Dual Battery Setup 1.5 Years In (AGM Woes)

[Bumbo]

You can link/jump your batteries with a DC/DC charger. I have it on my rig. Here's the Redarc wiring guide.

BCDC Dual with Jump-Start - The New Ultimate Dual Battery Setup | REDARC Electronics

Based on that diagram, the REDARC has nothing to do with jumping.

You are just using a solenoid to temporally put both batteries in parallel, bypassing the REDARC completely.

This could be applied to any system regardless of a ACR or DC-DC charger.

 

[SnoRnR]

You can link/jump your batteries with a DC/DC charger. I have it on my rig. Here's the Redarc wiring guide.

BCDC Dual with Jump-Start - The New Ultimate Dual Battery Setup | REDARC Electronics

This is the setup I will be starting to build late Feb. I am leaving the solenoid jump-start until later. The solar and DC/DC will be going in with group 34. You can also carry a lithium starter pack as a fail-safe. I mainly want the parallel running for winching. Don't intend to fit a winch until next year though.

 

[Bumbo]

This is the setup I will be starting to build late Feb. I am leaving the solenoid jump-start until later. The solar and DC/DC will be going in with group 34. You can also carry a lithium starter pack as a fail-safe. I mainly want the parallel running for winching. Don't intend to fit a winch until next year though.

How are you putting both in parallel for the winch load?

I actually went to a triple battery setup... I still have a traditional ACR based system with two regular starters, and then use a DC-DC and a smaller battery for the small accessory loads like the fridge.

Also, you could consider separates from Victron Energy instead of REDARC. I think they have a better overall system.

DC-DC
Orion-Tr Smart DC-DC Charger Isolated - Victron Energy

MPPT Solar Charge Controller which is substantially nicer than the integral one in the REDARC. Phone application, bluetooth connected.
SmartSolar MPPT 75/10, 75/15, 100/15 & 100/20 - Victron Energy

Both are programmable voltages so you can match it to any type of battery you want, including lithium.

Victron makes really good gear... been using them for years in my custom builds.

Here is a good case study when looking at solar and self recovery from a flat battery.
PROBLEM WITH REDARC DC to DC

 

[matoolie]

Based on that diagram, the REDARC has nothing to do with jumping.

You are just using a solenoid to temporally put both batteries in parallel, bypassing the REDARC completely.

This could be applied to any system regardless of a ACR or DC-DC charger.

Agreed. Simply using jumper cables to connect the two batteries for emergency starting when needed just as effective and cheaper than the additional fuses, wiring, and solenoid.

 

[Bumbo]

Agreed. Simply using jumper cables to connect the two batteries for emergency starting when needed just as effective and cheaper than the additional fuses, wiring, and solenoid.

If you consider most people would be carrying around a set of jumper cables anyways, I find little reason to wiring up an entire bypass circuit for the off chance you do need to self-jump. It adds cost and complexity for something you really shouldn’t even need.

The entire point of these dual battery systems is to prevent starting issues in addition to having more capacity for accessory loads.

If you are constantly running your starter flat, you designed your system incorrectly. I have yet to actually need to jump start myself, but I have helped others which is why I still carry cables.

On a side note: There is a reason ACRs like the BlueSea ACR SI-Series have a low voltage lockout protection. If the voltage is too low, internal short as an example, then you might end up with two dead batteries forcing them in parallel. If you killed your starter in the dual battery system, it would be best to investigate if you are on the trail where you can’t get quick help.

 

[matoolie]

If you consider most people would be carrying around a set of jumper cables anyways, I find little reason to wiring up an entire bypass circuit for the off chance you do need to self-jump. It adds cost and complexity for something you really shouldn’t even need.

The entire point of these dual battery systems is to prevent starting issues in addition to having more capacity for accessory loads.

If you are constantly running your starter flat, you designed your system incorrectly. I have yet to actually need to jump start myself, but I have helped others which is why I still carry cables.

On a side note: There is a reason ACRs like the BlueSea ACR SI-Series have a low voltage lockout protection. If the voltage is too low, internal short as an example, then you might end up with two dead batteries forcing them in parallel. If you killed your starter in the dual battery system, it would be best to investigate if you are on the trail where you can’t get quick help.

Yep. A proper dual system should prevent drain, but you have to be prepared for when a starter battery suddenly takes a dump. I woke up one morning with my truck completely dead. The starter battery was only at 6v. It had dropped cells overnight. I was able to start the truck with auxiliary battery. In my opinion not having that capability when you have two batteries is not smart. And it can be done with typical solenoid dual systems or jumper cables. Just make sure you have the capability.

 

[ruff4runner]

Based on that diagram, the REDARC has nothing to do with jumping.

You are just using a solenoid to temporally put both batteries in parallel, bypassing the REDARC completely.

This could be applied to any system regardless of a ACR or DC-DC charger.

Thats right, The Redarc has nothing to do with the jump/linking of the batteries, but as [MENTION=134661]Xtremluck[/MENTION] implied there are some that think it will damage the Redarc if the batteries are linked temporarily.

 

[Bumbo]

Thats right, The Redarc has nothing to do with the jump/linking of the batteries, but as [MENTION=134661]Xtremluck[/MENTION] implied there are some that think it will damage the Redarc if the batteries are linked temporarily.

Yes, bypassing the REDARC would not harm it in any way.

Perhaps I misunderstood your post… I though you implied the REDARC is doing the jumping.

 

[Bumbo]

Yep. A proper dual system should prevent drain, but you have to be prepared for when a starter battery suddenly takes a dump. I woke up one morning with my truck completely dead. The starter battery was only at 6v. It had dropped cells overnight. I was able to start the truck with auxiliary battery. In my opinion not having that capability when you have two batteries is not smart. And it can be done with typical solenoid dual systems or jumper cables. Just make sure you have the capability.

There are some OEM loads that can help run down the starter…. Leaving doors open, lights on, radio on.

I do use my stereo often when camping and because of that moved the main power feed for the head unit to the AUX battery side. It is more work but it was part of my design to ensure that there isn’t anything that I can really do under normal operating conditions that would leave me without power to start the truck.

If you find you use a lot of OEM loads and are unable to re-wire those circuits, then you should consider:

Adding a low voltage disconnect to the starter side
Adding solar to charge the starter to provide supplemental charge
Adding a basic DC-DC converter to charge from AUX to Starter to help supplement those loads.
Use a BlueSea BatterLink ACR which allows you to lower the disconnect voltage, essentially creating a bigger battery as both stay in parallel longer.


Here is a link to a basic DC-DC which would work very well for this.

For $65 bucks, you can have this on a switch to provide 9 amps of charge current from the AUX to the starter. It’s got a remote port so you don’t have to worry about any relays or high current switching.

Victron Energy Orion-Tr 12/12-9A (110W) Isolated DC-DC converter

 

[matoolie]

There are some OEM loads that can help run down the starter…. Leaving doors open, lights on, radio on.

I do use my stereo often when camping and because of that moved the main power feed for the head unit to the AUX battery side. It is more work but it was part of my design to ensure that there isn’t anything that I can really do under normal operating conditions that would leave me without power to start the truck.

If you find you use a lot of OEM loads and are unable to re-wire those circuits, then you should consider:

Adding a low voltage disconnect to the starter side
Adding solar to charge the starter to provide supplemental charge
Adding a basic DC-DC converter to charge from AUX to Starter to help supplement those loads.
Use a BlueSea BatterLink ACR which allows you to lower the disconnect voltage, essentially creating a bigger battery as both stay in parallel longer.


Here is a link to a basic DC-DC which would work very well for this.

For $65 bucks, you can have this on a switch to provide 9 amps of charge current from the AUX to the starter. It’s got a remote port so you don’t have to worry about any relays or high current switching.

Victron Energy Orion-Tr 12/12-9A (110W) Isolated DC-DC converter

I think you are missing my point.....my starter battery died with nothing on. Parked in my garage. Cells inside the battery went bad. The battery simply crapped out. Nothing related to loads. This sometimes happens to batteries. And if it happens in the middle of nowhere you want to make sure you have a way to start the truck with auxiliary. And I am happy with my setup and it suits all my needs.

 

[Bumbo]

I think you are missing my point.....my starter battery died with nothing on. Parked in my garage. Cells inside the battery went bad. The battery simply crapped out. Nothing related to loads. This sometimes happens to batteries. And if it happens in the middle of nowhere you want to make sure you have a way to start the truck with auxiliary. And I am happy with my setup and it suits all my needs.

I understand what you are saying… I just went on my own tangent.

I have experienced the same thing before in my Silverado. Internally some of the cells failed, permanently lowering the operating voltage of the battery rendering it useless.

 

[Xtremluck]

Spent two weeks in Baja Mexico with hundreds of off road miles and the new Redarc + solar system worked flawlessly. Ill update my original dual battery setup thread when I have time as I think this is a much better setup than using a basic solenoid. Although, one could probably get away with a solenoid + solar supplemental power.

 

[Bumbo]

Spent two weeks in Baja Mexico with hundreds of off road miles and the new Redarc + solar system worked flawlessly. Ill update my original dual battery setup thread when I have time as I think this is a much better setup than using a basic solenoid. Although, one could probably get away with a solenoid + solar supplemental power.

Did you end up getting a new AGM, or are you trying to nurse your old one back to health?

 

[Xtremluck]

Did you end up getting a new AGM, or are you trying to nurse your old one back to health?

Still using the original. The resting voltage is around 12.6V now which is totally normal. Seems to be ok at just about two years of use even after I drained it flat a couple of times and charged it with our weak alternator.

 

[Bumbo]

Still using the original. The resting voltage is around 12.6V now which is totally normal. Seems to be ok at just about two years of use even after I drained it flat a couple of times and charged it with our weak alternator.

That sounds much better.

If you had a hard time holding voltage then your internals are sulfated, but it can be repaired if it’s not too far gone. Sounds like you still have some service life in it.

I would keep bringing it up to its full charge voltage as often as you can.

 

[SnoRnR]

Spent two weeks in Baja Mexico with hundreds of off road miles and the new Redarc + solar system worked flawlessly. Ill update my original dual battery setup thread when I have time as I think this is a much better setup than using a basic solenoid. Although, one could probably get away with a solenoid + solar supplemental power.

Thanks for the recommend. I am planning on installing this system. What size AUx battery are you running? I am planning group 34 AGM. Also, what size and type of solar panels are you using? I am considering a flat panel on top of a rooftop tent. Mainly to charge at trailheads while we are away hiking and climbing. I will supplement with a flexible deployable mat when static at camp. Just don't fancy leaving a 1000 dollar solar blanket draped on the 4runner while away climbing for hours. What size wire did you use on the Redarc? Manual for the 1225D suggest 6AWG. I am going to add the Redarc smart solenoid down the line for jump starting and winching with both batteries linked.

 

[Xtremluck]

[MENTION=343163]SnoRnR[/MENTION] Im running a Group 34 55ah Odyssey battery mounted in the secondary OEM location and honestly wouldn't really go bigger/heavier. Our engine bay is made of soda can thin sheetmetal and stress fracturing is a real thing. Reused most of my wiring from my original setup 0/1AWG so a little overkill but it works fine.

For solar im running two 120 watt Richsolar which is total overkill IMO. I dont really think you need a solar blanket with a setup like this. It produces a lot of power even in the shade which was surprising.

I honestly think the use case of linking of batteries for jump starting and winching is a bit overblown. Unless you are constantly winching for extended periods your standard battery should be fine. As far as jump starting I have a set of jumper cables that I could use between the batteries or even more convenient my LI-ION jump pack.

Sent from my iPhone using Tapatalk

 

[SnoRnR]

[MENTION=343163]SnoRnR[/MENTION] Im running a Group 34 55ah Odyssey battery mounted in the secondary OEM location and honestly wouldn't really go bigger/heavier. Our engine bay is made of soda can thin sheetmetal and stress fracturing is a real thing. Reused most of my wiring from my original setup 0/1AWG so a little overkill but it works fine.

For solar im running two 120 watt Richsolar which is total overkill IMO. I dont really think you need a solar blanket with a setup like this. It produces a lot of power even in the shade which was surprising.

I honestly think the use case of linking of batteries for jump starting and winching is a bit overblown. Unless you are constantly winching for extended periods your standard battery should be fine. As far as jump starting I have a set of jumper cables that I could use between the batteries or even more convenient my LI-ION jump pack.

Sent from my iPhone using Tapatalk

Awesome answers all my questions. Is the cable down the windshield from the solar permanent mount or do you set it up when you stop? I also carry a li-ion jump pack.

 

[Xtremluck]

Awesome answers all my questions. Is the cable down the windshield from the solar permanent mount or do you set it up when you stop? I also carry a li-ion jump pack.

The wiring is permanent as well as the solar panels. On a side note I used my winch extensively this weekend when driving through 2-3 ft of snow on backcountry shelf roads (At least 15 times). Never had a problem with my M8000 drawing from my cheap Duracell 55ah starter battery.

 

[OBDGUY]

Dual Battery Setup

I'm running two Odyssey group 24 batteries on an Off Grid Engineering system. I added a fuse from Australia that bumps the alternator output so it charges the Odysseys between 14.2-14.5. The system works flawlessly and keeps the batteries charged consistently at 14.5. I almost went with the Genesis system, but the battery module simply gets too hot which is never a good thing regardless of what the manufacturer says. The Off Grid Blue Sea module runs cool and efficient, it's totally water proof and in auto mode requires nothing from me. I can self jump from either battery and run my fridge, lights, and teardrop trailer off either battery or both. When it charges it charges both until they are at max volts and automatically shuts the aux battery off and goes back to main battery charging. I love the system, been almost 3 years now with zero problems. Pricey but worth every penny.