Correct Settings in Motorhome Application?

Discussion about OutBack Inverters in RV Applications

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Jeff Near Houston
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Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Hello from just north of Houston Intercontinental Airport,

1st Post - Hoping to find information to keep from (possibly) ruining a second set of 8D house batteries in a motorhome application.

I have two 2006 vintage VFX-3524 inverter chargers supporting four 8D house batteries in a motorhome. The batteries are wired both in series and parallel. A single Outback temperature sensor is used.

I just installed, yet have not re-connected battery cables for four (4) brand new Napa (East-Penn) 8D AGM batteries that replaced four 2 1/2 year old Deka 8D "Dominator Extreme Gel" batteries and am hoping with your help to ensure as likely as possible that my charging settings are good and were not the cause of seemingly premature failure of the Deka batteries as if so, do not want to ruin a second set.

Current VFX-3524 Settings (2 stacked)

P1 Charger Control = ON
P2 Charger Control = Auto
Charging Current on P1 = 18 amps
Charging Current on P2 = 10 amps
Absorb setpoint 28.2 volts for 4 hours (P1 & P2)
Float setpoint 27 volts for 1 hour (P1 & P2)
Re-float setpoint 25 volts (P1 & P2)
Equalization OFF

One (1) Outback Battery Temperature Sensor is affixed.

NAPA 8D AGM LABEL CHARGING SPECIFICATIONS:

Charge/Absorption between 13.8 - 14.6 volts at 77*F
Float 13.4 - 13.6* F
"Temperature corrected charging required"
20 Hr. Rate = 245Ah

Another thought... We do not dry-camp or run off of inverter power for more than about an hour or two max as we are either driving down the interstate, stopped for lunch in a rest area for lunch, or plugged into 50 amp campground power. 50 amp power is used 99% of the time.

THANK YOU in advance for sharing your knowledge and or experience! Jeff...
raysun
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Re: Correct Settings in Motorhome Application?

Post by raysun »

A few thoughts before getting into the "brass tacks" of VRLA (AGM, Gel) battery charging.

The dual VFX3524 inverter stack is capable of delivering 7kW of AC power. That's a lot of juice for an RV. I run two homes on less. I assume its sized to run air conditioners, heaters, or other power-hungry systems. Yes?

The 8D battery format can contain a number of configurations, but most are starter/deep cycle hybrids. The hybrids can usually be identified by their literature specifying Cold Cranking Amps and Reserve Capacity Minutes. Neither figure is relevant in a "pure" deep cycle battery that would be the optimal type for this application.

The battery monoblocs mentioned appear to have a C20 capacity of 245AH. The 4 monobloc battery would have a total capacity of 490AH @ 24V. This equals 24V x 490AH = 11,760Watt Hours (11.76kWH) of which 50% is useable, or net of 5.88kWH.

Running the inverter stack at anything near full output would drain the battery in under 30 minutes. (There's DC to AC conversion losses, and a nasty battery property in that the higher the discharge rate, the lower the available capacity - see Peukert's Law).

As specified, the battery would be capable of delivering at C20 (20 hour discharge) a continuous power output of 294 DC Watts, or about 225 AC Watts out of the inverters. This is typical of an off-grid consumption profile, but not the usage you described. At higher discharge rates, much less capacity is available.

The fussiest battery to maintain: gel. The 2nd fussiest: AGM.

Important question before the new battery is even attempted to be hooked up:
Do you have a battery monitor?

Not one of those cheap voltage "fuel guage" displays, but a "current counting" monitor like the Outback FlexNet DC, or Victron BMV7xx series.

I'm stopping here, because the answer to the above question is the most important factor in battery longevity from an operator's perspective.
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Hello Raysun and THANK YOU very much for your reply.

Yes on the size of the system. It is indeed designed to be capable to run some ac / heat / microwave / refrigerator / televisions / coffee maker etc.

In our case, we are campground to campground folks and never dry-camp other than an hour or so lunch break in a rest area or a quick stop at a grocery store. We never run ac or heat off the inverter.

My system only has the Mate2 - no type of battery monitor, yet I am more than willing to purchase and install any such compatible device AND can envision much appreciation for one.

I am one that does all my own work as otherwise owning a motorhome would be cost prohibitive for me.

The existing settings are what coach converter recommends and programmed back in 2006 yet did not include any type of battery monitor. I did confirm with them the settings are still those recommended, yet understand your point that a battery monitor is necessary.

The batteries are the automotive hybrid type as they are (unfortunately) rack mounted in the engine bay.
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Re: Correct Settings in Motorhome Application?

Post by raysun »

I assume the system is inverters, mate, and hub. Yes?

If there is an available port on the hub, then the FlexNetDC could be added:
Pros
•Tightly integrates with the Outback system.
•Provides continuous State of Charge information that's displayed on the Mate
•Provides advanced charging control that is particularly important for sealed batteries. (End Amps triggered Automatic Charge Termination.)

Cons
•Expensive ($300, but worth it, IME.)
•Installation requires a Hub port, shunt installed in battery negative lead (sold separately), and 0.5A fuse (automotive in-line is fine) in battery + line.
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Thank you again!

The hub has 4 ports and the good news is 2 are available.

I read the FlexNetDC brochure online and its $300 cost is well worth the knowledge it provides.

If the installation directions and necessary parts list are clear, I can do it :)

Truly appreciate your help!

(Any install tips appreciated)
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Re: Correct Settings in Motorhome Application?

Post by raysun »

Charging VRLA (Valve Regulated Lead Acid) batteries.

Sealed lead acid batteries, AGM and Gel, are the "Goldilocks" of the battery world. They don't like it "too cold" (being undercharged), or "too hot" (being overcharged), they only like it "just right". If it isn't "just right", they just die. Being a little off optimum charge could easily account for a 2.5 year life span. Especially if combined with being over-discharged. The "double whammy" of sealed battery mortality. Well, that and heat. They literally don't like it too cold, or too hot, with the latter being the killer.

Given the daunting task of placating the princess, its best to have every tool at one's disposal.

• Good battery monitor. We've explored this, so hopefully the path is well marked. Flying blind: in a small aircraft, or maintaining batteries, has the same outcome, a guaranteed early demise. 'Nuf said.

• Good chargers. The VFX chargers qualify. Adding temperature compensation is critical, and that's in place. The Master inverter gets the Remote Temperature Sensor. The inverter, plugged into Port 1 on the Hub, will share temp. comp. data with the Slave inverter.

(Being a "Woke" dude, Master/Slave grates on the sensibilities. I prefer Primary/Secondary. Bear with me.)

• Proper charging parameters. Eventually we get to your actual question.

Undercharging causes sulfate buildup on the lead plates, reducing capacity and creating "plaque" that more sulfate can attach to.

Overcharging causes loss of electrolyte through venting with permanent loss of capacity, and separator grid corrosion. In gel batteries, it causes bubbles in the gel that separate it from the lead plates, causing permanent capacity loss.

The four horsemen of the battery charging apocalypse are: too high charge current, too high absorb voltage, too long absorb time, too high ambient temperature.

Looking at the current charging parameter values, I'd guess 4 hours is way too long for absorb time. The best way to determine, and control, absorb time is by measuring the net charge current going into the battery at the end if the absorb phase. More on that later.
Last edited by raysun on Mon Nov 08, 2021 7:01 pm, edited 1 time in total.
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Re: Correct Settings in Motorhome Application?

Post by raysun »

Jeff Near Houston wrote: Mon Nov 08, 2021 12:54 pm Thank you again!

The hub has 4 ports and the good news is 2 are available.

I read the FlexNetDC brochure online and its $300 cost is well worth the knowledge it provides.

If the installation directions and necessary parts list are clear, I can do it :)

Truly appreciate your help!

(Any install tips appreciated)
Its pretty easy to install. The current shunt is separate. One moment, and I'll have a recommendation on which one...

Outback offers 2 shunts:
250A / 25mv
500A/50mv

The maximum draw from the battery at 7kW output from the inverters would be around 300A, so the 500A shunt is needed (though its slightly less accurate at lower currents.)
Last edited by raysun on Mon Nov 08, 2021 3:47 pm, edited 1 time in total.
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Re: Correct Settings in Motorhome Application?

Post by raysun »

The East Penn AGM 8D battery.

Hard to find a complete set of specs, but numbers that I could scrape up that pass a "sanity check" are:
Maximum charge current: 30% of C20AH rating. 490AH x 30% ~ 145A
Lowest charge rate is usually pegged at 10% of C20 ~ 49A.
The above are DC Amps out of the charger (not AC Amps into the charger.) The current setup of the two chargers at 18 + 10A AC would be equal to about 115A DC @ 24V so all good.

I'm imagining the battery hold on an RV is probably a warm spot. If so, I'd start with the Absorb Voltage on the low end of the range. If the ambient temperature is much above 90°F, I'd delay charging, if possible, until cooler.

For Absorb Time, 2 hours should be more than enough. With the FNDC in place, Charge End Amps can be used to more reliably terminate battery charge.

As the Absorb phase proceeds, the charging current slowly declines. When it reaches about 3-4% of the C20 AH value, the battery can be considered fully charged. 490AH x 3%-4% = 15-20A.

*EDIT* Studying the curves for these battery blocks - the termination current for new units is in the 1% - 3% range, so 5-15A.

The Mate/FNDC can be programmed to terminate charging when the net amps into the battery reaches a selected value in this range.

A 1 hour Float charge is OK. It will gently "top off" the battery, and doesn't draw much juice from the grid, but IMO, isn't strictly necessary in your application.
20211108_113003.jpg
Scraped off a web site that sells East Penn batteries under their own label.
Last edited by raysun on Thu Nov 11, 2021 4:08 pm, edited 1 time in total.
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Raysun, I am truly speechless and even more appreciative for your thorough explanations. I have read, re-read, and will read them many more time. Clearly THE best, most thorough and concise explanation I have ever read, and have read many on the RV forums.

I have backed off of the 4 hours as suggested and will begin my search to order the FlexNetDC. I look forward to having it! Going out of town for about 10 days, and will order before my return so it is waiting on me :)

Thank you again and will keep you posted!
raysun
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REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Correct Settings in Motorhome Application?

Post by raysun »

Jeff Near Houston wrote: Mon Nov 08, 2021 5:05 pm Raysun, I am truly speechless and even more appreciative for your thorough explanations. I have read, re-read, and will read them many more time. Clearly THE best, most thorough and concise explanation I have ever read, and have read many on the RV forums.

I have backed off of the 4 hours as suggested and will begin my search to order the FlexNetDC. I look forward to having it! Going out of town for about 10 days, and will order before my return so it is waiting on me :)

Thank you again and will keep you posted!
Let us know when you're ready to dive into the switchover. There's a couple of install considerations, and a few programming steps, that are simple - but not necessarily intuitive.

BOM from the good folks at Stella Volta
https://www.stellavolta.com/Outback-Pow ... -FN-DC.htm

https://www.stellavolta.com/Outback-Pow ... UNT500.htm

https://www.stellavolta.com/Outback-Pow ... W-BBUS.htm

The last part is a mounting plate for the heavy Battery Negative cables feeding the inverters. Better than "pancake stacking" them on the shunt's mounting stud (though you *can* get away with that if you must.)

Stella Volta is my "go to" for the myriad of system parts needed to do an off-grid system right. 'Sides that, they're in Houston.
Last edited by raysun on Mon Nov 08, 2021 7:16 pm, edited 4 times in total.
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Will do! Can’t wait 👍🏻👍🏻👍🏻
Jeff Near Houston
raysun
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Re: Correct Settings in Motorhome Application?

Post by raysun »

Jeff Near Houston wrote: Mon Nov 08, 2021 5:18 pm Will do! Can’t wait 👍🏻👍🏻👍🏻
Made some edits. See above.
Jeff Near Houston
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Mate vs. Mate2

Post by Jeff Near Houston »

Good morning Raysun,

I spent some time last night researching installation and learned the FNDC is not compatible with a "Mate2m"

(Below Cut & Pasted)
Detailed Description:

The FLEXNet DC works in conjunction with up to three input current shunts (either a FW-SHUNT250 or FW-SHUNT500, each rated 500A/50mV) also available from OutBack. Only a single FLEXNet DC is needed for any system using OutBack components. The FLEXnet DC is not intended to be used with the MATE2M. It is designed to work with the MATE or the MATE2.



My RV did not come with any Outback manuals or documentation, so I went though the screens on my Mate in an attempt confirm whether it is or is not a Mate2m.

When I scrolled through the screens, I did not see any that referenced a battery monitor.

As far as I know, the only Outback components composing my system are the two inverters, a hub and a mate. In a mobile system, would you be inclined to believe all indicates I do indeed have a Mate2?
raysun
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Re: Correct Settings in Motorhome Application?

Post by raysun »

That's doing your homework!

The Mate2M is a simplified version of the Mate2. I've not used one.

The Mate2 menu screens should start like this:
Screenshot_20211110-062232_OneDrive.jpg
The DC submenus would contain the FNDC information.
Jeff Near Houston
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Darn! I have the Mate2M

Post by Jeff Near Houston »

Good Morning! and, Darn! I do have the Mate2M.

Now wondering IF I CAN and / or IF I SHOULD change to a different Mate.

In my novice mind, I think I would benefit most from a product that will automatically halt charging to prevent over-charging. Does one exist?

The reason I believe this is the most important feature I need is since this is in a motorhome application, the batteries are alternator charged while driving, then when we park and connect to shore power, the inverter charger automatically begins a new charging cycle. Also, if shore power is interrupted from a thunderstorm, etc., the inverter charger will again begin a new charging cycle despite the batteries being fully charged.

When I ask "if I can" or "if I should" switch to a Mate (or something stand alone) it is due to the fact I do not know what components are required, or unique, to a system that is truly mobile. THANK YOU Raysun and Sorry for all the ignorance & difficulty!
Jeff Near Houston
raysun
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REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Correct Settings in Motorhome Application?

Post by raysun »

A valid question with a simple answer: yes.

The Mate2/FNDC does support what you are looking for.

To my way of thinking, Automatic Charge Termination is one of the most important factors in proper battery charging. Most chargers terminate on a timer which is better than nothing, but nowhere near as effective as using the battery's own internal physics to terminate charge. Terminating charge by accessing the net charging amps is the way.

The Mate/FNDC handles the issue of overcharging from charger restarts.

The Mate2M was purpose-designed to be simple, removing many command options for the "less complicated" mobile and marine environments. However, I don't know if that is the best option in practice. Were I running a mobile electrical power plant, I'd want every option available, personally. As last winter so aptly demonstrated, self-sufficiency can be a life saver.

The Mate2 is a "no brainer" in my book. (Unless you have a couple hundred extra bucks burning a hole in your pocket and want to splurge on the semi-needless extravagance of the Mate 3s. TBH, the biggest reason would be most of us on this forum use the 3/3s and know its menus and features like the backs of our hands. I touch a Mate2 once every 3 years or so, can read the manual and provide guidance, but when it comes to actual button-pushing experience, you're on your own. That being said, the Mate2 will do the job just fine.)

A question about the alternator charging. Is this a DC charging source that uses a converter of some sort for the charging function?

Another question. Is this strictly a house battery, or is it also the engine start battery?

(BTW - I'm learning something here. I always take the opportunity to learn something.)
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Re: Correct Settings in Motorhome Application?

Post by JRHill »

Jeff, you are a rare guy who does research and factors things. For a while I've reviewed an RV forum not because I have an interest in RVing but in what some folks try to do - towing rigs and capacities, broken axles, black and gray water and my favorite: power. My gosh those threads on power get interesting. Some of the funniest things I've seen is advice on RV stuff for power. People with a native 12vdc system - why can't the 24vdc system be charged while driving down the road? Can't I just run +/- to each battery? On and on.

You've got a wonderful system that a lot of people don't have in an off grid house with those same goodies. But you need some additions like the Mate3s and the FNDC. Then you can really roll.

But I ask this: what are the favorite power hogs that you would leave in a dumpster? Ex: some ac / heat / microwave / refrigerator / televisions / coffee maker etc. We've lived off grid for 14 years and we don't use some of those things. A/C, darn, wrong place. Heat? Other options. Microwave? We have one and use but unless full sun and to make sure it doesn't steal from the batteries. TV, no problem. Coffee maker? Darn, a Keurig and have yet to use it - power hog till summer. We use a coffee press on propane. It's not Kona but good enough for us (Raysun, love ya).

It's a different way of life. You know that. So after you get your system under control what would you do different? You can't live the off grid thing with excess draw/appliances. What is that excess draw and how important is it?
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Hello Raysun, and I apologize for the extended delay in replying. My last post was on the morning just prior to departing for the trip to the Texas "Hill Country", specifically Kerrville - a beautiful area just fyi.

Well, the "get away" ended up requiring 95% of my time repairing an acute engine component failure discovered on the way to Kerrville. It was the first time all the tools that I have carried for more than a decade were needed to prevent having to be towed! Good news is, I removed the 31 pound engine coolant-related part, ordered another from a San Antonio dealer and re-installed the new part over 9 days. Bad news... just prior to departure, spent $2,200 on new "house batteries", and $2,500 for the new part and 24 gallons of coolant. Could have been much worse had I not been able to diagnose and repair myself!

Since returning, I have studied more and more, including watching several Youtube videos trying to grasp what I need to accomplish AND TO BETTER COMPREHEND your directions :)

I was not successful in finding good instruction on where to mount a shunt. I drew a diagram of my four 8D house batteries, which are wired in both series and parallel, in hopes you can tell me where in the system I would install a shunt. I am wondering to myself if it would be installed near the primary inverter...?

Getting back to your last reply, I cannot decide between a new Mate - either the Mate2 or Mate3s. The FNDC literature mentions only the 3s will cease charging when necessary. So, I guess I need to go ahead and purchase a Mate3s, despite the fact it will be more difficult for me to install (I will have to relocate items in my small interior electrical panel where the current Mate2m is installed). ***It appears from my reading that the current Cat5 going to my Mate2m WILL work with the Mate3s. Would you agree? (Running new cabling would be VERY challenging)

Regarding your question about the four 8D batteries, they are Not for engine starting and only serve as the power source when the rv is not plugged into 50 amp shore power.

Regarding the alternator charging, it is a Delco-Remy 50DN 24 volt alternator and when the engine is running, there is 27.99 volts at the batteries (per my digital multimeter) and the alternator has a voltage regulator which is set at 28vdc. (not certain if the alternator has a converter, but I am certain the end voltage output is 28vdc

One interesting comment from one of the Outback YouTube videos was "Consecutive Partial Charges Will Accumulate Errors with Each Charge". I wonder how alternator charging would affect my bottom line of the FNDC to prevent overcharging.

Attached is my house battery wiring diagram drawing I sketched in hopes it would be helpful regarding shunt placement and even whether or not my setup would allow FNDC accuracy.

SINCERE thank you's to you Raysun. Hope you have the "energy" for this ;-)
(yes, pun intended :)
880105AD-965E-443A-B165-08D744A61AE0.jpeg
Last edited by Jeff Near Houston on Sun Nov 28, 2021 2:34 pm, edited 2 times in total.
Jeff Near Houston
Jeff Near Houston
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Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Hello JRHill -

IT IS A CURSE!!! I often wish I was not so observant and detail oriented!!! Seems my mind is always running!!! hahaha

You asked what I would do differently in consideration of power demands and usage, and in our usage case, there is nothing I would do differently as we are campground to campground campers and do not "dry camp" / use inverter power other than eating lunch in a rest area or a quick stop at a grocery store - or run the generator. In our case, our inverters are definitely not pushed.

While driving down the road, the 24vdc engine driven alternator charges them and the load is light - refrigerator, microwave at a rest area, and a few always on electronics.
Jeff Near Houston
raysun
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REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Correct Settings in Motorhome Application?

Post by raysun »

The Texas Hill Country is quite beautiful, and in my wanderings I've actually passed through Kerrville.

Glad you could get the rig back running, but sorry skinned knuckles are a vacation momento.

In regards the shunt. It installs on the main battery negative circuit. The battery negative terminal connects to one end of the shunt, and everything else's battery negative lead connects to the other end.
20211128_124557.jpg
A typical FNDC with 3 shunts. Your system will only have 1 shunt (shunt c for example) with the Inverter and Alternator battery negative leads wired to the "load" side. If there are several devices that need to be connected to the battery, its best to get a small buss bar/plate so each device has its own attachment point, rather than "pancake stacking" several ring terminals.

The charging feature supported by thd FNDC/Mate is called Automatic Charge Termination. The Mate2 supports it, as does the Mate3s of course. Get the Mate2, its all you really need.

The Alternator charging is not controlled by the Mate, of course, but the current it puts into the battery will be tracked by the FNDC and figure into battery State of Charge calculations.

The trick will be to make sure the Alternator charger doesn't overcharge the battery on its own. There's a couple of strategies.

• Use the FNDC to sense when the battery is "full enough" via the alternator, then program the FNDC AUX port to drive a relay, disconnecting the alternator. (I don't know enough about these alternators to know if their output can be disconnected from the battery safely.) The FNDC can trigger on battery voltage or battery state of charge.

• My favorite approach would be to swap out the 24V alternator for a 120V AC generator or AC alternator (if either such things exist) and use the output, via a transfer switch, to drive the inverter charger. The "smart" charger in the inverter will do a much better job charging the battery, and the automatic charger control is 100% functional here. It would need to be safe to "drop" the generator/alternator output via the inverter's automatic AC IN control should it be warranted.
Last edited by raysun on Sun Nov 28, 2021 3:17 pm, edited 2 times in total.
Jeff Near Houston
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Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

Would proper shunt placement be between the Chassis Ground and the negative battery terminal that goes to the chassis ground? Not sure I understand whether this point would also pick up the engine alternator. (Please see photo noting where I "think" the shunt should be installed
F9199AFE-1848-480F-AC4F-910EBA78456F_1_201_a.jpeg
)
Jeff Near Houston
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Re: Correct Settings in Motorhome Application?

Post by raysun »

Jeff Near Houston wrote: Sun Nov 28, 2021 3:12 pm Would proper shunt placement be between the Chassis Ground and the negative battery terminal that goes to the chassis ground? Not sure I understand whether this point would also pick up the engine alternator. (Please see photo noting where I "think" the shunt should be installedF9199AFE-1848-480F-AC4F-910EBA78456F_1_201_a.jpeg)
Does the Alternator return to the battery negative via ground (rather than a cable that runs directly to the battery)?
Jeff Near Houston
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Posts: 28
Joined: Sun Nov 07, 2021 9:52 am
My RE system: Mobile VFX-3524 in 2006 Prevost Bus
Actually 2 Model VFX-3524 Stacked
Today 11-07-2021 installed four new NAPA (East-Penn) 8D AGM Batteries

Re: Correct Settings in Motorhome Application?

Post by Jeff Near Houston »

raysun wrote: Sun Nov 28, 2021 3:20 pm Does the Alternator return to the battery negative via ground (rather than a cable that runs directly to the battery)?
I do not know the answer, but will find it! THANK YOU very much!
Jeff Near Houston
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Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Correct Settings in Motorhome Application?

Post by raysun »

Ignoring ground for a moment, the shunt's "battery" end connects to the battery negative terminal, exclusively. Everything else connects to the "load" end of the shunt.

If equipment returns to the battery via chassis ground, then the chassis ground is connected to thd "load" end of the shunt.
raysun
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Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Correct Settings in Motorhome Application?

Post by raysun »

One last thing.

The FNDC *may* drift out of accurate State of Charge after extended series of partial charges, but will automatically synchronize when the battery is fully charged via the inverter charger.
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