Air ride causing battery drain

[amashal]

I've traced a battery draw to my air ride but don't know how to fix it. I've got the Accuair rocker switch with elevel. I have my compressors wired with the dual 40amp relays like shown in the Viair diagram instead of the compressor relay shown in the Accuair diagram. The red 12V wire off the ECU is plugged into slot 30 of the relays with my main power. Yellow wire is plugged into the keyed source slot 86 on relays. Everything works like it should but it kills my battery in 2 days if I skip a day starting the blazer. I realize(I think) with the 12V red plugged directly into main power off the battery it would keep the ECU energized, correct? How do I fix this? Another question is if I use the compressor relay that is shown in the Accuair diagram the 12V wire connects again with the main power wire. Wouldn't this again keep the ECU energized? Any help is appreciated. I'm not good with electrical. I know just enough to follow schematics and that's about it.

[VetteVet]

.....

Here's two that I have. The Viair and the Air zenith.






both of them are controlled by power from the key through a switch to the air pressure switch. It turns on the relays to power up the compressors, and fans if you have them.

I don't see any reason to wire the compressors off the ECU. if you are tied into 30 with the ECU wire and the battery power, then you could be backfeeding the ECU with the key off. I'll have to look closer at the diagram.

[VetteVet]

Well I can't read the Accuair diagram but I'm assuming that it has the
e-LEVEL automatic leveling system requiring the ECU. Your description of the drain sounds correct. Would it be possible to run the 12 volts red wire through a switch or the keyed powered source or could you run it through a 30 amp bosch relay to switch the wire off and on with the key.?

I would disconnect the wire and wait two days then see how the battery charge held up.

[amashal]

Originally Posted by VetteVet

Well I can't read the Accuair diagram but I'm assuming that it has the
e-LEVEL automatic leveling system requiring the ECU. Your description of the drain sounds correct. Would it be possible to run the 12 volts red wire through a switch or the keyed powered source or could you run it through a 30 amp bosch relay to switch the wire off and on with the key.?

I would disconnect the wire and wait two days then see how the battery charge held up.

I've been disconnecting the main fuse at the battery and battery stays charged when I do it that way. I was thinking to run the 12V through its own relay but wanted to see if I was missing something simple first. My fuse panel doesn't have anymore empty keyed power sources. Would it be ok you think to tap it into the same keyed source as my radio or do I need to look into adding more circuits to the fuse panel?

[Andy4639]

Disconnect the ECU 12v wire and see if it will come on and work like it should. If it does leave it like this and see if it drains the battery down. If not then don't hook the 12 volts back up it not needed.
If it doesn't work make sure the 12 volts from ECU is switched on/off with the truck key switch and not staying hot all the time.

Looking at the ViAir schematic only way it could come on is if the pressure switch is tied to a hot 12volts all the time instead of a switch. Without the accuair schematic layout it's a guess that it's back feeding because the 12 volts you say is on 30 which will not energize the the relay. The terminal should be hot all the time from the battery.

The relay could be bad are the pressure switch could be. Are you have a Hot 12 volts missed wired some where.

[gmachinz]

After reviewing that schematic, verify that if you remove the ground wire (assuming the ECU doesn't require memory) and your draw goes away, then simply wire that ECU to ground through a stand alone relay with IGN on. That should take care of the ECU creating a draw. But-imo the diagram shows using the 40A relays as ECU triggers from the tank pressure switch to activate that big 75A rated relay to actually power the compressors. Those 40A relays if you are using them as power relays, I suspect could be your source of the draw. I highly doubt those have any type of diode protection as the 75A relay does. I stock those relays myself-they are rated @ 250,000 cycles at 75A and 125,000 cycles at 100A draw so they are extremely stout and feature resistors and parallel diodes across the coils so you really should be using that type of relay to run those compressors.

[amashal]

i tried it a few days ago with the 12V disconnected and nothing worked. I then tied in the 12V wire from the ECU to the 87 lead leaving only the main power lead on 30. I got nothing that way either so just put it all back the way it was. I ordered the single compressor relay that shows on the Accuair schematic and it came in yesterday. I'm going to hook it up so everything is connected the way their schematic shows and see what happens. If I still have a draw I guess I will run the ECU wire up to a switched power source with a relay. If the relay or pressure switch was bad wouldn't that cause the compressors not to come on or not shut off setting off the relief valve in the tank?

[Andy4639]

Did you do this with the key on are off. If the 12 volts didn't have power from someplace it want work no matter where you hook it to. If it had 12 volts and you tied to 87 and it didn't work you have a problem because that is straight wired to compressors.
With your VIAIR diagram if you crank the truck up 30 should have power on it automatic from the battery, the pressure switch will only let the compresor run if it falls under the setting. Does the ECU have a 12 volt hot wire when the key is off? If so this has to be the problem it's feeding the pressure switch when you turn the truck off.



Ok with the key off find where you have the 12 volt draw at. The ECU the pressure switch the relay. The back side of relay on 87 shouldn't have 12v. 30 should. If the pressure switch is good then the terminal to the relay shouldn't have 12 v on it. If it failed in the closed position then it's going to be powering the relays. Take a test light and check all the connections with the key off.

[amashal]

Ok. Here's what I got. Taking everyone's advise and posting here. All this with key off.

11.8V at 30 pin to both relays
0 at 87 pin
Also have 11.8V at fuse to ECU so it is powered with key off
Also disconnected ground to ECU and draw goes away.

Gmachinz- if I understood your post correctly you are saying I should get rid of the 2 40amp relays and run the single 70amp one shown in the Accuair schematic? I planned to do this since the 70amp relay just showed up yesterday. My question though is the schematic shows both main power and the Batt-12V from the ECU connecting to the same pin. Wouldn't this again keep power to the ECU? Or does the diode protection you mention solve that problem?

[amashal]

Ok. I decided to give Accuair a call and got Matt on the phone. He says the Elevel design will constantly have a 65 milliamp draw. He says they recommend everyone running the elevel to put a battery tender on the vehicle unless it's a daily driver. He was very helpful as were all of you guys. I went over my volt readings and wiring and he said everything sounds right. Off to the parts store for a battery tender.

Thanks,

Alex

[gmachinz]

Most diagrams like there's are kinda generic when it comes to running a power feed "to a battery source". I suggest using an altogether separate relay (power or ground won't really matter) to kill the ecu with the key off. I would suggest killing the ground side of it to keep it easy to wire in. Here's a basic way to do it:

#30 & #85 to chassis ground
#87 to ecu ground
#86 to switched Ign source

Then, just wire the main 75A relay as they show. I'd suggest 8ga wiring from the alternator charge post or remote junction-NOT directly off the battery to #30 on that relay. Then 8ga from #87 to your compressor. #85 is chassis ground and #86 appears to be pink from the ecu presumably a trigger for when the low pressure switch contacts close. There is no reason to have that ecu live with the key off IMO unless you have programmed info in it for your setup. If that's the case, I'd put an Optima deep cycle yellow top battery in it then. Probably wouldn't be a bad idea to run a battery iso kit and have a dedicated deep cycle battery just for your air suspension.

[Andy4639]

That maybe his (Matt's) way of answering your question and that's fine but..... I would have the ECU tied to key switch to come on when the truck is cranked are have it wired to a switch to cut on once the truck is running. Why does the ECU need power when the truck is off for several days? Does it have to keep the memory in the ECU maybe? 65 milliamp draw shouldn't kill a good battery in 24 hrs.
The use of 2-40 amp relays are the 1-70 amp are just ones preferences. It just takes one relay out of the schematic but it also leaves you with no air if the one 70 amp relay fails. With the 2-40 relays you can at least have some air put into the system if you need it. Just my 2cents worth.
I don't like any draws on my battery when off except for the radio memory & clock. My truck can go over a week and still crank.

[amashal]

Yeah I hear you guys. I'll get under there sometime and wire in a relay so it kills power. I don't like draws either but just figured it was normal after talking to Matt. Gmachinz-Why do you say NOT to run directly off the battery? That is how I have it now. I'm not questioning you just wanting to learn. And i have 4 gauge running from the battery to relay now just because it was already there for an amp that was in there. Nothing wrong with running thicker than 8 gauge is there?

[gmachinz]

No, bigger gauge wire never hurts! The reason to not run off the battery directly is because the battery is really meant for storing power to start-not for supplying power. Its easier on the charging system to monitor system voltage and have the regulator adjust output accordingly if it can "sense" the sudden drop in voltage whenever you turn on an electrical device. The battery acts as such a huge buffer to the system that the alternator can't always keep the battery trickle charging while running. In other words, the alternator thinks the battery is happy with an 8A charge while your compressor is constantly stabbing it with 10-12A hits. It may not be a huge difference but between the two methods I'd suggest running power from a common junction where you also have the alternator's remote voltage sensing wire ran to. If you're still running an external regulator with what you're running for air assist, I'd think about converting to a CS style alternator-but that may be for a later time...lol

[amashal]

Makes sense. I did the alternator conversion in my '67 with the help of the forum. I'm waiting for the regulator or alternator to take a dump on the blazer before I do the conversion on it. Thanks again.

[VetteVet]

I couldn't get back online today until now but, it seems like you're stuck with keeping the ECU hot if you want to maintain the auto setting feature. Killing the hot or ground side with a relay kills the draw and the memory. IMO .65 amps is a lot of draw for a memory retention. The battery tender solves the problem as long as you are near an electrical source.

I'd also advise running the compressors off a junction with a connection to the battery in case you wanted to run the system with the key off.

Have you searched the suspension forum for answers. There's got to be someone else had this problem.

just had an afterthought, disconnect your positive battery cable and connect a multimeter set on amps ,most will read up to 10 amps, between the positive cable and the positive battery terminal. see if you get a reading with the key off. This will tell you if you have more than the ,65 amp draw.

[ddubbs]

Glad this thread was started. I'm having the same problem with my Accuair system. Need to take a look and see if I can figure it out with this info. Thanks

[gmachinz]

If you have to retain the ecu memory feature, then definitely go with a second, dedicated deep cycle battery and run a dual battery isolation kit. With what you've got invested in the air system, I'd say its time for an updated or modified charging/battery system. Is the ecu a solid state design?

[amashal]

I get a reading of .09 with my meter set on 10A. That's a 90 milliamp draw correct? Same test with air ride unplugged and meter reads 0.00. I don't think the ECU keeps a memory that is lost when it doesn't have power because I don't have to reset anything after having the fuse pulled. All heights are still preset like before. I'm not sure if the ECU is a solid state design. I googled 'solid state design' and still can't answer the question.

[Andy4639]

Originally Posted by amashal

I get a reading of .09 with my meter set on 10A. That's a 90 milliamp draw correct? Same test with air ride unplugged and meter reads 0.00. I don't think the ECU keeps a memory that is lost when it doesn't have power because I don't have to reset anything after having the fuse pulled. All heights are still preset like before. I'm not sure if the ECU is a solid state design. I googled 'solid state design' and still can't answer the question.

If this is correct then simply hook it up to come on with the truck and it will take the drain off the battery. Hook it into a fuse off the block under the dash are as stated a another relay. Really depends on where you have the ECU mounted I guess.

[gmachinz]

Then that pink lead from the ECU looks to be what you need to trigger via a switched IGN source. Do that, then take another reading with key on, then key off. Your draw should be there with key on, and gone with key off.

[C10Greg]

Were you able to find a solution to the battery drain?

[amashal]

It still has the draw but wiring the ecu into keyed power is how to fix it. Just haven't had time to mess with it. I run the truck every 3 to 4 days and so far it hasn't had any starting issues.