A122S Battery/Solar issue?

[Quest3]

Hi everyone,

I have a 2022 Rockwood A122S that I purchased new in February 2023. Before taking delivery, I had the dealership install a WEIZE 12V 100Ah LiFePO4 lithium battery (purchased separately from Amazon).

On our most recent trip, the battery ran out of power on the third day at the campsite. We had partial sun each day (temps around 75°F during the day and 50°F at night). We tried to minimize power usage:

• The fridge was running continuously.
• Lights were used briefly once or twice.
• The water pump was used sparingly for washing dishes (and turned off between uses).
• The radio was always on, but muted (I don’t see a way to turn it off completely).
• After detaching from the tow vehicle, the battery was used to adjust the trailer height.

The trailer was plugged into shore power for several days before we left, and it was connected to the tow vehicle during transport.
This performance seems consistent with what we experienced on previous trips.

My questions:

• Is it normal for a 100Ah LiFePO4 battery to run out this quickly under these conditions?
• Could there be an issue with the solar charging, the battery itself, or something else I'm missing?

Thanks in advance for any advice or troubleshooting tips!

 

[tomkatb]

Yes, it is the math.

Not likely.

Without knowing the size of the solar panel everything is a guess.

You have a 100 amp battery. Likely you have a compressor fridge. Thus you are likely using near 100 ah of battery per day. The numbers are all over the map. Study up on your usage.

Solar panels on the roof in the Midwest produce 25 ah per day per 100 watt panels. On their best days! Not everyday. Trees, clouds and rain are the enemy.

So you need more battery and panels likely. A second battery would be the cheapest step. We have 412 ah of battery. No solar.

 

[TacomaJoe]

X2, simple math. You have 100Ah of capacity. If you use 80Ah running things and add 50Ah from solar, you will have a net 30Ah loss. Three days of that and its dead. Adding a shunt will give you the real numbers rather than my guess.

Adding more battery is the quick fix.

 

[Aussieguy]

Get a solar suitcase to add to your charging

Or a small 1000w generator

I Get about 3 days from my 200ah battery so you are doing good

If you want to look at adding a second 100ah battery… you can add one anytime …. just gotta find the room

 

[pgandw]

In addition to what was already mentioned, you apparently have no worthwhile battery monitor to know how much charge you have.

I just bought my first LiFePO battery for my 2019 Flagstaff A-frame. I had had 2 GC-2 batteries previously, but these wouldn't hold a charge anymore (after 6 years).

I bought a 160AH off Amazon ($216 - cheaper than a pair of GC-2s and 70lbs lighter), and installed just before a camping trip last week. It did have Bluetooth (I would not buy a lithium battery without it) and I put the app on my phone to read battery charge and what was happening. Came with a 50% charge. Arrived at the campground still showing 50% charge. I also downloaded the Overkill app to compare, both gave same readings which I assume is what the BMS tells them.

Plugged into shore power with a non-lithium compatible converter. The converter never went above 13.4 volts. Battery charge was very slow, eventually reaching 90% after 12 hours - actually a little better than expected. Turned the battery off (I had long ago installed a battery cutoff switch), converter went to 13.1 volts.

On the way home, thanks to remote thermometer I carry in car with send unit in fridge, discovered propane regulator hose had busted, and my tank was empty. Switched to other tank, but regulator wasn't working enough to keep fridge running on LP. Switched to DC mode, which drew 16 amps from battery on the app. With vehicle running in idle, draw was reduced to 7.7 amps. With only 2 hrs remaining to home, I wasn't worried either way. So ended trip with battery at 72%, where it will stay until next trip.

I am not interested in solar, thanks to camping in shade whenever possible and don't want more weight to lift on the roof either. Am researching about balancing and charging rqmts for longest battery cycle life - internet advice is all over the place. Best I can make sense of is operating between the knees (20-80%) reduces need for cell balancing, and gives most cycles.

Will invest in another battery (same make and model) for the 19ft sailboat, and a portable 20A charger to take care of both batteries. The boat will also probably receive a 100 watt folding solar panel, but there's almost always some shading on a small sailboat. The battery will be able to recharge the battery of my electric outboard at least once during a trip, as well as power lights, phone (my navigator), fan. Solar may give a little back. Looking to use a 24v panel to minimize effect of shading on charging.

just my experiences
Fred W
2019 Flagstaff T21TBHW A-frame with PD-4135 converter
2022 Hyundai Palisade

 

[Quest3]

I appreciate all the responses.

The panel was already installed when I bought it. It measures about 4' x 3'.
The fridge is an Everchill 1.7 cu ft, model BC-47-04H .
Solar controller is a Go Power model GP-PWM-10-SQ .
Currently the panel is about 3/4 obscured by the tree over it and it is indicating it is in 'Absorption Charging' mode, '13.2 V', 0.5 A, and 4.8 Ah.

All of that might not make a difference to the already posted responses, but just in case.

 

[pgandw]

I appreciate all the responses.

The panel was already installed when I bought it. It measures about 4' x 3'.
The fridge is an Everchill 1.7 cu ft, model BC-47-04H .
Solar controller is a Go Power model GP-PWM-10-SQ .
Currently the panel is about 3/4 obscured by the tree over it and it is indicating it is in 'Absorption Charging' mode, '13.2 V', 0.5 A, and 4.8 Ah.

All of that might not make a difference to the already posted responses, but just in case.

There's your answer. You are charging at 0.5A (4.8AH per hour) and drawing 5A when the fridge is running. A 100 watt panel will put out 40 watts in the sun. You might hit 60 at noon, and nothing when the sun gets low. Again this is in the sun. The panel can't possibly replace what you are using - on the order of 60-70AH per day.

I have worked and made mods so that my A-frame uses about 20AH per day minimum (with fridge running on propane). Propane heater fan is the biggest user of battery. Stereo was a surprising 2nd, I had to install a switch to turn it off completely.

A 12V fridge is a power hog, a 100W panel is not really enough to support it for more than a few days.

Fred W
2019 Flagstaff T21TBHW A-frame

 

[Quest3]

There's your answer. You are charging at 0.5A (4.8AH per hour) and drawing 5A when the fridge is running. A 100 watt panel will put out 40 watts in the sun. You might hit 60 at noon, and nothing when the sun gets low. Again this is in the sun. The panel can't possibly replace what you are using - on the order of 60-70AH per day.

I have worked and made mods so that my A-frame uses about 20AH per day minimum (with fridge running on propane). Propane heater fan is the biggest user of battery. Stereo was a surprising 2nd, I had to install a switch to turn it off completely.

A 12V fridge is a power hog, a 100W panel is not really enough to support it for more than a few days.

Fred W
2019 Flagstaff T21TBHW A-frame

I appreciate your response. Watts, Amps, Amp hours, volts; has always confused me, but I think I get the overall point. At best I am delaying things with the panel, it will never keep up. I'm looking at adding more battery, a second 100 or a 160 to get me to 200 or 260?

 

[pgandw]

I appreciate your response. Watts, Amps, Amp hours, volts; has always confused me, but I think I get the overall point. At best I am delaying things with the panel, it will never keep up. I'm looking at adding more battery, a second 100 or a 160 to get me to 200 or 260?

Your understanding is correct. You are using more power than your solar panel can give back.

Adding a battery doesn't solve the problem, it just delays it. When I was figuring how to address this problem I started with - how many nights am I going to camp without shore power? The answer to this question drives the response.

In my case, I wanted 4 nights/5 days in Colorado with nights in the 40s and days in the 70s. I needed to be able to run the propane heater for 4 hrs/night (50% duty cycle drawing 5A when on). I figured that food and water in the A-frame would run out after 5 days. Turns out my figures were off - the heater only uses about 3A when running, but the vent fan on those sunny, warm afternoons using 1.7A running on low made up for it. In any case, it worked out - 80AH of battery would get me through 4 moderately cold nights. With deep cycle batteries, 2 Group 24 would give me 160A and the ability to keep the batteries above 50% most of the time. Back then solar was really expensive, and I didn't want to bother with it.

What also proved true was that DW had no interest in camping without power and showers for more than 4 nights. I switched to 6V GC-2 golf cart batteries which gave me a little extra reserve. I also became the power police when we were going to stay 4 nights without shore power, which further hardened DW's resolve to move on after about 2-3 nights if there was no shower or shore power.

You need to find out how many amps your fridge actually uses, and how many hours/day it is running. There is your daily AH requirement plus 16-20 AH for ghost loads (CO detector, occasional lights, occasional water pump). With your daily AH need known, plus number of days without shore power, you can size your battery and solar requirements.

Fred W
2019 Flagstaff T21TBHW A-frame
2022 Hyundai Palisade

 

[Colorado-A-Frame]

Fred is on it! One thing that’s been mentioned, but is probably most important is knowing what your battery consumption is. While the lithium batteries have onboard BMS (battery monitoring software or system) the cheaper batteries don’t have the best monitoring…a good battery monitor shunt will tell you a lot. For example I have a low parasitic draw that’s less than 1 amp…the on board battery BMS doesn’t see it but my Victron battery monitor does…as a result there is a large discrepancy between the 2…if I trusted the battery info I’d have much more remaining battery life than is actually truly available.

 

[Quest3]

Really dug into the topic more after reading your responses. I'm going to relocate the existing 100AH and a new 160AH battery to the space under the bed. Will run them in parallel for 260AH. That, along with the sola, should be sufficient for almost any camping situation I tend to do. I'm also adding a shunt and negative bus bar. When I have more time I will reground everything to the bus bar, but for now that should at least give me decent information on overall battery power. Also adding a switch to the radio.

 

[pgandw]

Don't hook unequal batteries in parallel. They need to be as matched as possible - manufacturer, age, model, capacity, etc. If an imbalance occurs, the good battery flows into the lesser battery. If the parallel cables don't have a fuse, the cables and the batteries can be melted down if the imbalance reaches more than 0.5V. I've had a battery compartment fire with parallel lead acid batteries. For the record, hydrogen burns the prettiest blue I have ever seen - just don't ask me how I know. The fire is also why I was using 6V golf cart batteries in series instead of 2 Group 24s in parallel. Hopefully, the BMS would shut an LiFePO battery down before serious damage was done - but that's the last line of defense. First defense is avoiding mismatched parallel batteries, second is proper fusing in the connecting cables.

You can switch one battery out for the other, but not run them in parallel.

I would see just how much you actually camp without electric, and for how many days at a time before investing a lot more. I have no solar, and don't want to deal with the panels. And my fridge runs on propane when there is no shore power. So a 160AH LiFePO battery gave me more power without recharge, cost less, and weighed less than the 2 GC-2 batteries it replaced. The GC-2s were adequate before they got old (7 years) and wouldn't hold a charge.

What you have lasts at least 2 full days. A second 100watt solar panel might be enough to get you fully recharged during the day. Or a portable generator as a backup when there is not enough solar - 10 years ago, A-frame owners sometimes carried a Honda or Yamaha 2000w generator to recharge battery and run the A/C. All depends on your camping style.

just some thoughts and experiences
Fred W
2019

 

[Aussieguy]

Lifepo4 can have different capacity batteries together
as long as the power usage is small. Giving the two batteries enough time to equalize

BUT

It’s best not to do it as you can have problems if your demand on the bank suddenly increases
Better to keep things equal wherever possible

Rule of thumb
Battery Capacity of around 3 days is good

Use enough panels to replace the power used from the battery the night before, by around 2 pm.

If you can get that balance you can survive on 12v quite well

A good starter system for 12v camping
200 ah battery 600-800w panels

 

[pgandw]

A good starter system for 12v camping
200 ah battery 600-800w panels

There isn't room on an A-frame for that many panels.

Fred W

 

[Aussieguy]

Yup no room
but that is what is needed for average 12v use

200 w on roof
2x200w ground panels?

If you can use less power…. You could shrink it a bit

If you use more power …. Expand it

Totally dislike the manufacturer’s 200w approach
where people often think (or lead to believe) that is enough ….
Only to get disappointed and blame the solar.

One day manufacturers will install a true starter system that actually works for camping
All they got to do is add a couple more panels and a semi decent controller