Rear Air Assist - do NOT use leisure battery

[MisterB]

After fitting rear air assist from Martech, it was working fine, then all of a sudden it wouldnt fire up the compressor to inflate !

after scratching my haed and testing everything, i figured out the compressor wasnt working so arranged to take it back to Martech, 2.5 hours away .... they did offer to send a replacement BUT i need it for tomorrow as i have the front coil springs booked in to be fitted, so shouldnt drive without having the air bags inflated i have been advised.

Martech offered to either stay open late on Saturday or even come back and open up if i didn't get there before they closed, which i think is brilliant of them, great service !

When i got there, Martin tested my compressor DOH! nothing wrong with it ..... but he still replaced it anyway to make sure. He asked how it was wired and i said through a busbar to the leisure battery, he asked if i had solar also connected, which i do ....

it appears that there can be an issue on some motorhomes when the solar is adding to the leisure battery that creates an over voltage (i am not an expert in those matters, but Martin probably is, so i took him at his word)

just refitted the compressor, this time direct to the vehicle battery RESULT! all working as it should do.

Big Thanks to Martin at Martech and just a suggestion to fitting directly to the vehicle battery, not the leisure battery, MIGHT be the better option ......

and it means my new front coils can be fitted tomorrow as planned !

 

[Two on Tour]

I don't understand why a dumb electric motor in a non-critical device like an air compressor would fail to run if an extra few volts are put through it.

 

[StillGoing]

I also don’t understand. If the air assist is that voltage sensitive I’d want a voltage regulator fitted to prevent it happening again.

 

[oldiesontour]

If the over voltage bit were true the alternator would likely have the same effect when charging

 

[Kannon Fodda]

Equally if wired from starter battery don't use compressor immediately before or after starting engine. If the battery is a little unhealthy it might be just enough for volt drop to trigger the infamous air bag warning light.

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[PeterCarole29]

Where in the system is your pump connected

 

[Happy Jack]

After fitting rear air assist from Martech, it was working fine, then all of a sudden it wouldnt fire up the compressor to inflate !

after scratching my haed and testing everything, i figured out the compressor wasnt working so arranged to take it back to Martech, 2.5 hours away .... they did offer to send a replacement BUT i need it for tomorrow as i have the front coil springs booked in to be fitted, so shouldnt drive without having the air bags inflated i have been advised.

Martech offered to either stay open late on Saturday or even come back and open up if i didn't get there before they closed, which i think is brilliant of them, great service !

When i got there, Martin tested my compressor DOH! nothing wrong with it ..... but he still replaced it anyway to make sure. He asked how it was wired and i said through a busbar to the leisure battery, he asked if i had solar also connected, which i do ....

it appears that there can be an issue on some motorhomes when the solar is adding to the leisure battery that creates an over voltage (i am not an expert in those matters, but Martin probably is, so i took him at his word)

just refitted the compressor, this time direct to the vehicle battery RESULT! all working as it should do.

Big Thanks to Martin at Martech and just a suggestion to fitting directly to the vehicle battery, not the leisure battery, MIGHT be the better option ......

and it means my new front coils can be fitted tomorrow as planned !

Mine is Martech too.
Got the full system including Rubena air bags.
Wired mine to the vehicle battery, was an easier route for the wiring and as it's not used often it won't drag the battery diwn.

 

[MisterB]

Where in the system is your pump connected

behind the front seats, in a void where the heating duct runs through, so out of the way, but accessible by removing four small screws (plus the screws holding the pump in situ)

as regards all the technical replies, i only know what i was told and i know that it is now working as it should, perhaps the compressor was the actual issue, which i originally thought it was, but so long as its now working (and yes i checked the fuse and all connections, inc the switch wires for continuity and i could hear the relay clicking when i operated the switches) i am happy !!

 

[MisterB]

A little tip if you are considering buying from Mar-Tech, ask for the knurled ring tees, that work like compression fittings, not the push fit ones.
I found that the push fit were a bit temperamental and could leak if the air hose connection was not perfectly in line. That happened when I tried to push all the 'gubbins' into the void in the dash. I changed to the knurled compression type fittings without a problem.

Front coils now fitted and the paperwork was sent off for vehicle weight change.

Did someone mention angles morts ....

 

[Happy Jack]

A little tip if you are considering buying from Mar-Tech, ask for the knurled ring tees, that work like compression fittings, not the push fit ones.
I found that the push fit were a bit temperamental and could leak if the air hose connection was not perfectly in line. That happened when I tried to push all the 'gubbins' into the void in the dash. I changed to the knurled compression type fittings without a problem.

Front coils now fitted and the paperwork was sent off for vehicle weight change.

Did someone mention angles morts ....

As it happens the knurled ones came with the Rubena kit I got from Martech.

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[jumar]

10 years ago I fitted rear air suspension to our Hymer...
I wanted a simple DIY set up...so I figured that I want the compressor in the garage...but failed to find an adequate power supply...my simple solution would be to put my own power supply next to the compressor....I bought a 12 v motorcycle battery and secured that next to the compressor and guages...
I don't see the need to control the air suspension from inside the cab, therefore the whole system is controlled from the garage...only when the garage is full and boarding ferries do I adjust the air settings..so no inconvenience whatsoever.

 

[Carpmart]

I have to say that I’m with the others, it can’t be an over voltage issue connecting to a leisure battery. You’re vehicle battery will be 13.5-14.5v when the alternator is delivering current. That’s the same or less than your lithium leisure battery.

 

[jezport]

There cant be a difference

 

[Happy Jack]

10 years ago I fitted rear air suspension to our Hymer...
I wanted a simple DIY set up...so I figured that I want the compressor in the garage...but failed to find an adequate power supply...my simple solution would be to put my own power supply next to the compressor....I bought a 12 v motorcycle battery and secured that next to the compressor and guages...
I don't see the need to control the air suspension from inside the cab, therefore the whole system is controlled from the garage...only when the garage is full and boarding ferries do I adjust the air settings..so no inconvenience whatsoever.

Yes, in hindsight if I was doing it again would do similar to what you've done.
I rarely need to adjust the pressures.
In fact, would not even bother with a compressor.
Tyre valves would do, I travel with a battery powered compressor for the tyres and that would do fine.

 

[Pausim]

I know nothing about air assist but if the solar is causing over voltage you could well be damaging other items, including the leisure battery.

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[Bill-H]

10 years ago I fitted rear air suspension to our Hymer...
I wanted a simple DIY set up...so I figured that I want the compressor in the garage...but failed to find an adequate power supply...my simple solution would be to put my own power supply next to the compressor....I bought a 12 v motorcycle battery and secured that next to the compressor and guages...
I don't see the need to control the air suspension from inside the cab, therefore the whole system is controlled from the garage...only when the garage is full and boarding ferries do I adjust the air settings..so no inconvenience whatsoever.

I've also located the gauges and filling point in the garage. Only feel the need to alter mine if I'm putting extra weight in the garage. Don't have a compressor - don't see the need, just inflate/deflate through the valve next to the pressure gauge - it's a tyre-type fitting so just attach my tyre pump to it as I have a 12v socket in the garage already. Switches and cables routed through to the cab just seems an over complication to me for a job that I only need to do very infrequently.
as noted by others in this thread I'm somewhat surprised that your compressor wasn't capable of working at a slightly elevated voltage as the same will happen with your engine battery when the vehicle is running - and your leisure battery will be the same with engine running and/or solar panel.
sounds like a poorly specified compressor if it's not designed to handle a couple of extra volts, or Martech were just telling you that to cover themselves for a faulty item.
Are you sure that there was enough charge in your leisure battery when you first tried it at home and the drive over to Martech just charged the battery back up -thats why it worked on your arrival?

 

[BouncyBoatFolk]

A simple bicycle pump located next to the schrader valves in the garage was my choice,[ extreme KISS],works for me,low tech low hassle.

 

[Landy Andy]

I fitted air assist and it’s wired into my leisure batteries. Controls on dash. And I alter it a lot. At least every time I use the van. I wouldn’t want to not be able to adjust it, and to not see their pressures. I’ve never had any problems, but have no solar so compressor would only see up to 14volt.

 

[Antique]

Equally if wired from starter battery don't use compressor immediately before or after starting engine. If the battery is a little unhealthy it might be just enough for volt drop to trigger the infamous air bag warning light.

Wish I'd seen this earlier.
Happened to me a week ago

All the best

 

[Happy Jack]

I fitted air assist and it’s wired into my leisure batteries. Controls on dash. And I alter it a lot. At least every time I use the van. I wouldn’t want to not be able to adjust it, and to not see their pressures. I’ve never had any problems, but have no solar so compressor would only see up to 14volt.

Although I said in hindsight I would go simple if I was doing it again I must admit it's reassuring to be able to refer to the gauges and it's very convenient.

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[Happy Jack]

I fitted air assist and it’s wired into my leisure batteries. Controls on dash. And I alter it a lot. At least every time I use the van. I wouldn’t want to not be able to adjust it, and to not see their pressures. I’ve never had any problems, but have no solar so compressor would only see up to 14volt.

What pressure do you normally run at?.
Got mine at 2.0 bar and not experimented yet.
Normally start a trip at 1550Kg front and 1450Kg rear.

 

[BouncyBoatFolk]

Although I said in hindsight I would go simple if I was doing it again I must admit it's reassuring to be able to refer to the gauges and it's very convenient.

I used a 6 pack of TPMS. 4 On the wheels, 2 on the gauges.
Mike.

 

[Landy Andy]

What pressure do you normally run at?.
Got mine at 2.0 bar and not experimented yet.
Normally start a trip at 1550Kg front and 1450Kg rear.

I run 2.5bar on roads, 3bar on motorway, and deviate around that depending road conditions.

 

[Al n Val]

I run 2.5bar on roads, 3bar on motorway, and deviate around that depending road conditions.

May I ask why you change pressures for different roads

tia

Al

 

[Landy Andy]

May I ask why you change pressures for different roads

tia

Al

Up so that I get blown around less when overtaking Lorrys, and if I have to do a sudden movement firmer suspension. Lower it on rough road, also will be going slower. Will drop even more in Belgium, and I drop it right down when parked at home to get the rain off the roof asap.

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[jumar]

2 bar for our loading and road conditions, found this provides stability and comfort..
With the bulk of our weight in the garage without Air suspension it may be a little too much for the old rear leaf springing.

 

[Al n Val]

i’m only about 2/300 miles in on my rear semi air so still playing with it. It’s a Tag axel so don’t really get the roll or swaying.

I’m pretty much fully laden wherever we go and atm running at approximately 2.5bar but may try 3/3.2bar on motorways going through europe next week.

Thanks for the info

 

[MisterB]

i am considering seeing if i can branch directly off the compressor to feed an airline for inflating the tyres. it should be simple enough to tap into the electrical circuit that activates the compressor. it would then require some way of switching the compressor on or off, which a momentary toggle or rocker switch could be used.

then it would need the connections between the 4mm hose from the compressor to the airline connection/take off point.

its one for the future though, i am in no rush and dont have the time to develop it .... unless someone knows a good reason why it wouldnt work - my thought is that the compressor as it is wouldnt be powerful enough, but i do have a 'ring' tyre compressor so could just install that - but then it doesnt give me anymore than i already have unless i can feed the air assist via the ring compressor ..... and i bet theres a good reason not to do that ??

 

[eddie]

I would personally ask for an explanation "why?" It reminds me of something I posted a while back:

Dave, (the workshop manager at Van Bitz) told me after lunch one day he‘d been in Halfords to get wiper blades and the guy being served was told he should change headlight bulbs in pairs as the ‘voltage surge’ when one went will have damaged to other bulb.

The guy said OK, paid and left with two, Dave jokingly said “That’s one way of increasing sales“ and the guy said ”No seriously, its true”

Funny stuff this electricity, its almost like no one can predict how it works

Oh I forgot

We can!

 

[MisterB]

Thanks for all the comments re the compressor and voltage requirements....
As I previously stated, I can only take his word for it BUT he did exchange the compressor 'just in case'. The main point for me though is that it's now working.
Perhaps I should rewire it back to the leisure battery having seen the posts re the airbag warning light? Is that an expensive fix?

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