Normal separator behavior?

[jrtozer]

Hi folks,
I recently noticed that the house battery doesn't begin to charge from the engine until after 10-30 minutes of driving in the morning. Isn't the separator supposed to "connect" when a charging voltage is detected from either house or starter battery?
In my case, the voltage at the vans cigarette lighter is 13.9v, but the house battery is sitting at like 12.4v and not charging. It doesn't seem to happen when I start the van to drive later in the day. Perhaps the engine alternator is first charging up the starter battery (sitting at 12.4v first thing in the morning), but I didn't think that was how it was supposed to work. My SMB is only 18 months old, and I have solar panels if that matters.
Is anyone else seeing this same behavior? Is it normal? (I ask because my house battery doesn't seem to charge fully or drops more quickly than I remember).

Thanks,
-J.R.

[John Kalmbach]

Hello J.R.

You're correct, the Battery Separator should be connecting the battery banks whenever either bank reaches 13.2 volts, and disconnects when the voltage drops to 12.8 volts.

Double check the small 14 gauge black ground wire that connects to the Battery Separator and then to the chassis. Make sure the crimps are good and that the mounting hardware is tight. With the engine running, pull the ground wire terminal from the Battery Separator, and then touch it momentarily to the spade terminal on the Battery Separator you removed it from. You should hear the Battery Separator "click" whenever the ground wire makes contact (the Battery Separator is a modified solenoid switch).

It's also possible there is a loose house battery cable, check both the positive and the negative cable connections, especially where the negative cable mounts at the chassis.

Good Luck!

John K.

[jrtozer]

Thanks for the advice John. The ground wire does indeed trigger a clicking sound (after about 3 seconds of contact). All the wires I can easily see from the top of the separator are tight. You mention checking the battery terminals, but I can't seem to figure how to get to them. I have an RB50 and the 4D battery is under the floor at the side door opening - do I have to lower the battery to check the connections?

Thanks, -J.R.

[scatter]

Yup, ya got to lower the battery. Suggest you use a floor jack, cause that sucker is heavy. You can check the other end of the cables by following them out of the battery box.
Good luck!

[Ford_6L_E350]

Originally Posted by jrtozer

Hi folks,
I recently noticed that the house battery doesn't begin to charge from the engine until after 10-30 minutes of driving in the morning. Isn't the separator supposed to "connect" when a charging voltage is detected from either house or starter battery?
In my case, the voltage at the vans cigarette lighter is 13.9v, but the house battery is sitting at like 12.4v and not charging. It doesn't seem to happen when I start the van to drive later in the day. Perhaps the engine alternator is first charging up the starter battery (sitting at 12.4v first thing in the morning), but I didn't think that was how it was supposed to work. My SMB is only 18 months old, and I have solar panels if that matters.
Is anyone else seeing this same behavior? Is it normal? (I ask because my house battery doesn't seem to charge fully or drops more quickly than I remember).

Thanks,
-J.R.

The only thing that might make sense is if the device you are checking voltage with is out of calibration. If your meter is reading high, then maybe the separator just hasn't reached a high enough voltage to switch over. Maybe you should measure the voltage at the separator, in case there is some resistance in the system. I had my separator develop some corrosion and a high resistance right at the battery connection. Pull the cables off (very carefull, do not allow the cable to touch anything!!!), clean the terminal and cable, grease it up to prevent corrosion and put it back together. Now do the other side.

So, a couple of questions -
- What are you using to check voltage?
- What does the voltage measure at the separator terminal?
- What does the voltage measure at the separator battery wire?
- Why aren't your solar panels charging your house batteries?
- When parked in full sun, does the house battery charge up? Does it then start to charge the starting batteries?

Good luck,

Mike

[daveb]

The battery separator is designed for use in multi-battery applications as a solenoid priority system to protect the chassis charging system from excessive loading while allowing auxiliary batteries to be charged. The battery Separator has two basic operational characteristics:

1. Assist in engine starting.
When the starter is activated, the battery separator compares the voltage of both banks. If the chassis battery is lower than the auxiliary battery bank, the battery separator will engage allowing the auxiliary battery bank to aid in vehicle starting. (The start signal must be at least three volts for this operation to occur).

2. Protecting the charging system.
Once the engine has been started, the separator monitors the chassis battery (twin starting batteries in the case of a Ford diesel) and charging system. When the charging system reaches 13.2 volts indicating a charged main battery and functioning charging system, the battery separator will engage, connecting the auxiliary battery bank to the vehicle charging system. If the drain on the charging system by the auxiliary battery bank reduces the system voltage below 12.8 volts, the separator will disconnect the auxiliary battery bank, thus protecting the chassis charging system. The process is repeated until the charging system is turned off. A delay function has been incorporated in the circuit to prevent the separator from reacting to momentary voltage fluctuations and chattering. The priorities are to assist in starting, if required, and to protect the charging system from excessive drain.
This is from the company.

The newer units (2006 and up) are bi-directional according to SMB but I'm not too sure about this so I will just assume they are correct.

The first problem is your van is new.

Are you plugging into shore power at night?

Is the voltage at the dash 13.9 before you start the engine?

Are you leaving something on that is draining the starting batteries?

It would be a good idea to check what the others have posted but before I would drop the house battery I would exhaust some of the easier tasks first.

Do you have a diesel? If so you might have to check both starting batteries with a Carbon Pile tester. Don't rely on Ford to give you the truth here. Both starting batteries must be removed and tested individually.

If you have a gas engine, pull the ground wire off the Separator and try to start the engine. If it cranks hard your starting battery may be bad or the terminals could be corroded. This can be done with a diesel but may still start if one is good.

It sounds like a poor starting battery is causing the separator to stay open after it utilizes the house battery to start, and then after a long drive the charging system brings your starting battery up to a correct voltage in which it engages and continues to charge both banks.

The carbon pile tester is the best way to check but you have to drop the battery(s).

I had one good starting battery and one bad. It still started w/o aid from the house battery.

With a bi-directional separator, if there is a short causing the charging system voltage to drop below 12.8 the separator will open up. But I would think you would know if this is happening. It would be inconsistant I would think, not only in the morning.

Then again I might be wrong about the whole thing so don’t let me lead you astray. Good Luck.
Dave B

[jrtozer]

Excellent info and suggestions everyone - thanks. Here's what I know:

Starter Battery votage:
12.3-12.6v in the morning
13.9-14.2v when engine is running

House Battery voltage:
12.4 - 12.7v (up to 13v when the sun is shining on the solar panels)

Solar panels do charge the house battery, but we've had some rainy days in a row (or been covered inside the ferry) here in Alaska, so engine charging is necessary. We only plug in at night about once per week or less - on the road for the last two months (never plugged in at night when parked at home - san diego sun and once/week errands should keep things charged).

My measurements are made with a Radio Shack digital multi-tester (generally matching the readout from the scangauge and the solar charger readout). I try to take measurements only after lights/frige have been off for >5 minutes. The van is a 2006 - it is gasoline (19k miles).

This morning I started the engine and measured voltage at the separator terminals (as suggested). The Starter terminal had 14.2v (engine running), but the house battery had only 12.9 (solar charging happing at the time). Since they are not at the same voltage, I am assuming the separator is keeping them separate (open?), but since the engine is on and the starter terminal is over 13.2 volts, shouldn't the separator be closed to charge both batteries? Is this proof the separator is bad and should be replaced?

I agree my starter battery is suspect too though. It is less than two years old and has never been abused (drained). I had the Ford dealership test it and they measured 12.6v (just driven) and after a few second automated test of some sort, said it was okay. What voltage should a two year old battery show in the morning?

Thanks again for all the advice,
-J.R.

[daveb]

Don't sound right. If your getting 13.9 (on either side), the solanoid should click closed. Mine did the same thing for a few days on my last trip. It took about 5 min before it operated. Normally it takes a about a minuite to close which is normal for a diesel alternator to start the charge. Now no problems. I actually bought a manual bypass switch because I was so far from home but never installed it as it was finally engaging.

What charges your house battery off shore power? An inverter? With the engine off put your voltmeter on either side of the separator in the morning before the solar can work and check the opposite side. Note the voltages then plug into shore power and start your charge. If the inverter is putting out over 13.2 the separator should operate and the voltages should be the same on both side of it.

Ya it sound like the separator is bad
The model is 1315-200 made by Sure Power (503) 692-5360
Ask them about it before you pull everything.

Dave