Ford Dual Battery Setup - Page 6

carringb · 07-19-2015, 08:00 PM

Quote:

Originally Posted by FarmerFrederico

OK - I'm finally at a place where I can start working on this battery set-up and thanks for all of the replies, everyone.

I do have the auxiliary battery on my 2010 V10 and it came that way from the factory with a factory installed hitch. All of my DC sockets are up at the dash of the van.

Could I wire an outlet in to the harness behind the panelling running up the pillar behind the driver's seat?

If I want to use it as a house battery with no solar right now, can I plug things into 12v sockets with the key in ignition turned backwards and just run a fan and fridge off that battery?

Or do I need to run a separate line inside the van to run a fridge and fan?

Am I correct that it is isolated from the main battery with a relay?

How do I test everything to see if it set up correctly?

The van already has 12 hot source in the driver side B-pillar. I believe this is directly connected to the aux battery, and should not drain the primary batter.

FarmerFrederico · 07-19-2015, 08:55 PM

Thanks so much, for the last few replies to my questions/posts! Sorry I haven't replied! I've got a multi-meter and some wiring diagrams and am going to start double checking for myself that everything is as it should be. I'll keep you updated. Unfortunately, where I was storing pictures (Google +) and then linking to here is causing problems with posting because the images are now too large for this forum and I can't change them in Google + FRUSTRATING! It works in Expeditionportal but not here so I've been spending more time in that area with build updates and questions with pictures...thanks for everyone's help!

dhally · 07-20-2015, 02:14 PM

From my recollection, there is a circuit from the aux battery to power a trailer even when the ignition is off. And the aux battery is disconnected when the engine is off. The relay and fuse are about 50 amp if I recall, so if you start adding AGM batteries this circuit may need to be upsized to handle fast charging.

FarmerFrederico · 07-20-2015, 04:35 PM

So my main battery in engine compartment reads 12.3v when engine is off and 14.2v when engine is on so I'm getting a charge from alternator. Auxiliary battery though reads 12.3v regardless of whether engine is running. So, it's not getting charged, right? How could it be 12.3v if it probably hasn't been changed in 5 years?

One thought I just had. When I had the 4x4 conversion done the shop didn't know there was an auxiliary battery and that one didn't have the cables disconnected before welding. Could the battery be holding a charge from normal charging a few weeks ago before the conversion happened but the relay between the two has been shorted?

mikracer · 07-21-2015, 11:37 AM

Funny you should post about this... I recently installed a cig lighter port in the rear of my van running off the factory aux battery. I had checked the voltage while running this morning to see what it was at, and it was at 12.5v with the van running and 12.5 with the van off. I'm wondering if the factory isolator gave out at some point and its just holding the residual charge.

If the factory isolator is bad, can anyone recommend an isolator to install in place of the factory one? I imagine the factory one is probably expensive.

carringb · 07-21-2015, 03:11 PM

Keep in mind the factory isolator give preference to the starting battery, so it sometimes won't connect for 5-10 minutes after starting.

Napa can match the relay. Its pretty much a continuous-duty starter relay. If you want really robust you can swap in a glow-plug relay but those are quite a bit more expensive.

mikracer · 07-21-2015, 03:14 PM

Quote:

Originally Posted by carringb

Keep in mind the factory isolator give preference to the starting battery, so it sometimes won't connect for 5-10 minutes after starting.

Napa can match the relay. Its pretty much a continuous-duty starter relay. If you want really robust you can swap in a glow-plug relay but those are quite a bit more expensive.

Thanks for this info! I'll recheck after the van has been driven a little to see if I get north of 12.5v.

FarmerFrederico · 07-22-2015, 12:46 PM

Well I started up the van and let it run for 10-15 minutes and my auxiliary battery is still at 12.3v. Not sure how to test my isolator because it is hidden under the main battery and I can't remove the battery and still have it connected to the leads.

FarmerFrederico · 07-22-2015, 02:09 PM

I put some alligator clips on the two posts coming out of the isolator with the engine running. One is insulated with a rubber cover but I just clipped on to one of the ring terminals on that side. Then I used my Greenlee multimeter which is totally new to me. It didn't measure but 2-3 volts and I only had it running for a few minutes. Then I checked for continuity and I believe the instructions say to push a button and listen for a sound...so I pushed the button and got the sound. I also looked up and found that you can check for continuity by turning it the dial to ohms and it says that if there is a reading of 0 ohms then I have continuity which it did. I also turned off the engine and then did not get a continuous sound as I did when the engine was running and the ohms reading was 0.L - but I can't figure out what that indicates in my multimeter manual.

Any thoughts?

Still getting a reading of 12.3V at my auxiliary battery.

carringb · 07-22-2015, 03:35 PM

Have you cleaned the terminals on the aux battery? I had a similar problem once and that's all it was.