AGM in confined spaces

[Craig09]

Ok so ive changed my mind and haveing a deep cycle under the bonnet isnt going to give me enough juice.

1.because it wont get 100% charge

2.because the biggest is 105 ah because i cant get agm under the bonnet due to heat.

so to my main question can i put an agm in a completely confined space???,im building a big square 1200x1200 draw system to fit into the dog box.the bottom row will have a large water storage tank then a divider then the battery,charger,inverter and compressor and anything else that is a permanent thing.so effectivley the battery will be in a compartment roughly 40cm wide and 1200 deep (with the other things mentioned) that is enclosed all sides with a side door on a hinge for access, is that ok or should i put ventilation in that compartment???????

secondary questions

1.to set up for full charge i want to go
starter batt.....30cm........>sidewinder 140a isolator..>100a fuse?................4-5metres to dog box..........>100a fuse?...>inverter....>charger....>AGM

have i got the layout right?am i missing anything?

2.options are 270ah centry AGM,will this above layout charge it to full?
or the biggest optima spiral wound i can find (i think the biggest is 160ah)

what size inverter and charger will i need?

i know that theres heaps of threads on dual batterys but none regarding my main question and as for my secondary questions after reading all the other threads im more confused than a 18yr old stripper in LA thinking she was going to be an Actor

anyway any help would be great

 

[RustyNav09]

Mate aslong as you have a DC to dc charger you will be able to charge your batteries to full at some point. Agm or completely sealed agm can be installed in unventilated locations as they don't leak fumes when being charged. Your setup is completely up to you. As for the inverter it depends on what your running. Add up everything you will be running off it at once and buy the inverter to suit your needs. Also buy pure sinewave as they work better. Also work out the best size cabling between everything to reduce your voltage drop.


Goodluck

 

[Old.Tony]

Ventilation isn't required for AGMs, although if you get the MSDS from the manufacturers they'll say to keep them ventilated - probably to cover their asses just in case, but the Australian regs allow AGM, Gel and VRLA batteries to be stored, used and charged in an enclosed and unventilated area.

That said, a small gap near the top of the enclosure won't hurt one bit - hydrogen (the gas that causes the problems) is lighter than air and will rise to the highest point.

Your inverter choice should be made based on the capacity of the charger being used. This should also govern the cable size from engine bay to the aux battery location. If you have a 25A charger (like the CTek) you'll need to get an inverter that handles 25*13+100 = 425W constantly. I'd get a 600W inverter, so that you're not constantly sitting just over the 400W.

If you can't afford a pure sine wave (and I should write that as "pure" sine wave because they are never actually pure unless they're generated by a rotating power source) then a modified sine wave is acceptable, BUT you MUST make sure that the inverter is "Electrically Isolated".

You don't need the last fuse between the inverter and the cable run because the inverter doesn't supply power to that cable, it only takes it and it has its own fuse.

Now, with a 600W inverter (possibly drawing 425W = over 30A the normal 6mm cable is going to come up short. I'd put a pair of 8Ga cables in and enclose them in flexible conduit to protect it (this is what I am in the process of doing). Using an inverter you don't need to worry too much about voltage drop, but you do need to be able to carry all that current. A typical 600W inverter will peak at 1200W which is near 100A!

 

[Craig09]

awsome,thats what i wanted to hear,will put a small vent in but its good to know it doesnt need it.
theres 600w pure sine wave inverters for $80 on ebay so thats sweet.

with the inverter charger set up can you still link batterys to start the car if the main cranker fails??
ive got 2 b&s somewhere,is that too big?got this because i was told it would handle the current of connecting batteries and starting the car if needed.

Tony i saw in another post you had the 7amp ctek charger for your 165ah optima,would this still charge a 270ah batt if i was to get one that big?
cheers

 

[Old.Tony]

A 7A charger can charge a 1,000Ah battery - it just takes longer to do it.

I need to find where I've got that info about the battery size because it's wrong! The battery is a D31A Optima Yellow-top Spiral Wound AGM. It's 75Ah, or 155 minutes of "Reserve Capacity". I'm a little disappointed with myself for that, but thems the breaks!

As for starting the car from it - seriously, the starter is going to pull 500+ amps out of the battery. If your leads are 4m long, you could generate a huge amount of heat doing that, maybe enough to start a fire.

It would be worth considering lifting the aux battery out and using ultra-heavy duty jumper leads - especially since (we all hope) you won't need to do it very often. I'm going to make my own jumper leads, too - 2.5m long, 0 gauge wire. Should be good for about 1500A! Should cost me about $90 in bits from Jaycar and a little time to solder, crimp and admire.

 

[equipt]

$80 for a pure sinewave sounds way way too cheap. Check out Jaycar, they are $350 probably a bit over priced but that is about what I would expect to pay for a pure sinewave.

http://www.jaycar.com.au/productView.asp?ID=MI5164

 

[Old.Tony]

That's a good point, Equipt. I missed that one.

Charger power supplies are usually switchmode supplies these days. Inside, the first thing that happens is the input (AC) is rectified to DC providing about 300+V DC which is then fed to the input of a step-down transformer then turned on and off by a transistor, producing a nice square wave output which is flipped to produce a solid and stable DC power output. This basically means that a modified sine wave inverter will happily supply power for the charger and it won't cause any harm to the system.

Jaycar sell those too.

If you were looking around for an inverter - look at Jaycar. Whichever way you go - pure or modified sine wave - it HAS to be electrically isolated. All of Jaycar's units are.

I did check my Aldi 600W inverter - it's isolated as well, but I've no idea when they're going to flog them again.

 

[Craig09]

http://www.navara.asia/showthread.php?t=1957&highlight=dual+battery&page=9

will just have the aux easily removeable in case of the need to use it as a starter,hopefully never.
yea i figured that sounded a bit cheap,will go to jaycar tommorow if there open and have a look.
also like the idea of the homemade jump cables.
just one thing im assuming you have cut the aligator clips of the charger and put lugs on it?
thanks heaps for the help,much clearer in my head now.just have to bring the nav back to life and the project will be on

 

[Old.Tony]

I use them both ways. The C-Tek in my caravan (which is where my Optima is now housed, as well as the 100Ah Gel) has both clips and rings. Both batteries, because I'm mounting them permanently with no desire to remove them even for short periods, have the connectors bolted into place. The crappy 50Ah deep cycle (non-starter) in my tub uses clips, and when that battery dies I'll be putting a decent DC/starter AGM in there with its carry handle in place, clips to make removal easy an my home-made jumper cables handy - for Justin Case (nice guy but I still wish he'd piss off).

Jaycar actually sell all of the gear you need to make your own jumper leads.

Red power cable is here. Black cable here. Alligator clips are here. I know the clips are rated at 400A but they should still do the job quite nicely. I wouldn't mind finding a heavier set somewhere - maybe someone knows a place we can get them from? Something that can handle 1,000A would be good!

 

[Krankin]

Here's a real inverter...

http://www.12volttechnology.com.au/product.php?id_product=195

 

[womble]

http://www.navara.asia/showthread.php?t=1957&highlight=dual+battery&page=9

will just have the aux easily removeable in case of the need to use it as a starter,hopefully never.
yea i figured that sounded a bit cheap,will go to jaycar tommorow if there open and have a look.
also like the idea of the homemade jump cables.
just one thing im assuming you have cut the aligator clips of the charger and put lugs on it?
thanks heaps for the help,much clearer in my head now.just have to bring the nav back to life and the project will be on

you say you are going to make your aux easily removable "just in case". Has any one seen or used one of these

http://www.ebay.com.au/itm/Porta-Jump-Emergency-Car-Battery-Starter-/200809330878?pt=AU_Car_Parts_Accessories&hash=item2ec12b38be#ht_1687wt_1139

I have had one for the last few years, it has got me out of trouble quite a few times without having to lift a heavy battery/battery pack get out jumper leads etc. I know it takes about 10 mins to charge your main battery before you can start your vehicle again, but would be about the same time as removing the aux battery starting the vehicle and replacing your aux battery. plus its a lot smaller and easier to store.mine lives in my glove box.

 

[Craig09]

heres som rated to 600A.maybe a welding shop would have some rated to 1000A for industrial welders??might check it out tommorow as id like to make a pair.
http://www.ebay.com.au/itm/4-X-600-...=AU_Car_Parts_Accessories&hash=item19d45c7f1a

haha i could almost plug my house into the ute when theres a blackout Krankin.

so ive decided to go with a 120ah or 140ah centry AGM for now (may add another down track to bring it close to 300ah) .
To charge will go with the inverter to charger to battery opption for sure BUT id like to be able to charge it when im in one spot for more that 2 days or so. To do this i will use a foldable portable solar panel trying to figure out the maths but i think 120w will do?or maybe have to go bigger?

where im stuck is where does the solar panel link into the system ie:after inverte,before the inverter or what??

doing research ive found this from cteck http://www.ebay.com.au/itm/CTEK-D25...=AU_Car_Parts_Accessories&hash=item43b2f44725 they say this boost the voltage from the alternator and is able to deliver full 100% charge so does that therefore mean there is no need for a inverter??

from my understanding of there claims on this device it eleminates the need for an isolator (already got 1 so that dont matter anyway) and a inverter.is this correct??

if so what would be the most effectve set up:
the above device which seems to be an isolator,invertor so to speak and a solar regulator all in one or,
the inverter-charger-battery with the solar panel linked in wherever it goes,and if i go with this setup will the charger act as a solar regulator or will i need one of those too??

i want this to be the most effective and fast charging sytem i can have,dont care about price too much as if i do it once right then i wont have to modify it later.

this device if it is what i understand will throw a huge spanner into the set ups of dual battery systems and make them much better and more cost effective.

sorry for all the questions but im hopeing this not only helps me with my setup but many others

 

[Old.Tony]

Here's a real inverter...

http://www.12volttechnology.com.au/product.php?id_product=195

Oddly enough - because you'd expect to see this for a product that ticks so many boxes - they don't mention that it's electrically isolated.

Not electrically isolated = potentially dangerous. Might be worth them updating their web site if the units are isolated and if they aren't ... choose something else for a mobile solution. Household units generally don't need to be isolated because the houses have to have RCDs and usually don't have multiple independent supplies, unlike in a caravan, where you could conceivably run two or more small inverters to perform different tasks.

Otherwise, that looks like a solid unit. On 12V deep cycle batteries though it'll suck them dry - 9.7V cutout is below the lower threshold for batteries (even spiral wound AGMs shouldn't be dropped below 10.75V). I guess you'd use larger cells @ 2V per cell - those things can probably handle it better because they were designed for extremely deep discharge.

 

[Old.Tony]

Craig, the C-Tek D250S is the one to go for because it will choose the best input and use that as a source. From that source, it then charges the battery properly - I've been using C-Tek now for some time and I'm extremely happy with it.

The D250S has a built-in solar regulator (read about it here).

In the original configuration, you could set the solar panels (and regulator) up in parallel, so that both are directly connected to the battery. It's not ideal for charging when both sources are delivering power, but it does work and will charge the batteries to completion. The (better) alternative is the D250S because rather than having two units charging the battery, you have two units supplying power and the best one of those two is chosen to power the single charger.

 

[Craig09]

awsome,my understanding was the D250S was the best way to go.

just to make sure haveing a inverter with the D250S is pointles (ill still put one in if it gives a little extra benifit)??

so this will be my setup for anyone looking to do simillar (assumeing theres no extra benifit to haveing an inverter):
Main battery.......>sidewinder 140amp isolator with incab management.........>Ctek D250S which also has a 120w solar panal connected to the dual input........>120 or 140ah centry AGM.

the solar panel should put by my calculation 10amp per hr into the battery,my fridge takes on average 3.5amps plus whatever lights i am useing and other small devices like charges.shouldnt top 10amps.rechargeing at 10ah it will take 13.2 odd hrs to recharge a 120ah battery,so yes there will be days without sun but for the most part i should never run to low and worst case i will just start the car,all this is if i am stationary for a good couple days.

calculations are as follows:
1.Calculate the Ampere per hour of the charger: 120 Watts /12 Volts = 10 Amperes
2.Calculate the division (battery): 120 amp hours / 10 ampers = 12 Hours of direct sunlight
3.Add 10%
i like this setup, for $260 the D250S is a great device and the money that would of gone to an inverter goes to a portable foldable solar panel therefore giveing you 2 power sources

if anything is wrong here im sure ill be corrected

 

[Krankin]

Oddly enough - because you'd expect to see this for a product that ticks so many boxes - they don't mention that it's electrically isolated.

Not electrically isolated = potentially dangerous. Might be worth them updating their web site if the units are isolated and if they aren't ... choose something else for a mobile solution. Household units generally don't need to be isolated because the houses have to have RCDs and usually don't have multiple independent supplies, unlike in a caravan, where you could conceivably run two or more small inverters to perform different tasks.

Otherwise, that looks like a solid unit. On 12V deep cycle batteries though it'll suck them dry - 9.7V cutout is below the lower threshold for batteries (even spiral wound AGMs shouldn't be dropped below 10.75V). I guess you'd use larger cells @ 2V per cell - those things can probably handle it better because they were designed for extremely deep discharge.

they also dont mention its NOT elec isolated....and anyway, I dont reckon anyone here would pay that sort sort of coin anyway...



Here ya go then...I'm sure this one will tickle your boxes....

http://www.12volttechnology.com.au/product.php?id_product=180

 

[Krankin]

heres som rated to 600A.maybe a welding shop would have some rated to 1000A for industrial welders??might check it out tommorow as id like to make a pair.
http://www.ebay.com.au/itm/4-X-600-...=AU_Car_Parts_Accessories&hash=item19d45c7f1a

bought stuff from him before...good seller

 

[sparra04]

if you are using a ctec d 250s you dont need an isolator
it wont charge till it sees correct voltage at cranking battery

 

[Old.Tony]

You won't need an inverter at all with that setup, unless you want some 240V - and then you'd supply the inverter with power from your aux battery.

Don't worry about charging the entire battery capacity. You shouldn't ever use more than 80% of an AGM anyway, and if your fridge is drawing 3.5A per hour (let's say 4) then in a 24 hour period that's 48Ah. Add another 10A for lights per day = 58Ah. The D250S can charge @ 20A = recharged in 3 hours. Solar can supply 10A = recharged in 6 hours.

Solar energy is a fickle thing. If you have polycrystalline panels then shade and clouds will reduce their effectiveness = less power. Monocrystalline panels are shade-tolerant. In either case, maximum power is obtained between 10am-3pm in winter and 9am-4pm in summer (a bit longer in the outback, I noticed - good light until about 5pm-ish when you're west of Cobar). This means on a good day you'll collect 5hrs * 10A in winter = 50A, and 7hrs * 10A = 70A in summer.

That's not a bad thing. In winter your fridge won't be working that much anyway so you'll be good on amps there. In summer it'll use more but your panel is oversupplying anyway so it's still all good.

You'll probably find that your car will produce about 10A or so when idling - that's all mine produces, but then the engine is ticking over at 750rpm which isn't a lot.

 

[RustyNav09]

I have to add in that ctek 250 is a top unit. I would recommend it to anyone. Only time my fridge has turned off due to low voltage is sitting for 3 days running in 35deg heat power lights and also running an Engel mt45 for a day that was purely being used as a freezer. A lot of amp draw. Was using solar during the day but it was a pain trying to get Sun in between trees. Also I was using the regulator which came on the panel not the ctek solar reg which would of been better