Things learned from installing bat/inverter..

[Blue]

A properly sealed and vented ammo box does not make that bomb and the steel would protect in case of an accident. Jeeze zil you trying to scare me into destroying and rebuilding a really good mod or what?

 

[SternWake]

Properly sealed and properly vented should be fine.
I'd worry most about how that ammo box is secured to the floor, and that the vent cannot introduce rainwater, or get kinked and blocked and that wire chafing is not possible.

Confining anything will increase the energy released if/when spark and hydrogen/oxygen meet.

There are reports of Li-ion batteries in machined aluminum tubes "venting with flame" to such a degree, explosion is a more accurate term. Fingers have been lost.

http://www.candlepowerforums.com/vb/showthread.php?340028-Flashlight-Explosion

http://www.candlepowerforums.com/vb/showthread.php?280909-Ultrafire-18650-3000mA-exploded

Granted Li-ion is a different game.

 

[Blue]

so, I'd want some kind of U joint for the vent with a small tap or hole? (to stop rain water) box is pretty solid, long wood screws through wood blocks that have been metal screwed into the frame, (though there is one side with a little gap I want to shiv)

 

[Zil]

Yes Blue, you are a friend on the forum. I do want you to be very cautious. I have seen a flooded acid battery explode a cell, with the cap off, and throw shrapnel. I know the strength of an ammo box. I know the power of a confined lead acid battery off gas explosion. Be sure to have lots of ventilation when charging. I would have a small computer fan flowing air through the box. Or a ammo box less the lid.

 

[Blue]

Humm... I should be able to attach a fan to the isolator switch I installed so when I flip the switch to charge the battery the fan goes on. I could also drill a small hole in the frame and a 1/2 inc PVC pipe up the side with a joint to allow air from the bottom of the vehicle (pipe and joint would be to stop water from splashing up into the battery box, good idea?) I also planned on attaching fans to the exit points of the vent (I plan on using the vent to get rid of heat in the sleeper mid day as well rather than use an obvious roof fan) is there a way to attach some kind of temperature gage to the fan to have it activate when it gets over 70?

 

[LFM]

You will get longer life from your fan if you use it to push out nasty gases, rather then pulling them out pass/thru the fan.

 

[GrayWhale]

@gray whale - those capped batteries are the gell aka AGM batteries most people here use, safer yes but shorter lifespan and more expensive, also recharging must be done differently...

This battery of mine is an Optima RED top that was in a car (and meant for a car). Is it still AGM?

I've been charging it with this, but not under AGM option. http://www.harborfreight.com/battery-chargerengine-starter-10250-amp-12-volt-60653.html

Those Costco batteries that says "Marine Deep Cycle" with like 120 amp hours for only $90 aren't AGM's right? They can start a boat motor, so they're not true deep cycle right? But do you think I can use those for part time vandwelling?

 

[Bela's Mom]

Your Optima Redtop is an AGM battery according to their website. They also have the charging specs for them on their website. It is a starting battery so you cannot cycle it like you can a deep cycle battery. Depending on what size you have, you may only have about 45 amp hours to work with.
Gell batteries and AGM batteries are not the same thing. AGM can take higher charging voltages and if properly cared for, can last 10 years. They produce little to no hydrogen gas when charging which makes them good for interior locations. They can also be mounting sideways if needed. They do not freeze the way regular batteries can and do not require the addition of water. They are, however, more expensive. For me, the pros outweigh the cons. But everyone has their own preferences based on their experiences....and budget!

I bit the bullet and bought a Lifeline AGM 4 years ago. I have never regretted it. It is still going strong.

 

[GrayWhale]

Bela, thanks for that info.

 

[GrayWhale]

Bela's Mom, do you know why this HB battery is only 35ah for $75
http://www.harborfreight.com/12-volt-amp-hour-sealed-lead-acid-battery-68680.html

but then there are those Marine Deep Cycle batteries at Costco for $90 that are like 120ah?

So even if the Costco batteries aren't true deep cycle and shouldn't be drained pass 50%, wouldn't 120ah still be better? The battery is like 30-40% bigger than this HB battery too.

 

[SternWake]

Marine batteries are supposed to be a crossover design between starting and deep cycle duties, excelling at neither.

I suspect that some batteries sold as marine batteries are just starting batteries with threaded posts and a fancy sticker added.

A true 12v deep cycle group 27 battery will weigh 62 Lbs.
A marine battery group 27 will weigh about 52 Lbs
The starting battery, group 27, is about 48 Lbs.

I do not think I'd consider a Harbor freight battery.

Many Asian AGM batteries do not have the benefits of other AGM's. The self discharge rates are not much better than flooded batteries, and the maximum recharge current is not very high either, seriously compromising the 'AGM's recharge faster" advantage.

If they cannot take high recharge currents, then their CCA ratings are lower too, which might be a factor if the battery is to crank a starter motor.

The only real benefit is the lack of offgassing and terminal corrosion.

 

[Blue]

Here..
http://www.chbattery.com/Asp/003_show.asp?id=61

What are the advantages and disadvantages of gel, AGM, and flooded lead acid deep cycle?

Generally, gel and AGM batteries have about 20% less capacity, cost about two times more, and have a shorter cycle life than comparable flooded lead acid batteries. However, Gel and AGM batteries do not need watering, are safer (no acid spilling out), can be placed in a variety of positions, have a slower self-discharge characteristic, and are more efficient in charging and discharging than flooded batteries (see table below). Gel batteries are more suitable for deep cycling applications whereas AGM batteries are more for light cycling and engine-starting applications.

Flooded Gel AGM
Charge/Discharge Efficiency 89% 98% 99%
Self discharge rate (per month) 13% 1-3% 1-3%
Finish Voltage (V) 15.3-16.0 14.1-14.4 14.1-14.7
Float charge(V): 13.2-13.7 13.4-13.8 13.4-13.8

so... led acid... cost half as much, last a bit longer, carry a 20% higher charge (20% MORE stored power) have more mantinance issues, must be vented (I think, though I suspect its best to vent any battery) cant be put in weird positions. AGMs and Gells dont last as long, cost twice as much, and the AGMs are the worst of the three for deep cycling. pretty much spelled it out for me.

 

[Optimistic Paranoid]

Not sure I agree with you Blue.

Lifeline agms are true deep cycles, with an expected lifespan of 5 to 8 years under "average" conditions (whatever that is).

A group 27 Lifeline weighs 62 lbs, which is certainly in the true deep cycle range..

Regards
John

PS download and read their technical manual. Quite a good read.

 

[GrayWhale]

Blue, thanks for the detailed write-up + pictures. This is exactly what I need to do my setup.

 

[Blue]

No problem, take a look at that Australian guys site I gave the link too, it's got better pics, details, options (for the isolater), a electrical schematic, etc. that's where I got most of my info, there's also a good thread on "indestructables.com" about building a moveable ammo can/battery/inverter.

 

[VanLifeCrisis]

I have 82 dollar batts from sams club, they are true deep cycle and made by east penn, a reputable company so ive read. They are 215 amph but 6v so i had to buy 2. Working good so far but its only been 8 months or so.