Battery Solenoid Clicking On and Off

[Cinequip]

While walking the dogs in Arcata, CA last night, I noticed regular clicking (about every 30 sec.) coming from the battery compartment. The large solenoid that connects the two 12vdc busses was clicking on for a couple seconds and then off. This repeated every 30 secs or so. #19 on the Vansco illuminated at the same time. Thinking about the switch on the dash, I operated that several times, which operated the solenoid normally. But it returned to the cycle of off and on. I then checked battery voltage on the Xantrex panel. Voltage was right at 13vdc and charger on float. Since we normally run 13.6vdc when plugged in, I started turning off lights. With just a few lights burning, the voltage starting creeping up. As soon as the float started creeping upwards, the solenoid clicking stopped.

After a short while, voltage was back at 13.6vdc. I started progressively turning on lights. After just a few, I saw the voltage start to drop. It appears that one can turn on enough 12vdc stuff to draw more than the float charging, which then starts drawing the battery down as the demand increases.

Is this normal? Seems to me that the Xantrex should be smart enough to increase charge rate as the coach load increases. Please tell me how your coaches deal with DC load when on shore power.

2nd question: Is it normal for the solenoid to join the chassis and house busses when coach voltage drops to a particular point? Seems like chassis battery voltage should be preserved at all costs.

The manual is little help. It states that "the solenoid connects the battery banks at certain times to supply additional charging to the batteries."

3rd question: Does the solenoid ALWAYS operate when in charging mode?

I wonder if I had just the perfect load enabled to cause the battery to drop into charge mode briefly (the 2 seconds or so mentioned above) while topping off the battery, and then 30 seconds for the system to draw it back down?

OK, enough thinking for now...

[Flagelpater]

I am not an expert. I think the solenoid closes, connecting both 12 volt systems, after the House Battery reaches a certain voltage. This protects one set of batteries. When on the Alternator it works in the opposite mode, protecting the chassis battery set. I would guess that you are hearing the chassis battery set being disconnected because the house set is too low. What happens if you leave everything else alone and just turn off the Chassis Battery Switch? Check all cables for corrosion, both ends. Put a voltmeter right on the batteries and see what is going on as you hear the solenoid click. FWIW

[EngineerMike]

1) Solenoid may be going bad, i.e. corroded contacts w/high resistance across the closed circuit. Check voltage across large contacts when solenoid is closed. If 0.2V or more then this is at least contributing.
2) Check chassis batt voltage- if it is way down then closing of solenoid contacts will draw down batt voltage seen by Vansco possibly below the "connect" trigger voltage causing cycling (this may happen too fast to read accurately on the Xantrex display, or maybe you can read it there; positive check is volt meter on ea. batt bank when solenoid not connected & #19 off)
3) solenoid (&#19) is always "on" when in charging mode & house batteries above trigger voltage, or at least that's the design logic.

[LVJ58]

Scott, we have an Intellitec Battery Control Center on our gas coach, and the way our BCC works, is when the charge voltage from any source i.e., engine alternator, inverter or solar panel reaches 13.3 volts, the isolator solenoid engages connecting the house and chassis batteries together so both will charge from the charging source.

When voltage drops below 13.3 volts the isolator solenoid will disengage breaking the connection between house & chassis battery to prevent one from discharging the other.

The intermittant clicking usually occurs when the voltage fluctuates between 13 & 13+ volts causing the isolator solenoid to cycle on & off.

Hopefully that's all yours is doing and there are no problems with your electrical system.

Best of Luck

[wa8yxm]

Well.. I have done a bit of research, I often post that many rigs the chassis battery is not charged by the house converter.. Yours, and Mine, (And many others I might add) it appears they are.

Now.. The charge controller,, or rather the battery controller, on my rig measures voltages, and only connects them if the {Source} battery is near full charge.... So if the hosue batteries drop to 13 volts (no where near full charge) the BCC will "Drop" the chassis battery when on shore power

Likewise if the chassis battery is low,, the BCC should "Drop" the house when the main engine is running.

Your symptoms indicate to me that the chassis battery is either

1; Very low

-or-

2: has a shorted cell

I would get a dual-meter battery load tester from Harbor Freight

- Harbor Freight Tools - Quality Tools at the Lowest Prices

DISCONNECT the chassis battery (you only need to disconnect the ground or usually the negative lead) and test it.. May need a new one


As LVJ58 said, the clicking is because of the voltage going up and down

WHY is this happening?

Because when the BCC connects the two (picks up the chassis battery) the chassis battery is drawing so much current the house battery is going down.. when it hits 13 the BCC drops the chassis battery (Disconnects it) and then the house starts to re-charge.. When it gets high enough the BCC picks up again.

THAT, by the way, is why I suspect the chassis battery of being bad,,, it's drawing way too much charge current.

[Dale777]

Cinequip,

I've had the same problem with my coach since it was new. The problem has never been resolved, but I work around it by always making sure that the chassis and house batteries are never significantly discharged. If either bank is significantly discharged, then I encounter the symptoms you describe. See this link:

http://www.irv2.com/forums/f104/rela...lem-19174.html

That link only describes the symptoms where charging is occurring from the chassis alternator. However, I've also had the similar symptoms that you describe where the Xantrex is doing the charging and the house batteries are somewhat discharged. My workaround for that problem is to charge the house batteries via the GenSet. Using the GenSet, I never have a problem.

Try charging using the GenSet to see what happens.

My theory on this situation is this:
1. One bank gets charged just enough (13+ volts - don't know exact voltage) to reach the Vansco threshold to cause the Vansco unit to trigger LED 19 which causes the battery isolator/solenoid to close, which causes charging of both banks.
2. Once both banks are connected and charging together, this causes a very large current draw, which drops the voltage (to about 12.7-12.9 volts) precipitously thus reaching the Vansco threshold that indicates to open the battery isolator/solenoid (takes about 2 seconds)
3. Once the battery isolator/solenoid opens, then the charger (Xantrex or Alternator) is able to provide adequate current and charging on one bank only is back to normal voltage. Once back to normal voltage, then after about 10-30 seconds loop back to item #1.
4. This cycle continues.
5. The Xantrex and the chassis alternator cannot handle the large current surge when connecting both banks without precipitously dropping voltage, but the GenSet can handle this current surge.
6. I suspect this condition in my coach is exacerbated since I have 8 AGM house batteries which are capable of drawing a lot more current during charging than the lead-acid batteries.

Now, what I've described may not apply to all Alpines, since many have only 4 or 6 house batteries and most do not have AGM. There have been other posts about the 160 Amp alternators on the Alpine being marginal for the current draw on some Alpine Coaches. The 2000 Watt Xantrex units might also be marginal for the conditions that I described, although I have not confirmed this. I do know that some Alpine owners have switched to 3000 Watt Xantrex units.

Also, there could be other conditions that cause large current draw - high resistance in the battery isolator/solenoid, a battery going bad in one bank, bad battery connection causing high resistance, etc.

Comments on this?

[Flagelpater]

The 2000 or 3000 number should be referencing the Watt output. I don't think it has anything to do with the charging capacity. I do not have the units but you need to look at a different part of the specifications to determine the battery charging capacity. If the battery set that is being temporarily disconnected while charging is in good health, including clean connections, the time between solenoid clicks should increase. If it does not decrease then it is not deriving any positive benefit from the short charge period. Either the draw on the battery set is equal to the last period of charge or there is no charge ability. I also come down on the side of an unhealthy battery set.

[Cinequip]

Well, the house batteries were just changed in July, and the chassis are original. I suspect that the previous owner allowed full discharge on the house batteries, plus they were all low on water when I took delivery, which resulted in their early demise (1.5 years). Since the charge cycle to bring chassis back up is so short, I'm leaning toward the idea of a shorted cell in my chassis set. Interesting, since I have no problem cranking the engine, even when I accidently leave the headlights on.

I will perform some testing and report the results. I'm headed to Henderson's Lineup in Grants Pass to see if they can solve my wandering problem. I constantly have to make minor corrections to keep going straight down the road - exhausting.

Thanks guys...

[Dale777]

Flagelpater,

The Xantrex 2000 Watt and 3000 Watt Inverter/Chargers that I referred to are, more specifically, the Xantrex RS2000 and Xantrex RS3000. The RS2000 specifies output charging current at 120 Amps DC with a battery voltage range of 10.0 - 15.5 VDC. The RS3000 specifies output charging current at 150 Amps DC with a battery voltage range of 10.0 - 15.5 VDC. Hence, the RS3000 does, in fact, have more current charging capacity.

References:
Xantrex Technology Inc. - Recreational Vehicles - RS2000 Sine Wave Inverter/Charger - Specifications
Xantrex Technology Inc. - Recreational Vehicles - RS3000 Sine Wave Inverter/Charger - Specifications

[Flagelpater]

Dale77, Thank you for the INFO. It will be interesting to see what Cinequip comes up with after his battery testing.

[dgerstel]

Scott.

Dale77 explained the situation very well and it does apply to all Alpines that have the Vansco system. It sounds to me, that your problem is the low output from the Xantrex. Have you checked what the Xantrex "power share" is set at, a low setting would limit the charger output. Also see what the battery temp is reading when this is happening.

[Cinequip]

Here were the conditions when I noticed this anomaly:

1. Cool coastal air - battery temps upper 60's.
2. 30a shore power with Xantrex power share at 30a.
3. 7 ceiling lights and all cove lighting on.
4. Xantrex in "float" mode.
5. House voltage at 13.0vdc (this is the solenoid trigger voltage on my coach).
6. Turning off all ceiling lights allowed volts to creep back up to my normal 13.6vdc float. Progressively turning on more lights starts to bring voltage down. I didn't experiment to determine just how many lights on drives voltage below 13vdc.

Here are the results of my tests today at Henderson's Line-Up in Grants Pass:

1. HOT. Mid-90's outside. Battery temp: 88
2. 30a shore power with Xantrex power share at 30a.
3. NO lights on.
4. Xantrex in "float" mode.
5. House voltage at 13.3vdc with Solenoid engaged normally.
6. Removed ground wire from Solenoid coil to disengage house from chassis.
7. Chassis measured about 13.1 vdc.
8. Removed ground cables from one chassis battery. Re-measured each battery, and found each one to match.
9. Put everything back.
10. Turned on every light in the coach plus ran the HWH pump for a bit. House voltage dropped to 12.5, and VERY slowly continued to drop.

Conclusions:

1. Chassis batteries likely OK.
2. House batteries definitely OK - 2 months old.
3. Charger in "float" mode does not produce enough power to keep up with a large DC load. As you progressively add 12v load, the house battery voltage begins to drop as the float charger can't keep up.
4. If you create a situation which draws the voltage down to 13.0 vdc, but no further, we then enter this anomaly where the solenoid drops, thereby taking the small charging load off the chassis batteries. This slightly less load on the house, allows the float charger to actually gain ground, and begin to increase voltage above 13.0 - which then kicks the solenoid back on. We are in an endless loop at this point, unless coach load increases or decreases.

Solution:

If you hear your Solenoid going off and on as I have illustrated, then turn off or on a few more lights! Another idea would be to install a solenoid defeat switch on the ground wire. The concept would be to NOT allow float charging on the house batteries when on shore power for short stays (say one week or less). Engine alternator would recharge chassis batteries during driving from location to location. You'd only have to flip the switch when you take your coach into or out of storage (for us non-full timers).

Maybe, someone smarter than me can figure out a way to re-program the xantrex to allow this defeat from the control panel. (I assume the Vansco is just the messenger)

[Dale777]

Cinequip,

To help isolate the problem, I suggest that when you experience the continual cycling of the battery isolator/solenoid, run the GenSet, instead of using shore power, to see if the problem goes away. If it does, that suggests the problem is related to the Xantrex Inverter/Charger. If the problem remains, then any conclusion is less clear.

The reason that I suggest this approach is that when I run the GenSet, my float charge is about 13.6 volts no matter what the DC or AC load. I can run both A/Cs, turn on all AC and DC lights, and run the Microwave - with no drop in the float charge from about 13.6 volts.

[Renipladlo]

Cinequip, we had the same situation in our coach batteries when we purchased from dealer. I have not done a load test, nor every run out of power, except one time, when it was stored. I think I have weak house batteries, the coach batteries are fine, and are the sealed kind. I will most likely have them checked and then decide if we want gel-cells or stay with the acid type. Since it's mostly always plugged in, I never hear the clicking, but I head it once when not plugged in, while working on it. I always turn off master switches when stored. Hey, we are across the river from you guys as well. You know that place where there is no income tax!!