Lead Acid Battery Recommendation

[frater secessus]

most traditional 12 volt charging systems will require modifications to support them

I disagree. Any reasonably-configurable components can be set up for LiFePO4. Existing alternator charging is also probably fine for the stated use case (drop in house battery).

an overview

and they still will shut down hopefully when high amp loads like a starter is powered.

???

OP is looking to replace the house battery, not starter battery. In OEM configurations the house battery is not used to start the engine.

 

[frater secessus]

A lead acid door stop of unknown manufacture. It does not hold a charge for more than an hour when I'm not connected to shore power and nothing is on

I mean voltage (6v, 12v, 24v), approximate size, capacity in Ah. Right now all we know is "battery". A picture would be better than nothing.

hot water heater,

This is an electrically-ignited propane water heater?

 

[tradesman]

"Can we stop spreading the fable that LA batteries can only be discharged to 50%. Both chemistries (LA and Li-Ion) can be discharged until the voltage is no longer hight enough to be useful. For typical RV usage (low amps) voltage drops too low at about 25%-30% for lead acid and 15% to 20% for Li-Ion."

Lithium can be discharged further and more times than lead acid.
AGM batteries depleted 100% have up to 300 cycles.
Lithium depleted 100% have up to 2000 cycles.
I think it comes down to penny wise & pound foolish in more ways than one. Lithium are about 1/3 the weight of AGM.

 

[Walt]

A pair of Walmart RV/Marine batteries will be under the $200 limit. Can be replaced every year if you want - Walmart is good that way. Mine have never been tested - I tell them it's not holding charge, they confirm purchase date, they hand me a new one. I purchased a second, which has stopped the voltage drop under load and is finally functioning correctly. Walmart.

 

[bullfrog !]

Some times the old motorhome vehicle battery fails to start the engine. It is pretty common practice to run jumper cables from the house battery to the vehicle battery, in fact a few have a OEM switch to do just that. My old built in generator is 7,000 watts and puts a pretty good load on the house battery as well when I fire it up. Sometimes I will get the generator running while jumper cables are attached to charge up my vehicle battery. The vehicle may have been sitting in below freezing or in 110 degree weather in an uninsulated battery compartment. In my opinion you shouldn’t try just putting a lithium battery in place of a lead acid battery, as there are differences that need to be considered and dealt with especially if you are a novice with an older motorhome that may have been modified by the previous owner. In my opinion the lithium power stations provide a stand alone system and is a good system for a novice at a now slightly higher price. One of the big advantages to me of lead acid is the ability to interchange or use them with the vehicle battery with no problems. Yes there are work arounds but not everyone knows how or is able to do those things safely.

 

[user 22017]

All batteries can be discharged until there is nothing left. Lithium can be discharged further and more times than lead acid.
AGM batteries depleted 100% have up to 300 cycles.
Lithium depleted 100% have up to 2000 cycles.
I think it comes down to penny wise & pound foolish in more ways than one. Lithium are about 1/3 the weight of AGM.

Aren't fires a concern with lithium batteries? This report is from February 7, 2023:

https://www.nbcnews.com/news/explod...hium-batteries-are-confounding-fire-rcna65739

 

[lonerwolf52]

Onuse Group 29 deep cell marine batteries with two uear

Hello All:

I cannot currently swing the cost of a lithium battery and need to replace my house battery. Does anyone have recommendations for a maintenance-free (I don't have to add water) lead acid battery for around $200.00?

I have a Thor Freedom Elite, Class C Motorhome. A functional battery is required for my propane auto-igniters (they cannot be lit manually) for the fridge, hot water heater, and heat pump.

I have an Onan on-board 4000 watt generator and 100 watts of solar that I intend to connect to the battery when I boondock to help keep the battery from discharging.

I appreciate your thoughts/feedback!

Thanks!!!

Warranty from Walmart for $100.

 

[SierraVanCampers]

For a quality AGM battery shipped to you for no extra charge, see vmatanks. com. I spent 30+ years in my career working with batteries and have been very impressed with these batteries. A 100ah AGM is 274.00 shipped.

 

[frater secessus]

Aren't fires a concern with lithium batteries?

Different lithium chemistry than what we are talking about here. LiFePO4 is very, very safe.

 

[lonerwolf52]

A pair of Walmart RV/Marine batteries will be under the $200 limit. Can be replaced every year if you want - Walmart is good that way. Mine have never been tested - I tell them it's not holding charge, they confirm purchase date, they hand me a new one. I purchased a second, which has stopped the voltage drop under load and is finally functioning correctly. Walmart.

Always check my battery to see if it's good. Always.

 

[Zerpersande]

All batteries can be discharged until there is nothing left. Lithium can be discharged further and more times than lead acid. AGM batteries depleted 100% have up to 300 cycles.
Lithium depleted 100% have up to 2000 cycles.

And then there are others that disagree. And give more explanation as to why. Most commercial batteries have a BMS (battery management system) that prevent over-discharge. So ‘nothing left’ just means the point where the BMS tells you the bar is closed, you’re cut off for the night and sends you home.

https://electronics.stackexchange.c...rged-is-it-harmful-for-it-to-remain-in-this-s

 

[tradesman]

I should have clarified that I was referencing this earlier post from someone else in general terms:

"Can we stop spreading the fable that LA batteries can only be discharged to 50%. Both chemistries (LA and Li-Ion) can be discharged until the voltage is no longer hight enough to be useful. For typical RV usage (low amps) voltage drops too low at about 25%-30% for lead acid and 15% to 20% for Li-Ion."

I have removed the offending sentence from my earlier post about "all batteries":

 

[jasper]

Willow4303, are you still here?

 

[Willow4303]

I mean voltage (6v, 12v, 24v), approximate size, capacity in Ah. Right now all we know is "battery". A picture would be better than nothing.



This is an electrically-ignited propane water heater?

I will do my best to get a picture of the battery this week. I am doing a care-taking gig for a patient who had spinal surgery, so I am on the clock 24/7. Sometimes I don't have the time to get back here with a clear head. I only have a few minutes right now, while my patient is in the bath.

Yes, the hot water heater is electrically-ignited and there are warnings every where that say do not attempt to light manually, or you will blow up the rig and or die (I'm paraphrasing, LOL). Thank you!!

 

[Willow4303]

Willow4303, are you still here?

Hi, I AM here, just not as frequently as I'd like, particularly after posting my question here. I'm working as a care-taker right now and I'm on the clock 24/7. I hope to review all of the input and reply later this week while my patient is in physical therapy. Thank you!!

 

[awesum]

Some times the old motorhome vehicle battery fails to start the engine. It is pretty common practice to run jumper cables from the house battery to the vehicle battery, in fact a few have a OEM switch to do just that. My old built in generator is 7,000 watts and puts a pretty good load on the house battery as well when I fire it up. Sometimes I will get the generator running while jumper cables are attached to charge up my vehicle battery. The vehicle may have been sitting in below freezing or in 110 degree weather in an uninsulated battery compartment. In my opinion you shouldn’t try just putting a lithium battery in place of a lead acid battery, as there are differences that need to be considered and dealt with especially if you are a novice with an older motorhome that may have been modified by the previous owner. In my opinion the lithium power stations provide a stand alone system and is a good system for a novice at a now slightly higher price. One of the big advantages to me of lead acid is the ability to interchange or use them with the vehicle battery with no problems. Yes there are work arounds but not everyone knows how or is able to do those things safely.

I do think that what tempurature you will be exposing them to would matter in which type to choose between lead acid, lithium and LifePo4. Some will become damaged or ruined by extreme tempurature exposure and if you try to charge them while they are exposed to extreme tempuratures, can be dangerous. Am I right in my thinking? I was looking into the Everstart, deepcycle Marine battery at Walmart. They have gone up in price a bit as with everything. The 109 ah I believe is around $95.
EverStart Lead Acid Marine/RV Deep Cycle Battery, Group Size 27DC:

• 1 Year free replacement warranty
• 12-volt marine deep cycle battery
• 750 MCA
• 109 amp hour
• Dual post
• Superior cycling and recharge capabilities
• Battery is maintenance free under normal operating conditions
• Free battery testing and installation at your local Walmart Auto Care Center
• If you need to get rid of your old battery, there is free lead acid battery recycling at your local Walmart

 

[bullfrog !]

My concern is that I’ve been around lead acid and later AGM batteries and have learned how to use them safely. Lithium batteries are affected more by current flow/temperature/charging and have additional components in a Battery Management System (BMS) to act as a safety and I don’t trust electrical components so much when it comes to my safety, especially ones made in countries where quality control is less than perfect.

 

[tx2sturgis]

Most smaller motorhomes have house batteries installed (from the factory) in an un-heated compartment or 'shelf' that exposes them to the outside temps.

Which is another reason to stick with lead acid (agm or flooded) in this situation.

 

[jasper]

Willow, don't be afraid of Deep Cycle lead-acid batteries, especially if you already have two mounting locations and wiring to use them. Do you know if your vehicle has a relay that connect the house battery to starter battery with the vehicle running and disconnects with it off?

With proper charging voltage, the electrolyte level seldom needs distilled water added. For decades, inexpensive specific gravity testers have been used to determine state-of-charge. They can identify a weakening cell to show a need for a higher charging voltage for equalization voltage, about 14.8.

An inexpensive digital DC voltmeter and ammeter, greatly helps. If your alternator charging voltage ranges from about 14.0 to the high fourteens, you are good to go for lead-acid and so-called drop-in lithiums. Some newer vehicles do not provide sufficient charging voltage long enough, mainly for possible fuel savings, hence bullfrog's comment about needing modification to supply recommended charging voltage.

In the fifties, I saw analog ammeters on vehicles, then idiot lights, and now analog voltmeters. Now that digital voltmeters and digital ammeters are inexpensive and accurate, I don't know why they are not both provided, especially on factory built vans and campers.

For lead-acid, there must be enough voltage to charge, and charging current should start high when discharged, then drop. Most typical group size wet lead acid and AGM, mid to high 14vdc, about 30-40 amps initially, then drop to about two amps when fully charged.

Some people don't like to have possible off-gassing from a lead-acid in their living quarters.

I use Walmart deep cycles for both starting and house in my van. I've retrofitted a few dozen in golf carts to get away from 6 and 8v batteries for light users. Some are still good after six years.

Lithiums are great. I use multiple 30ah small ones due to trust issues about anything manmade. Even a 100ah, with a current output limiting BMS cannot run my loaded 2000 watt inverter to give me a typical 120v, 15 amp source due to high current shut down. Lead-acid and AGM can. That same 100ah lithium will demand more charging amps than my alternator can provide for the length of time before that battery is charged. If a single 100ah dies, you're done.

Lead acids and AGMs highly resist being charged, as mentioned above when you watch the charging amps quickly decrease. That makes it much easier on your vehicles alternator.

Lifepo4 lithiums demand to be charged. Without a BMS to control charging amps, they can be hazardous to your alternator. You have to look at the charging voltage, current, and maximum amp output given by the manufacturer.

Picture shows digital voltmeter and ammeter, both from Amazon. Bayite DC hall effect ammeter reads voltage or current, or displays back and forth. The flashing is annoying. Multiple cigarette outlet and USB plug device will show alternator voltage.

For charging from a 120vac source, I have three 30 amp power supplies, adjustable to almost 15vdc. Crude, but effective. About 30 bucks with no wiring. Ammeter to adjust charging voltage to amps desired.

 

[Willow4303]

Willow, don't be afraid of Deep Cycle lead-acid batteries, especially if you already have two mounting locations and wiring to use them. Do you know if your vehicle has a relay that connect the house battery to starter battery with the vehicle running and disconnects with it off?

With proper charging voltage, the electrolyte level seldom needs distilled water added. For decades, inexpensive specific gravity testers have been used to determine state-of-charge. They can identify a weakening cell to show a need for a higher charging voltage for equalization voltage, about 14.8.

An inexpensive digital DC voltmeter and ammeter, greatly helps. If your alternator charging voltage ranges from about 14.0 to the high fourteens, you are good to go for lead-acid and so-called drop-in lithiums. Some newer vehicles do not provide sufficient charging voltage long enough, mainly for possible fuel savings, hence bullfrog's comment about needing modification to supply recommended charging voltage.

In the fifties, I saw analog ammeters on vehicles, then idiot lights, and now analog voltmeters. Now that digital voltmeters and digital ammeters are inexpensive and accurate, I don't know why they are not both provided, especially on factory built vans and campers.

For lead-acid, there must be enough voltage to charge, and charging current should start high when discharged, then drop. Most typical group size wet lead acid and AGM, mid to high 14vdc, about 30-40 amps initially, then drop to about two amps when fully charged.

Some people don't like to have possible off-gassing from a lead-acid in their living quarters.

I use Walmart deep cycles for both starting and house in my van. I've retrofitted a few dozen in golf carts to get away from 6 and 8v batteries for light users. Some are still good after six years.

Lithiums are great. I use multiple 30ah small ones due to trust issues about anything manmade. Even a 100ah, with a current output limiting BMS cannot run my loaded 2000 watt inverter to give me a typical 120v, 15 amp source due to high current shut down. Lead-acid and AGM can. That same 100ah lithium will demand more charging amps than my alternator can provide for the length of time before that battery is charged. If a single 100ah dies, you're done.

Lead acids and AGMs highly resist being charged, as mentioned above when you watch the charging amps quickly decrease. That makes it much easier on your vehicles alternator.

Lifepo4 lithiums demand to be charged. Without a BMS to control charging amps, they can be hazardous to your alternator. You have to look at the charging voltage, current, and maximum amp output given by the manufacturer.

Picture shows digital voltmeter and ammeter, both from Amazon. Bayite DC hall effect ammeter reads voltage or current, or displays back and forth. The flashing is annoying. Multiple cigarette outlet and USB plug device will show alternator voltage.

For charging from a 120vac source, I have three 30 amp power supplies, adjustable to almost 15vdc. Crude, but effective. About 30 bucks with no wiring. Ammeter to adjust charging voltage to amps desired.



View attachment 33665View attachment 33666

Hi, thank you for all of the info. I got a picture of my battery, but am having issues getting it to send to my email account. I know what to do to fix that, but don't have the time right now, so here are the particulars:

It is a Super Start Marine Deep Cycle battery. Part number: 31DCMJ. Cold Cranking amps 675; Marine Cranking amps at 32 degrees Farenheit is 845; Reserve capacity is 210. It has a place to add distilled water, and the usual warnings about sulfuric acid on another little hatch one is not supposed to fiddle with.

I believe it is a 12 volt battery. It is in an open compartment under my second stair from the bottom (there are three stairs if you count the RV floor level as the third). I MIGHT be able to get two batteries into that compartment, I would have to choose and measure said batteries. I am leaning toward two Walmart batteries (lead acid, you have educated me, lol) if they will fit. I'm not sure how to connect one battery to another, and my battery compartment currently has only one set of wires, which are all connected to the current battery.

I don't believe I have a relay from house battery to vehicle battery.

I am avoiding temperature extremes by spending winters in Arizona (even though we had a few near-freezing temps, we did not have several days in a row of freezing temps) and summers in Colorado. I will leave Az for Colorado in late April, before we start getting triple digit temps consistently.

I believe I will be mooch-docking for awhile longer (possibly several months). I will not buy the batteries until I MUST, but wanted to educate myself as much as possible so I know what I'm budgeting for financially, and to determine if I can do this myself for the first time .

The previous owner installed a Jupiter inverter (mounted to the side of my counter top) that is connected directly to the battery. Apparently he used it for a CPAP machine. I have not investigated the inverter yet, but I have a manual for it and believe it could be handy to have. My RV manual says that all of my outlets in the rig are already going through the factory installed inverter and i can plug regular house hold items into the outlets when I'm on shore power. I charge my phone and laptop through regular outlets in the rig, and power a small lamp while plugged in.

I'm not sure given those circumstances, why the previous owner wanted a separate inverter. The separate one has two USB ports and two outlets and an on/off switch. Perhaps he was after the USB ports, but that's a guess.

I did experience a power outage to the house where my rig is connected and was in the middle of a BIOS update on my machine. It was plugged into the separate inverter, and it had sufficient power to finish the update without interruption. Interrupting a BIOS update on an IBM laptop can permanently damage the hardware, so I was glad I chose to plug into the inverter that day.

I'm going to price some batteries and watch some videos on installing two house batteries when I have a bit more time.

Thanks again for all of the useful info; I learn something new with practically every post I read here. I appreciate all who contributed, so much!!!