AGM and Lithium together

[RagexTico]

So I’m gonna be running an XS POWER AGM under the hood and then an XS POWER XMAX45 in the trunk to power my system. Would I need a DC to DC charger or a battery isolator? Or what would be the safest way to run this system safely?

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[CarAudio.com - Hal AI Bots]

So I’m gonna be running an XS POWER AGM under the hood and then an XS POWER XMAX45 in the trunk to power my system. Would I need a DC to DC charger or a battery isolator? Or what would be the safest way to run this system safely?

When running a dual battery system like you're planning with the XS POWER AGM under the hood and the XS POWER XMAX45 in the trunk, it's crucial to ensure that both batteries are properly managed to avoid any potential issues. Here’s a breakdown of your options and recommendations:

### 1. **Battery Isolator**
A battery isolator is a great choice if you want to keep the main battery and the secondary battery (in your trunk) separate. This prevents your secondary battery from draining your primary battery, especially when the car is off. It allows the alternator to charge both batteries when the vehicle is running. There are two main types of isolators:
- **Diode Isolators**: These are simple and reliable but can cause a voltage drop.
- **Smart Isolators**: These manage the charging more efficiently and typically do not have a significant voltage drop.

### 2. **DC to DC Charger**
A DC to DC charger is ideal if you're looking for more advanced charging capabilities. It can charge the auxiliary battery to the optimal level regardless of the voltage of the primary battery, ensuring that the secondary battery gets the correct charge. This is particularly useful if you're running high-demand audio systems, as it helps maintain battery health and performance.

### **Which One to Choose?**
- **Battery Isolator**: If you want a simple solution and are not concerned about the voltage drop, this is a good option. It will keep both batteries charged and separate.
- **DC to DC Charger**: If you want the best performance and battery longevity, especially for a high-power audio system, then this is the recommended choice.

### **Additional Considerations**
- **Gauge of Wiring**: Make sure to use appropriate gauge wiring between the batteries and your system to handle the current without overheating.
- **Fuses**: Always use fuses or circuit breakers to protect your wiring and equipment.
- **Battery Placement**: Ensure the secondary battery is securely mounted and that there’s proper ventilation to avoid any gas buildup.

### **Conclusion**
Both options can work, but a DC to DC charger will provide better performance and battery management for your audio system. Consider your specific needs, budget, and installation preferences when making your decision.

If anyone else has experience or additional insights on this setup, please chime in!

 

[Doxquzme Premium Member]

They play well together without a lot of extra's at all.

I run a BOSCH AGM under the hood and a GlowweVoltage in the rear of my hatch, 500A smart isolater, in between, because I had already purchased one and could not return it!

That said, both the GloweVoltage and the XMAX45 are LiFePO4 batteries with almost identical charging specs, which is the criterion for when you want to isolate the Lithium.

I recommend the following when connecting the two in parallel (including a parallel ground):

I have another picture depicting the same thing for multiple amps if you need.

This is the isolater I installed:

https://www.amazon.com/dp/B084VTXN9B/?tag=caraudiocom-20

NVX and Stinger offer what I think are likely identical units:

https://www.amazon.com/dp/B084VTXN9B/?tag=caraudiocom-20

The stinger model is $100+ if you can find them.

I like this type as they incorporate a smart circuit and an ON/OFF switch you can install near you and operate whenever needed, using the 20ft cable supplied.

This allows me to disengage the front battery from the rear, if and when I want to, such as during long periods of time during the winter when I may not be driving the car.

 

[RagexTico]

They play well together without a lot of extra's at all.

I run a BOSCH AGM under the hood and a GlowweVoltage in the rear of my hatch, 500A smart isolater, in between, because I had already purchased one and could not return it!

That said, both the GloweVoltage and the XMAX45 are LiFePO4 batteries with almost identical charging specs, which is the criterion for when you want to isolate the Lithium.

I recommend the following when connecting the two in parallel (including a parallel ground):

View attachment 71128

I have another picture depicting the same thing for multiple amps if you need.

This is the isolater I installed:

https://www.amazon.com/dp/B084VTXN9B/?tag=caraudiocom-20

NVX and Stinger offer what I think are likely identical units:

https://www.amazon.com/dp/B084VTXN9B/?tag=caraudiocom-20

The stinger model is $100+ if you can find them.

I like this type as they incorporate a smart circuit and an ON/OFF switch you can install near you and operate whenever needed, using the 20ft cable supplied.

This allows me to disengage the front battery from the rear, if and when I want to, such as during long periods of time during the winter when I may not be driving the car.

Thank you very much. I can run a lithium and Agm battery in parallel together with no isolator or dc to dc charger?

 

[Doxquzme Premium Member]

Thank you very much. I can run a lithium and Agm battery in parallel together with no isolator or dc to dc charger?

You can run any set of batteries without anything in between if the charging voltage specs are identical or very close to being the same.

The charging voltage is the consideration, not the chemistry - so one is 13.8V, the other is 14.4V, that's not an issue.

If one is 16V and the other is 13.8V, that's an issue.

Granted, different Lithium solutions, where the charging voltage is significantly different from that of the other battery, require that you use an isolator or other device that separates the two.

In your case, the LifePO4 is virtually the same charging voltage as the AGM under the hood, so you don't have to use an isolator.