Coach batteries and inverter capacity in our 99'U270

Topic: Coach batteries and inverter capacity in our 99'U270 (Read 2244 times) previous topic - next topic

Re: Coach batteries and inverter capacity in our 99'U270

Reply #25 – September 06, 2011, 05:08:53 am

That's a nice setup you've got there Dave.

Don't mean to get off topic, but I noted that you've installed the Camco Cyclone holding tank vents. Was looking at those recently, and wondering if they are an improvement over the factory-installed vents.

I've been looking at what's out there in terms of solar panel mounts. Seems there are two choices - mounted flat to the roof or just off the roof, and tiltable panels require you climb up and move them yourself. I ask myself why no one has produced a solar tracking system. Something that would allow the panels to position themselves for optimal energy production and track the sun across the sky. Wondering if there is a significant enough gain to justify the expense and complexity of such a system.

I have several ideas on this. Looks like I'll have the winter to come up with a design and see if it's feasible. Take some photocells, linear actuators, an articulating aluminum frame, and a nano PLC programmable controller, and there you have it. And it could use the solar energy it collects to power itself. Of course, being a two axis system, you would still have to angle the coach for best results. A three axis system would be ideal, but very complex and expensive, not to mention heavy.

Nice to see prices coming down on some solar gear.

Steve

Re: Coach batteries and inverter capacity in our 99'U270

Reply #26 – September 06, 2011, 09:28:20 am

Hi Dave,
I too have the AM Solar system like yours. They are very good people to work with. The system works well only I wish I had more panels. I've had no problems with my 3M adhesive either. There seems to be no end to my insatiable desire for power, hence my wind generator as well - though I haven't figured out how to keep both systems at full output simultaneously. Maybe pray for wind only at night?? In your roof pictures I see what I believe is a quite large power roof vent. There's nothing like a few questions: what brand is it, where did you find it, how well does it work for you, does it install in a normal vent opening and what is the current draw? We seem to think alike because I too have two Camco tank vents which allow me to use no tank chemicals except when parked on the hottest, windless days.

Recently I changed my engine batteries. On a '02 '42' they are such fun to handle from underneath. Using a steel plate on a floor jack to lift them up into position made the job a lot (well, somewhat) easier. Now if I could figure out where to put more of those light weight AG8Ds!!

I hope to see you again at Quartzsite this winter to check out your mods more carefully. Ain't it fun

Re: Coach batteries and inverter capacity in our 99'U270

Reply #27 – September 06, 2011, 09:59:29 am

That is a nice setup! Was there a particular reason that lead to the panels placement? It is hard to tell from the pics, are the panels all hinged from the same side? Also, how does the controller tie into your inverter charger system? Probably ignorant questions, but if you have any links to a good primer on the subject, I will attempt to educate myself!
Don

Quote from: Dave Katsuki – September 05, 2011, 11:48:44 pm

Installation of the panels on the roof was quite easy. I used the 3M super adhesive tape that AM Solar supplied (used for structural bonding on cars and other applications.)

Re: Coach batteries and inverter capacity in our 99'U270

Reply #28 – September 06, 2011, 11:32:16 am

AM Solar panels hinge from both sides, so we can tilt either way, and they were placed mainly to allow tilting without shadowing from the AC covers. luckily the controller just ties into the batteries directly, so no messing with the inverter/charger. No problems with both charging systems being on at the same time as long as you set parameters for each to the correct type of batteries you have. Recommend the AM Solar site for a good overview of solar technology.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #29 – September 06, 2011, 02:34:27 pm

Quote from: Jim Frerichs – September 06, 2011, 09:28:20 am

Hi Dave,
I too have the AM Solar system like yours. They are very good people to work with. The system works well only I wish I had more panels. I've had no problems with my 3M adhesive either. There seems to be no end to my insatiable desire for power, hence my wind generator as well - though I haven't figured out how to keep both systems at full output simultaneously. Maybe pray for wind only at night?? In your roof pictures I see what I believe is a quite large power roof vent. There's nothing like a few questions: what brand is it, where did you find it, how well does it work for you, does it install in a normal vent opening and what is the current draw? We seem to think alike because I too have two Camco tank vents which allow me to use no tank chemicals except when parked on the hottest, windless days.

Recently I changed my engine batteries. On a '02 '42' they are such fun to handle from underneath. Using a steel plate on a floor jack to lift them up into position made the job a lot (well, somewhat) easier. Now if I could figure out where to put more of those light weight AG8Ds!!

I hope to see you again at Quartzsite this winter to check out your mods more carefully. Ain't it fun

The power roof vent is a Kool O Matic kitchen vent, and was standard on (I think) 96-99, but unfortunately no longer made. Folks replace them with Fantastic Fans, but the Kooi O Matic really exhausts well and doesn't draw much 12v.

Not sure we'll be at Q this year. After NAC, we're planning to be wandering South TX to hit various birding hot spots, and then probably over to Benson AZ sometime Feb/Mar.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #30 – September 06, 2011, 10:25:43 pm

I have been in Michigan for the last three months, and recently replaced my three DEKA 8G8D Gel batteries for $395.00 each, plus 6% Michigan State Sales Tax. They weigh 161 pounds each.
We live (boondockers) full time on our batteries, solar and wind, and they usually last us about 5 years before they start loosing capacity. Better management on our part in the future will extend their life as will using more LED lighting. Gels need critical care, AGM units not so much but, 1/2 the duty cycles. Good monitoring pays dividends.
Regards,

Re: Coach batteries and inverter capacity in our 99'U270

Reply #31 – September 07, 2011, 02:51:04 pm

I boondock for months every year and based on my research, and experience, I use the following:

COACH BATTERIES & SOLAR PANELS
One 8D battery (200 amphour) will provide 40 amphours (discharged to 80%) at night and requires 200 watts of solar (60 amphours) for recharging during the day. The charge efficiency for batteries is circa 90% at 50% charged but drops to circa 50% at 90% charged (the 90/50 rule).

I have 750 watts of panels on my motorhome with two 8D AGM batteries, so 400 watts solar is for charging batteries while 300 watts of solar is for running ceiling fans all day and charging telephones, cameras and computers.

I use sealed batteries only because the outgassing of flooded batteries causes corrosion and high maintenance when cycled every day.

I used to use Gel only because they have been the "deep cycle king". However, I now use AGM because they are less expensive, easier to obtain and are almost as good at deep cycling as gel batteries are.

If you want your deep cycle batteries to last, reset your alternator from 14.6 to 14.2 volts (also your solar controller) and never "EQUALIZE". I have an 8 year old gel 8D which is still serviceable.

INVERTER/CONVERTER
With a combination inverter/converter only one function is available at any time while I want to be able to use both the Inverter and the Converter at the same time.
With seperate inverter and converter units I can power the microwave from the inverter and at the same time charge the batteries from the converter which is powered from 15 amp shore power. Then, while connected to 15 amp shore power, I can power the converter and the refrigerator from the shore and still use the microwave without blowing the 15 amp shore power breaker. Coach operates as if on 30 amp shore power, while on 15 amp shore power.

A "pure sign" inverter is more efficient on 12 volt useage then a modified inverter. The Freedom 2500 that was in my 1996 U320 has high harmonic distortion (about 25% THD) which was clearly visible when I observed the wave pattern with my oscilloscope. Also, running the microwave with my "pure sign" 1800 watt inverter (3% THD) draws 165 amps from the batteries while running the microwave from the Freedom 2500 required 175 amps from the batteries. This is because the microwave uses more amps with modified 120AC than it does with "pure sign" 120AC. A lot of people will look at the efficiency of the inverter to make comparisons, but that is not the whole picture.

A 2000 watt inverter is a good choice because it will run anything that you can plug in while drawing less than 170 amps.

I use an IOTA 55 amp converter with two voltage set points, 13.3 volts for trickle charge and 13.9 volts for accept charge with a switch in the kitchen. I do not use the converter for bulk charge (14.3 volts) and never equalize ( 15-16 volts).

I desulfate instead of equalize and seldom use the generator.

I hope this information is useful to some folks.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #32 – September 07, 2011, 05:40:48 pm

Very interesting, Wyatt. Thank you!

I'm considering doing more boondocking in our Summer travels, travelling less, and using the generator less.

So I'm thinking more about Solar for next spring when we leave El Centro, CA.

We have 3 8D AGM's at 255 ah each. (And 3 Optima starter AGM's)

Taking advantage of your experience, what would you recommend for us Solar-wise?

BTW, is the 14.2v below for alternator a typo? I usually see 13.2v as an appropriate float voltage for AGM's.

On a related topic. I think the conclusion of a previous thread was that the starter batteries controlled the alternator amps so using the alternator to charge the house batteries while driving was OK (and would not put excess load on the alternator). Is this correct? Does this vary from coach to coach or year to year?

best, paul

Re: Coach batteries and inverter capacity in our 99'U270

Reply #33 – September 07, 2011, 06:30:35 pm

Thanks Dave,
Good info! That helps, still so much to learn though... enjoying the process nonetheless!
Don

Quote from: Dave Katsuki – September 06, 2011, 11:32:16 am

AM Solar panels hinge from both sides, so we can tilt either way, and they were placed mainly to allow tilting without shadowing from the AC covers. luckily the controller just ties into the batteries directly, so no messing with the inverter/charger. No problems with both charging systems being on at the same time as long as you set parameters for each to the correct type of batteries you have. Recommend the AM Solar site for a good overview of solar technology.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #34 – September 07, 2011, 06:34:13 pm

Wow! That is some really useful information... getting off the grid has been a long time dream of ours, so the process of figuring it out for our coach will stand us well once we find a piece of land that speaks to us...
Thanks, Don

Quote from: P. Wyatt Sabourin – September 07, 2011, 02:51:04 pm

I boondock for months every year and based on my research, and experience, I use the following:

COACH BATTERIES & SOLAR PANELS

Re: Coach batteries and inverter capacity in our 99'U270

Reply #35 – September 08, 2011, 02:30:21 pm

REsponse to Paul's questions?

You said: So I'm thinking more about Solar for next spring when we leave El Centro, CA.
I plan to be in Niland by mid November and would like to meet you in person.

You said: We have 3 8D AGM's at 255 ah each. (And 3 Optima starter AGM's)

The amphour capacity of a battery will be maximum at 5 to 10 cycles, then reduce with each cycle. The battery capacity increases when new for a few cycles then reduces with each cycle until replaced. This is the nature of this physical, chemical, electric device. How a battery is made and treated both have a strong effect on what the capacity will be over it's life. I use 200 amphours per 8D battery for caculating because the actual amphour capacity of an AGM 8D will peak at 255 amphours but only be circa 150 amphours at replacement.

What is hard on batteries?: heat, equalizing, fast charging, deep discharging.

You said:
Taking advantage of your experience, what would you recommend for us Solar-wise?

With three AGM 8D batteries you need 800 watts of solar with a high end controller (I use a BlueSky Energy, Solar Boost 50, which sells for circa $600. There are others that are equally as good.) This will provide about 120 amphours each night.

You said:
BTW, is the 14.2v below for alternator a typo? I usually see 13.2v as an appropriate float voltage for AGM's.

Not a typo. Automobile alternators are typically set at 14.6 volts for bulk charge (not float). The Reece Neville alternator on my coach is 160 amp with a two stage regulator (bulk and float), which was set to 14.6 volts. I reset mine to 14.2 volts. The regulator on top of the alternator is a three step (not to be confused with stage) which refers to the bulk charge voltage of 14.6, 14.2, or 13.8 volts.
My start battery voltage is 14.2 after start, but will drop to 13.2 when driving, until the inverter demands power to run the fridge, when it jumps back up to 14.2 volts.

NOTE: I run my fridge with the inverter when driving with the propane turned off.

You said: In a related topic. I think the conclusion of a previous thread was that the starter batteries controlled the alternator amps so using the alternator to charge the house batteries while driving was OK (and would not put excess load on the alternator). Is this correct? Does this vary from coach to coach or year to year?

I do not believe that the alternator can be overloaded, it is a regulated mechanical, electrical device which provides less amps as it gets hotter. The wear on the brushes of my alternator at 95,000 miles was 1/16 inch while the sense voltage wire was very corroded. This probably means the alternator was never removed and was lightly used.

I drive with the boost switch "on" so that the alternator sense voltage comes from all batteries which are all charged at the end of the trip, even though the inverter is running the fridge. I have run with Boost "off" and found undercharged coach batteries at the end of a trip.

Some folks on the forum believe that running the generator to charge the coach batteries before starting is better than charging coach batteries with the alternator. This may be true if the coach batteries are discharge to less than 50%, which mine never are (seldom below 80%).

BOONDOCKING: I believe it is critical to reduce the phantom loads on coach batteries to successfully boondock (this means "NO" generator to me). The phantom load on my coach at purchase was 7 amps and it is now 10% of that.

How did I reduce phantom loads?
Replaced 2500 watt inverter/converter with 1800 watt inverter and 55 amp converter.
Replaced all interioe lights with LED lights.
Replaced 120AC automatic selector switches with 120AC manual selector switches.
Disconnected unused burglar alarm.
Installed dash switch to disconnect power from dash radios.
Disconnect start batteries for long stays (engine/tranny computers).

Re: Coach batteries and inverter capacity in our 99'U270

Reply #36 – September 08, 2011, 10:54:43 pm

Quote" Automobile alternators are typically set at 14.6 volts for bulk charge (not float). The Reece Neville alternator on my coach is 160 amp with a two stage regulator (bulk and float), which was set to 14.6 volts. I reset mine to 14.2 volts. The regulator on top of the alternator is a three step (not to be confused with stage) which refers to the bulk charge voltage of 14.6, 14.2, or 13.8 volts"

Wyatt- how do you reset the voltage from the Alternator down to 14.2 ?? I am not that great with the electrics but if explained I can do it (most times)
John

Re: Coach batteries and inverter capacity in our 99'U270

Reply #37 – September 09, 2011, 07:13:28 am

Remember the voltage drop across the isolator.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #38 – September 09, 2011, 08:55:55 am

Quote from: acousticart – September 03, 2011, 08:40:58 pm

On a related note, a Heart Freedom 20 is listed as standard which as I understand it, is a 2KW inverter. The picture I took clearly shows that it is a Heart Freedom 10. It seems huge, but unless I am mistaken, that means that we only have a 1KW inverter in our coach, is that correct?
Thanks in advance!
Don

I believe that you are correct. It is a 1 KW inverter/charger. I found this Freedom 10, 15, 20, 25 Owners manual on the web
www.xantrex.com/documents/Discontinued-Products/Freedom_combie_Owner_manual.pdf
If you do not have one it may be of help.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #39 – September 09, 2011, 06:12:49 pm

How to adjust "Reece Neville" alternator output voltage?

Remove four screws holding regulator to top of alternator on "Three Step" regulators.
Remove regulator carefully because springs holding brushes will be hanging out and must be pushed in and held with a drill bit (circa 9/16) during reassembly.

Turn regulator over and you will see two screws attaching a small conductor bar. There will be another unused mounting hole. Three mounting holes in a trianglular pattern so that conductor bar can be put in three different spots which are labeled "H", "M", "L". I had to do this twice because while I thought I was putting the contactor on "M" for 14.2 volts, I put it on "L" for 13.8 volts the first time. I attached a digital volt meter to the lighter socket in the dash to read voltages while running.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #40 – September 09, 2011, 09:22:22 pm

I suggest that those of you with GEL batteries set your alternator at 13.8 volts or below as that is the "float" setting for those batteries.
My alternator voltage regulator has a screw adjustment for setting the voltage. It is Leece-Nevile. Mine is set at 13.7 checked at the coach batteries.
Regards,

Re: Coach batteries and inverter capacity in our 99'U270

Reply #41 – September 09, 2011, 10:27:42 pm

Wyatt - how do you check/measure phantom loads?

Re: Coach batteries and inverter capacity in our 99'U270

Reply #42 – September 09, 2011, 10:31:32 pm

In our recent Leece Neville alternator rebuild we insalled a variable voltage regulator to replace our 3-step regulator. I now use a screw driver to change voltage output from our alternator with a screw driver while alternator is mounted with all wires attached. This has been great for our recent 100+ degree batteries to keep them from be charged at a too high voltage when engine is running.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #43 – September 09, 2011, 11:41:21 pm

Optimum gel battery float voltage is 13.7 volts WHEN battery temperatures are 50-59 degrees.
Maximum gel battery float voltage is 13.7 volts WHEN battery temperatures are 70-79 degrees.
Our gel batteries were closer to 100 degrees for months when we were in Texas and are still not much below 75 degrees these Ohio days & nights. So I think 13.7 volts is way too high for hot weather.

Optimum gel battery float charge for a 90 degree battery is 13.10 volts. With a max float charge of 13.40.
When house battery is float charged at 13.10 volts, a start battery being charged with Trik-L-Start can be float charged at less than 12.6, which is no-charge, and not good for the start battery bank.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #44 – September 10, 2011, 12:53:21 am

All these different float charges and temp' of batteries makes one think that maybe a decent fan set up in that bay is not a bad idea, what does everyone think of that ?? I gather the only problem would be the exiting of the heated air from the top of compartment- maybe ducting?
John

Re: Coach batteries and inverter capacity in our 99'U270

Reply #45 – September 10, 2011, 01:53:47 am

Thanks for the link Ron! As it turns out, our coach has the Freedom 20 Inverter. We had been looking at a number of coaches and I would snap pictures of various parts to help me remember the details... well, I had the picture of the inverter from another coach we looked at and was pleasantly surprised to see that our coach does indeed have the 2KW version. Though, I do plan to upgrade to a pure sine wave type, just not in a hurry now, so I will take my time to do the research for the total package involving solar etc. It will be incremental, but everthing I change will be aiming towards becoming less dependent on the "grid". Especially after So Cal's huge outage yesterday...
Don

Quote from: Ron Sedgley – September 09, 2011, 08:55:55 am

I believe that you are correct. It is a 1 KW inverter/charger. I found this Freedom 10, 15, 20, 25 Owners manual on the web

Re: Coach batteries and inverter capacity in our 99'U270

Reply #46 – September 10, 2011, 02:58:56 am

Quote from: John Haygarth – September 10, 2011, 12:53:21 am

All these different float charges and temp' of batteries makes one think that maybe a decent fan set up in that bay is not a bad idea, what does everyone think of that ?? I gather the only problem would be the exiting of the heated air from the top of compartment- maybe ducting?
John

There should be a pvc pipe coming from the top of the battery compartment and out underneath the center of the coach.
I am going to try a marine blower motor fan on the end of it.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #47 – September 10, 2011, 12:14:18 pm

Phantom Loads:
I use the current indicated by the amphour meter which was installed by Foretravel for daily monitoring.

This next part is ackward to do because it requires disconnecting the coach batteries with all loads disconnected.
I disconnect the positive terminal of the coach batteries and install a 25 amp analogue meter and a 10/2 amp digital meter with a shorting patch cable. The shorting patch cable on the digital 10 am meter can be removed to obtain more accurate readings than the 25 amp analogue meter can provide.

Note1: Do not use inverter for 120AC power at this point for anything requiring more than 2amps.
Note2: Twelve volt electrical devices will be without 12 volt power when battery plus is disconnected unless a shorting patch cable is used while disconnecting the positive post. You may lose preset radio stations and amphour meter will be reset to zero. Dip switch type settings will not be affected.

Now it is a process of pulling fuses on your 12 volt panel while watching the amp meters. Also turn on know loads like the inverter with "power save" off and "power save" on for comparison. After noting how many amps are used by each 12 volt circuit, then the tedious job of tracing what is actually using the amps.

Devices to look at are: the control boards for the refrigerator, ice maker, hot water heater, and furnaces. Also look at AM/FM radios, clocks, CO2 sensors, propane sniffers, fire/smoke alarms, burglar alarms, inverters, converters, automatic valves at the propane tank, "key fob" door locks, security lights, lights in closets or storage comparments and other.

This not an easy task and will require tracing wires behind cupboards, but for me the rewards are worth it.

Re: Coach batteries and inverter capacity in our 99'U270

Reply #48 – September 10, 2011, 12:57:47 pm

Some folks have discussed the effect of battery temperature on charging voltage.
My solar controller is temperature compensated with a temperature sensor attached to a battery. I would like to have temperature compensation with alternator charging and discussed with "Blue Sky" the possibility of patching the alternator output through the solar controller. The problem is that the Blue Sky controller frequently measures "open circuit voltage" and uses it to obtain maximum charging of the batteries. The "open circuit voltage" will vary with the intensity of the sun light reaching the panels. The diodes in an alternator will be destroyed by the transient voltages produced when going open circuit (ie do not disconnect the charge wires to the alternator when the engine is running).

I also discussed with Blue Sky, patching the converter through the solar controller, and while my scope indicated that the transients from the converter were acceptable, the total amperage of both the solar panels and the converter would overload the controller on a sunny day.

So, I have no "temperature compensation" when charging batteries with the alternator or the converter.

The effect that temperature compensation has on battery charging while I am in Victoria, Canada, is opposite to what it has for you folks in Texas at this time of year.

Another factor to consider when charging both start and coach batteries with the alternator is types of batteries (sealed or flooded). Flooded batteries will be undercharged at 14.2 volts, so should not be combined with sealed batteries.

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