battery question for boondook/solar users

so what are the amp/hr totals you are using for your battery banks? how many batteries are you using and why? in that would you want more batteries / amp hours if you could get a smaller/lighter battery with more a/hr ? what would be a average a/hr battery bank that s currently common? 200,400?
for those boondocking can you give me a idea of what your average amp draw is per/hr or per 24/hr?

esscobra said:

so what are the amp/hr totals you are using for your battery banks? how many batteries are you using and why?

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We have 3 Trojan T-1275 (12v) that have 150ah each...so total of 450ah in our system.

Here is the link to our battery setup
https://www.rvwiththetanners.com/single-post/2017/07/25/Adding-a-3rd-Battery-to-Our-RV-3

Over 10 years, we have been 100% Trojan batteries and have never had any issues. Being a BIG dry camper, this is very important to us...more so than saving a few $$$ on lower cost batteries. IMHO of course.

esscobra said:

....would you want more batteries / amp hours if you could get a smaller/lighter battery with more a/hr ?

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For now I think we are good. I have 4 Solar panels on the roof at 136w/24v/5.1amp each (in series and parallel) providing 554w/48v/10.2amp to our Renogy MPPT controller. I've seen times where the MPPT controller has converted excess voltage (which is its job) so there was ~25amp going to our batteries....very nice.


I also have a portable GoPower 120w Portable solar panel, for times, where the perfect campsite, happens to put the Bighorn in shade.

You can read about the portable solar on this blog of ours
https://www.rvwiththetanners.com/single-post/2017/08/13/We-Need-More-Power-Scottie-Star-Trek-Humor

esscobra said:

what would be a average a/hr battery bank that s currently common? 200,400?

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I had 300ah to start the season and added the 3rd Trojan this summer, get us to 450ah. I think if you 400ah or above, you're looking good. Unless you plan on using a LOT of power during the day via an inverter. BTW...you didn't ask about inverters...so I assume you have this under control. ???

esscobra said:

....for those boondocking can you give me a idea of what your average amp draw is per/hr or per 24/hr?

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Honestly, I have no clue. I just added a GoPower IC2000 (warning...NOT cheap) (click here for that blog page) that has this function, but I never had that ability before. With the solar in place, we typically start the day around 50-60% charge and by 2-3pm, the batteries are full. In 2015 we spent 21 days straight dry camping and never once had to get our portable Yamaha generator out of the back of the truck. Soooo awesome!

esscobra said:

so what are the amp/hr totals you are using for your battery banks?

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3 - 12 volt / 114 amp interstate (1)/everstart Maxx (2) batteries 342 amps total.

esscobra said:

how many batteries are you using and why?

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3 batteries Group 29/31 size, Limited by mounting space and cost.

esscobra said:

in that would you want more batteries / amp hours if you could get a smaller/lighter battery with more a/hr ?

Click to expand...

If I were stationary, I could have a "portable" battery box that contains more batteries connected via heavy duty connecter to the batteries mounted on trailer

Using Trojan batteries would increase my costs by 50% or more and increase my total capacity by about 100 Amps. A taller battery box and more tongue weight would also be issues that would need to be addressed.

esscobra said:

what would be a average a/hr battery bank that s currently common? 200,400?

Click to expand...

esscobra said:

for those boondocking can you give me a idea of what your average amp draw is per/hr or per 24/hr?

Click to expand...

I run 100% of my 12v system off my solar system and no longer use the shore powered charge controller.
I use about 600-1200 watts per day when connected to shore power and roughly the same when on battery only. A bit more in late fall/early spring if relying on furnace fore heat.

Adding a larger inverter would add using microwave capability and could potentially heat water from excess solar power.
small inverter used to power TV if necessary.

Solar system power details.
I have 9 panels x 85 watts. (765 watts total solar) My panels are 32v panels using serial/parallel connections to keep wire sizes and power losses in cabling to a minimum.

3 strings of 3 panels each allow for power generation early morning to very late in the day along with fairly shaded conditions.


This system works well to supplement when on 30 amp power as I can dedicate shore power to heat strip heating/dual air conditioning and microwave. Rarely trip breakers on 30 amp since I wouldn't have the converter or water heater using shore power competing with the hair dryer and air conditioners.

We have 6 batteries with a total capacity of 660 amp hrs. So half or 330 amp hours are usable. We have a residential refrigerator that uses about 200 amp hours in 24 hours. We use another 100 or so for incidental usage ( microwave, tv, lights, etc). This allows us to go at least 24 hrs of usage without solar or generator recharge. We have 1120 watts of solar on the roof that has allowed us to boondock or dry camp 91 days without having to run our generator very often ( about 10 times in 3 years).
For more information about our solar set up check our blog and search for solar.
hope this helps.

jrzygrl64 said:

...... We have 1120 watts of solar on the roof that has allowed us to boondock or dry camp 91 days without having to run our generator .....

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Holy Smokes....I am VERY VERY impressed. 1120w on the roof is awesome. How many controllers (MPPT) are you running? Do you have the batteries for the refrigerator in a desperate group from house battery usage?

We only have one MPPT charge controller on the solar system. Also, we have one common battery bank for the RV. We do have two inverters, a 1000watt for the fridge, and a 2800 watt for everything else. Each has their own automatic transfer switch.

We have four Crown 6v batteries, totaling 480 amp hours. I have 600 watts of solar panels on the roof, and a 30 amp Bogart Engineering solar controller connected to a Trimetric battery monitor. I'd always like to have more, but this system largely serves our needs.