Battery upgrade, maybe solar option also

[Quint_Da_Man]

Trying to learn a little bit about battery upgrades including a solar option.

I have a 2020 Thor Class C, it has 2 house batteries. Last year we joined Harvest Host and did a little more boondocking than usual. I found that the house batteries seem to drop below acceptable levels in about 4 or 5 hours of light duty use (TV and a few lights for a couple of hours). What happens is all the electronic devises hooked up to the battery system I.E. CO2, Leveling system, Fire alarm all start beeping at around 2am. The only thing that is running after around 10pm is the refrigerator and those smaller electronic devises. I've researched lithium battery upgrades and that doesn't seem to be an option because of their limitations in cold weather (below 40 degrees). I live in Massachusetts and early spring late fall camping have many a night below freezing. Another option from my under standing would be AGM batteries these seem to be better than standard batteries but not as good as lithium. I have also had priced out a solar option. My rig is solar prepped so the upgrade would be 4 AGM batteries and two 150w solar panels for about $4500.00 installed. That was a lot more than I expected. Now I'm thinking about maybe just upgrading to 4 AGM batteries and hope they will hold charge at least long enough to get through the night.


I'd love to hear peoples ideas, and options, things they have done. We plan on doing a hell of a lot more boondocking in the near future so would like to resolve this issue.


Please educate me.


Thanks

[otrfun]

Veebyes wrote:
No question in my mind now, lithium is the way to go however it is is still a bit on the pricey side for our frequency of dry camping.

Given a budget to work with for upgrades I would spend the money on the battery bank size, a multi stage charger & an inverter generator before solar.

I am currently on my second AGM battery, a 4D case size with about 215amps, in fourteen years. I have the programable charger, pure sinewave inverter & an inverter generator which works day or night regardless of weather, something solar does not do.

The key link is the useable size of the battery bank & how much you are prepared to pay for it.

I'd say you've definitely gotten your money's worth out of your 4D AGM's! You've obviously taken very good care of them.

We're high ah users. Power the microwave several times a day, along with the a/c on summer travel days with our battery. Based on the limited real estate on top of our truck camper, plus the fact we've only needed our generator for a supplemental battery charge 1 time in 2 years (our dc2dc charger gets a lot of use), we, like you, haven't made solar a big priority for now.

After replacing 2 GC2's with a lifepo4 (200ah DIY; $750) a year ago---can't imagine ever going back to lead-cell again. 1/2 the space, 1/3 the weight---plus more than double the useable ah's with low to moderate loads. Amazingly, we're experiencing closer to triple the useable ah's powering high loads (>110a). 2 GC2's experience high voltage drop under high loads which can reduce inverter run-time. Lifepo4's have superior voltage stability under high load which nets you max inverter run-time.

[3_tons]

Quint Da Man wrote:
Very interesting video on an extensive test of AGM vs Lithium batteries.

Enjoy

Testing RV Batteries

Except that it won’t make the hardened Luddites all too happy :), the presenter pretty much demonstrates empirically what many former lead-acid, now turned LFP users have already figured out, whether intuitively or if by means of real-world experimentation…

Yet, the presenter overlooked as well that LFP’s are far better suited at exploiting critical solar peak harvest hours…However (unless I misunderstood…), I don’t get the presenter’s assessment on the built-in heater option which in my mind ought to only kick in when there’s a concurrent charging source, especially since even non-heated LFP’s will continue to discharge down to about -4 f…

I sensed too that he may have had a ‘post-results’ bias, though I also believe his testing and findings are realistic, and from my perspective mostly a reflection of the real-world - JMHO

3 tons

[otrfun]

Very nice, EMD360! No doubt doing it DIY made it especially rewarding. Any plans to add another Lion or two?

[EMD360]

I added all the power upgrades. 360 watts solar, Progressive Dynamics 9160 charger/converter, Progressive Industries power protection, Victron MPPT 30 amp solar controller, transfer switch, Renogy DC to DC converter and two Lion energy 105 amp hour batteries. Then I installed a 3000 watt Samlex inverter. I wanted enough wattage to run the microwave comfortably. According to the rules I don’t have enough batteries for 3000 watts but we only run it briefly. Also added the Victron battery monitor and the Victron WiFi remote reporting device-Cerbo. Then I splurged on a hot spot for the RV and a temp stuck to monitor the battery compartment. Several lithium battery monitors just cut off charging if too cold. The Lions stop charging below 32°. I also have a battery warming pad that I can plug in if it really gets cold. We drove down through Colorado and New Mexico last week and didn’t worry about the battery power at all. Temps got into the teens one night and 20’s another two before we got far enough south. I did all the install myself and the total cost was about $5000.

[Veebyes]

No question in my mind now, lithium is the way to go however it is is still a bit on the pricey side for our frequency of dry camping.

Given a budget to work with for upgrades I would spend the money on the battery bank size, a multi stage charger & an inverter generator before solar.

I am currently on my second AGM battery, a 4D case size with about 215amps, in fourteen years. I have the programable charger, pure sinewave inverter & an inverter generator which works day or night regardless of weather, something solar does not do.

The key link is the useable size of the battery bank & how much you are prepared to pay for it.

[Quint_Da_Man]

Very interesting video on an extensive test of AGM vs Lithium batteries.

Enjoy

Testing RV Batteries

[Lwiddis]

“Misconceptions” is an interesting video, Wizard. Since I avoid colder camping (below 32F) I am not affected much by that Lithium limitation.

[Quint_Da_Man]

theoldwizard1 wrote:

Quint Da Man wrote:
I live in Massachusetts and early spring late fall camping have many a night below freezing.

2 recent videos from Will Prowse.

CHINS $579 12V 100Ah, with heaters: Actually impressive!

LiFePO4 Cold Temperature Misconceptions: Do you really need internal heaters?

Excellent video's thank you....

[Quint_Da_Man]

otrfun wrote:
If I were in your shoes, I'd want to do some kind of energy audit before going any further. I'd want to know how many ah's equate to "4 or 5 hours of light duty use". This data would help size any future system. Plus, it would be the perfect time to verify there are no high current parasitic situations drawing down your batteries excessively. You'd definitely want to rectify that problem before proceeding.

Have you had your 2 house batteries load-tested? Bad cells in relatively new batteries is not unheard of. It takes a fair amount of current, roughly 20-25a, to draw down two properly charged mid-sized, Group 27 12v batteries to 50% SOC in 4 or 5 hours. If you're hearing alarms, odds are the batteries are being discharged much lower than 50% SOC. This significantly reduces their longevity, ah capability and compounds your problem. Unless you're powering a residential fridge or some other higher current device, something doesn't sound quite right.

A voltmeter and a clamp-on DC ammeter would help answer all these questions in relatively short order.

Thanks for your input and suggestions.

There may very well be parasitic drain that I am not aware of I'll take a look at that.

I do have a residential refrigerator and a couple of monitoring devices (about 10 watts a piece)that are a continuous drain. Refrigerator is a single door style with a top freezer and ice maker I estimate about 1kWh per day.

I can pull the batteries and do a load test that's the only way I'll know if they are being fully charged.

[theoldwizard1]

KD4UPL wrote:
A group 31 AGM is about $350 each.

A pair of 6V golf cart batteries from Sam's Club or Costco cost about $200 and will have as much or more energy storage as those Group 31.
Tes, you have to add water.

[theoldwizard1]

Quint Da Man wrote:
I live in Massachusetts and early spring late fall camping have many a night below freezing.

2 recent videos from Will Prowse.

CHINS $579 12V 100Ah, with heaters: Actually impressive!

LiFePO4 Cold Temperature Misconceptions: Do you really need internal heaters?

[otrfun]

Quint Da Man wrote:
. . . I have a 2020 Thor Class C, it has 2 house batteries. Last year we joined Harvest Host and did a little more boondocking than usual. I found that the house batteries seem to drop below acceptable levels in about 4 or 5 hours of light duty use (TV and a few lights for a couple of hours). What happens is all the electronic devises hooked up to the battery system I.E. CO2, Leveling system, Fire alarm all start beeping at around 2am. The only thing that is running after around 10pm is the refrigerator and those smaller electronic devises . . .

If I were in your shoes, I'd want to do some kind of energy audit before going any further. I'd want to know how many ah's equate to "4 or 5 hours of light duty use". This data would help size any future system. Plus, it would be the perfect time to verify there are no high current parasitic situations drawing down your batteries excessively. You'd definitely want to rectify that problem before proceeding.

Have you had your 2 house batteries load-tested? Bad cells in relatively new batteries is not unheard of. It takes a fair amount of current, roughly 20-25a, to draw down two properly charged mid-sized, Group 27 12v batteries to 50% SOC in 4 or 5 hours. If you're hearing alarms, odds are the batteries are being discharged much lower than 50% SOC. This significantly reduces their longevity, ah capability and compounds your problem. Unless you're powering a residential fridge or some other higher current device, something doesn't sound quite right.

A voltmeter and a clamp-on DC ammeter would help answer all these questions in relatively short order.

[Lwiddis]

“A group 31 AGM is about $350 each.”

A 200 amp hour Lithium is priced below $700. See…

https://www.amazon.com/LOSSIGY-Maintenance-Free-Perfectly-Batteries-Application/dp/B08S7799BD/ref=asc_df_B08S7799BD/?tag=hyprod-20&linkCode=df0&hvadid=485450968700&hvpos=&hvnetw=g&hvrand=16993605537789544832&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9031138&hvtargid=pla-1156127055106&psc=1

[2oldman]

KD4UPL wrote:
I don't believe lithium is worth the money for most people

In the long run it may be, but it's the up-front cost that's the scary part.