Dual battery for Gen 5 Rav4 (2019)

[Anazlu]

So Im looking into setting up a dual battery for my Rav4 XLE AWD. I do not have the Immediate need for it, but since Im planning out my lights right now, Im trying to think ahead. Because of how Toyota does the designs for the Rav4s there is a spot a battery would go if I had the Hybrid model. I dont so this spot is empty and unused. I am thinking of putting the battery in that spot. The downside is this spot is in the back trunk area. so it is inside the the passenger area of the vehicle. I need a battery that would be safe to store in the passenger area, and one that would be fine with the Texas summers we normally get down here. I also need to route the wiring from the front to the back and hook up this battery.

A few questions I hoping the OB community can help with.
What battery would be best to get? As of right now I only have a midland radio, but im going to be getting a full light setup, and id like to figure out a way to do an onboard compressor for airing up. so Id like to try and set up this battery plan assuming I have all that extra need.
Would it be better to put the relays and fuses in the engine compartment closer to my main battery or closer to the Aux battery?
Im assuming it would be best to put the Aux fuse box back by the Aux battery. but could I be wrong on this? by Aux fuse box im talking about the fuse box Michel has in his 87 for lights and extras.

 

[Michael Golden]

You will want several fuses in your system to keep your rig from burning down. Over engineer your wiring. Its better to have thicker wire to carry the juice than the skinny wire getting hot and catching fire. I would suggest a fuse between every length of the positive (+) side of the system.
If the battery is in the passenger compartment you’ll want a sealed battery to be safe. Don’t take chances, do it the safe and right way with this.

 

[Kilo Sierra]

Probably the best solution would be a LiFePO4 battery (due to weight and power capacity). You power it with a DC/DC charger (which you can turn on through the ignition, a manual switch, or a series of both). Definitely fuse the positive at each point. Then you wire the fuse box close to that to distribute the power as needed. For the air compressor, you can either hardwire it to the battery, or find an amp appropriate plug to allow you to remove it if not needed.

The only thing to keep in mind is that LiFePo4 batteries do not charge in freezing temps, and could cause damage to the battery. That is why you would want it in the cabin with you (so you can heat it up) and why I power the DC/DC through a manual switch. Many batteries have a low temp shutoff, but I prefer the control as a backup. Won't be a huge issue in you area but needed up where I am. Also many batteries' BMS (Battery Management System) also have Bluetooth interface, so you can check the power and temp through your phone. Also the other reason I manually switch it is to keep the battery from incidental charging when I haven't used it.

 

[Anazlu]

You will want several fuses in your system to keep your rig from burning down. Over engineer your wiring. Its better to have thicker wire to carry the juice than the skinny wire getting hot and catching fire. I would suggest a fuse between every length of the positive (+) side of the system.
If the battery is in the passenger compartment you’ll want a sealed battery to be safe. Don’t take chances, do it the safe and right way with this.

That is exactly what planning. which is why Im trying to make sure its future proof for all the power needs I will need, not the power need I have now.

 

[Anazlu]

Probably the best solution would be a LiFePO4 battery (due to weight and power capacity). You power it with a DC/DC charger (which you can turn on through the ignition, a manual switch, or a series of both). Definitely fuse the positive at each point. Then you wire the fuse box close to that to distribute the power as needed. For the air compressor, you can either hardwire it to the battery, or find an amp appropriate plug to allow you to remove it if not needed.

The only thing to keep in mind is that LiFePo4 batteries do not charge in freezing temps, and could cause damage to the battery. That is why you would want it in the cabin with you (so you can heat it up) and why I power the DC/DC through a manual switch. Many batteries have a low temp shutoff, but I prefer the control as a backup. Won't be a huge issue in you area but needed up where I am. Also many batteries' BMS (Battery Management System) also have Bluetooth interface, so you can check the power and temp through your phone. Also the other reason I manually switch it is to keep the battery from incidental charging when I haven't used it.

Thank you very much. I wouldnt have taken cold weather into account but I do need to just incase I am in a situation like Texas had back in at the beginning of the year or if Im out in a cold environment.


LiFePo4 is a Lithium Iron battery right?

 

[Kilo Sierra]

Thank you very much. I wouldnt have taken cold weather into account but I do need to just incase I am in a situation like Texas had back in at the beginning of the year or if Im out in a cold environment.


LiFePo4 is a Lithium Iron battery right?

Yep. I custom built mine using cells to fit a specific space, but you probably will be buying a cell/BMS built battery (like Battleborn although you should be able to find cheaper options). Checking out Will Prowse on youtube might be able help out about batteries (and if you want to build one). A picture of my setup for the X.

 

[Anazlu]

Yep. I custom built mine using cells to fit a specific space, but you probably will be buying a cell/BMS built battery (like Battleborn although you should be able to find cheaper options). Checking out Will Prowse on youtube might be able help out about batteries (and if you want to build one). A picture of my setup for the X.

Well given the spot I am thinking of using is designed to hold a normal car Battery for the Hybrid Rav4s. It should be a standardized dimension for a Car or Truck Battery.

 

[Anazlu]

Thank you very much. I wouldnt have taken cold weather into account but I do need to just incase I am in a situation like Texas had back in at the beginning of the year or if Im out in a cold environment.


LiFePo4 is a Lithium Iron battery right?

Yep. I custom built mine using cells to fit a specific space, but you probably will be buying a cell/BMS built battery (like Battleborn although you should be able to find cheaper options). Checking out Will Prowse on youtube might be able help out about batteries (and if you want to build one). A picture of my setup for the X.View attachment 205519

So doing some research you can get 3.2 volt LiFePo4 cells fairly easily and putting 4 in series gets you a 12.8 volts.

So would it be best to make a battery to fit the area? Or buy an existing car battery that's LiFePo4?

 

[IceBear505]

I guess my general question back to you would be: "Are you sure you need a dual battery setup?"... from some of your comments it seems general power back up whether on road, base camp, or home may be your real need (power outage in TX due to unexpected weather event, etc.). Having a small cabin rig myself ('18 Subaru Crosstrek) I initially looked at dual battery and using the inadequate spare tire well. Ultimately, I decided that having some sort of portable (in car and out of car) power source/battery was more desirable. I still have accessory/trail lights and other items like Midland 275. I even added a convenience outlet (USB and cigarette port) in the back for hooking up my Jackery 500, which then feeds my refrigerator (both removable and portable). For extended periods off grid/at base camp, I added a solar panel (Jackery SolarSaga 100) which does a decent job in full sun to recharge what the refrigerator draws along with any other incidental battery draw (cell phones, etc.). Bottom line was I was going to use those accessories on the road while car was running, as long as the alternator could handle the loads (and still charge the portable battery) I couldn't justify the dual battery configuration...

Do you really need a dual battery set-up or is a portable solution more flexible and adaptable to your needs? ... only you can really answer that question, but one you might want to consider before you lock into a vehicle mod that is well, locked. Just food for thought (especially if this is your daily driver).

 

[Anazlu]

I guess my general question back to you would be: "Are you sure you need a dual battery setup?"... from some of your comments it seems general power back up whether on road, base camp, or home may be your real need (power outage in TX due to unexpected weather event, etc.). Having a small cabin rig myself ('18 Subaru Crosstrek) I initially looked at dual battery and using the inadequate spare tire well. Ultimately, I decided that having some sort of portable (in car and out of car) power source/battery was more desirable. I still have accessory/trail lights and other items like Midland 275. I even added a convenience outlet (USB and cigarette port) in the back for hooking up my Jackery 500, which then feeds my refrigerator (both removable and portable). For extended periods off grid/at base camp, I added a solar panel (Jackery SolarSaga 100) which does a decent job in full sun to recharge what the refrigerator draws along with any other incidental battery draw (cell phones, etc.). Bottom line was I was going to use those accessories on the road while car was running, as long as the alternator could handle the loads (and still charge the portable battery) I couldn't justify the dual battery configuration...

Do you really need a dual battery set-up or is a portable solution more flexible and adaptable to your needs? ... only you can really answer that question, but one you might want to consider before you lock into a vehicle mod that is well, locked. Just food for thought (especially if this is your daily driver).

This is my daily driver first off.
Part of the reason I want to put in an Auz battery is to put all my accessories on that and keep it isolated from my main power. Just incase something does happen it wouldn't effect my stock system. I plan on having a physical switch that would disconnect the two systems, in addition to a solenoid.

But I am planning out to use a refrigerator, off road lights, camp sight lights, and a radio.

I've also been looking into a solar setup to charge the Aux battery while at the campsite, so I don't have to run my engine to keep that battery charged.

 

[rtexpeditions]

A vehicle that new would probably have a smart alternator, so a DCDC charger matched to that is probably the only option whatever battery tech you use.

 

[IceBear505]

I guess my general question back to you would be: "Are you sure you need a dual battery setup?"... from some of your comments it seems general power back up whether on road, base camp, or home may be your real need (power outage in TX due to unexpected weather event, etc.). Having a small cabin rig myself ('18 Subaru Crosstrek) I initially looked at dual battery and using the inadequate spare tire well. Ultimately, I decided that having some sort of portable (in car and out of car) power source/battery was more desirable. I still have accessory/trail lights and other items like Midland 275. I even added a convenience outlet (USB and cigarette port) in the back for hooking up my Jackery 500, which then feeds my refrigerator (both removable and portable). For extended periods off grid/at base camp, I added a solar panel (Jackery SolarSaga 100) which does a decent job in full sun to recharge what the refrigerator draws along with any other incidental battery draw (cell phones, etc.). Bottom line was I was going to use those accessories on the road while car was running, as long as the alternator could handle the loads (and still charge the portable battery) I couldn't justify the dual battery configuration...

Do you really need a dual battery set-up or is a portable solution more flexible and adaptable to your needs? ... only you can really answer that question, but one you might want to consider before you lock into a vehicle mod that is well, locked. Just food for thought (especially if this is your daily driver).

This is my daily driver first off.
Part of the reason I want to put in an Auz battery is to put all my accessories on that and keep it isolated from my main power. Just incase something does happen it wouldn't effect my stock system. I plan on having a physical switch that would disconnect the two systems, in addition to a solenoid.

But I am planning out to use a refrigerator, off road lights, camp sight lights, and a radio.

I've also been looking into a solar setup to charge the Aux battery while at the campsite, so I don't have to run my engine to keep that battery charged.

Ok, so I am running the following off my alternator/main battery with no issues:

Trail lights (low driving LED bar 20", pairof ditch lights, 32" LED light bar, pair of backup LED pods)
Midland 275 GMRS 15w radio
Rear accessory charge port with volt meter, connected to Jackery 500, connected to refrigerator.

Seems a very similar set up... Not sure the reason to not have connected to main alternator/battery... Worries about possible loss of starter crank amps? Me too, but I solved that with a jump power pack battery. I didn't need it on my last outing, but a guy in next campsite ran his VW Golf battery down and I happen to have my jump battery. Saved his bacon and helped him get on the road.

Seems a lot of expense and complications for the loads you mentioned and for a small rig daily driver (IMHO)...