Test Deep Cycle batteries capacity/condition, and what replacement/upgrade?

[JoshH1]

The group 24 deep cycle battery that came in our camper is about 5 years old now. I'm about to do a trip off grid soon and I want to make sure the battery will hold up. I have a 100 watt solar panel for charging during the day, and my use at night will be minimal. Mostly I want to keep the refrigerator running on propane (it does require a small amount of electricity for the electronics), the water pump for flushing the toilet and washing my hands, and possible occasional furnace use if it gets cold at night.

I've been fine in similar conditions with this solar panel and type of use, never had the battery go dead during the night, however it has been a few years since I've done this, the battery is older now, and the battery has been completely drained a couple times which I know is not good for it.

Is there an easy way to test the batteries capacity and see if it is still performing? Or would I be better off just replacing it?

If I do replace it I'd like to upgrade it. Any suggestions? I've seen Lithium type options.

Will my charger on the camper handle different types of batteries OK?

Will any type of battery handle solar charging OK? I have a solar charger regulator.

The battery box is a group 24, I would consider a larger box as well.

I don't want to get too carried away on price but I'd be willing to spend a decent amount for an upgrade in capacity and having the ability to completely discharge the battery without damage would be nice.

Thanks!

 

[Gary RV_Wizard]

At age 5 I'd just replace it. If you manage to eke out this trip. it probably won't make the next one anyway.

Assuming it's a flooded cell type with removable caps, get a simple battery hydrometer to check the Specific Gravity in each cell. A fully charged cell should read 1.27-1.28. Much less than that is no good. A less accurate but easier check is to measure the voltage with the battery at rest (no charging and no load). Should be about 12.6v.

 

[Mark_K5LXP]

Is there an easy way to test the batteries capacity and see if it is still performing?

Yes, but agree with Gary that its best years are behind it. If you're the curious type you could run a capacity test anyway just to become familiar with the process, and see where this battery sits.

Lithium batteries check a lot of boxes but if your camper is set up to operate with lead acid, then there might be more to installing one than a battery R&R. Just prior to a trip wouldn't be the time I would do a refit of disparate components, and go on the trip based on faith.

The make/model of the solar controller would dictate compatibility with different battery chemistries.

Group 24 is a pretty small battery for cyclic use. Group 27 and group 31 would offer more energy storage options.

Mark B.
Albuquerque, NM

 

[Kirk]

Group 24 is a pretty small battery for cyclic use. Group 27 and group 31 would offer more energy storage options.

I absolutely agree with this statement. I would probably not bother with taking the hydrometer readings since your battery is clearly near the end of it's life but I would just replace it. I would also suggest that you at least upgrade to an AGM battery of Group 27, if not going to lithium. Of the things that you mention, the furnace is by far the most power using and especially so if it runs often.

 

[Henry J Fate]

If you are mostly without any plug in power or just want to be as energy independent as you can be, a lithium upgrade will make a large difference in both charging and discharging. Upgrading your solar to at least 200 watts will complement the lithium upgrade.

If you choose to go lithium and time is short until departure, you may want to consider getting by with what you have and do the switch when there is a better opportunity.

If you have a generator, it is good to fire that up first thing in the morning to get the bulk of charge to the batteries. Solar can spend the daylight hours bringing the batteries up to a higher level or to full charge. This is good practice for flooded cell batteries.

 

[SpencerPJ]

If you are about to go on a trip, I'd go to Walmart, buy a deep cycle group 27 and box, come home install it, charge it, and go on your trip. Many better options, lithium, more solar, sky is the limits. When you get home, fully charge battery and disconnect ground until next trip, it will help immensely saving the battery from parasitic draining.

 

[John From Detroit]

I agree replace it and go with LiFePo4 Your battery is about 75 AH and about 25 you can use without killing it dead


Even if the converter does not get the Li type up to 100% (it will get close but not clear full)
One: Recommended you only charge to around 80-90% and 2: 80% of a 100 AH LiFePo4 is like 3 times the usable power of a Group 24 Lead Acid.

You might wish to replace the converter if you upgrade (unless it's adjustable. some are)

 

[RayIN]

Interstate Battery stores will load-test the battery for free. It must be fully-charged when tested, and have been "at-rest" for 1 hr after removing the battery charger.

 

[workinonit]

I think the chain auto parts stores will too.

 

[Mark_K5LXP]

Only problem with that plan is a transient load test will not give you merit of a storage battery. There are some tests (I think USBattery shows one online) of a high draw test and recovery period but this is more of a go/no-go test for weeding out stinkers in fleet applications. As a battery ages it's internal impedance will go up which will limit high amp draws but it can still have useful capacity at more tepid (and typical) extended levels. Generally if one suspects a battery to the point of desiring to test it, the ship has probably already sailed so it's my practice to test capacity at regular intervals to ascertain when things might be starting to go downhill, rather than plug merrily along in ignorant bliss until the fateful day I wake up to a cold dark RV. In the middle of a long trip. Far from a battery dealer. With a cranky DW. There are enough other reasons the DW gets cranky, this is one you can prevent.

Mark B.
Albuquerque, NM

 

[Mark_K5LXP]

Your battery is about 75 AH and about 25 you can use without killing it dead

80% of a 100 AH LiFePo4 is like 3 times the usable power of a Group 24 Lead Acid.

We have no idea what battery he has or what shape it's in. The DoD and "usable" claim is arbitrary, based on application constraints that likely don't apply in this, or most use cases. Yes, lithium is better in many respects but you're painting a picture of lead acid that doesn't allow for reasoned comparison.

Mark B.
Albuquerque, NM

 

[JoshH1]

Well there is no longer a need to test the battery. We took a trip this weekend and used a site with full hookups. On the way home I was running the fridge from propane and we stopped for dinner. After eating I got in the fridge to get some drinks before hitting the road again and I noticed the light in the refrigerator was blinking, and when the light in the refrigerator came on the light I turned on in the camper got dim, so the battery is certainly bad. Surprisingly the burner on the fridge kept right on going despite the low voltage which was nice to see. I'm guessing the blinking light is a low battery warning?

How can I tell if the charger system on my camper will handle a lithium battery? I have about a month before I leave on my trips so I have some time, since I know I will have to replace the battery I'd like to go with lithium but not if it means replacing the entire charging system on my camper. If that is the case I'll probably just go with a group 24 deep cycle for light use and perhaps get a lithium battery with it's own charger I can take with me on longer off grid trips.

Thanks everyone for your replies.

 

[Tulecreeper]

Well there is no longer a need to test the battery. We took a trip this weekend and used a site with full hookups. On the way home I was running the fridge from propane and we stopped for dinner. After eating I got in the fridge to get some drinks before hitting the road again and I noticed the light in the refrigerator was blinking, and when the light in the refrigerator came on the light I turned on in the camper got dim, so the battery is certainly bad. Surprisingly the burner on the fridge kept right on going despite the low voltage which was nice to see. I'm guessing the blinking light is a low battery warning?

Since your fridge was running on propane, the battery has nothing to do with keeping it going. Once it gets up to temp the only thing you would need the battery to do it provide enough juice to spark the ignition the next time it needs to light off and even a 'dead' battery can do that.

 

[Henry J Fate]

Since your fridge was running on propane, the battery has nothing to do with keeping it going. Once it gets up to temp the only thing you would need the battery to do it provide enough juice to spark the ignition the next time it needs to light off and even a 'dead' battery can do that.

Usually a minimum voltage needs to be realized at the control board. If voltage drops below the minimum, the fridge will shut down.

 

[Henry J Fate]

Well there is no longer a need to test the battery. We took a trip this weekend and used a site with full hookups. On the way home I was running the fridge from propane and we stopped for dinner. After eating I got in the fridge to get some drinks before hitting the road again and I noticed the light in the refrigerator was blinking, and when the light in the refrigerator came on the light I turned on in the camper got dim, so the battery is certainly bad. Surprisingly the burner on the fridge kept right on going despite the low voltage which was nice to see. I'm guessing the blinking light is a low battery warning?

How can I tell if the charger system on my camper will handle a lithium battery? I have about a month before I leave on my trips so I have some time, since I know I will have to replace the battery I'd like to go with lithium but not if it means replacing the entire charging system on my camper. If that is the case I'll probably just go with a group 24 deep cycle for light use and perhaps get a lithium battery with it's own charger I can take with me on longer off grid trips.

Thanks everyone for your replies.

Voltage readings at the battery bank should be over 13 volts minimum if the battery bank is charging. In the 13.5 - 14 volt range. You must be plugged in to power for your charger to be sending charge voltage to the batteries

Your charger will charge a lithium battery but may not be able to do it to the highest standards. Post the make and model number of your charger for more accurate info

 

[Mark_K5LXP]

x2 converter make/model.

Do you have a battery monitor? Seems you got pretty far down this road unaware.

Mark B.
Albuquerque, NM

 

[John From Detroit]

Since your fridge was running on propane, the battery has nothing to do with keeping it going. Once it gets up to temp the only thing you would need the battery to do it provide enough juice to spark the ignition the next time it needs to light off and even a 'dead' battery can do that.

The Battery powers the fridge control system. It lights the flame. Opens the gas valve so yes the battery DOES operate the fridge.

To the O/P. for now the major difference is the LiFePO4 needs a bit more voltage to fully charge. So your converter may not bring it to FULL (some folks recommend not bring it to Full anyway) Now some converters. (Progressive Dynamic) I'm not sure of.


I found this article

https://www.power-sonic.com/blog/how-to-charge-lithium-iron-phosphate-lifepo4-batteries/

If you have a modern 3-or 4 stage charger Or even a 2 stage charger. I do not think you will have a problem. but an upgrade (Progressive Dynamics makes one specifically for Li Batteries and some are adjustable) it might be better.

For the record I looked up the Charge Wizard profile.
BOOSE 14.4 This is the highest voltage (And is less than the 15 "Max" for Li)
Normal 13.6 Dead match for LI
Storage 13.2 (After 30 hours of non use)
But it pops back up to 14.4 every 20 hours or so for 15 minutes to equlize/desulfate. If I'm reading the linked article correctly this should be OK

But you will not be filling the battery to FULL.

My phone limits charging to 80%

 

[JoshH1]

So it looks like the charger is a WFCO WF-8955PEC

 

[JoshH1]

Accidently hit send too soon.

https://www.wfcotech.com/shop/power-centers/wf-8955-power-center-3/

https://www.amazon.com/s?k=wfco+wf-...09&tag=googhydr-20&ref=pd_sl_4ee38p7i8y_e_p67

 

[Kirk]

I am thinking that you have this one.