Generator Auto Start

Topic: Generator Auto Start (Read 1330 times) previous topic - next topic

Generator Auto Start

January 10, 2022, 09:43:26 am

On my 2000 U320, the auto start did not work when we lost power the other night. It's my understanding that it should come on when shore power is lost and when coach battery voltage reaches a pre determined voltage. What would that voltage be?
Does the auto start have its own system for operation?

Re: Generator Auto Start

Reply #1 – January 10, 2022, 09:50:08 am

Don't know on your 2000 but on my 1997 there was a switch in the front overhead center compartment that would turn on and off auto start. The control box that did the starting and shutdown was in the front drivers side compartment where the blower for the generator was. I ended up disconnecting it since it seemed to have a mind of it's own and would start the generator even if the batteries were charged and shore power was connected.

Re: Generator Auto Start

Reply #2 – January 10, 2022, 09:52:13 am

Bill,

I have no personal knowledge of Auto-Start.

Have you looked in your Owner's Manual? There should be a section covering the auto-start operation. If you have the DynaGen ES52 module, the info below may be of interest:

Generator Auto Start

https://www.foreforums.com/index.php?action=media;sa=album;in=204

Re: Generator Auto Start

Reply #3 – January 10, 2022, 10:19:47 am

The BCM-12 is what is in my 2003 U320. There is a switch on the dash that has to be set to AUTO for the auto start to be engaged.

The first link above has the manual in reply #6. There is a pot on the circuit board that lets you adjust the start voltage threshold and the run time. Mine is set for 11.85VDC. Some may tell you to set it higher. I got this number from my battery manufacturer.

The BCM-12 is mounted under the false floor in the dash cubby compartment. 4 screws and that comes up, revealing the BCM-12.

Re: Generator Auto Start

Reply #4 – January 10, 2022, 10:28:24 am

Quote from: WS6_Keith – January 10, 2022, 10:19:47 am

The BCM-12 is what is in my 2003 U320. There is a switch on the dash that has to be set to AUTO for the auto start to be engaged.
The BCM-12 is mounted under the false floor in the dash cubby compartment.

Excellent info! The thread linked below may clarify the relationship between the BCM-12 and the ES-52. It seems they are both required for the Auto-Start to function?

Sounds like Keith has delved deeply into this system, and is the MAN if you have questions.

The ES52 generator controller, ES52(F) and the unavailable BCM-12?

Re: Generator Auto Start

Reply #5 – January 10, 2022, 11:13:22 am

On mine the auto start has to be on and mine is set for 12.2volts.

Re: Generator Auto Start

Reply #6 – January 10, 2022, 11:15:09 am

What I read suggests an autostart voltage low enough so that turning on the Microwave when you are on inverter, for example, doesn't drop the voltage enough to trigger a start. What your resting battery voltage might be for this to happen is unknown. If your resting battery voltage (no major loads) is less than 12.2v you should be recharging soon in any case. At 12.2v you have used 50% of the battery's capacity.

And you should set the run time for at least 2 hrs, probably 4hrs.

I am very hesitant to leave this function on if we are not at the coach. If the batteries need generator charging I just turn it on and make sure the inverter is set to charge.

Re: Generator Auto Start

Reply #7 – January 10, 2022, 08:11:59 pm

You should also be aware when cleaning – and run your hand accidentally over the automatic start button you will come back in the garage and find that thing running don't ask me how I know

Re: Generator Auto Start

Reply #8 – January 10, 2022, 08:26:26 pm

Thanks for the reply's and information. I know nothing about this system in our coach so I will study the links and see what I can learn. Coach is at Nacogdoches Motorhome Service and they are looking into that tomorrow. Hopefully they can fix but in any case, I should be failure with this system. I will post if we come up with the fix.

Re: Generator Auto Start

Reply #9 – January 11, 2022, 06:05:51 pm

Left Nacogdoches Motorhome Service a happy customer today. Got leaks in AC lines/connections fixed, leaks in air system fitted, one awning tension adjusted, ride height adjusted and verify auto start on generator working. The auto start only works on low voltage. It is set to start when it sees 12 volts for 2 minutes and shut down when it sees 14 volts for 2 minutes, or 4 hours.
It appears to not function on loss of shore power. I have more learning to do on this system.

Re: Generator Auto Start

Reply #10 – January 11, 2022, 07:00:02 pm

Quote from: Bill B – January 11, 2022, 06:05:51 pm

The auto start only works on low voltage. It is set to start when it sees 12 volts for 2 minutes and shut down when it sees 14 volts for 2 minutes, or 4 hours.
It appears to not function on loss of shore power. I have more learning to do on this system.

This auto start system is only for low battery voltage. When you lose shore power, the transfer switch opens and the inverter kicks over and starts generating AC on demand from your DC house battery bank. It will do this until it hits it's low battery shut off voltage. In theory, that should be set lower than the generator auto-start voltage, so as battery voltage drops, the AGS will start the generator and start charging the batteries and provide AC to the coach before the inverter low battery voltage is ever reached.

Re: Generator Auto Start

Reply #11 – January 11, 2022, 07:49:23 pm

Preferring to not stress/wear/damage house batteries, we have our gen autostart set above 12.2 volts. One of the ways autostart has saved the batteries is when we plug into a new campground, go in the coach to relax and soon hear the gen autostart, only to realize, I forgot to flip the 50-amp breaker to on position, so we were on inverter during that time. Batteries that don't get discharged below 50% will last longer, maybe over 10-years.

Re: Generator Auto Start

Reply #12 – January 11, 2022, 11:06:50 pm

Quote from: Barry & Cindy – January 11, 2022, 07:49:23 pm

Preferring to not stress/wear/damage house batteries, we have our gen autostart set above 12.2 volts.

Check with your battery manufacturer. Lifeline told me to set it for 11.8VDC for best battery life of their 8D's I have. I have mine set to 11.85.

Re: Generator Auto Start

Reply #13 – January 12, 2022, 08:44:29 pm

Hi Keith,

I just checked with Lifeline Technical Support via:
6-0101F-Lifeline-Technical-Manual-Final-5-06-19.pdf

They want Lifeline owners to know that bringing battery voltage below 50% will shorten life of battery. This is similar to other sealed batteries which often use 12.2 volts.

The attached chart shows Lifeline's 50% level at 12.18 volts.

Maybe the lower quoted voltage is encourage increased sales as maybe repeated 20% discharges could accomplish.

I do agree that getting most out of every battery charge cycle would be to use it to 20% which maximizes time between charges at the cost of shorter battery longevity. It is all a balancing act. I see GEL batteries lasting over 10 years at a cost of more electric, generator, & solar charging time.

Re: Generator Auto Start

Reply #14 – January 12, 2022, 09:30:42 pm

The auto start only works on low voltage. It is set to start when it sees 12 volts for 2 minutes and shut down when it sees 14 volts for 2 minutes, or 4 hours.

Last week when I was broke down I put the generator on automatic start for the first time since I brought it home
and it started up and only ran for a couple of minutes and shut down. If it shuts down in 2 minutes after reading
14 volts I know now why cause the Magnum charger was charging over 14 volts.

Re: Generator Auto Start

Reply #15 – January 13, 2022, 12:19:52 am

Oldguy, my auto start is set to start at a specific voltage and then shut off after a preset amount of time.

Barry, I can only imagine perhaps you are right about their tech support saying 11.8V. I will considering increasing my start voltage. Thanks for the info.

ETA: While looking at the BCM manual this morning, there is a setting for high voltage, but with the way the inverter charges the batteries, I don't think it can be used to shut the gen off when they are full, but only rather if they are being over charged. The inverter charger first starts charging BULK at 14.5V or so, then goes into absorb and finally floats about 13.4V. If you set the unit to shut off at 13.5V or something, it would shut off as soon as it went into bulk charge. I've got mine set to 15V should the batteries ever get that high, it will shut the gen off.

Re: Generator Auto Start

Reply #16 – January 14, 2022, 11:17:52 pm

If it's cold the generator can overcrank on "auto start" and the safety shuts it down and you may not know it has stopped working.
On ours we have to reset the generator by switching the generator off and back on using the on/off switch on the panel on the generator.
Equally it may need a double glow which is done manually using the start switch to get it to start in cold weather.

Re: Generator Auto Start

Reply #17 – January 14, 2022, 11:32:33 pm

The auto start is something for me to learn about someday as when I was broke
down and I thought I was leaving the coach for the night I put it on. Maybe I should
learn about it and see how to set it up. My batteries only need a couple of hours to
charge up so no need to run the generator for 4 hours.

Re: Generator Auto Start

Reply #18 – February 01, 2022, 02:46:31 pm

Just an update, I called Lifeline again today now that I have the Victron BCM-712 to monitor voltage AND Amp hours used and asked which is best to determine the state of charge - voltage or Ah used. They say to use the voltage. I also asked again what the correct 50% SOC voltage should be. The tech on the phone said the technical document we are using is "outdated" and the correct battery voltage for 50%SOC is in fact 11.8V. As the capacity drops due to age, improper charging, etc, Ah available will diminish which means you will achieve the 50%SOC (or whatever your set point value is), sooner.

He said they now consider 13.0V to be fully charged and 10.5V to be completely drained. You can do the math to determine the voltage steps and equivalent SOC% from that. 13.0-10.5 = 2.5V range. Given this is a linear function, if the range is 100% over 2.5V, the math is 2.5/100 = .025. So for each 0.025V drop, that's 1% battery life. So each 0.25V is 10% battery life. 50% would be 1.25V down from 13. 13-1.25 = 11.75V for 50% SOC.

I asked their tech about recharging at a higher SOC, like 70% or something like that and he said that that would likely increase the life of the battery. So if you choose to start charging at 12.2V, or 68%SOC, that may help battery life; however, the batteries also have a rated # of cycles, which depletes quicker if you recharge earlier in the discharge cycle.

Maybe this is only valid for Lifeline batteries, but this is what they specifically say.

Re: Generator Auto Start

Reply #19 – February 01, 2022, 03:21:49 pm

When using voltage as a monitor of SOC, it is CRITICAL to define under what conditions it is being evaluated.

Generally, when one refers to voltage as a monitor of SOC it is with "the batteries at rest".

Very hard to accomplish if you are using the RV, as the higher the load, the artificially lower than "at rest" the readings will be.

So, I would suggest that voltage is probably not the best determinate of SOC if the RV is in use. Battery monitors that monitor amps used and allow you to monitor amps in while charging are probably more reasonable.

Sure, if your motorhome is in storage (batteries at rest), voltage IS a pretty good indicator of SOC.

Re: Generator Auto Start

Reply #20 – February 01, 2022, 03:31:34 pm

That being said, if it's in use and you use a specific voltage as your trigger point, the actual SOC should be higher than the current voltage reading may indicate, giving a little bit of extra margin.

Re: Generator Auto Start

Reply #21 – February 01, 2022, 03:33:18 pm

Quote from: WS6_Keith – February 01, 2022, 03:31:34 pm

That being said, if it's in use and you use a specific voltage as your trigger point, the actual SOC should be higher than the current voltage reading may indicate, giving a little bit of extra margin.

Absolutely. And, the higher the load the more skewed the readings would be from true SOC.

Re: Generator Auto Start

Reply #22 – February 03, 2022, 12:59:36 pm

I've got to do some reading on this. I would like to know what my minimum voltage is for my generator to start.

Re: Generator Auto Start

Reply #23 – February 03, 2022, 02:34:43 pm

Quote from: wolfe10 – February 01, 2022, 03:21:49 pm

When using voltage as a monitor of SOC, it is CRITICAL to define under what conditions it is being evaluated.
Generally, when one refers to voltage as a monitor of SOC it is with "the batteries at rest".
Very hard to accomplish if you are using the RV, as the higher the load, the artificially lower than "at rest" the readings will be.

I was just reading a article on this subject this morning. To be absolutely accurate, if one wants to measure the voltage of "batteries at rest" then the battery temperature is also a factor. It is the author's opinion that many of the "Battery SOC" charts found online are inaccurate if applied to batteries measured under load, and that using them to monitor battery SOC could lead to reduced life of batteries. He says:

"Please be aware that some charts on the internet are for resting voltages. A resting voltage is 12 – 24+ hours of no loads or charging at 77°F. The "at 77°F" is absolutely critical because at temps above 77°F surface charge dissipates more rapidly and at temps below 77°F the surface charge dissipates more slowly."

See link below for complete reference page:

Under-Load Battery Voltage vs. SoC - Marine How To

We don't have generator autostart on our coach, but I still find this thread interesting and informative.

Re: Generator Auto Start

Reply #24 – February 03, 2022, 03:03:42 pm

Quote from: Chuck & Jeannie – February 03, 2022, 02:34:43 pm

We don't have generator autostart on our coach, but I still find this thread interesting and informative.

Had AGS on our last coach and immediately disabled it. If I am no smart enough to know when to run the generator...........

Now, if I had pets and needed climate control when I was away from the coach-- that would be a different matter.

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