and I sure don't want to get under there to do maintenance on it or run extra wires to it in the future. I also do not want to cut out the rear floor of the Wrangler to fit a battery large enough to justify the cost and trouble.

So, that leaves us with the space under the back seat. Here's how I see the pros/cons of using that space.

Pros:

• Super easy to install
• You only need to purchase one battery
• You don't have to toss your stock battery
• Many more options for battery size, not limited to just one specific size
• Run your accessories even longer with larger batteries - up to a Group 27F for the Wrangler, and up to a Group 31 for the Gladiator
• Potentially longer battery life away from extreme under hood temperature swings
• Extra battery weight located low and center of the vehicle
• Easy future battery maintenance
• No modifications to anything under the hood
• Less chances of any problems after the install
• Easier for your mechanic to perform normal diagnostics/maintenance under the hood
• Easy to move the kit to a new vehicle in the future
• Factory Stop/Start system remains untouched

Cons:

• Consumes limited storage space inside the vehicle, especially for the Gladiator
• Cost of the kit is slightly higher, mainly due to the extra power cable for the Wrangler, plus the new storage box for the Gladiator, but the overall cost with one battery is very nearly the same as the gas engine kits with 2 batteries
• Rerouting any previously installed accessory wires from under the hood to the back seat
• Retraining the market that accessory wires now go under the back seat rather than going to the engine bay
• Does not eliminate the small stop/start battery which a lot of people like about our gas engine kits, but there's other ways to deal with that

I think the biggest hurdle for most of our customers is "But that's where I keep my fill in the blank ." And hey, I get it, some people use the space under the seat for their gun case, tool bags, baby diaper bags, tow straps, or whatever else. The simple truth is that the days of putting an auxiliary battery under the hood are over. The new Bronco, the new Tundra, all the new full size trucks and SUVs, they are all jam packed under the hood with hoses and wires and who knows what all that stuff is. Going forward, we will have to find somewhere else to add extra battery capacity.

The kit we designed for the Gladiator is a more universal design. All 3 components - the Power Hub, the adjustable battery brackets, and the new storage box are all available for purchase separately. Our diesel Wrangler kit comes with mounting bases for securing the Power Hub and the adjustable battery brackets under the legs of the back seat. Don't want to put the battery under the seat? Ok, you can find somewhere else to mount the battery - the rear storage area, or the bed of the Gladiator, or where ever else you want - using our adjustable battery brackets, and just mount our Power Hub to control the system. Now you have much more flexibility than before.

Any time we modify our vehicle, there's always trade-offs. The demand for extra power in vehicles is only increasing, and it will continue to increase.

So what do you think? Are you a 'Never Under Seater'? Or is putting a battery under the back seat the future for how we build our Jeeps? Got questions? I'm here to help, fire away!

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[Genesis Offroad]

Here's a few pictures. You can see more on our website.

The diesel/392 Wrangler kit -

And here's the diesel Gladiator kit

 

[TX_Ovrlnd]

I really like the kit, y'all put some great effort into it. It's a hard pass on under the seat though, I need to use that full space from time to time. If y'all could go to the rear and design a storage option that incorporates the whole kit, I would reconsider. I really feel there is enough room for a custom tub setup to be created, I know it would cost more than the current kit.

 

[phageghost]

Having just finished a ton of wiring around the battery tray, I feel your pain. Talk about tight! Not surprised at all that you had to go elsewhere for a second battery without warping space/time or moving the engine (!).

Unfortunately I'm not in the market anymore, since I'm putting the finishing touches on a custom aux battery + electronics set up for my rear cubby. As @TX_Ovrlnd mentioned, a lot of folks are probably interested in using that location instead of under-seat. How easy is it to adapt your current kit to there?

 

[Extremneon]

Interesting setup with the battery under the rear seat.

I really like the benefit of having a second battery to have the ability to jump off the engine battery in an emergency. Also to have a separate battery to run all the accessories connected in the Jeep and isolated from the main cranking battery.

I don’t like the fact of needing to redo all the wiring for lights, etc.. to run them under the rear seat to the Gen 3 hub distribution block seems like a pain.

I gave it some thought, it might be good option to add addition power distribution block in the engine bay with connections available and then wired to the aux battery post in the Gen 3 hub. One large wire to the engine bay with connections available to the aux battery is better then a bunch of individual connections running back under the seat.

The other option is the addition of SPOD or similar in the engine bay and the power supply ran to the Gen 3 hub underneath the seat. So the you would have aux connections inside the Jeep on Gen 3 hub underneath the rear seat and connection in the engine bay that is powered by the aux battery. The draw is that is would cost over 2k for this setup. I also don’t think SPOD has a kit with a power supply wire long enough to reach the back seat, so it would have to be replaced with longer power wire.

 

[gsbrockman]

A solution to a problem...that doesn’t exist.

 

[Ratbert]

A solution to a problem...that doesn’t exist.

I'm fairly confident that the same could be said about just about every new feature we've added to our Jeeps that people don't understand the need for.

To be clear: I don't currently have a need for a second battery.

 

[Genesis Offroad]

Interesting setup with the battery under the rear seat.

I really like the benefit of having a second battery to have the ability to jump off the engine battery in an emergency. Also to have a separate battery to run all the accessories connected in the Jeep and isolated from the main cranking battery.

I don’t like the fact of needing to redo all the wiring for lights, etc.. to run them under the rear seat to the Gen 3 hub distribution block seems like a pain.

I gave it some thought, it might be good option to add addition power distribution block in the engine bay with connections available and then wired to the aux battery post in the Gen 3 hub. One large wire to the engine bay with connections available to the aux battery is better then a bunch of individual connections running back under the seat.

The other option is the addition of SPOD or similar in the engine bay and the power supply ran to the Gen 3 hub underneath the seat. So the you would have aux connections inside the Jeep on Gen 3 hub underneath the rear seat and connection in the engine bay that is powered by the aux battery. The draw is that is would cost over 2k for this setup. I also don’t think SPOD has a kit with a power supply wire long enough to reach the back seat, so it would have to be replaced with longer power wire.

All great ideas and easy to do! If you already have a bunch of accessories running to the battery under the hood, you can run one more appropriate sized power lead from our bus bar up to a connection point under the hood. We sell bus bars for exactly this purpose here -

https://www.genesisoffroad.com/wiring-and-supplies

 

[Genesis Offroad]

A solution to a problem...that doesn’t exist.

Our solution solves several problems -

- Needing to be able to run your accessories with the engine off, without draining down your cranking battery.

- Jump starting yourself if/when your cranking battery is dead for whatever reason.

- Providing a simple and clean way to connect multiple accessory wires that need battery power without stacking wires directly on the post clamp.

- Adding a dual battery system to your vehicle without having to source all the tools and components and read a wiring schematic to figure out how to hook it all up.

- Spreading the demand of high amp accessories such as a winch over 2 batteries to prevent one from being drained down too quickly.

- Easily charging a second battery from the engine's alternator.

 

[Bevo]

I was eagerly anticipating this kit for my JLU Ecodiesel and even spoke to Genesis in person at Overland Expo East. However, I just can't get on board with the under seat design so I guess I'm a 'Never Under Seater' in response to the question above. I am in process of installing a Goose Gear plate system and want to use the storage cubby space for tools, spare parts, and more. This kit's second battery and power hub just consume way too much interior space. I do appreciate the detailed explanation in this thread but the design is a show stopper for me. Instead, I'll go without dual batteries and run a replacement premium primary battery only. I'll also carry my NOCO jump pack and Jackery.

 

[Catdom]

Our solution solves several problems -

- Needing to be able to run your accessories with the engine off, without draining down your cranking battery.

- Jump starting yourself if/when your cranking battery is dead for whatever reason.

- Providing a simple and clean way to connect multiple accessory wires that need battery power without stacking wires directly on the post clamp.

- Adding a dual battery system to your vehicle without having to source all the tools and components and read a wiring schematic to figure out how to hook it all up.

- Spreading the demand of high amp accessories such as a winch over 2 batteries to prevent one from being drained down too quickly.

- Easily charging a second battery from the engine's alternator.

 

[NickJar]

Genesis Offroad now has dual battery systems in stock for the diesel Wrangler and Gladiator!

Below we have our overview videos and also our detailed installation videos that cover a lot of information.

To address the biggest topic of our new kits, yes, we have to put the extra battery under the back seat, not under the hood. We typically like to keep the batteries and all the wiring together under the hood, but the reality is that those days are over. The diesel engine bays are just too compact. When I got our diesel Gladiator, at first glance it seemed like we would be able to drop a couple Group 25 batteries in there, just like the gas JL. The first hurdle I ran into was getting the stock plastic battery tray out of the engine bay. It was obnoxiously, stupidly difficult to remove. It looks like the factory must have installed the battery tray before they installed the engine or anything else, because there was so much stuff in the way. The stock battery tray runs from the firewall all the way up to right behind the headlight, and there's an obscene number of wires in the way. After fighting with it for hours, I finally stood up on top of the engine, reached down and yanked the tray so hard I almost fell off. Once the tray was out, again at first glance it looked like the batteries would fit. The factory wire bundles along the fender were a problem, and they have no slack at all to move them anywhere. I ended up buying a 3d scanner to get a very detailed scan of the space we had available to try to design a battery tray in CAD that would fit precisely. I spent a huge amount of time trying to find a way to get 2 batteries to fit, but it was so tight that a Group 25 battery was bumping the fender side and the engine side. I looked at using a smaller battery, but any standard normally available battery that was any smaller had far less cold cranking amps and capacity than even the stock battery, so it just didn't make sense. Even if the batteries would fit, the first step of our installation instructions would be to move the engine over by one inch just to get the stock tray out.

Our design philosophy from the very beginning is to make the most complete and easiest to install dual battery systems on the market. So even if we found a battery with enough capacity that fit, it still would be WAY too difficult to install. So, after all that, it was time to abandon ship and come up with a new plan.

I looked all over the vehicle, front to back, top to bottom. I considered mounting an extra battery under the vehicle, maybe tucked up behind the rear wheel, or maybe bolted to the side of the frame, as I believe I've seen one or two guys on here doing a DIY job like that. Also thought about using the bed of the Gladiator, or the rear storage cubby in the rear floor of the Wrangler. However, again I kept coming back to the same issue - none of those would be easy to install. I know I personally do not want to lay on my back and lift a 50+ lb battery up to a bracket under the vehicle even once, and I sure don't want to get under there to do maintenance on it or run extra wires to it in the future. I also do not want to cut out the rear floor of the Wrangler to fit a battery large enough to justify the cost and trouble.

So, that leaves us with the space under the back seat. Here's how I see the pros/cons of using that space.

Pros:

• Super easy to install
• You only need to purchase one battery
• You don't have to toss your stock battery
• Many more options for battery size, not limited to just one specific size
• Run your accessories even longer with larger batteries - up to a Group 27F for the Wrangler, and up to a Group 31 for the Gladiator
• Potentially longer battery life away from extreme under hood temperature swings
• Extra battery weight located low and center of the vehicle
• Easy future battery maintenance
• No modifications to anything under the hood
• Less chances of any problems after the install
• Easier for your mechanic to perform normal diagnostics/maintenance under the hood
• Easy to move the kit to a new vehicle in the future
• Factory Stop/Start system remains untouched

Cons:

• Consumes limited storage space inside the vehicle, especially for the Gladiator
• Cost of the kit is slightly higher, mainly due to the extra power cable for the Wrangler, plus the new storage box for the Gladiator, but the overall cost with one battery is very nearly the same as the gas engine kits with 2 batteries
• Rerouting any previously installed accessory wires from under the hood to the back seat
• Retraining the market that accessory wires now go under the back seat rather than going to the engine bay
• Does not eliminate the small stop/start battery which a lot of people like about our gas engine kits, but there's other ways to deal with that

I think the biggest hurdle for most of our customers is "But that's where I keep my fill in the blank ." And hey, I get it, some people use the space under the seat for their gun case, tool bags, baby diaper bags, tow straps, or whatever else. The simple truth is that the days of putting an auxiliary battery under the hood are over. The new Bronco, the new Tundra, all the new full size trucks and SUVs, they are all jam packed under the hood with hoses and wires and who knows what all that stuff is. Going forward, we will have to find somewhere else to add extra battery capacity.

The kit we designed for the Gladiator is a more universal design. All 3 components - the Power Hub, the adjustable battery brackets, and the new storage box are all available for purchase separately. Our diesel Wrangler kit comes with mounting bases for securing the Power Hub and the adjustable battery brackets under the legs of the back seat. Don't want to put the battery under the seat? Ok, you can find somewhere else to mount the battery - the rear storage area, or the bed of the Gladiator, or where ever else you want - using our adjustable battery brackets, and just mount our Power Hub to control the system. Now you have much more flexibility than before.

Any time we modify our vehicle, there's always trade-offs. The demand for extra power in vehicles is only increasing, and it will continue to increase.

So what do you think? Are you a 'Never Under Seater'? Or is putting a battery under the back seat the future for how we build our Jeeps? Got questions? I'm here to help, fire away!

not really in the market. However, I just had to say this was awesome post about the thought process and behind the scenes we as consumers don’t see. This is the type of marketing I love to see

 

[Genesis Offroad]

I was eagerly anticipating this kit for my JLU Ecodiesel and even spoke to Genesis in person at Overland Expo East. However, I just can't get on board with the under seat design so I guess I'm a 'Never Under Seater' in response to the question above. I am in process of installing a Goose Gear plate system and want to use the storage cubby space for tools, spare parts, and more. This kit's second battery and power hub just consume way too much interior space. I do appreciate the detailed explanation in this thread but the design is a show stopper for me. Instead, I'll go without dual batteries and run a replacement premium primary battery only. I'll also carry my NOCO jump pack and Jackery.

Thank you for the feedback Bevo, I appreciate it!

 

[Genesis Offroad]

not really in the market. However, I just had to say this was awesome post about the thought process and behind the scenes we as consumers don’t see. This is the type of marketing I love to see

Thanks, I'm glad you liked it!

 

[AusJeepNoob]

I hear you about the battery tray. I've got an RHD diesel JLUR and the battery space (or lack thereof) is ridiculous. I was recently installing an upgraded audio system and trying to pull the battery tray out so I could run the power cable through the firewall proved to be impossible. They must fit the tray before the fuse box because there are some studs off the firewall that are used to hold the tray that are about 1.5" long that you just can't get passed. I was very tempted to cut them down but didn't have anything that would work in the tight confines.

I understand why you've gone with the underseat option but I drop my seats fairly regularly and not being able to fold as flat as possible is why I wouldn't go with this approach. One approach I would consider is a bracket to mount the hub in the engine bay on top of the factory battery with the second battery in the rear, opposite the factory sub (passenger side for RHD). Thinking you might be able to get a Group 25 in that spot with minimal protrusion. The only downside that I can think of for that location is that it is above the height of the side rail so when the roof is off it will be visible.

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