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Charging Batteries wih Generator


jacwjames
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So I have 4 new flooded battteries and seem to be doing fine keeping the residential refrigerator running all night.  Went to bed last night with 93% and woke up with ~77%.

I have 325 watt solar panels, not quite enough to keep up, so I have to run the generator just before bed to top off the batteries.

What has me stumped is that while running the generator the % charge showing on the inverter panel is lower but after I shut the generator off the % charge goes up.  Last night when I started the generator I had ~70% charge before but it dropped to ~50% while the generator was running and then when I shut the generator off it climbed to ~93% after 1/2 hour.  It's doing about the same thing now, was 73% of charge but when I started generator it dropped to ~60%.

Whats the trick on getting the display to show actual state of charge.  At some point if/when I use AGS controlled by battery % of charge how does it determine when to shut off it the display is showing lower then actual.

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The invert does a poor job of measuring state of charge. You should buy a battery monitor that uses a shunt. This is the only accurate way to measure SOC. Look up a Victron BMV-712, It will be the best thing you ever did for your batteries.

Tim

 

 

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13 minutes ago, Timaz996 said:

The invert does a poor job of measuring state of charge. You should buy a battery monitor that uses a shunt. This is the only accurate way to measure SOC. Look up a Victron BMV-712, It will be the best thing you ever did for your batteries.

Tim

 

 

I will eventually add a battery monitor but my question is how does the inverter work with AGS to start/stop the generator if the display is that wonky. 

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1 minute ago, jacwjames said:

I will eventually add a battery monitor but my question is how does the inverter work with AGS to start/stop the generator if the display is that wonky. 

The answer is not very well. The inverter is reading battery voltage so if you put a heavy load on the batteries it will shoe them low and recover after a while like you saw. The BMV will always be accurate. If you use the AGS to start and stop your generator have it shut off at 90%. But again, your only guessing measuring batteries state of charge with voltage. 

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I have never used AGS.  I have a document showing recommended settings.  They suggested stop at Absorb. 

I'll check my setting and my actually test it one night. 

Having to run generator & AC's in late afternoon/evening.  Got to 96F at Devils Tower Wy today, may be time to head to cooler weather, where ever that is.

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Good luck finding cooler weather out west here right now... I was in Denver last week for record setting high temps, now in Nephi UT "enjoying" high daytime temps...

On your battery subject... I have found that my engine driven alternator does not seem to charge my house batteries when I'm on the road.... gen or shore power charges the house batteries, if I select "charge" on my Xantrex panel.  Do I have a problem or a switch-ology problem...?

Ken

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1 hour ago, Cubflyer said:

On your battery subject... I have found that my engine driven alternator does not seem to charge my house batteries when I'm on the road.... gen or shore power charges the house batteries, if I select "charge" on my Xantrex panel.  Do I have a problem or a switch-ology problem...?

Ken

Same here on essentially the same coach.  Endeavor manual says the engine should charge the house batts but when I get to my destination first thing I have to do is charge the coach batteries with the on-board genset, (Onan 7500) then I can switch to the quieter external genny (Predator 3500) after the batts have charged. 

- bob

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Bob,

so it's not a problem with how I have my switches... it's the way things work..... 

When I drive, I've been using the inverter to power the (household) refrig... from the house batteries, as it is now, this leaves me with low batteries when I get off the road, requiring that I either have shore power of run the genset to keep the frig working.... hummm I gotta do something about this....

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Without looking at how your electrical system is set up I have no idea if an Endeavor is suppose to charge both the house & chassis batteries while driving.

On my coach I had a BIRD and Isolation relay that allowed the house batteries to be charged while driving and then a Lambert LE415 that maintained the chassis battery while plugged in.  I started to have trouble with the Lambert so decided to replace them all with a Bluesea ML-ACR.  It was an easy install for me (other then having to pull one extra wire to the front dash.  If there is a charging source (shore/alternator) it will charge both batteries and it will also serve as a battery boost. 

When I get to my destination after driving my my house batteries are 100% charged and while the inverter was working the whole way. 

Blue Sea ML-ARC.jpg

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14 hours ago, jacwjames said:

I have never used AGS.  I have a document showing recommended settings.  They suggested stop at Absorb. 

I'll check my setting and my actually test it one night. 

Having to run generator & AC's in late afternoon/evening.  Got to 96F at Devils Tower Wy today, may be time to head to cooler weather, where ever that is.

Which inverer / AGS system do you have?

My '07 vintage Magnum ME2012 only gives you the option of the length of time you want the gen to run, once the AGS has been triggered.

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10 minutes ago, 96 EVO said:

Which inverer / AGS system do you have?

My '07 vintage Magnum ME2012 only gives you the option of the length of time you want the gen to run, once the AGS has been triggered.

Based on the info I have I can choose between Auto stop at 90, 95, or 99% SOC or I can auto stop at Absorb or Float.    I've set mine at Absorb which was recommended by the author of the write-up I have 

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Jim, I have the same vintage Inverter, Trace/Xantrex RV-2012 and always use the AGS with the RC7-GS remote control. I also have the Onan WIreless EC-30W which I set to Auto whenever we are running the AC and have to leave the coach for any length of time with our dog inside. That will start the generator by using a set temperature or if shore power has been severed whereas the RC7-GS will not until it reaches the AGS Battery SOC set point. I do NOT want the AC to NOT be on while our dog is inside the coach.

I have set the AGS to stop when the house batteries are at Auto Float SOC as I don't mind the generator running longer versus trying to save fuel. That way I know for sure that they are fully charged whereas at any other setting you are only partially charging the batteries. Deep Cycle batteries like to be fully discharged (50% SOC) and then fully charged Float SOC. I have attached a write-up of my RC7-GS settings that I use.

I think this next winter while back home in Florida I will finally install the Blue Sea ML-ACR system. Van Williams had recommended it to me years ago but at that time everything was working as it should but now I am having a few minor issues with the charging system that is causing me some concern.

I will send you a PM when that time comes to discuss the installation with you at length.

Trace RC7-GS Programming List.doc

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2 hours ago, Dr4Film said:

Jim, I have the same vintage Inverter, Trace/Xantrex RV-2012 and always use the AGS with the RC7-GS remote control. I also have the Onan WIreless EC-30W which I set to Auto whenever we are running the AC and have to leave the coach for any length of time with our dog inside. That will start the generator by using a set temperature or if shore power has been severed whereas the RC7-GS will not until it reaches the AGS Battery SOC set point. I do NOT want the AC to NOT be on while our dog is inside the coach.

I have set the AGS to stop when the house batteries are at Auto Float SOC as I don't mind the generator running longer versus trying to save fuel. That way I know for sure that they are fully charged whereas at any other setting you are only partially charging the batteries. Deep Cycle batteries like to be fully discharged (50% SOC) and then fully charged Float SOC. I have attached a write-up of my RC7-GS settings that I use.

I think this next winter while back home in Florida I will finally install the Blue Sea ML-ACR system. Van Williams had recommended it to me years ago but at that time everything was working as it should but now I am having a few minor issues with the charging system that is causing me some concern.

I will send you a PM when that time comes to discuss the installation with you at length.

Trace RC7-GS Programming List.doc 29 kB · 2 downloads

Thanks Richard

I had a write up that was posted by another member which has similar settings. 

I've never used the AGS before but now with the residential refrigerator I have to understand and start using it. 

I had to replace my house batteries 6/27/2021 and it made a big difference on power usage using the inverter.  Last night I ran the generator to top off batteries and run AC's since it was in +90F.  Went to bed with 91% battery level and woke up with 71%, enough to run the coffee maker before I hit the road at 6AM (the other campers near me would not have appreciated me starting the gen at 5:30AM🤬)

I had also talked with Van Williams re the Blue Sea.  I was having trouble with the Lambert LE415 battery maintainer and decide to just make the change.  The best price I found on the Blue Sea was here  https://www.fredwarner.net/product/blue-sea-7622-ml-acr-automatic-charging-relay-with-manual-control-marine/   I had it on my front door in 2 days, free shipping no TAX!

It was extremely simple other then running the spare wire to the front.  I removed the isolation relay, mounted the Blue Sean in it's place, hooked up the house/chassis battery cables and then connected the wiring for the remote switch.  Works as it is described.   I've now put ~1600 miles on the rig without a problem. 

I'm at Theodore Roosevelt NP in North Dakota now, temps suppose to hit 100F but I'm at a horse camp with full hookups and both AC running.   

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I ended up lowering my AGS trigger voltage to 11.6V so that my morning pot of coffee wouldn't start the generator for no reason.

Once the coffee had brewed, and the load came off my batteries, they would shoot back up to 12.3 - 12.4V.

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9 hours ago, 96 EVO said:

I ended up lowering my AGS trigger voltage to 11.6V so that my morning pot of coffee wouldn't start the generator for no reason.

Once the coffee had brewed, and the load came off my batteries, they would shoot back up to 12.3 - 12.4V.

As your batteries age you'll need to reduce AGS trigger voltage to 11.5 . . . then 11.4, 11.3 etc.  Eventually you'll be making coffee the day before and putting it in a thermos LOL

- bob

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4 minutes ago, cbr046 said:

As your batteries age you'll need to reduce AGS trigger voltage to 11.5 . . . then 11.4, 11.3 etc.  Eventually you'll be making coffee the day before and putting it in a thermos LOL

- bob

Good to know, it will be a gauge as to when you need to replace.

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