New Battery Charge Not Lasting Long

[Zapnod]

I have a Thor Omni 2021. I have 4 new batteries that when fully charged will only last about 8 hours. Is this normal?

[16ACE27]

So many unknowns:

Type and capacity of the batteries?
State of charge of the batteries?
Loads on the batteries?

[Zapnod]

These are the specs. It seems like they are not charging properly.

SPECS
BATTERY TYPE: BLUETOP
MODEL: 34M
STARTING POWER: 800 CCA
MCA: 1000
C20 CAPACITY: 50 AH
RESERVE CAPACITY @25 AMPS: 100 minutes
HEIGHT: 7.94 IN
WIDTH: 6.88 IN
LENGTH: 10.06 IN
WEIGHT: 38.4 LB
VOLTAGE: 12 V

[ducksface]

Can we buy a vowel about if you're running the a.c. and hot-tub or just the t.v.?

[DavidEM]

The C20 spec- 50 amp hours, is half of what a good deep cycle battery should be, so yours are starting batteries, not deep cycle. That notwithstanding, you must have a very high amp load on them. Eight hours is not normal.

David

[Bob Nodine]

Originally Posted by Zapnod

I have a Thor Omni 2021. I have 4 new batteries that when fully charged will only last about 8 hours. Is this normal?

If you have a residential frig running off an inverter then you were lucky to get 8 hours. Check what is consuming current. Turn off anything that is not necessary. Make sure that when you are plugged into shore power that you are charging the batteries. It will take a long time to charge the batteries from the converter. A minimum of 4 hours and my guess is more than 8 hours. If your alternator will charge the batteries then that will be a faster route.

[Mark54]

Originally Posted by Zapnod

These are the specs. It seems like they are not charging properly.

SPECS
BATTERY TYPE: BLUETOP
MODEL: 34M
STARTING POWER: 800 CCA
MCA: 1000
C20 CAPACITY: 50 AH
RESERVE CAPACITY @25 AMPS: 100 minutes
HEIGHT: 7.94 IN
WIDTH: 6.88 IN
LENGTH: 10.06 IN
WEIGHT: 38.4 LB
VOLTAGE: 12 V

I'd say someone put starter batteries in, instead of deep cycle batteries! Should be written on the battery case somewhere "Deep Cycle", or at least DC in the part no. somewhere.

I could not find any evidence that this is nothing more than a starter battery:
https://shop.advanceautoparts.com/p/...b61d&gclsrc=ds

Also 50A x 4 = 200Ah x 12 = 2400Wh , enough to run a 1200W toaster or roof AC for about 2hrs.
If using a 120V fridge, typically 30-40A, so 2400/40=60 hrs.

Add up your watts- how much are you using?

8 hrs run time would suggest plate sulfation, or you're simply using too much for the purpose of those batteries, or they are indeed shot. Lead acid batteries must be stored at 100% SOC when not in use, or they will die.

Add your watts up and see why they are draining, but first verify the battery type!

AGM's are typically used, or Lithium if set up for those.

Sounds like typical battery/tire store with some teenager at the sales desk uneducated about RV battery types...

[EA37TS]

Didn’t the Omni Magnitude come with 2 six volt batteries? If so, why were they swapped for automotive 12volt?

[Beau388]

Originally Posted by Mark54

I'd say someone put starter batteries in, instead of deep cycle batteries! Should be written on the battery case somewhere "Deep Cycle", or at least DC in the part no. somewhere.

I could not find any evidence that this is nothing more than a starter battery:
https://shop.advanceautoparts.com/p/...b61d&gclsrc=ds

Also 50A x 4 = 200Ah x 12 = 2400Wh , enough to run a 1200W toaster or roof AC for about 2hrs.
If using a 120V fridge, typically 30-40A, so 2400/40=60 hrs.

Add up your watts- how much are you using?

8 hrs run time would suggest plate sulfation, or you're simply using too much for the purpose of those batteries, or they are indeed shot. Lead acid batteries must be stored at 100% SOC when not in use, or they will die.

Add your watts up and see why they are draining, but first verify the battery type!

AGM's are typically used, or Lithium if set up for those.

Sounds like typical battery/tire store with some teenager at the sales desk uneducated about RV battery types...

Optima blue tops are marine batteries. They are suitable for both DC and starting as in starting an inboard and running a trolling motor. The blue tops are more rugged than other Optima types to be able to survive pounding in a bass boat or in an off road side-by-side. Optima recommends blue tops for RV use. Optima's starting batteries are red top and the closest to true deep cycle are yellow tops. Optima batteries are made by a division of Johnson Controls at its Denver, CO plant. All Optima's are AGM batteries.


I bought two Optima group D31M for my Ultravan in 1999. The were still working well after 188,000 miles when I sold it in 2015. The Ultravan is an all aluminum, Corvair powered, 22 foot, class a motorhome made in 1965-70 and uses two identical batteries for starting and coach operation. Only the charger and roof A/C require 120 volt AC.

[16ACE27]

Originally Posted by Beau388

Optima blue tops are marine batteries. They are suitable for both DC and starting as in starting an inboard and running a trolling motor. The blue tops are more rugged than other Optima types to be able to survive pounding in a bass boat or in an off road side-by-side. Optima recommends blue tops for RV use. Optima's starting batteries are red top and the closest to true deep cycle are yellow tops. Optima batteries are made by a division of Johnson Controls at its Denver, CO plant. All Optima's are AGM batteries.


I bought two Optima group D31M for my Ultravan in 1999. The were still working well after 188,000 miles when I sold it in 2015. The Ultravan is an all aluminum, Corvair powered, 22 foot, class a motorhome made in 1965-70 and uses two identical batteries for starting and coach operation. Only the charger and roof A/C require 120 volt AC.

At only 50 AH each they aren't much for deep cycle use. And Optima specifically says they are best for STARTING BATTERIES.

[OldWEB]

I was curious why they don't tout "Made in USA" and so checked.
This video indicates all(?) batteries are made in Mexico
https://www.optimabatteries.com/expe...atteries-plant
Then this page explains who owns it, but it could be wrong, I did not check further.
https://www.motoraudit.com/who-makes-optima-batteries/


I personally never liked the Optima design, always thinking you want MORE acid for more power... but reading these pages got me thinking I will give them a try, I am due for new batteries all around.

[OldWEB]

Originally Posted by 16ACE27

At only 50 AH each they aren't much for deep cycle use. And Optima specifically says they are best for STARTING BATTERIES.

The company states to use Yellow Top ones for RVs.
https://www.optimabatteries.com/products/yellowtop

And I see the highest AH rating they have is 80. AND expensive.
So I guess I will look elsewhere, thx.

[MCP]

Responding to Mark54 post.

"If using a 120V fridge, typically 30-40A, so 2400/40=60 hrs."

Math Police here! I don't think your numbers work, Mark. Or perhaps I'm not understanding. Did you mean 12v fridge at about 5 amps, so 60 watts. Then 2400wh available (if Lithium) divided by 60w would equal 40 hours. Of course, if agm, about half that if using the 50% theory.

Or, if 120v fridge at about 10 amps (that's a guess) so 1200 watts. Therefore 2 hours for 2400wh divided by 1200 w.

That's based on my jr high school math/electrical knowledge.

[Judge]

Originally Posted by Zapnod

I have a Thor Omni 2021. I have 4 new batteries that when fully charged will only last about 8 hours. Is this normal?

I don't post on here anymore but do a search for a topics I posted about the BIM being wired backwards from the factory. It will effect battery charging and operation of 12V systems, like the slide.

Thor may have fixed this problem but I doubt it. I know for a fact that almost every Omni / Magnitude from 2020 - 2022 had this issue.

It is possible that your Converter / Charger is not charging properly when on shore power or when the engine is running if the BIM was wired backwards. My posts listed ways to verify of the BIM was wired properly and allowing the house batteries to charge properly.

[Mark54]

Originally Posted by MCP

Responding to Mark54 post.

"If using a 120V fridge, typically 30-40A, so 2400/40=60 hrs."

Math Police here! I don't think your numbers work, Mark. Or perhaps I'm not understanding. Did you mean 12v fridge at about 5 amps, so 60 watts. Then 2400wh available (if Lithium) divided by 60w would equal 40 hours. Of course, if agm, about half that if using the 50% theory.

Or, if 120v fridge at about 10 amps (that's a guess) so 1200 watts. Therefore 2 hours for 2400wh divided by 1200 w.

That's based on my jr high school math/electrical knowledge.

Oops!!!- yes- I meant watts for a 12V unit. 40A would be a lot! I meant Watts...

My Engel SR60 used about 30W @ 12VDC. so then 2400/30= 80 hrs, but still the wrong battery!!

[Beau388]

BLUETOP® D31M
$399.99
OPTIMA BLUETOP® Marine Battery

• Dual purpose for both deep cycle and starting applications
• Maintenance free for maximum convenience
• Completely non-spillable, mountable in many positions
• 15x the vibration resistance of a standard flooded battery
• Up to 3 times longer life vs. standard flooded batteries
• SPIRALCELL TECHNOLOGY with 99.99% pure lead delivers more power and consistently outperforms conventional flat-plate batteries

Best for Support high electrical demands



This was the only group 31 AGM battery carried by Interstate Batteries in 1999 with a 5 year guarantee. The dealer lent one to try free for a month. When I returned from a trip, he had been to a factory conference and brought three D31 that had cracked cases, which he had sealed with hot glue. I bought two for $150 in 1999 dollars. They lived in a compartment under the bed beside the air cooled pusher engine were the compartment's temperature exceeded 150 degrees. The dealer insured me than the ruggedness of the marine batteries was what I needed in an RV.

[ducksface]

My 1999 optima lasted 15 years openly exposed to. Lake Havasu/Mohave desert weather.
The newer Mexican made lasted 3 years tops. MAYBE 12 batteries before I dizzed up.

I now use odessey, the equivalent of old school optima batteries.

[NordicVetMBA]

Originally Posted by Zapnod

I have a Thor Omni 2021. I have 4 new batteries that when fully charged will only last about 8 hours. Is this normal?

I'm sure everyone will ask the same question... what are you doing with them? Lead acid or AGM batteries will lose about 3%+ per day just sitting there and not plugged into anything.

If you are running your microwave and hair dryers on them - they are certainly not going to last very long. Running a large TV on them for 6-8 hours is probably about right.

There are too many variables.

[NMRVer]

CCA is starting battery info. For coach battery you want Amp Hours (AH) really you need to look at the WATT Hour (WH). And 4x 50 AH isn't enough to run incandescent lights all-night. Like everyone else stated an invertor running any AC circuit loses 5-10% just converting 12 VDC to 110VAC. That plus a load equals short life. So to answer your post, is normal with your configuration to have short running time. I would look at replacing them with deep cycle.

[dkoldman]

OP says battery are 50AHs, with 4 batteries, did he say or do we know if serial or parallel? I assume parallel and that means 100ah actual available before considered discharged.

I don't agree that a good battery will discharge at 3% per day? If true that means in 17 days a good standing 100ah AGM will be down to only 50ah available?

Longest I have tracked is that with two 125ah AGMs, I went 10 weeks with batteries still connected but USE switch was off and batteries were at 12.75vdc before I turn the batteries back on.

Not my Harley (FLA) still connected will not make 1 week due to security system, so it has a float charger; but my Yamaha V star also with FLA may go 4 months connected and start right up. It has no parasitic loads. But both batteries from both bikes if taken out I would think would last a very long time? But that is a test I will never find out in real life.

My boat has two 24M Interstate FLA, I just turn the disconnect switch OFF during the winter and while winterized, 6 months later, I turn the switch back on and both engines turn over. With that said my Boat batteries are 7 years old and I plan to replace this spring. Not sure which batteries to buy, because I really don't want to buy FLA although I have had ZERO issues with my Interstate FLA in my boat. Never added any water either.