House Batteries

Outbumn · 05-28-2007, 02:18 PM

We just spent 4 hot days dry camping at Lowes Moter Speedway. Most of that time was running off the house batteries. Now for the question, what is the average charge life of the house batteries? With just the roof fan on low, we were getting about 3 to 4 hours before they were discharged to the point of not being able to start the generator. Is this normal? These batteries are only about a year old and I check the fluid levels and top off every month.

I have also heard about inverters/chargers that auto start the generator when the batteries get low. Can anyone shed some light on this?

How long should you charge the house batteries off the generator if they are discharged? I was running the generator an hour or two when this happended.

Outbumn · 05-28-2007, 02:18 PM

We just spent 4 hot days dry camping at Lowes Moter Speedway. Most of that time was running off the house batteries. Now for the question, what is the average charge life of the house batteries? With just the roof fan on low, we were getting about 3 to 4 hours before they were discharged to the point of not being able to start the generator. Is this normal? These batteries are only about a year old and I check the fluid levels and top off every month.

I have also heard about inverters/chargers that auto start the generator when the batteries get low. Can anyone shed some light on this?

How long should you charge the house batteries off the generator if they are discharged? I was running the generator an hour or two when this happended.

Pusherman · 05-28-2007, 03:23 PM

Ron,

Discharging your house batteries in 3-4 hours w/only the fan running seems excessive. We boondock in the Adirondacks each fall and get about 12 hours out of the batteries with the furnace running. I will run the generator morning and evening to top the batteries off.

The device you are mentioning is an Onan EC-30 which will automatically start the generator when the batteries need a charge, or when the AC calls for cooling and there is no shore power sensed. I just installed one in my coach. Read about it Here.

Don The Ham · 05-28-2007, 03:32 PM

Ron

Your roof fan running only 3 to 4 hours to get complete battery discharge in an indication of poor battery condition, if the battery was fully charged to start with.

I just went through a house battery replacement at 15 months into my coaches life. Take it to your dealer and have them do a battery load test to determine your house batteries amp-hour capacity.

My house battery failure indication was the voltage was down to 10 volts in 3 days while parked in my yard. After the load test by my dealer, I received a pro-rated warrenty replacement by Interstate batteries. I understand that Winnebago no longer uses Interstate batteries, may be an indication that this was a high failure component item.

On my past motorhomes, the house batteries lasted a minumum of 5 years before needing replacement.

Outbumn · 06-10-2007, 11:36 AM

Update,
Just returned from 4 days of camping (with full hookups). Parked the coach and checked the battery gauge on the One Panel. After a 2 hour drive back from the campground, the house batteries were at 11.2. Started the engine and checked again and the reading was at 14.2. Connected shore power and checked the gauge, 14.2. Disconnected shore power after 3 hours and the batteries registered 11.1.

To me, it looks like the batteries are being charged from the engine and shore power, but are not taking the charge. Am I correct?

I will be calling the dealer tomorrow or going to Batteries Plus for replacement batteries.

If there is nothing wrong with the charging system, is it worth replacing these batteries with gel packs? If so, what would be the best batteries to replace these Interstate SRM-24 batteries.

Pubtym · 06-10-2007, 02:30 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Outbumn:
Update,
Just returned from 4 days of camping (with full hookups). Parked the coach and checked the battery gauge on the One Panel. After a 2 hour drive back from the campground, the house batteries were at 11.2. Started the engine and checked again and the reading was at 14.2. Connected shore power and checked the gauge, 14.2. Disconnected shore power after 3 hours and the batteries registered 11.1.

To me, it looks like the batteries are being charged from the engine and shore power, but are not taking the charge. Am I correct?

I will be calling the dealer tomorrow or going to Batteries Plus for replacement batteries.

If there is nothing wrong with the charging system, is it worth replacing these batteries with gel packs? If so, what would be the best batteries to replace these Interstate SRM-24 batteries. </div></BLOCKQUOTE>

I have an 06 Itasca 35U. I went through two converter failures with symptoms like yours.
Once you get converter fixed...expect house batt failure/early replacement because failing converters takes their toll on those batts.

vicsryd · 06-10-2007, 05:57 PM

Can you tell us more about your battery maintenance habits?

Do you have a voltmeter so you can read the voltage without a load (i.e. with the 12v system shut off via the Aux Batt switch)?

At 11.2 volts loaded you are probably starting out at below the 50% discharged level which is as low as you normally want to go for this type of battery before recharging. 12 volts with no load is the 50% discharged threshold for flooded lead acid batteries like the SRM24. If they (two in your configuration, right?) were accidentally discharged below 10.5 volts for more than a few days then that would explain the symptoms too.

If they don't find a problem with the converter/charger and the load and hydrometer tests don't find at least one bad cell in each battery then it's likely they'll say it's not covered by warranty.

If the batteries do turn out to be bad the SRM27's have a 30 month pro-rated warranty and your coach is new enough that so you should be able to get some kind of credit from an Interstate dealer (not Winnebago).

I don't know if it's possible but maybe they'd give you credit towards Optima Blue Top (AGM) deep cycle batteries. In your case the SC34DM is as close as their is to the SRM24 but with slightly less amp hour rating. But AGM's can be discharged a little deeper

If you end up having to go out of pocket for new batteries and $150+ per battery doesn't phase you then I'd recommend you go with Trojan or Lifeline AGM deep cycle batteries. Your current batteries are 11 x 6.875 x 9.5 inches. If you have an inch to spare to go 12" wide then the Trojan 27-AGM will fit your application and provide at least 20% more amp hours than direct group 24 replacements.

John_Canfield · 06-11-2007, 02:58 AM

There are many threads about battery problems and auto gen start - do a search and read all about it.

Ditto for Jon's advice, but a battery is completely discharged (not a good thing) at 11.2 volts. A battery is 50% discharged at around 12.0 - 12.3 volts at rest. It is difficult to measure the voltage at rest unless you completely disconnect the battery bank and let it rest for 24 hours. However, taking batteries down to 11.2 volts is dramatically shortening their life-span (you probably have a bad cell or cells.)

John Hilley · 06-11-2007, 04:12 AM

I believe you are right about the alternator and the converter charging the batteries, but the batteries aren't accepting the charge. One thing to check is all battery connections, especially the ground connection. If you have a bad connection, you will see a 14.2 v charge, but you may not be passing much current.

Outbumn · 06-11-2007, 01:02 PM

I did more checking tonight. Found 1 dead cell in one battery and 2 dead and 1 marginal cell in the other battery.

I pulled shore power and tripped the battery switch this morning, then took a voltage reading across the battery terminals tonight. Not good, 9.9 on one battery and 10.2 on the other.

To answer the maintenance question, I check the fluid levels every month. Last time I checked them was before going to Charlotte over memorial day weekend.

CC38EL · 06-12-2007, 04:13 PM

It's been my experience that house batteries in new coaches are not taken care of by some of the dealers or delivery folks.

At many RV's shows and on RV lots, we've seen the batteries abused and neglected so it's not surprising that you're having a failure in such a new coach.

We've had this happen in 2 of our 3 RVs. After replacing the batteries, the new ones lasted well over 3 years each.

When I was trying to figure out how my batteries died, I religiously checked the water and performed checks on the converter/charger to make sure it was correct, but to no avail. After about a year, the batts just wouldn't hold a charge and would only last about 3-4 hours as you've experienced.

Hopefully you can get replacements with minimal cost and trouble.

inphx · 06-25-2007, 07:10 AM

I had a similar problem of receiving my 05 Suncruiser new and having the batteries go dead within a week. Dealer never checked the water in the batteries. Completely dry.

I now have to put in water in the batteries every two weeks, in the summer. I live in Phoenix.