I'm killing batteries -- time to go LiFePo4?

[monkeyodeath]

I think I'm at a decision point for my fridge power setup.

I've got a 300w solar panel on my RTT attached to a Victron MPPT. Only thing I use it for is an ARB Elements fridge ( the bigger one ).

I'm having issues with the fridge shutting off and the problem (I think) is the battery. My first battery was a second-hand Optima Yellowtop. Worked fine for a year and a half, but eventually I started to have issues with the battery not being able to make it through the night.

Replaced it with a Group 34 lead-acid (Costco) battery that worked fine at first, but then started to manifest the same issue after a few hot months.

I don't think charging is the issue -- I've got a huge solar panel and the MPPT logs indicate that the battery is getting fully charged really quickly. It seems that the main issue is the erosion of the battery. I have the battery-saving cutoff set on the fridge, but overnight it's still drawing down low enough to shut off the fridge entirely.

Looking through the MPPT logs I'm seeing low-end voltages of <12v for the battery, and huge voltage drop whenever the fridge runs.

I'd consider doing golf cart batteries, but the weight is a dealbreaker for me. Battleborn batteries look like an easy solution, but the price is tough for me to swallow.

Any ideas what I should do next? Is there a bigger lead-acid I can switch to? Or do I need to break down and get a Battleborn or something like that? I'm surprised that I'm having so many issues just powering a fridge, but most of my time is spent in the Southwest so I suppose that this is a part of my issue.

 

[2.ooohhh]

What temp is the fridge set at? Does the vehicle have any ventilation of the area with the fridge? You may just need to increase the size of the battery bank relative to the load. I can pull off a single battery mainly b/c I'm running a smaller 50qt arb set for conservative refrigeration(i only set it to freezer mode for occasional weekend trips). I'm not sure a single battery can support a very cold set point long term with out more reserve capacity.

 

[Hegear]

Check out sok lithium battery’s. Great reviews half the price of battle born. I think along with your solar it should run your fridge even in freezer mode with no problems.

 

[monkeyodeath]

What temp is the fridge set at? Does the vehicle have any ventilation of the area with the fridge? You may just need to increase the size of the battery bank relative to the load. I can pull off a single battery mainly b/c I'm running a smaller 50qt arb set for conservative refrigeration(i only set it to freezer mode for occasional weekend trips). I'm not sure a single battery can support a very cold set point long term with out more reserve capacity.

It's set to a bit above freezing. When I'm using it, it sits in a truck bed with pretty decent ventilation.

 

[2.ooohhh]

It's set to a bit above freezing. When I'm using it, it sits in a truck bed with pretty decent ventilation.

Hrm, looking at the specs that fridge doesn't pull much more than mine and I'm not getting near that much draw down on my battery. Can you plug the fridge into ac for a few days and monitor the battery or connect the fridge to the load output of the mmpt to be able to view exactly what it is drawing?

Concerned there may be another current draw on your battery unaccounted for.

 

[NatersXJ6]

You’ve likely cooked your battery. How much water is in it? It sounds like you probably boiled off the water from a small battery with a large solar panel.

If you upgrade to a group 31 (much bigger) battery and use the lead acid setting on the controller, and top off the water monthly, you probably won’t have any more issues. $120 at Oreilley and your good to go.

 

[Hilldweller]

I went to a LiFePo4 battery over a year ago and will never go back to other types.

I used to work for JCI back when they made batteries. I got batteries at employee prices so I didn't really take care of them; I'd typically run two 100ah Optima D31 Bluetops at a time and they'd croak after 2 years.
Then JCI sold Optima. But my wife worked for Exide. Two big Exides lasted 2 years.
sigh

The Battleborn doesn't break a sweat, recharges quickly off my 200w solar. It's just superior all the way around.
Renogy has batteries as well and they run sales. Sign up for news and they'll send you sales info and discounts.

 

[2.ooohhh]

You’ve likely cooked your battery. How much water is in it? It sounds like you probably boiled off the water from a small battery with a large solar panel.

If you upgrade to a group 31 (much bigger) battery and use the lead acid setting on the controller, and top off the water monthly, you probably won’t have any more issues. $120 at Oreilley and your good to go.

The victron is a pretty advanced solar controller, power supply, and battery charger. Set up properly it really shouldn’t cook a battery regardless of solar input.

I did find in my notes that my 75/10 had a forced firmware update a while back. Looking at logs it appears it was limiting charger output prior to the update. Once updated I went back to bulk charging at 4.5-8 amps when in the sun in the mornings. Seems to be hitting float around noon. On average.

 

[Joe917]

You need to be using true deep cycle batteries. The Costco battery is a starter battery
You need to look at golf cart or a manufacturer that makes true deep cycle batteries such as Lifeline or Rolls Surette, and you need to get them back to full charge at least once a week, more often if possible.
If weight is an issue, Lithium, and full charge does not matter.

 

[dstefan]

I went to a LiFePo4 battery over a year ago and will never go back to other types.

I used to work for JCI back when they made batteries. I got batteries at employee prices so I didn't really take care of them; I'd typically run two 100ah Optima D31 Bluetops at a time and they'd croak after 2 years.
Then JCI sold Optima. But my wife worked for Exide. Two big Exides lasted 2 years.
sigh

The Battleborn doesn't break a sweat, recharges quickly off my 200w solar. It's just superior all the way around.
Renogy has batteries as well and they run sales. Sign up for news and they'll send you sales info and discounts.

+1 on this …

Also, don't be reluctant to forget about solar and just run a fused cable back to your LiFePo battery through a DCDC charger. It beats, long, insufficient solar charges that put you at the mercy of the weather. I just camped 5 days without moving/charging or solar and used 69 ahs with the fridge going and plenty of other demands.

Here’s more details from another thread:

To update this:
Just ran my ARB 50 for 5 days, 4 nites without charging. Here’s the details:
- Battleborn 100 ah battery run down to 36%; shunt said I used 69 ahs
- Temps were low 60s at night to high 70s, maybe 80 daytime
- Fridge is in an ARB insulated cover, and I’ve also lined the cover inside with reflectix. Its in my campser shell, but open to outside air much of the day, but also closed up for hours at a time in the sun. No direct sun on fridge
- open at breakfast, lunch, dinner and happy hour, but we typically aren’t in it all the time for drinks all day
- temp set at 35° with range of 32 to 38 as it cycles, we typically put 2 to 3 warm beers in daily to cool
- shunt shows fridge took 3.8 amps consistently as it runs. Best guess is it ran maybe 15x per day for maybe 5 mins, but wasn’t counting
- also running Maxair fan all night on low (.3 amp), when cooking and other times medium to med-hi (.8 to 1.5 amps) daily
- charging 2 phones, an iPad, 2 Kindles, running a small 12v heating pad for 2 hrs, running a few small draw (< 2 amps) other devices for maybe 2 hrs total

Hope that helps! YMMV …

 

[monkeyodeath]

Hrm, looking at the specs that fridge doesn't pull much more than mine and I'm not getting near that much draw down on my battery. Can you plug the fridge into ac for a few days and monitor the battery or connect the fridge to the load output of the mmpt to be able to view exactly what it is drawing?

Concerned there may be another current draw on your battery unaccounted for.

Looking back through the MPPT logs, the fridge pulls a little more than 5A when the compressor switches on.

 

[monkeyodeath]

Spent some time looking through the MPPT logs...

I had inadvertently set the fridge to a "medium" battery voltage cutoff, 11.4V. I'm guessing that this is too low, so I set it to the "high" setting of 11.8V. Is this still too low of a cutoff voltage for a lead-acid starter battery? Looking back into the logs, on really hot days I'm seeing a daily low voltage of about 11.8V on the battery. Wondering if this alone is enough to nuke it.

Part of the reason I'm asking about this is because I left town for a couple months and had the fridge running on solar the entire time. I live in SoCal and the vehicle was parked in a sunny spot so I figured there'd be no problems keeping the battery topped off.

When I came back, the fridge was running, but at ambient temp and displayed an internal fault code.

The battery was charged and the MPPT logs didn't indicate anything odd happening with the charging in the past few weeks -- it's just that at a certain point the per-day battery load dropped off -- assuming this happened after whatever caused the fault.

I tried switching the fridge on and off -- it would start the compressor and then hit the low voltage cutoff a few seconds layer -- at least that's what the fridge display said.

What's even weirder is that I disconnected the fridge from power for 30 seconds and then reconnected it, and since then (a couple days ago) it's been working fine.

I'm assuming that it's a battery issue, as this thing started to happen pretty frequently during the waning days of my old Yellowtop. And I'm guessing that drawing it down to 11.8V regularly is too low to be sustainable. But I suppose it could be a fridge issue as well.

I know that starter batteries aren't ideal for this use case, but I had thought that a large-ish battery with this much solar capacity (battery basically always gets charged back up to 100% during the day) would be enough to run a fridge (and only a fridge) in the Southwest (i.e., cool nights). But maybe I'm wrong.

 

[pluton]

I know that starter batteries aren't ideal for this use case, but I had thought that a large-ish battery with this much solar capacity (battery basically always gets charged back up to 100% during the day) would be enough to run a fridge (and only a fridge) in the Southwest (i.e., cool nights). But maybe I'm wrong.

Starter batteries, used in a deep cycle situation, are guaranteed to fail. My experience: The "dual use" AGM batteries from reputable companies like Odyssey and Northstar work as advertised. I have a Group 34 Die Hard Platinum (actually an Odyssey) bought in 2013 and used exclusively for fridge duty and fully recharged after returning from every trip that still works. (Out of caution, I retired it in 2020.)

 

[Peter_n_Margaret]

If you are "killing" decent LA batteries, you will "murder" lithium batteries, it will just cost more.
Diagnose the issue before changing.
I run deep cycle AGMs, they last up to 9 years. But it is important to recharge LAs fully on a regular basis. Are you achieving that? I suspect you have insufficient solar. What physical size is the panel?
Cheers,
Peter

 

[monkeyodeath]

If you are "killing" decent LA batteries, you will "murder" lithium batteries, it will just cost more.
Diagnose the issue before changing.
I run deep cycle AGMs, they last up to 9 years. But it is important to recharge LAs fully on a regular basis. Are you achieving that? I suspect you have insufficient solar. What physical size is the panel?
Cheers,
Peter

Panel is 300W residential solar panel about 3.5ft x 2ft in size. Looking back at the MPPT logs, the battery is getting fully charged every day, and usually pretty quickly.