Community Forums

jrusselltx · 01-19-2017, 07:26 PM

Wonder if anyone else has seen this. I recently added a solar array and charger system to my RV. When going down the road with full sun the solar charger puts out enough voltage/current that the alternator warning kicks in. I saw this rarely if I were running the generator and, therefore, the charger. Any ideas on a fix?

twinboat · 01-19-2017, 07:47 PM

The warning light senses a differencial in the alternators output and battery voltage, not the actual voltage.

If there is higher voltage at the battery then the alternator, it senses it's not working and turns on the warning light.

Turn on the headlights or other high draw chassis item and see if the light turns off.

Assuming your solar is hooked to your house batteries, another option is to disable your isolation relay or solar, while driving.

John Hilley · 01-20-2017, 08:36 AM

Mine does the same thing. I switch the solar off when it does it. While driving the alternator is charging the batteries.

computerguy · 01-20-2017, 08:44 AM

Same thing happened on my '05 Monaco Knight. Simple fix was to always drive with the lights on.
I called Monaco way back then and they said there is a way to disable the isolator. They also said driving with the lights on should be fine. I never pursued a different fix and since sold that coach advising the new owners of the issue.

vsheetz · 01-20-2017, 10:17 AM

Does it only occur when the solar controller is in absorption stage? Is the absorption voltage set correctly for the batteries? Maybe it's too high.

harryn · 01-21-2017, 12:58 AM

Quote:

Originally Posted by jrusselltx

Wonder if anyone else has seen this. I recently added a solar array and charger system to my RV. When going down the road with full sun the solar charger puts out enough voltage/current that the alternator warning kicks in. I saw this rarely if I were running the generator and, therefore, the charger. Any ideas on a fix?

Can you tell us a bit about the solar array and charge controller that is being used?

harryn · 01-23-2017, 02:48 PM

I am wondering if this is occurring because the batteries cannot absorb the charge current quickly enough.

If the house batteries are AGM or LiFe, they can absorb charge pretty fast until they are charged.

You could put a diode on the alternator side of the bank to prevent charge back flow.

If the charge controller is a PWM type, the "on pulse" voltage might be higher than your system expects, but it is a little surprising that your alternator would sense this with a substantial battery bank.

A higher end charge controller is temperature compensated and the voltage increases when cold to charge up the house bank. Most alternators don't include this, so in cold weather, the alternator voltage regulator would see higher than expected voltages.

twinboat · 01-23-2017, 03:43 PM

Placing a diode to prevent " charge back flow " would defeat the bi-directional funtion of the BIRD.

A smarter BIRD that opens the isolation relay, when 2 charging sources are detected, would work.

harryn · 01-24-2017, 05:00 PM

Quote:

Originally Posted by twinboat

Placing a diode to prevent " charge back flow " would defeat the bi-directional funtion of the BIRD.

A smarter BIRD that opens the isolation relay, when 2 charging sources are detected, would work.

Any suggestions on this type?

What if you really want to charge from both sources at the same time?

twinboat · 01-24-2017, 05:14 PM

This combiner offers a voltage limiting feature. It would replace the BIRD.

I think I would hook the high voltage sense wire to the house bank. At that voltage, I wouldn't need help from the alternator.

http://www.yandina.com/c600Info.htm

harryn · 01-25-2017, 07:49 AM

Thanks for the link to that combiner. The site has some interesting products.

Unplanned Tourist · 01-25-2017, 07:58 AM

Headlights on, much safer and also fixes the problem. Sounds like an easy fix.

jrusselltx · 01-26-2017, 04:22 AM

Thanks for all the feedback. Turning the headlights on definitely quiets the alarm.

YC1 · 01-26-2017, 06:14 AM

This is why a BIRD system in some cases has a generator detect circuit. Driving down the highway keeps the charging system supplied by the generator Inverter/charger system from competing with the alternator.

Funny thing though, while on shoreline and the engine running the BIRD is NOT defeated and you can get that issue. Normally you have enough loads and lower battery voltage from the starting of the engine to keep it from complaining.

As you have found, turning on headlights gives enough of a load to solve the issue.