ARB Dual Air Compressor and a Lithium LiFePO4 aux Battery (1 Viewer)

[DPA200]

I recently had a local 4x4 shop do a dual battery install in my 200. They finished the job weeks later than planned, so the end result was i just got the truck back a day before a 2 week Wyoming/Colorado trip. Overall he did a good job, but being his 1st LiFePO4 Battery setup I'm not sure he got it all right. The basics of the setup all worked fine, the 175w solar panel on the roof, down to the Red Arc BCDC 1225, to the 100ah Renogy LiFePO4 Battery in my drawer wing all kept my fridge and accessories running.

1 part that didn't work out at all was the dual ARB compressor. I'm no electrical expert by any means, I'm just learning as I go. I was under the impression that the air compressor (like a winch) needed to be wired straight to the start battery, and then only ran with the engine on to get the high alternator voltage. The install shop though did it different. He installed a Switchpros 9100. The main Switchpros unit is next to the battery in the drawer wing. The Switchpros control panel is in the sunglass holder using the Slee mount. Apparently the air compressor is too high to use the actual switch pro, so the control panel button is just used as a on/off switch, which that part works fine. The air compressor itself is under the hood using the SDHQ mount. Where things take a turn though is he wired the air compressor all the way back to the aux LiFePO4 Battery. So, the issue I'm having is, the air compressor turns on and off and makes noise like expected, but the actual air pressure out of it is only about as strong as a strong wind. If i try to air up a tire, the pressure is so low it just ends up deflating the tire. Not even enough air pressure to dust things off. I tried attaching the air pressure guage/handle right to the compressor with no air cable, still same result.

So, don't really know what to do from here. My truck is currently at a local Lexus dealer, as somebody recommended a particular technician that works there as having a good 4x4 electrical experience. The shop that did the actual install is almost impossible to get a hold of, and I'm not sure I really want to bring it back to them. As mush a the $$$ Lexus bill is gonna hurt I'm sure, I really wanted a neutral party to look over all the work that was done.


So, my question is...can the ARB compressor run off a LiFePO4 Battery? All the wiring and everything is under the carpet and under the drawers, so to re-wire would be a pretty involved job. Just curious if anybody else has tried and succeeded or failed running a compressor off the aux LiFePO4 Battery like this. Or if this is a lost cause.

 

[RET2]

Run the compressor power line to the starter battery using the ARB supplied fuses (2) then utilize your Switch Pro to activate. Shouldn't require a lot of rework.

 

[DPA200]

Run the compressor power line to the starter battery using the ARB supplied fuses (2) then utilize your Switch Pro to activate.

He used the supplied ARB fuses, but he then ran the power back to the LiFePO4 aux Battery. Is there no way to power this compressor from that aux battery? I did quite a bit of googling, but couldn't find any concrete answer saying either way. Wiring to the start battery yeah i assumed that'd work, just didn't know if there is any way to run it with the way he currently has it setup

 

[TeCKis300]

This sound to me more like a compressor or air line issue rather than electrical. Does the ARB sound like angry bees when on? If so, it's getting the power it needs.

Most air compressors are positive displacement pumps. Meaning it's not a fan depending on speed, rather it will build significant pressure even if slow. So losing pressure is a sure sign there is something wrong with the air line, or internal to the pump.

 

[RET2]

He used the supplied ARB fuses, but he then ran the power back to the LiFePO4 aux Battery. Is there no way to power this compressor from that aux battery? I did quite a bit of googling, but couldn't find any concrete answer saying either way. Wiring to the start battery yeah i assumed that'd work, just didn't know if there is any way to run it with the way he currently has it setup

Just for clarification a single or dual compressor?

 

[DPA200]

This sound to me more like a compressor or air line issue rather than electrical. Does the ARB sound like angry bees when on? If so, it's getting the power it needs.

Most air compressors are positive displacement pumps. Meaning it's not a fan depending on speed, rather it will build significant pressure even if slow. So losing pressure is a sure sign there is something wrong with the air line, or internal to the pump.

@RET2 ual compressor. And yes sounds like angry bees when on. I know quite a few others with the same compressor, and yeah mine sounds the same as that. And yeah the install shop originally thought air line could be the issue when i told them, but again i tried attaching the airgun/handle with no line at all straight to the compressor and same thing. Stupid question (being that i didn't read the manual), do you have to leave the compressor on for some amount of time to build up pressure? Just a thought because most of the tests i tried i didn't wait any time at all. Longest I waited was possibly a couple minutes, and still same result

 

[TheGrrrrr]

I recently had a local 4x4 shop do a dual battery install in my 200. They finished the job weeks later than planned, so the end result was i just got the truck back a day before a 2 week Wyoming/Colorado trip. Overall he did a good job, but being his 1st LiFePO4 Battery setup I'm not sure he got it all right. The basics of the setup all worked fine, the 175w solar panel on the roof, down to the Red Arc BCDC 1225, to the 100ah Renogy LiFePO4 Battery in my drawer wing all kept my fridge and accessories running.

1 part that didn't work out at all was the dual ARB compressor. I'm no electrical expert by any means, I'm just learning as I go. I was under the impression that the air compressor (like a winch) needed to be wired straight to the start battery, and then only ran with the engine on to get the high alternator voltage. The install shop though did it different. He installed a Switchpros 9100. The main Switchpros unit is next to the battery in the drawer wing. The Switchpros control panel is in the sunglass holder using the Slee mount. Apparently the air compressor is too high to use the actual switch pro, so the control panel button is just used as a on/off switch, which that part works fine. The air compressor itself is under the hood using the SDHQ mount. Where things take a turn though is he wired the air compressor all the way back to the aux LiFePO4 Battery. So, the issue I'm having is, the air compressor turns on and off and makes noise like expected, but the actual air pressure out of it is only about as strong as a strong wind. If i try to air up a tire, the pressure is so low it just ends up deflating the tire. Not even enough air pressure to dust things off. I tried attaching the air pressure guage/handle right to the compressor with no air cable, still same result.

So, don't really know what to do from here. My truck is currently at a local Lexus dealer, as somebody recommended a particular technician that works there as having a good 4x4 electrical experience. The shop that did the actual install is almost impossible to get a hold of, and I'm not sure I really want to bring it back to them. As mush a the $$$ Lexus bill is gonna hurt I'm sure, I really wanted a neutral party to look over all the work that was done.


So, my question is...can the ARB compressor run off a LiFePO4 Battery? All the wiring and everything is under the carpet and under the drawers, so to re-wire would be a pretty involved job. Just curious if anybody else has tried and succeeded or failed running a compressor off the aux LiFePO4 Battery like this. Or if this is a lost cause.

I would be happy to take a look at it, but it sounds to me like a compressor issue. That lithium battery should be able to put out more than the ARB can use. I didn’t run the compressor off my lithium because it’s already so close to the starting battery, but I can’t think of a reason it wouldnt work. The twin ARB pulls less than 80A, which is well within what I would expect the lithium to handle.

 

[RET2]

@RET2 ual compressor. And yes sounds like angry bees when on. I know quite a few others with the same compressor, and yeah mine sounds the same as that. And yeah the install shop originally thought air line could be the issue when i told them, but again i tried attaching the airgun/handle with no line at all straight to the compressor and same thing. Stupid question (being that i didn't read the manual), do you have to leave the compressor on for some amount of time to build up pressure? Just a thought because most of the tests i tried i didn't wait any time at all. Longest I waited was possibly a couple minutes, and still same result

Put a pressure gauge on it and see what the cycling cut off pressure is. Keep in mind these are very small compressors on the scope of things.

 

[RET2]

Sounds like you Az. guys are getting it done!! Mudd to the rescue, again.

 

[UPR LC]

ARD Dual compressor can pull upwards of 70 amps at full load. With DC electrical, you need to size the wires according to the load and length of cable (both positive and negative cable combined). If you are running wiring from the front to the rear of the vehicle with a 70 or 80 amp fuse, you need to be running minimum 4 AWG gauge wire and it would be better to have 2 AWG wire. See this chart from Blue Sea https://www.bluesea.com/resources/1437

Also, a quick google for the compressor shows a vendor selling 4 AWG gauge wire kit for a remote mounted compressor. Wiring Kit - Rear Mount - American Adventure Lab - https://americanadventurelab.com/product/wiring-kit-rear-mount/

If there is excessive resistance in the wiring, the compressor will see a large voltage drop and may not be able to generate the air pressure required. With wiring, be very careful that the wire size is large enough for the fuse that is installed upstream, given the length of wire.

This is also the case for your wire size feeding your REDARC BCDC charge controller, make sure the wire is large enough (low gauge number = larger wire).

Yes, the way you have it wired, compressor running off house battery make for long cable runs, but it is safer to make sure you do not deplete your starting battery. In general, it is fine as long as your wiring is large enough for the long runs of wire.

 

[UPR LC]

I would be happy to take a look at it, but it sounds to me like a compressor issue. That lithium battery should be able to put out more than the ARB can use. I didn’t run the compressor off my lithium because it’s already so close to the starting battery, but I can’t think of a reason it wouldnt work. The twin ARB pulls less than 80A, which is well within what I would expect the lithium to handle.

Wire size could be an issue for the long runs of cable, the compressor could be seeing a low voltage condition.

 

[UPR LC]

ARD Dual compressor can pull upwards of 70 amps at full load. With DC electrical, you need to size the wires according to the load and length of cable (both positive and negative cable combined). If you are running wiring from the front to the rear of the vehicle with a 70 or 80 amp fuse, you need to be running minimum 4 AWG gauge wire and it would be better to have 2 AWG wire. Google "Blue Sea Wire Chart" for a handy chart for DC cable lengths and wire size.

Also, a quick google for the compressor shows a vendor selling 4 AWG gauge wire kit for a remote mounted compressor.

If there is excessive resistance in the wiring, the compressor will see a large voltage drop and may not be able to generate the air pressure required. With wiring, be very careful that the wire size is large enough for the fuse that is installed upstream, given the length of wire.

This is also the case for your wire size feeding your REDARC BCDC charge controller, make sure the wire is large enough (low gauge number = larger wire) to get as much voltage at your house battery as possible.

Yes, the way you have it wired, compressor running off house battery make for long cable runs, but it is safer to make sure you do not deplete your starting battery. In general, it is fine as long as your wiring is large enough for the long runs of wire.

 

[TheGrrrrr]

Wire size could be an issue for the long runs of cable, the compressor could be seeing a low voltage condition.

I thought about that but it should be two separate runs each fused at 40A. Even if it was a 10ft run 8awg should be able to handle 40A.

 

[DPA200]

Got this video from the Lexus tech this morning. So far this is what he's found. Is there any good way to keep these from all rattling loose again?

Wire size could be an issue for the long runs of cable, the compressor could be seeing a low voltage condition.

yeah i had that same thought. I believe he ran 6 gauge. I found some random jeep thread where some guy says his ARB dual only lasted a year with this configuration and he thought the issue was cable size. He upgraded to a big Puma and switched to 4 gauge and said he had no issues after that

 

[TheGrrrrr]

The device is the shunt for the victron BMS. I mounted mine directly to the interior panel. Those terminals definitely need to be tight. I don’t think they rattled loose.

 

[UPR LC]

Got this video from the Lexus tech this morning. So far this is what he's found. Is there any good way to keep these from all rattling loose again?



yeah i had that same thought. I believe he ran 6 gauge. I found some random jeep thread where some guy says his ARB dual only lasted a year with this configuration and he thought the issue was cable size. He upgraded to a big Puma and switched to 4 gauge and said he had no issues after that

The copper lugs with the large bolt heads is your power monitor called a "shunt", looks like my Victron unit. Those came with slit lock washers to keep the connect tight. I would recommend that all the bolted type connections have split lock washers as a minimum. Also, any connection that has a through bolt could have a true lock washer added. Your shunt should be secured to a panel, not just sitting there loose, you don't want that coming close to any positive lugs or terminals to arc.

That looks like a poor install, I would go through all the system connections and make sure everything is tight and correct ASAP. You may also want to check and make sure that all the wiring is protected from abrasion and no metal is exposed in the system, electrical fault diagnostics can be very frustrating down the road, especially in the middle of the woods/desert.

 

[UPR LC]

The device is the shunt for the victron BMS. I mounted mine directly to the interior panel. Those terminals definitely need to be tight. I don’t think they rattled loose.

Ha, beat me to the reply. Agreed.

 

[TheGrrrrr]

Given how loose everything is you may want to check that one of the two 40A fuses to the ARB haven't blown. I ran my compressor (airing up in Moab) with the hood closed and the truck running and blew both fuses due to what I believe was overheating, but if the loose wiring caused just one of them to blow you would be working with only one piston instead of two, which would obviously cut your airflow in half.

Now I only run the compressor with the hood open and have not had any more issues. I also now carry two spare fuses for the ARB.

 

[DPA200]

The copper lugs with the large bolt heads is your power monitor called a "shunt", looks like my Victron unit. Those came with slit lock washers to keep the connect tight. I would recommend that all the bolted type connections have split lock washers as a minimum. Also, any connection that has a through bolt could have a true lock washer added. Your shunt should be secured to a panel, not just sitting there loose, you don't want that coming close to any positive lugs or terminals to arc.

That looks like a poor install, I would go through all the system connections and make sure everything is tight and correct ASAP. You may also want to check and make sure that all the wiring is protected from abrasion and no metal is exposed in the system, electrical fault diagnostics can be very frustrating down the road, especially in the middle of the woods/desert.

yeah the shunt was attached to the underside of the drawer wing lid, but 2 self tapping screws came almost completely out. I didnt like the location either because it prevented me from opening the lid all the way. Gonna remount that to a panel like @TheGrrrrr did. Good tips on the various washers. I did check abrasion wise and didnt' see anywhere that he didn't use split loom. Like I'd said it's currently in the shop with the Lexus tech basically going through the whole thing looking for any issues like this, so hopefully he will at least spot any problem areas. Air compressor wise based of this thread, it's sounding like the solution would be either just running to the start battery like everybody else does, or most likely thicker wiring for the long run to the back

 

[indycole]

Does your LiFePO4 only charge from solar? If so, I'd definitely recommend re-running the power to the starter battery and using the compressor with the vehicle running. Otherwise, a couple air refills in the winter may take up way more Ah than your solar can generate.