Best Battery for a Boondocker?

[camptyler]

I am at the point in my build where I need to start making a decision on a battery/batteries so I can test all my electrical before I close anything up.
I am leaning toward using two 6v golf cart batteries such as the Trojan T-105's.
My electrical needs are pretty minimal. I am going LED everything but don't see myself being in a campground with electric (I am a backpacker at heart). Also, I will have a solar panel.
So, let me have it!
What batteries do you guys use?

[Lgboro]

It will depend on your estimated usage which battery setup will work best for you. I did an early test to my overhead led lights I built into my fan and ran it for 20 hours using very little current. I ran them off of a 18 amp hour car starter/jump unit. I haven't tried yet with the fan and lights but unless your lights are really big ( I put 40 10mm leds in my overhead light) I don't think you will need two batteries especially with a solar panel to assist.

If you can come up with an estimated usage there are several guys on the forum that can give you a solid answer to your question. They need to know how many amps you anticipate using in a day to give a really good estimate of battery size.

[camptyler]

OK,
So this is how I figure it at worst case scenario.
2.8 amp Fan x 8 hours = 22.4
1 amp Dome x 2 hours = 2
2x2 amp Reading Lights x 2 hours = 8
2x2 amp Galley Lights x 3 hours = 12
2x2 amp Courtesy Lights x 2 hours = 8

For a whopping total of 52.4 amps (I Think )
I am new at this so I am reading a book called RV Electrical Systems and figuring it out as I go.
So, If my math above is way wrong let me down softly.
Thanks guys,
Tyler

[48Rob]

Two Trojan T-105's

Works for me, but as LG, mentioned, the only way to get anywhere close with your guessing is to know/attempt to calculate how many combined Amps you will be drawing per day, how many days at a time you'll need them, and how many Amps your solar setup will likely return.

I see you just posted your anticipated usage.
LED's shouldn't draw that much power?
If you research LED's for your intended purpose, you should be able to cut your usage by nearly half.
Some people find that LED's are too uncomfortable for reading, but are fine for general illumination.

Rob

[Shadow Catcher]

You can greatly reduce the demand by converting to LED's and using computer case fans. I chose a Lifeline AGM battery http://www.lifelinebatteries.com in part because of its toughness (I plan on boondocking). My personal feeling is that a well taken care of AGM will outlast a conventional wet cell battery and that much of the hype form RV folks comes out of myth. One of the other considerations is weight which the big RV folks don't have to consider as much as we do. But then they are panicking at the prospect of $4 or $5 gas.

LED color temperature is the key to comfort for some in reading, go for a "Warm White" 3200K
Our reading lights use a G4 base LED.

[camptyler]

Rob,
You're right it looks like I was guessing way to high for the amps.
This is probably a better representation:
Fan 2.8 amps x 8 hours = 22.4
Reading Lights 2x0.15 amps x 2 hours = 0.6
Dome Light 0.25 amps x 3 hours = .75
Galley Lights 2x0.25 amps x 3 hours = 1.5
Courtesy Lights 2x1 amp x 3 hours = 6
Equals 31.25
This should be fairly close to my max usage.
I am planning on installing a 65w solar panel (If I have the room)

Tyler

[eamarquardt]

First I think you can probably move as much air with a couple of computer fans and save a bunch of juice over the fantastic fan and perhaps save some money. As a plus, using multiple fans, you can probably direct the air to where it will provide the best comfort.

In the "cruising world" (sailing) Surrette batteries are ledgendary for their quality and performance.

http://www.surrette.com/

Maybe worth considering.

Hope this helps.

Chees,

Gus

[48Rob]

Gus,

I just got done working on that info for another post...

Fantastic fans are 920 cfm @ 4 Amps
The Ventline fans are 100 cfm @ 1.5 Amps
The big computer fan is 265 cfm @ 2.25 Amps
Average computer fan is 30 cfm...

Rob

[48Rob]

is there a light wieght battery that will put out a lot of juice for boondocking.

Mr. Cowboy,

Yes.
The new generation batteries are much lighter than the standard lead acid batteries, but are many times more expensive.
The fuel you would save by saving 30 pounds on a battery would not be enough to pay the higher cost for the battery.

A standard 12 volt deep cycle should be "enough" though the best way to know what you need is to measure the draw on your fan and lights, then keep a log to show how many minutes/hours per day you use them, and how many days total per trip.

Once you have that answer, you can match your power needs to a specific capacity battery.

Rob

[camptyler]

So I called today and checked on pricing for the T-105's and they are $178 each w/o an exchange so $356 for the pair.
I am going to stop at Costco on the way home and check out the Kirkland GC batteries. If they are a ton cheaper they might be the way to go. Seems like people have only good things to say about them.
I will follow up with a price update.

Tyler

[eamarquardt]

Gus,

I just got done working on that info for another post...

Fantastic fans are 920 cfm @ 4 Amps
The Ventline fans are 100 cfm @ 1.5 Amps
The big computer fan is 265 cfm @ 2.25 Amps
Average computer fan is 30 cfm...

Rob

Good stuff! Thanks! How much air do you need to move to improve the situation and feel comfortable. Will directing the flow exactly where you want it give more comfort/amp?

How bout something requiring no power:

http://www.downwindmarine.com/Windscoop ... 10280.html

or

http://www.freewebs.com/3sidedwindscoop/

Cheers,

Gus

[Steve F]

Well I just went 5 days with 200W of solar and a 100AH sealed battery, the battery was close to fully charged when I left camp but it had been overcast so wasn't getting as much sun as was ideal.

On that battery I ran a 50lt Waeco fridge on a fairly low setting and kept it in the shade. Numerous LED lights including some external strip lights that were on from sunset (5:30pm ish) until around midnight each night and charged my daughters DVD player and phones etc everynight.

Without the fridge on overnight (I left it in the jeep the first night) the battery was already fully charged when I got out of bed, around 7:30am, basically it was pumping in 6A an hour in full morning sun with a MPPT controller (which makes all the difference with my 24V panel)

I'd say get as much solar as you can fit/afford and go for less battery.

Cheers
Steve

[48Rob]

Steve,

Sounds good!

Do you know what the dollar amount is that you have invested to get the 200 Watts of solar power?

Rob

[48Rob]

Gus,

The windscoop is a good idea!

Rob

[Steve F]

Steve,

Sounds good!

Do you know what the dollar amount is that you have invested to get the 200 Watts of solar power?

Rob

I was very lucky, the solar panel was given to me by a mate that installs them on houses. The frame was damaged so they couldn't use them and they dont give them to employees as they tend to 'damage' a lot more then...

The regulator and LED display cost around $150AUD, you can get cheaper but I wanted the LED display and it needed to cope with an open circuit of 46V which only the MPPT ones do (they also run the panel at it's most efficient voltage and effectively boost the output into the battery)

Then there was cableing and plugs, probably cost me $200AUD all up but if I'd bought the 167W panel (I already owned a 30W panel) it would have cost around $1000AUD more.

Here's a pic as an example fo the size of the panel.



Also I'd say go for the 24V panel and MPPT controller, you can use thinner cables and the higher the voltage difference between battery and panel the more boost the MPPT controller can provide. At one point I saw under 2 AMP at the panel and over 5 AMP going into the battery. If I slide the panel off the roof and set it up properly I'd expect to see close to 10AMP going into the battery.

Cheers
Steve