2014 Thor Vegas 24.1 lithium battery upgrade and DC-to-DC charging

outro702 · 05-09-2022, 04:31 AM

I see there are lots of threads on this very topic but as a newbie, there's one question that I haven't been able to locate an answer to. My Thor Vegas came with the alternator charging enabled so whenever I drive my rig, it has been charging my existing AGM batteries. However, now that I'm starting a project of upgrading my AGM batteries to lithium and planning to use the DC-to-DC charger to charge my new lithium batteries, my question is... how do I disable(?) the current alternating charging mechanics. I assume there are wires already hooked up to my AGM batteries from the alternator/solenoid... Do I just disconnect the wire and tape it up or something? Any help will be greatly appreciated!

Thanks!

DavidEM · 05-09-2022, 11:09 AM

Given that you have a 2014 coach, I suspect you have the older BIRD/Trombetta relay device that connects the two battery systems when voltages are right as well as provides aux start capability. You can neither wire the DC2DC in parallel or in series with the BIRD and it must be replaced entirely with the DC2DC.

You will lose the aux start capability and the ability to charge the chassis batteries from the coach DC system when you do this. There are ways of adding switches to recover these capabilities.

My 2021 Axis 24.1 has the newer Precision Circuits BIM 160 installed under the hood in front of the driver's side wheel well. Don't know where yours might be.

I would first install the LFP batteries without the DC2DC charger and see how it works. One big concern is that the new batteries will pull too much current for the chassis alternator, but the wiring size may limit that. Check the current with a DC clamp on ammeter and the case temp with an IR gun with the batteries well discharged. You should keep it below 60 amps and 200 F case temp.

It won't charge optimally that way, but it may be good enough if the current and temp aren't too much.

David

michaelrider · 05-09-2022, 03:56 PM

I am in exactly the same spot and having the same problem. I found a post some time ago that included a generic wiring diagram here: https://intellitec.com/bi-directiona...r-relay-delay/
but would really like to see a diagram specific to the Axis/Vegas, one that might include locations as well as wiring. Am I dreaming??? I know other members have found them, but I have yet to come up with the right search term to take me to one.
Anyone know if our rigs have the isolator relay AND the two disconnect relays?? There are many advantages to having the sophisticated software in the DC2DC controller besides just keeping the alternator from frying, including isolation of the chassis battery from the house battery and proper conditioning of the charge rate specific to the lithium battery. Any help would be great!

outro702 · 05-10-2022, 12:42 AM

Quote:

Originally Posted by DavidEM

Given that you have a 2014 coach, I suspect you have the older BIRD/Trombetta relay device that connects the two battery systems when voltages are right as well as provides aux start capability. You can neither wire the DC2DC in parallel or in series with the BIRD and it must be replaced entirely with the DC2DC.

You will lose the aux start capability and the ability to charge the chassis batteries from the coach DC system when you do this. There are ways of adding switches to recover these capabilities.

My 2021 Axis 24.1 has the newer Precision Circuits BIM 160 installed under the hood in front of the driver's side wheel well. Don't know where yours might be.

I would first install the LFP batteries without the DC2DC charger and see how it works. One big concern is that the new batteries will pull too much current for the chassis alternator, but the wiring size may limit that. Check the current with a DC clamp on ammeter and the case temp with an IR gun with the batteries well discharged. You should keep it below 60 amps and 200 F case temp.

It won't charge optimally that way, but it may be good enough if the current and temp aren't too much.

David

Thanks for your response David. Greatly appreciate it.

I'm ok with losing the ability to charge chassis battery from coach batteries as well as the aux start. Then, what would be the simplest way to stop the alternator from charging my coach batteries? I'm sorry but I'm so new to this and trying to figure things out on my own...

Thanks in advance,
Ryan

outro702 · 05-10-2022, 12:59 AM

Quote:

Originally Posted by DavidEM

Given that you have a 2014 coach, I suspect you have the older BIRD/Trombetta relay device that connects the two battery systems when voltages are right as well as provides aux start capability. You can neither wire the DC2DC in parallel or in series with the BIRD and it must be replaced entirely with the DC2DC.

You will lose the aux start capability and the ability to charge the chassis batteries from the coach DC system when you do this. There are ways of adding switches to recover these capabilities.

My 2021 Axis 24.1 has the newer Precision Circuits BIM 160 installed under the hood in front of the driver's side wheel well. Don't know where yours might be.

I would first install the LFP batteries without the DC2DC charger and see how it works. One big concern is that the new batteries will pull too much current for the chassis alternator, but the wiring size may limit that. Check the current with a DC clamp on ammeter and the case temp with an IR gun with the batteries well discharged. You should keep it below 60 amps and 200 F case temp.

It won't charge optimally that way, but it may be good enough if the current and temp aren't too much.

David

BTW, I know for sure that dropping in the lithium batteries without DC-to-DC charger in place will definitely kill the alternator eventually.

**16ACE27** · 05-10-2022, 01:06 AM

Quote:

Originally Posted by outro702

Thanks for your response David. Greatly appreciate it.

I'm ok with losing the ability to charge chassis battery from coach batteries as well as the aux start. Then, what would be the simplest way to stop the alternator from charging my coach batteries? I'm sorry but I'm so new to this and trying to figure things out on my own...

Thanks in advance,
Ryan

Find the relay controlled by the BIRD. On one of the wires connected to the control (small) terminals is an inline fuse. Remove that fuse. The battery banks can now NOT be connected together.

outro702 · 05-10-2022, 01:20 AM

Quote:

Originally Posted by 16ACE27

Find the relay controlled by the BIRD. On one of the wires connected to the control (small) terminals is an inline fuse. Remove that fuse. The battery banks can now NOT be connected together.

Thanks Ted.

I got this diagram from somewhere just now. Which one is the relay you are referring to?

Thanks!

outro702 · 05-10-2022, 01:22 AM

Quote:

Originally Posted by 16ACE27

Find the relay controlled by the BIRD. On one of the wires connected to the control (small) terminals is an inline fuse. Remove that fuse. The battery banks can now NOT be connected together.

Do you know where it's located in 2014 Thor Vegas?

outro702 · 05-10-2022, 01:27 AM

This thread gave me some clue as well. I have Battery Control Center (BCC) and I know there are fuses there. Should I just figure out which fuse to pull out from the BCC?

outro702 · 05-10-2022, 01:39 AM

Quote:

Originally Posted by michaelrider

I am in exactly the same spot and having the same problem. I found a post some time ago that included a generic wiring diagram here: https://intellitec.com/bi-directiona...r-relay-delay/
but would really like to see a diagram specific to the Axis/Vegas, one that might include locations as well as wiring. Am I dreaming??? I know other members have found them, but I have yet to come up with the right search term to take me to one.
Anyone know if our rigs have the isolator relay AND the two disconnect relays?? There are many advantages to having the sophisticated software in the DC2DC controller besides just keeping the alternator from frying, including isolation of the chassis battery from the house battery and proper conditioning of the charge rate specific to the lithium battery. Any help would be great!

Which year/model of Vegas do you have? Check this thread out... leaning something. https://www.thorforums.com/forums/f1...etta-5524.html

Based on what I'm reading, my 2014 Vegas has BCC (which I know) and I'm guessing there might be a fuse in there that I can just take out...

outro702 · 05-10-2022, 04:31 AM

Quote:

Originally Posted by 16ACE27

Find the relay controlled by the BIRD. On one of the wires connected to the control (small) terminals is an inline fuse. Remove that fuse. The battery banks can now NOT be connected together.

Based on my further research, my 2014 Thor Vegas comes with Battery Control Center (BCC) and I see that solenoid is inside that box (which I can and see). And there are many fuses in there and none of them seems like related to the alternator charging.

JamieGeek · 05-10-2022, 02:25 PM

yup no BIRD on a 2014.

You can search around for "RV Custom Products Battery Control Center" and find a bunch of different .pdf files of schematics (of course none will match your Axis exactly, however).

It looks like that board is customized to each coach.

(I found one for a Four Winds RV that I used just to figure out what it was doing for our old 2014 Axis 24.1.)

outro702 · 05-11-2022, 01:05 AM

Quote:

Originally Posted by JamieGeek

yup no BIRD on a 2014.

You can search around for "RV Custom Products Battery Control Center" and find a bunch of different .pdf files of schematics (of course none will match your Axis exactly, however).

It looks like that board is customized to each coach.

(I found one for a Four Winds RV that I used just to figure out what it was doing for our old 2014 Axis 24.1.)

So, are you saying that I can basically disable alternator charging of my coach batteries by taking a fuse (still need to figure out which one) from the BCC? Do you have an idea which fuse typically fits the bill for what I'm trying to do?

michaelrider · 05-15-2022, 06:02 AM

After much stumbling around and a couple of phone conversations with John at RV Custom Products, as well as downloading and reading Ed Felker's excellent Thor Axis/Vegas manual I decided to skip the DC2DC charge controller in favor of upgrading the alternator. I installed a shunt and amp/volt/charge meter and will be able to see how many amps the alternator is trying to put into the lithium battery. If it looks like the alternator is working too hard, which it will be if it is the 120 AMP one, I'll go to the 225 Amp alternator - problem solved (I hope). Ford's price for the OEM part is very competitive.
Look in the compartment under the drvs seat. If there is a black box with a lot of fuses and battery cables going to it, you have an RV Custom Products BCC
Here is the Battery Control Center Schematic we have in our older Axis/Vegas:
https://rvcustomproducts.com/th-1020
The "troubleshooting guide" gives a lot of information
Ford make three different alternators for the E350 chassis with the 6.8L engine, a 120 Amp, 155 Amp, 195 Amp, and a 225 amp
https://www.varsityfordparts.com/v-2...al--alternator
Without being able to look at the tag on the alternator (long mirror and a flashlight after taking the air cleaner assy out?) out Thor's could have any one of the three fitted, depending on what Thor spec'ed.

outro702 · 05-16-2022, 09:55 PM

Thanks for the reply. I actually got it working over the weekend. I got a reply from RV Custom Products and followed their instruction to disable the alternator charging from the BCC. I installed and tested the Renogy 40a DC-to-DC Charger as well. All seem to be working fine. Here's the reply from RV Custom Products.

"Remove the ring terminal of the yellow wire from the coil terminal of the interconnect relay. You can retain the aux start function by snipping the wire from P1-1 and wire it over to the terminal from which you removed the yellow wire. If you need an ignition signal to control your DC to DC converter, you can tap (don't cut) onto the wire connected to P6-5. Reference the block diagram (schematic) on our website, rvcustomproducts.com, under the TH-1020.

John Mock
RV Custom Products"

michaelrider · 05-21-2022, 07:05 AM

It looks like you will have to tip the circuit board out of the steel box the BCC is in to make those modifications John recommended, but there looks to be plenty of room to do so. One of the reasons I was going to try an alternator only solution was both simplicity and room. I fitted a Chins 200 Amp Hour Lithium Battery (Amazon) in the compartment to the left of the entryway door, mounting the 100 amp breaker, positive cable terminal, and shunt for my meter on a piece of plywood next to the battery. There wasn't a whole lot of room left over. I reinforced the compartment with a couple of pieces of angle iron hung on allthread from the coach floor (Brian from Tito's RV You tube channel does this in his install). Putting everything there made it more accessible an let me keep my cable runs short. Where did you put your charge controller and lithium battery(s) and manage the cable routing?

michaelrider · 06-23-2022, 08:27 AM

Hi Outro77. Can you post a picture of your Renogy DC to DC charge controller installation? I'm curious where you put it and how did you choose which wires to hook up to it. The alternator lead goes to the starter battery which is wired to the starter and to the isolation relay with #0 or #1 cable, it looks like. The positive chassis post that is to the rear of the stock house battery compartment has 3 cables - the fused house battery cable, a cable to the converter charger next to the refrigerator, and a third cable to?? the isolation relay?
Thanks for posting!

TomThorVegas · 02-06-2023, 02:56 AM

I know am a bit late to the party, but hopefully a few folks still around to throw some thoughts around upgrading the Battery Isolation Manager.

Any reason that no-one considered/suggested a BIM designed for Lithium batteries? Presumably this would maintain charging between chassis and coach and avoid damage to batteries and alternator.

I saw this one on the BattleBorn site. Based on their description (below), I assume it is disconnecting the alternator every 15 min to avoid overloading and burning up the alternator.

From BattleBornBatteries.com:
"The LiFePO4 Battery Isolation Manager (BIM) monitors voltage and connects batteries when needed. Under normal charging conditions, the BIM will connect for 15 minutes every 35 minutes. That means that the BIM will connect for 15 minutes, disconnect for 20 minutes, and repeat this cycle until the coach battery is charged.

If the coach battery resting voltage exceeds 13.4 V then the BIM will disconnect. A resting voltage greater than 13.4 V indicates a fully charged battery. Note that “resting voltage” means that no current is flowing to the coach battery.

The BIM will disconnect if the alternator voltage exceeds 14.4 V. This protects the coach battery from overcharging. The LiFePO4 Battery Isolation Manager will disconnect if the voltage difference between the alternator and the coach battery is less than 0.1 V. If the voltage difference is too low, then there is a negligible charging current, and no need to connect to the coach battery.

The BIM will disconnect if the alternator voltage drops below 13.3 V. If the alternator voltage is too low, then it cannot adequately charge the coach battery, so there is no reason to connect."

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