Caution. Vehicle Battery/Charging Incompatible with House Battery.

[wayne49]

Hi Everybody,


Last year I had an issue with my van where the alternator shorted out after a long drive with the house system connected to the vehicle system.

Recently, I upgraded my solar to a TriStar MPPT and while reading the manual to set the charge characteristics switches, I noticed there is one type of battery that does NOT have absorption or equalization phases and a constant voltage is maintained. That would be GEL type batteries.

Gel charging requires constant 13.7 v. The alternator will never go above 13.7. This will NOT correctly charge the other types of batteries. [I had wondered why the voltage from the alternator never went above 13.7. D'oh. I suspected the alternator was iffy.]

Connecting my house batteries with solar charging to the vehicle charging system did two bad things.

1. The house batteries were not being charged.

2. Worst thing, the vehicle's alternator was seeing the solar controller putting out 14.7 (in sunlight) to correctly charge the house batteries and over voltage to the Gel vehicle batteries.

The vehicle's alternator reacted by trying to reduce the 14.7 to 13.7. Which was impossible in this situation. I assume the alternator shunts to ground to reduce the extra voltage. The solar controller would put out more amps to keep the voltage up at 14.7.

Leading to Meltdown. Smoke was released.

The proper method with compatible charging and battery systems when connecting via a solenoid would be to use the extra terminals on the solenoid that do the opposite of the main terminals. When the main terminals are open circuit, not connected, the extra terminals are closed circuit. That way the charging systems could not influence the other.

In my case, the house and vehicle must never be connected electrically [unless I switch to house to GEL]. Vehicle is 2006 Ford E350 Super Duty.

Never assume.

Thanks for reading,
Wayne

 

[AlreadyGone]

Hi Everybody,


Last year I had an issue with my van where the alternator shorted out after a long drive with the house system connected to the vehicle system.

Recently, I upgraded my solar to a TriStar MPPT and while reading the manual to set the charge characteristics switches, I noticed there is one type of battery that does NOT have absorption or equalization phases and a constant voltage is maintained. That would be GEL type batteries.

Gel charging requires constant 13.7 v. The alternator will never go above 13.7. This will NOT correctly charge the other types of batteries. [I had wondered why the voltage from the alternator never went above 13.7. D'oh. I suspected the alternator was iffy.]

Connecting my house batteries with solar charging to the vehicle charging system did two bad things.

1. The house batteries were not being charged.

2. Worst thing, the vehicle's alternator was seeing the solar controller putting out 14.7 (in sunlight) to correctly charge the house batteries and over voltage to the Gel vehicle batteries.

The vehicle's alternator reacted by trying to reduce the 14.7 to 13.7. Which was impossible in this situation. I assume the alternator shunts to ground to reduce the extra voltage. The solar controller would put out more amps to keep the voltage up at 14.7.

Leading to Meltdown. Smoke was released.

The proper method with compatible charging and battery systems when connecting via a solenoid would be to use the extra terminals on the solenoid that do the opposite of the main terminals. When the main terminals are open circuit, not connected, the extra terminals are closed circuit. That way the charging systems could not influence the other.

In my case, the house and vehicle must never be connected electrically [unless I switch to house to GEL]. Vehicle is 2006 Ford E350 Super Duty.

Never assume.

Thanks for reading,
Wayne

Did you have an isolater? Or just connect the solar straight to the vehicle charging system?

 

[Trebor English]

Does your 2006 Ford E350 Super Duty have a gel starter battery?  That seems odd.  I would expect a regular maintenance free flooded starter battery.

 

[SternWake]

A 2006 ford E350 alternator, according to rockauto, has the voltage regulator located on the alternator itself.  In this scenario, I do not believe the 'alternator' would not have shorted, but the Voltage regulator, but I am not seeing that happen either, but do not know for sure.

If the system voltage is higher than the voltage regulator wants, it simply stops sending field current to the brushes and waits for voltage to drop.  Nothing gets directly shorted in an attempt to lower voltage, AFAIK.


If the Stator shorted it was because the alternator was regularly overheating. The main cause for alternator overheating would be excessive idling unmoving to recharge a depleted house battery bank.

It appears the voltage regulator is Not even inside this particular alternator, and should have been simple to replace.

http://www.rockauto.com/en/moreinfo.php?pk=474386&cc=1432379&jsn=438

http://www.rockauto.com/en/catalog/ford,2006,e-350,5.4l+v8,1432379,electrical,voltage+regulator,4884

I have having difficulties believing the conclusions reached in the OP.

I cannot find anywhere saying the maximum voltage for a gel battery is only 13.7v.  Most sites say 14.1 to 14.4v.

I am also not seeing a voltage regulator in a 2006 only allowing only 13.7v with no variability regarding engine alternator or voltage regulator temperature, but I am not sure.

This could be a simple alternator voltage regulator failure blamed on another charging source being present.  If the solar system caused the failure of an alternator or its voltage regulator, it would be the first that I have read about anywhere.  If this were an issue, One would think this scenario would be a red flag, and there would be many warnings on every electrical automotive forum to not to allow solar charging when the alternator is charging the same battery bank, but this thread is the very first I have read about it.

I am going to ask someone who helped engineer the some GM alternators and their voltage regulation back in the day, as to the possibility of solar voltage frying the Alternator's voltage regulator.

I am currently using a Ford external adjustable voltage regulator (transpo540HD) in my 89 Dodge, and my solar and the alternator have no issues working together.  I often allow my solar to power my engine electrics when my battery is already full, and my temp sensor on the ford voltage regulator shows it gets colder during these events. The way I do this is to lower the transpo voltage to below the setpoint on my solar controller.  No smoke has been released in the ensuing 14 months of doing this regularly.

 Previous to wiring up my external Ford regulator, my engine computer has the voltage regulator within, and controlled the alternator output.  My solar controller and engine computer had no issues working together either for nearly a decade, and both are still fully functional. I have simply bypassed and tricked the engine computer's VR into believing it is still connected to the alternator so it does not illuminate the check engine light.

I think this 'warning' is premature without knowing more about the actual failure, but I will ask an authority and post his response, if he chooses to respond to my query.

 

[John61CT]

Any charging source output and what the battery needs, must of course match up.

With a large deeply cycled House bank and a lot of driving, it is best to run the alt directly to that bank, as the Starter just needs a tiny fraction of topping up.

If the two banks have different charging needs, an intelligent DCDC (converter) charger is usually required, rather than the simpler and cheaper "voltage following" solutions.

But if the (source) House bank is higher voltage than the (target) Starter, some simple solutions will "buck" convert, step-down the voltage, like the Xantrex (ex-Heart) Echo Charger, which limits to 14.4V.

 

[SternWake]

My alternator contact got back to me. I will quote the relevant parts of his reply

The Chinese can make some pretty crappy voltage regulators - off brand O'Reilley grade stuff.

I've accidentally whacked plenty of 12 volt rated voltage regulators with 37.5 volts 2 amperes potential on a Transpo voltage regulator tester and had no ill effects. Machine was set to test a 32 volt regulator and I just goofed-up.

The 2-G Ford regulator image you linked is for the 45-75 ampere 2nd generation Ford alternator. The one that the idiots at Ford designed to have a pair of push-on terminals deliver total amperage output power. The result is many harness connector fires.
....

Disconnect the battery, allow high voltage panels to reach OCV then turn on the ignition switch and then SHIT happens. But solely to a voltage regulator? The poster you mentioned hasn't a hint of concept.

As far as a gel battery on for use in an Automobile, they are indeed incompatible as many voltage regulators will allow higher voltages than the Gel battery wants.

GEL batteries make excellent deep cycle batteries, they can out Cycle flooded and AGM batteries, but they must be recharged according to their stricter guidelines.

I cannot imagine using one for a starter battery, and would never employ one in a vehicle whose voltage regulator i could not program/control.


I don't think anbody here needs to worry about the Solar controller frying their vehicles voltage regulator or alternator when both are charging at the same time. I know some have had concerns along these lines but this is the first time i have read about someone attributing a failed alternator/ voltage regulator to the Solar holding voltage higher than the vehicles voltage regulator wants.

And all 12v batteries will charge at 13.7v, they will just charge much slower and take considerably longer, exponentially longer, than if the voltage regulator was seeking 14.7v instead, and a not so healthy battery might NEVER get fully charged if all it ever sees is 13.7v.

My engine computer's voltage regulator chose 13.7v or 14.9v 95% of the time, with little apparent logic or reason for choosing either.

13.7v with a still depleted battery infuriated me, so did 14.9v applied to an already fully charged battery. So I did somethign about that.

And one other thing, When a dual battery system is installed the Usual reason for doing so, is to always be able to start engine on engine battery. So the engine battery should in theory rarely ever be discharged much more than a few %.

When batteries are not depleted very far, then charging voltages do not matter nearly as much compared to when the battery is deeply discharged. it could be argued that 13.7 is just fine in such a situation.
The voltage regulators in vehicles assume this is the case, and are programmed so as to insure overcharging is extremely unlikely. The timid voltage allowed is hardly ideal for maximum recharging of deeply cycled batteries whenever driving, there is not too much than can be done about it unless one modifies their alternator to accept a more refined voltage regulator, or installs a DC to DC converter.