Volt meter on dash and battery charging

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Volt meter on dash and battery charging

October 07, 2013, 08:24:25 am

When I start the coach and raise the RPMs to bring the air up the volt meter moves very little. Sometimes it stays in the area below 12 volts. Also, Plugged into 50a now but have been on solar for 7 weeks. All looked fine with solar bringing batteries up by noon or so each day throughout that period. Now that I'm plugged in the amp hour meter on my Heart Interface shows 438 amp hours added. The batteries seem to be fine, all are AGMs. Anybody got and ideas I'd be appreciative of hearing them.

Re: Volt meter on dash and battery charging

Reply #1 – October 07, 2013, 10:05:05 am

From inside the coach, use a digital voltmeter in each of the two 12v lighter plugs and compare to dash reading. Dash is engine, plug next to air is house. Also, a good idea to go to the batteries and put a digital voltmeter on them also. Even if they are charged, you should be seeing somewhere in the 13volt plus range after it starts. Compare readings before starting and after.

Pierce

Re: Volt meter on dash and battery charging

Reply #2 – October 07, 2013, 10:26:12 am

After checking the voltage from the alternator, put the alternator under load by turning on the headlights, dash heater fans, and any other loads that come from the engine battery. The alternator voltage should stay high enough to charge the battery, probably around 13volts. Have a great day ---- Fritz

Re: Volt meter on dash and battery charging

Reply #3 – October 07, 2013, 10:31:19 am

Hi Larry,

I noticed the very same problem with my dash voltmeter - registers low and seldom raises above 12 volts.

I found that my batteries are OK and so is the alternator. I think the long lines from the rear to the front are causing a significant voltage drop. So I plan to use a digital multi-meter to adjust the dash voltmeter to be the same reading as directly on the batteries. On my 2002 the VDO volt meter has an adjustment on the side that you can see after removing it from the dash.

As Gen Norman Schwarzkopf might say..."other than that it is a fine dash voltmeter".

Re: Volt meter on dash and battery charging

Reply #4 – October 07, 2013, 10:33:53 am

I recently added the Innova voltmeter from Amazon to plug into the 12VDC outlets on the dash. I like the instrument and the information. I leave mine plugged to the chassis system. I can observe the charge, float, and cranking (brief but informative) voltages.

I also bought from Amazon a Solar BA-7 battery tester. I did not find it to be an impressive looking instrument, but it immediately gave me the diagnosis that one of my Optima 34 Red Top starting batteries was bad and the other was fine. The bad battery probably failed a long time ago. The engine hasn't started with the vigor I expect for a long time. I replaced the bad Red Top and starting is more as it should be.

The BA-7 provides voltage readings and a value for CCA. The bad battery showed CCA of 5 and the good one was 770. There was not physical evidence that the battery was bad. It would show appropriate voltages under charge and float. The brand new battery showed about 950 CCA on the meter. The values are probably not nearly as accurate as high quality instruments and good test protocols would yield, but they provided useful information for me.

Re: Volt meter on dash and battery charging

Reply #5 – October 07, 2013, 03:03:00 pm

I checked volts at dash lighter plug...only got one...and it was 12.46vdc. I'd check the batteries but with about 8 in of rain since 6:00 am I'll have to wait for the "river" washing under the coach to slow down.

Re: Volt meter on dash and battery charging

Reply #6 – October 07, 2013, 03:55:09 pm

Using the Innova voltmeter plugged to the chassis 12VDC port on the dash, I have observed the following voltages during the last two weeks while traveling: (all values are +- a few hundredths)

Float voltage using the Battery Tender: 13.35
Charge/Accept using the Battery Tender: 14.45
Charge while driving with headlights/markers off: 13.9
Charge while driving with headlights/markers on: 13.6
Lowest voltage observed while cranking the engine: 10.64

I am satisfied that the charging system and batteries are doing what they are supposed to do. The analog voltmeter on the dash shows voltages about 0.4 to 1.6 volts less than the Innova meter. Several of the analog electric gauges show values that vary depending on whether the headlights are on.

Re: Volt meter on dash and battery charging

Reply #7 – October 07, 2013, 08:11:45 pm

Had loose wire connections to the dash voltmeter on my 97. Tightened the connectors on the gauge itself

Bob

Re: Volt meter on dash and battery charging

Reply #8 – October 11, 2013, 10:59:01 am

OK, the puddles have mostly dried up. (8 in of rain last Sunday) Anyway, I've checked the batteries. Start Red-Tops show 13.49 vdc, not hot to the touch. They were new at Christmas 2010. House batteries are HOT to touch, boiling, leaking. They are Deka, AGM, bought new in April 2011. Of course not to use a pun but I'm sure they're toast. The inverter/converter is a Freedom 25 that I'm sure was new with the coach. It's a '96 U-295. I have 465 watts of solar that's been installed since 2008. I checked the batteries in Illinois in Sept. and they were OK. We'd been on solar for a month. Two weeks to Punta Gorda, FL, and the dash volt meter was not always showing charge at startup. My Heart Interface began showing way too many amp-hours after we'd plugged in to 50 amp. Volts and polarity were/are fine. AS mentioned at the start of this thread, the amp-hours went way over 400 during the first three days. Usually, when on the road and solar only they will show 10-15 above zero when first plugged in. Rain came before I had a chance to check things out and this site was so wet that we really couldn't have driven out to a dry patch to check things out. Anyway, could the freedom 25 be going bad and therefore the batteries are ruined or could the batteries have had a problem that finally came to a head?

Re: Volt meter on dash and battery charging

Reply #9 – October 11, 2013, 11:35:29 am

Larry,

Hard to answer without any diagnostic tools. Batteries should never exceed 125 degrees when charging. Your solar controller probably has a sensor at the battery(s) that sends temp info back to the controller limiting charging as not to go over temp. Your OEM shore power charger may have cooked the batteries or one battery may have gone bad causing all to overcharge and cook.

When we bought our U300, the house 8Ds were cooked. One was completely dry. I replaced the 8Ds with 6 sealed lead acid solar batteries and just watched the voltage. The OEM shore charger works fine with them and usually floats at 13.1 volts. In short (npi), my problem was with the batteries.

I do have a couple of digital voltmeters mounted where the CRT was. The analog voltmeter is not so accurate so I just connected into the Audit wiring for the engine and house battery voltage. I have checked at the batteries and the digital displays are exactly on. Dash mounted digital voltmeters keep you ahead of the curve and the $8 each/delivered is a tiny percentage of what even one new house battery costs.

We also have solar on the roof and use the digital meters to monitor the batteries with the PV panels powered up. The MPPT controller has all the info also but easy to watch the dash while driving or when sitting anywhere in the main salon.

See my post yesterday of the attached photo of the installation.

Best of luck

Pierce

Re: Volt meter on dash and battery charging

Reply #10 – October 11, 2013, 04:14:21 pm

Have an appointment for 8:30 am Monday to have the system looked at. They said after my description, that it sounded like a bad cell(s) in one or both batteries. They don't like Deka, and would recommend Interstate. I've used Interstate on cars for years. Anybody know about their 8D AGMs?

Re: Volt meter on dash and battery charging

Reply #11 – October 11, 2013, 04:44:06 pm

Larry,

Very difficult to tell whether it is a battery or charger issue, as the symptoms can be the same.

The best charger in the world when charging a battery bank with a dead cell WILL boil them-- it is trying to charge a 10 VDC battery as if it were a 12 VDC battery. The remaining cells will definitely boil/overcharge.

The Xantrex inverter/charger you have is a good one, IF, repeat IF it is properly programmed. Early ones had dip switches on the inverter itself. Mid year had dip switches on the back of the remote. Newer ones are programmed from the front of the remote panel. Your inverter/charger book gives all the details. If questions, ask.

Also, do you have a good controller on the solar and is it properly programmed?

Brett

Re: Volt meter on dash and battery charging

Reply #12 – October 11, 2013, 04:55:58 pm

This comment may be redundent but why-if you have solar- do you use the inverter to charge them when plugged in?? I only use the alt' when driving and stopped solar. Always switch the inverter charger off when wanting 120 from it. I have 750 watts of solar and it is proving to be sufficient. Frige on seperate inverter as is tv and sound system etc and after parking the amps used for all of that plus microwave cooking till 9am next morning is only 10-12% according to Trimetic. Very happy with it.
I have Lifeline AGM 8D (3) and they are allways cool to the touch.
John H

Re: Volt meter on dash and battery charging

Reply #13 – October 11, 2013, 05:45:31 pm

John,

Excellent question. I try to keep a tarp over the coach (so no sun) until I get the rest of the RV garage up (#1 on the list so hopefully in a couple of weeks) now the new roof is on the house garage. The coach is parked next to the house and I go out and watch TV with the Tailgater on. I don't like to run the inverter all the time and when I switch it on, the satellite receiver takes it's time finding satellites, updating the programming, etc. so easier to just keep it plugged into shore power. Once the new garage is finished, I won't have any sun so will also have to keep it plugged in. The U300 makes a great guest room and somewhere to go so I don't have to listen to the abuse about the noise the car races make.

In the back of my mind is the worry that the inverter will catch fire and burn up not only the coach but the house since we are only six feet away. Any time we are gone for a day or two, I flip the breakers and shut everything down. I also like to keep the battery cycles to a minimum and running the inverter all night (so I don't have to wait for the satellite and reset the microwave) would add to the number of cycles. Shore power minimizes that.

With a 1140 watt potential, when we are on the road, we can watch TV or run the microwave, etc and when the sun comes up, it will be back to "float" in a short time. The fridge is almost new but I also shut it down if away from the coach (two way fridge) and most of the time if we park somewhere for dinner, etc. unless I'm sure the rig is level. Just have to go to the RV wrecking yard web sites and look at the fire photos to figure where most started. Probably ninety percent of our road time is dry camping so we are just the opposite while on the road using solar most all the time.

Pierce

Re: Volt meter on dash and battery charging

Reply #14 – October 11, 2013, 07:24:46 pm

So, Pierce, it sounds like if you were in my position with my FT in an RV Park for the entire month of Dec while we're in Mexico, you'd trip the AC breaker at the pedastile and rely on my 1200 watts on the roof to run the fridge (on DC). (There's no shortage of sun here in El Centro, CA. We just stopped having three digit temps ;o)

That will keep the house batteries topped off.

The starter batteries are AGMs, too, and their low internal resistance probably means I don't need worry about them and turn the boost switch on for a month.

Ant other suggestions?

best, paul

Re: Volt meter on dash and battery charging

Reply #15 – October 11, 2013, 07:54:06 pm

Paul- my thoughts on your question to Pierce--
Depends on were you are going in Mexico and the power there? My original reason for solar was to get away from the surges and lows of the power there-even in some of the better spots it tends to climb at night. I have had it as high as 136 at night and as low as 90 in day in some places. We wanted to enjoy Mexico without screwing up the coach so did the solar. With your fancy fridge if you have LED lighting inside you must not need much power and with the sun all day it is a breeze to get batteries back to 100%, we did it with 750w for 3 months and that was before I changed all the wiring to #2 and #4 !!
John H

Re: Volt meter on dash and battery charging

Reply #16 – October 11, 2013, 08:58:03 pm

Quote from: Paul Smith – October 11, 2013, 07:24:46 pm

So, Pierce, it sounds like if you were in my position with my FT in an RV Park for the entire month of Dec while we're in Mexico, you'd trip the AC breaker at the pedastile and rely on my 1200 watts on the roof to run the fridge (on DC). (There's no shortage of sun here in El Centro, CA. We just stopped having three digit temps ;o)

That will keep the house batteries topped off.

The starter batteries are AGMs, too, and their low internal resistance probably means I don't need worry about them and turn the boost switch on for a month.

Ant other suggestions?

best, paul

Paul,

Sounds as if you have it covered. How far down are you going? Yes, park voltage either here or in Mexico is a worry. I will probably buy a surge/voltage protector but for winter and no need for AC, the solar will do the trick. Just not enough juice for the roof ACs plus in summer, it stays hot at night. Our MidNite controller is working well. Have to adjust the voltage readout as it's different from my meter at the batteries but easy to do. Voltage seems excessive while on the road with engine alternator and panels both on. It was getting past 14.5V on the dash digital so I switched the panels off. Easy to adjust too, just have to find some time. MidNite tech said to leave the panels/controller on regardless of any other source. Most electronics are rated for 13.8V and that pretty close to what the engine alternator supplies.

I have to leave the top can storage door open so the controller gets some ventilation or the fans come on. Not very loud but I need to figure out how to get some air in there with the door closed.

Pierce

Re: Volt meter on dash and battery charging

Reply #17 – October 11, 2013, 09:17:46 pm

Thanks for the advice on Mexico and all.

Re: Volt meter on dash and battery charging

Reply #18 – October 11, 2013, 10:00:32 pm

I now see I was not very clear. (First time again ;o)

The FT will be in El Centro, CA while Kathleen and I will be in Mexico (in PaaMul, south of Can Cun/Playa/Cozumel - on the Caribbean).

My plan is to trip the breaker at the pedestal in El Centro, CA and let the solar keep the house batteries topped off.

With no AC into the FT, the fridge will automagically switch to DC.

I would think the starter batteries will be fine with no charging for a month.

best, paul

Re: Volt meter on dash and battery charging

Reply #19 – October 11, 2013, 10:29:53 pm

Paul, thats better.
I would not only switch off power at pedstal but put the cord away just in case a friend switches it back on thinking it was turned off on you. With that much solar you have no worries even on a cloudy day.
JohnH

Re: Volt meter on dash and battery charging

Reply #20 – October 12, 2013, 09:55:01 am

Sorry about the snotty comment about the Mexico advice. Brett, I have a Xantrex c35 controller. The highest observed amps on the solar is 26.4. If I were to slant the panels and keep them clean and had no clouds, dust, etc, I would overload the controller. Of course that's never going to happen. I did build a frame to be able to slant the panels N-S,E-W, which allows them to be stood on a corner if necessary. I decided that I didn't need to be getting up there all the time so just leave them with about a 3 degree slant to the side of the coach for drainage. I guess my question was about the Interstate 8D batteries. Anybody know?

Re: Volt meter on dash and battery charging

Reply #21 – October 12, 2013, 09:59:06 am

Believe they are East Penn private label. NAPA definitely East Penn. I asked private label question at GV of East Penn rep.

Re: Volt meter on dash and battery charging

Reply #22 – October 12, 2013, 10:11:14 am

East Penn makes DEKA, a brand the garage doing the work says is having trouble recently. Of course, they sell Interstate only. I can't find Interstate 8D's AGM from Google but they said they could get them in a day if that's what's needed. Clearly mine are ruined or at least one is.

Re: Volt meter on dash and battery charging

Reply #23 – October 12, 2013, 10:20:29 am

Interesting, FT must use DEKA, or they wouldn't had them speak at GV. Wonder if dealer profit is coloring opinion? What are the issues they are seeing with DEKA?

Re: Volt meter on dash and battery charging

Reply #24 – October 12, 2013, 10:40:28 am

They said there were several (don't know how many that is) with bad cells. I bought these DEKAs at the battery place just north of MOT on Stallings in April of 2010. Good price and they did a good job of installing them.

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