Battery with solar vs dual battery

[jay see]

As per Ronin post.

What are your thoughts/ideas on this.

[AB]

As per Ronin post. What are your thoughts/ideas on this. both unfortunately mate, both!

You have two types of camping which is touring and boys weekends of driving each day where the dual battery system is essential and the family long stay camping trips where you are set up for many days.

I have been camping on the Murray for many years for weeks on end and watch people drive around in circles and sit their cars idling for hours every year to charge their second battery off the alternator.

[mudski]

Yeah i got both, in the car and in the camper. If you rely on battery power, you need a charging source other than an alternator in my opinion.

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[Ronin]

if someone is driving everyday then the crank battery is getting charged by the alternator.. with out depleting to dangerous levels ?

although I am still working on my setup , so I could end up like one of those ideling up to charge the second battery or end up with a flat crank battery :)



PROs

- Simplicity: no mucking around as its easy DIY (dont need auto leccy)

- Cost savings: the whole thing would cost me about 350 as compared to about atleast 500 to 1000 for battery isolator and other bits and pieces and even more if I go for a decent BMS. More money if installed by a auto leccy. Dont need massive AH battery.

- Long runtime: Potentially unlimited run time with decent sunny days and correct placement.

- Future proof: Can add a dual battery system down the line if I feel the need and wont have to throw any existing bits away.

- Light weight dont need super massive battery for this setup.

CONs

- cant wire up accessories like UHF or light bar to it easily.

- needs manual cut over from crank battery to the spare deep cycle when u reach camp site.

On a average we go once a month camping for about 3 nights max so this setup should work for us.

[jay see]

Most of my camping is during the colder months. Could be a problem with solar, but most trips are only 2 or 3 days with a 4 nighter sometimes.

[mudski]

if someone is driving everyday then the crank battery is getting charged by the alternator.. with out depleting to dangerous levels ?

although I am still working on my setup , so I could end up like one of those ideling up to charge the second battery or end up with a flat crank battery :)
Putting constant drain on the battery say via a fridge wont be good for it. Having an auxilary battery and wired up so your cranking battery is for only that, cranking, is the best way. The cheapest way to set up dual batts is via a solenoid, like the Redarc Sbi12. This will work good but as you stsrt to rely on the aux battery more a dc-dc charger is a better choice. Plus with most of the dc-dc chargers you can hook up solar to them to so when your parked for a bit the battery will get charge as they have built in regs. You can still hook up solar with a solenoid but the panels need a regulator. Hopefully ET or Cuppa will jump in a explain it better than i can.

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[the evil twin]

my plan (in theory) to skip the whole dual battery setup completely.

I have a cheap AGM deep cycle that was given to me. SO when I am driving I will have the fridge/freezer connected to the rear 12v cig socket that runs off main battery. Once I am at camp site, I will plug it into the spare deep cycle and connect the solar to the battery via a mppt controller.

No problems with that setup at all, it will work fine.

The two main reasons for having dual battery systems are;
1. The second battery is for deep cycle low current use and permanently on board as is the load IE fridge etc all stay with the vehicle
or
2. You need a dual battery for high amp applications on the vehicle IE lots of winching, humungous doof doof sound system, etc

If all you do is chuck a battery in the back when you go camping and the fridge etc all stays at the camp then your idea is fine

[LaughingBeagles]

I have been pondering this whole "to solar or not to solar" thing as we are thinking of heading over to Vic in mid Nov to pick up a camper trailer we purchased there (WA to Vic and back). What I have learnt so far from reading a bunch of posts is that a solar panel really comes into it's own if you are going to stay somewhere and set up camp for more than a day and are using a reasonable bit of current draw (I will be running a 70lt fridge in the trailer, some LED's etc after replacing the fluros it currently has).

Is that about right?

As to which panel is better and the best way to wire it, it seems to be a 'how long is a piece of string' question judging by the variety of posts on the subject. The common thing everyone says is to get the relay as close to the battery as possible.

There is seems to be no definitive answer to this one...

[threedogs]

When touring I use an esky for cold drinks for two reasons ,First beer tastes better out of ice.
As Im touring chances are Im driving more than 2 hrs a day to fully recharge any battery.
If I need fuel every second day I can also get ice. Plus the ice water can be used for heaps of things.
Washing your face in the morning certainly wakes you up, Also second If I have radiator problems I can use the esky water,
try doing that with an Engel or Waeco lol

When camped on the Murray you have a good chance it will be sunny most days, so topping up the batteries via solar
would be my choice. With the low power draw of LEDs I think multi panels and multi battery setups are old school.
You need to travel light without going without too much

I probably wouldnt take Panels to Cape York for example, as Id be driving most days with a two-three day lay over at the Tip.
You also need to be smart about what you take, my Engel is mainly food only so rarely gets opened.

This is touring with two mates BTW, I would take less if Lily came along [esky]

Good thread Jay See

[the evil twin]

snip... What I have learnt so far from reading a bunch of posts is that a solar panel really comes into it's own if you are going to stay somewhere and set up camp for more than a day and are using a reasonable bit of current draw (I will be running a 70lt fridge in the trailer, some LED's etc after replacing the fluros it currently has).

Is that about right?



Yes and esp here in WA where it gots hotter'n hades and you want your camper/van/truck in the shade



snip... As to which panel is better and the best way to wire it, it seems to be a 'how long is a piece of string' question judging by the variety of posts on the subject. The common thing everyone says is to get the relay as close to the battery as possible.

There is seems to be no definitive answer to this one...

There kinda is but the answer is definitive based on individual patterns and useage.

Panels...

Equal quality Mono and Poly Panels are close enough in performance to consider them identical for practical purposes.
To quantify the difference... a good Mono will be about 15% and a good Poly about 14% efficient.
Quality is the key as there can be a bigger efficiency difference between crappy versus quality panels of the same family rather than Mono V Poly.
Bottom line for Mono V Poly?... look for bargains in either, compare the panel output specs versus cost and buy the one that suits the budget

Solar Reg or Charge Controller terms and PV versus MPPT...

The term Solar Reg "should" really be restricted to a device that regulates the Panel output by voltage limiting (PV)
A very loose analogy is that these are like an Alternator IE your Alternator can produce waaaay more than 13.8 volts but the Reg limits the Alternator to a lower voltage so the ability of the Alternator to produce more power cannot be harnessed.
The term Charge Controller "should" really be limited to MPPT devices.
A very loose analogy is that these are like a Mains Charger IE they take a power source and change it to get the most efficient output IE they run the Panel at 17 to 19 volts (the peak efficiency for the panel) but the ouput is 13.8.
Bottom Lines for these devices...
Budget - PV Regs will cost $15 to $50 bucks, MPPT Controllers will cost $100 to $300 depending on amperage
Performance - in a practical application IE you aren't re-positioning your panels every 30 minutes an MPPT will be 10% to 30% better
Which one? - kinda depends on space, battery discharge and how you camp. A 100 watt array into an MPPT can easily perform up near to a 140 watt array into a PV Reg

MPPT doesn't need a 12 volt panel for a 12 volt battery or a 24 volt panel for a 24 volt battery IE an MPPT controller will accept 70, 100 150 or more DC volts input and select the output so you can even use domestic roof panels.

NOTE - 90% of the Ebay devices that say they are MPPT are not (lying #$%$#).

[threedogs]

In hot conditions opening and closing you fridge all the time for drinks, I think you'd be pushing 3 days.

Thats why even going to the Murray I take my Baileys Ice Box, best ice box ever imo,
When every one else has run out of ice my Ice box has plenty, plus there is a caravan park about 10 k away.
I take LED flood lights on adjustable poles and move them about if needed like down the bank of the river
with a dedicated 18 ah deep cycle battery in a plastic box, they use very little power, thats for sure

[jay see]

Good thread Jay See

Yeah it is, isn't it.:D

[LaughingBeagles]

Thanks ET, I might speak more at the next club meeting. It's not a massive priority at the mo having just spent on a camper trailer. But it will be when we go for a few days away.


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