Batteries & Dry Camping

[CapeMayAl]

53 minutes ago, bobsallyh said:

Solar Bill has his weekly ad in the Yuma White Sheet for this week that came out 2-27-2018 looking like he is still there.

I'll check it out.  I had spoke to Peggy and she said they would be closing.

[CapeMayAl]

8 minutes ago, billr said:

Al,  I followed a slightly different path regarding gennys and inverters. It works good for us and install and cost is low. But it is not as convienient as what you propose. 

We use two Honda’s as well. I installed two 1000watt Pure sine wave inverters.  4 ea 6v deep cycle batts. The smaller inverters have almost zero draw in standby and use far less when running for the intended loads  

One is on dedicated fridge circuit (residential Fridge) with an auto transfer switch. 

Another powers the entertainment area with same setup. 

Remote on off inverter switches inside coach  

Also have a 300 watt dedicated to bedroom tv. 

We just use the gennys for heavy draw items as req. usually during routine recharge times anyway. If fire them up as needed   

One thing to keep in mind is whatever you pull out of the batts has to be put back with genny run time. It’s a balance  

We mansge real well and do what we need on this setup just takes a bit of thought. 

We watch TV and movies anytime with no gennys   Fridge is covered  

Our total investment incl a trimetric , wiring , fuses, batts, inverters is under $1200.  Self installed. We did find clearance priced inverters when Magnum took over Xantax. 

Did you do the install yourself?

What exactly did you put in?

I know the genny's would be needed, which isn't a problem, but figured if I had enough storage then it wouldn't need to be recharged all that often.

[CapeMayAl]

10 minutes ago, billr said:

Al,  I followed a slightly different path regarding gennys and inverters. It works good for us and install and cost is low. But it is not as convienient as what you propose. 

We use two Honda’s as well. I installed two 1000watt Pure sine wave inverters.  4 ea 6v deep cycle batts. The smaller inverters have almost zero draw in standby and use far less when running for the intended loads  

One is on dedicated fridge circuit (residential Fridge) with an auto transfer switch. 

Another powers the entertainment area with same setup. 

Remote on off inverter switches inside coach  

Also have a 300 watt dedicated to bedroom tv. 

We just use the gennys for heavy draw items as req. usually during routine recharge times anyway. If fire them up as needed   

One thing to keep in mind is whatever you pull out of the batts has to be put back with genny run time. It’s a balance  

We mansge real well and do what we need on this setup just takes a bit of thought. 

We watch TV and movies anytime with no gennys   Fridge is covered  

Our total investment incl a trimetric , wiring , fuses, batts, inverters is under $1200.  Self installed. We did find clearance priced inverters when Magnum took over Xantax. 

If you can message me or email me.

[billr]

Yes installed myself. 

If you have propane fridge you can cut out the second inverter. 

Before we had the residential fridge we used two 6v batts and did just fine. 

No matter how many batts you run you still have to put back in what you use. 

Depending on your needs for power , pocketbook and convenience needed. You can choose best route. 

[Yarome]

2 hours ago, CapeMayAl said:

...figured if I had enough storage then it wouldn't need to be recharged all that often.

Precisely! Also, implementing a charging strategy can dramatically reduce your genset runtime and subsequent fuel consumption.

You probably already know much of this, but for those that don't... bored... and reading along...

A genset is only capable of "pushing" as much current into a battery bank as the battery bank is willing to accept. As the SOC (state of charge) increases, so does the resistance. IOW, the amount of charge/current rate the battery will "absorb" decreases. Your genset in eco mode and charger may be capable of "pushing" 45amps, but the batteries may be only accepting 5. Here's the rub... you burn as much fuel and incur just as much "wear and tear" on your genset pushing 45amps to your battery bank as you do pushing 5... or 2.

The lower the battery banks SOC... the less resistance there is. IOW, you can "push" more current [slash] refill your battery bank [slash] replace AH's used much faster at a lower SOC.

How that "translates" into practical terms? It may only take you 2-3hrs of genset run time to charge your battery bank from 50%SOC to 80%SOC. However... it may take an additional 3-4hrs or more to charge your battery bank from 80%SOC to 100%SOC.

The following is simply to illustrate the principles. Ie., Take a 400ah battery bank discharged to 50%SOC. Using the (purely) example above... you're replacing 120ah's in 2-3hrs of genset time. The remaining 80ah's though might take another 3-4hrs or more... at the same rate of fuel consumption.

Here's where your larger battery bank (400ah's) pays off! If you only use 15% or so of your bank daily... call it 60-70ah's... you've got a good solid couple 2 or 3 days before it even makes sense to run your genset. Meaning... it doesn't make a lot of sense to run your genset 3 or 4 hours daily just to put back 60-70ah's (15%) when you still have plenty to hold you over a couple more days.

Point 2 comes into play. It's not necessary to charge your battery bank to 100% daily (if you don't need the ah's).

In the same example... 3 days later your battery bank is down to 50%SOC. In 2-3 hours (vs. running 3-4hrs daily to put back the AH's a little bit at a time) you can have your bank back up to 80-85%SOC. Enough for another 2 solid days of juice. Let it ride....

Point 3... in order to maintain battery health... it's not advisable to run your bank between 50%-85% long term. So a charge strategy might look something like:

Day 0- 100%
Day 1- 85%
Day 2- 70%
Day 3- 55% Run genset 2-3hrs to 85%
Day 4- 70%
Day 5- 55% Run genset 5-6hrs to 100% (But if it doesn't work into your play schedule... no harm putting if off another couple days every once in awhile.)

Rinse and Repeat. Total genset runtime: 8-9hrs.~ish vs. daily 15% top-offs at around 16+hrs.~ish. Savings? 3 full days of no babysitting duty, more than half the fuel consumption and "wear'n tear" on your genset.

In comparison: A small battery bank (or single)... call it 100ah's. @ 50%SOC you have 50ah's "available" daily. From the above example (60ah's daily) you'll need to be careful with your energy usage to stay above 50%SOC. ~3-4hrs daily genset runtime.... REQUIRED. Most folks in that boat tend to run their gensets an hour and a half or two in the morning and again at night. Which is rather smart since they also tend to make better use of the excess (above what is required to recharge their batteries) genset output by running their coffee makers or such off it in the morning or their induction hotplates at night without having to cut into their battery bank.

Where solar comes in? A sufficiently sized array over... say 5hrs of solar production... can have your 400ah bank back up to 100%SOC by late morning... early afternoon... and still have plenty of excess production to charge your electronics or such...  daily. No babysitting or fuel consumption. During poor weather or times of excessive power usage... kick the genset over a couple hrs to bring your battery bank back up to 80-85%SOC and then let your panels finish the job.

The advantages of a large battery bank in that case is "wiggle room". In a camp spot with limited sun exposure... you've got a few days before you need to worry about a genset. A few overcast days? Meh... who cares? 

* Inevitably, somone is going to come along and mention that dropping your batty bank to 50%SOC will reduce lifecyces. In another thread I already let the cat out of the bag on how I feel about that. Let's just say that "lifecycles" have no bearing on AH life capacity" of a battery... and leave it at that. 

[bigbillsd]

Before you spend anything you need to figure out what you pull out of your batteries every night.  That will allow you to specify your inverter and batteries to supply them power.   I tested it all out during  a week at Quartzite a few weeks back during the big show.  I was pulling out around 170 amp hours from 6pm to 8am.  I had put in 4 crown 265 amp 6 volt wet CR-265's  So I was pulling out about 30% of the charge each night.  This included heat in the morning, a few hours of 40" TV per night pulled off the DVR.  Led lights on a lot.  Kurig in the morning along with a couple pieces of toast.  

The batteries were approx $800, I installed them.  The Magnum MS2812 PSW inverter was $1500 from Imarine.  I had to buy a small circuit breaker box and hook it up to the outputs of the inverter,  box, breakers, wire and split loom maybe $100.   But I did all the work myself.  Took time, but was fairly simple.  Figure $100  for all the 4/0 cables for the battery interconnects and connections to the inverter.  Plus a bit for a battery disconnect switch.  I found the difference from the 220 amp 6 volt deep cycle to the 265 deep cycles was $16 each.  I went with the larger.  I also sprung for a Bogart Trimetric to monitor the use and replenishment of the batteries.   -Bill

 

[Yarome]

9 hours ago, bigbillsd said:

Before you spend anything you need to figure out what you pull out of your batteries every night.

Exactly!

Great example of a very solid "backbone" electrical... and, as noted, it doesn't necessarily have to break the bank even for upper end gear/components like Bill's to give you an extraordinary amount of self sufficiency if you're the type that appreciates time off cord.

These days, with the internet, there are so many readily available resources that self-installs are a practical and highly cost effective option for just about anyone. Not to mention the benefits and cost savings of being able to troubleshoot and service a system you are intimately familiar with.

Just a "plug" on imarine (no affiliation). Their selection isn't always the best at any given time but are good at stocking decent "core" selections. Offerings rotate often, very well priced, and when you can get them, their refurbs over the years have proven to be reliable performers. 

[CapeMayAl]

I definitely like the DIY route.  I wired an addition in my home - for a 18x20 room - sun porch etc, after the framing rough in.  Passed on the 1st inspection :).

I just don't know about the right way to do it.  

If there are instructions out there it would be great.  It might take some time, but I'm sure I can muddle through it.

The only thing that might make my pea-brain dumber than it is, is to turn the inverter on/off on the install I've been quoted.  They're not using a sub-panel.

If you can point me to a website that would give install directions it would be great.

Thanks, 
Al

 

[Yarome]

47 minutes ago, CapeMayAl said:

If you can point me to a website that would give install directions it would be great.

Jack Mayer's RV electrical pages/write-ups is a good place to start.

[CapeMayAl]

Yes, Jack's site is a great place.

I've read it numerous times.

Al