Ignition wire voltage

[ant]

Howdy. I have a 2005 D22 and in the tray I have a BCDC1225 installed by an auto sparky charging my aux battery. Has been working perfectly for over 12 months since installed. The week just gone we went camping for the week and it decided to start playing up. The charger would not turn on at all, and would just remain in standby mode (battery type led flashing). Its wired with a relay for auto switching to solar panels as per redarcs wiring diagrams and all was working fine on solar. On the 9+ hour drive from Yeppoon back to Brisbane it switched on for about the first 15/20 mins then never came on again. My waeco was running off the aux battery the entire trip and the battery volts got very low but it never received any charge. This morning I did some checking with the multi meter and found everything seemed ok except the ignition wire where the charger gets its signal to switch off and on was low, by low It was at around 12.5 volts. The charger doesnt switch on until it sees 13.2 volts which might explain why it was staying in standby mode. I bought the revs up and no change. Went for a drive for about 10 mins and the highest it got was 12.8v, still too low. Later in the arvo after leaving the car sit for the day I retested and almost instantly the charger switched on and the reading on the ignition wire was 13.2. I have a led on the dash that shows the status of the charger and this has never happened before. Im not exactly sure what wire this feed is coming from but its the white wire in the main ignition plug in the steering column. Nothing in the install has changed so I dont know why this feed is not always at 13.2 v or even after 9 hrs it did not come on. Anyone else got this charger installed in the same way (relay for solar switching) and if so where do you have the input (blue) wire getting its feed from? Is there somewhere else I could connect this wire that would give 13.2v but only when the ignition is on?

Wow, long post, sorry all but any help would be appreciated.

 

[Old.Tony]

I'd have to wonder if your alternator is putting out a decent voltage - perhaps it's developed a fault?

Many problems like this are caused by faulty earths, because people rely on the vehicle chassis earth (negative, actually) and rely on the body (tub) maintaining that connection indefinitely.

Unfortunately, rust and debris can get in the way of a good connection, that's why it's always a good idea to run a separate earth to your tub for the aux power system.

If the power to the tub is solid, I'd suspect the alternator - or one of ITS wires being slightly erratic.

 

[ant]

I thought of alternator too but at idle its 13.8 and at 1100rpm its 14.4. Checked all earths and they all seem fine. Earth to tub is good and earth from tub to chassis is good too. I do plan on getting the auto electrician to have a look but because the issue seems so erratic I know it will be difficult to trace. Just thought id put it out here and see what others thought.

 

[bods]

Could easily be a dodgy earth, can you run a jumper wire from the earth on the charger to the chassis or the main battery earth? Could also be a dry solder joint on the ignition switch where the wire is tapped into... Failing that it could be a bit of crap or corrosion in the loom connector that goes from the engine bay to the cabin. I'd check all the wires on the ignition barrel and see if you get the same volts. If you do, it could even be a bit of a dodgy earth from the ignition barrel.


It is a bit to check, but at least it gives you somewhere to start...