[Shayne18]

Off topic a little bit but I found out the hard way a couple months ago that bigger batterys do arc out on the bonnet. Bit spewin I was in the middle of no were when mine arked out it fried my earth first then melted the clutch cable grommet because my cluch cable decide to be an earth untill that snapped as well so I drove 300km with no clutch and even got pulled over by a big ass defect station and some how the let me go. But that was my experience wit big batteries lol

[Bugsta]

Good point Shayne. I'm not sure if mine is any taller, but I didn't take the chance. I place a piece of 3mm rubber arcoss the top and tuck it down at each end.

[Shayne18]

Yer that was my quick fix sulution to still got a hole in my bonnet now tho I fair arked it out lol

[got_bar_work]

I thought it was 35mm but when I went to crimp it the 35 lug didn't fit
Oh well no voltage drop problems

[youda]

royce wrote:

joel wrote:

youda wrote:

probaly something to note:
If you run different sized batteries and they are connected while not being charged the larger of the two batteries will always try to "charge" the other and will shorten the life of both your batteries. This is one area where you should try to make sure that they are isolated unless charging which is trickier than it sounds as some people use the acceries wire in their car. why is this a problem? think of all the times you sit in your car listening to the radio without the car running and so on and so forth. If going for a simple setup i would use the "on" position to minimise this time.
I know people will say they have run theirs for ages without problems i will leave it at giving your batteries the best chance at long life.

this is correct from what i know as well, thats why i have an isolator, so the only time the second battery is in the circuit is when its charging.
also other things to consider, my isolator is under the bonnet on the for wall (a PITA flick on and off, as i have to stop and pop the bonnet)
so either dont be lazy like i was, wire it in so its in the cab, or get an auto one like mentioned above!

No it doesnt, batteries will equalise voltage, doesnt matter a pinch of shit what their capacity is, they all rest at teh same voltage.

I know this cause I have a 7ahr and 80ahr joined all the time and its big one isnt flat and the little one doesnt glow in the dark

If you have a battery that is buggered and wont hold 100% charge, then all batteries will discharge to the level it can hold

If they are joined all the time then its not going to achieve what we want is it?
7amp hour and 80amp hour joined all the time....why?
the amp hour rating is very important in this case because as we all know the battery dosent hold exactly 12.7 volts for the entire amp hour rating. usually drops to about the high elevens for the last third and around 10-9 volts for the last ten percent. now picture this senario. you've been camping overnight with fridge running and your battery is now down to lets say 10 volts. before you leave the spot you turn the ignition to acceseries to get the radio going and maybe check lights general mucking around anything like that. during this time your much lower amp hour rated battery is running your car and trying to charge your other battery. If your lucky all is well car starts fine and you move off, if your unlucky............................ These are just some of the things Im pointing out for everyones consideration. I got this from a very experienced auto elec so before you dissmiss the helpful advice of other back up your claims with supporting evidance. again im not having a dig and feel free to prove me wrong i promise i will not take offence and will accept it without complaint and good grace

[royce]

youda wrote:

royce wrote:

joel wrote:

youda wrote:

probaly something to note:
If you run different sized batteries and they are connected while not being charged the larger of the two batteries will always try to "charge" the other and will shorten the life of both your batteries. This is one area where you should try to make sure that they are isolated unless charging which is trickier than it sounds as some people use the acceries wire in their car. why is this a problem? think of all the times you sit in your car listening to the radio without the car running and so on and so forth. If going for a simple setup i would use the "on" position to minimise this time.
I know people will say they have run theirs for ages without problems i will leave it at giving your batteries the best chance at long life.

this is correct from what i know as well, thats why i have an isolator, so the only time the second battery is in the circuit is when its charging.
also other things to consider, my isolator is under the bonnet on the for wall (a PITA flick on and off, as i have to stop and pop the bonnet)
so either dont be lazy like i was, wire it in so its in the cab, or get an auto one like mentioned above!

No it doesnt, batteries will equalise voltage, doesnt matter a pinch of shit what their capacity is, they all rest at teh same voltage.

I know this cause I have a 7ahr and 80ahr joined all the time and its big one isnt flat and the little one doesnt glow in the dark

If you have a battery that is buggered and wont hold 100% charge, then all batteries will discharge to the level it can hold

If they are joined all the time then its not going to achieve what we want is it?
7amp hour and 80amp hour joined all the time....why?
the amp hour rating is very important in this case because as we all know the battery dosent hold exactly 12.7 volts for the entire amp hour rating. usually drops to about the high elevens for the last third and around 10-9 volts for the last ten percent. now picture this senario. you've been camping overnight with fridge running and your battery is now down to lets say 10 volts. before you leave the spot you turn the ignition to acceseries to get the radio going and maybe check lights general mucking around anything like that. during this time your much lower amp hour rated battery is running your car and trying to charge your other battery. If your lucky all is well car starts fine and you move off, if your unlucky............................ These are just some of the things Im pointing out for everyones consideration. I got this from a very experienced auto elec so before you dissmiss the helpful advice of other back up your claims with supporting evidance. again im not having a dig and feel free to prove me wrong i promise i will not take offence and will accept it without complaint and good grace

You said when you connect 2 batteries together the larger one will always try and charge the smaller one and will shorten its life.

No it wont, they will equalise and stay like that, if one battery is no good and sits at a lower state of charge then they both will.

youve now added discharging the battery by connecting a load to it which is a totally different situation, but you will still get the combined capacity of the batteries, there wont be any missing electrons.

your last situation doesnt make sense, why do you have your isolated batteries now joined (which we havent been discussing here) without there being means to charge them? IE the engine running? using a voltage sensing battery isolator will prevent this anyway

The reason for the batteries in mine is hte little one stays plugged in the back and I pull it out to hook a portable light up to, it happily sits beside my drawers not hurting anyone

[got_bar_work]

My old Sierra ran a switch in line with the ign controlling my solenoid
When the deep cycle were flat u just turns the switch off
started the car
The turned the switch back on and charges again as normal when the ignition is back on
If the aux batt is only for low power things and not winching or starting then a ctek dc to dc charger is one of the best dual battery isolators u can get. I run this on my camper charging my 160ah battery. It even has a mppt to control a solar panel

[Bugsta]

got_bar_work wrote:

I thought it was 35mm but when I went to crimp it the 35 lug didn't fit
Oh well no voltage drop problems

35mm... Thats 3.5cm. That's still a HUGE cable. The sort you see coming out of an Energex generator to power a suburb.

Do you mean 3.5mm and 5mm perhaps?

[royce]

Bugsta wrote:

got_bar_work wrote:

I thought it was 35mm but when I went to crimp it the 35 lug didn't fit
Oh well no voltage drop problems

35mm... Thats 3.5cm. That's still a HUGE cable. The sort you see coming out of an Energex generator to power a suburb.

Do you mean 3.5mm and 5mm perhaps?

cable is not measured by its diameter, 35mm SQUARED cable is not even close to 3.5cm across

[got_bar_work]

Sorry 50mm2

[Moag]

Something like this....

[got_bar_work]

37A on 2.09mm2
Voltage drop much
Auto electrical indistury is so dogy

[Moag]

Just a crazy retarded thought you could use one of these RC helicopter batteries for starting Linky Thing

or keep in the glove box for jump starting.

Got to love nano technology...

A smaller one shame about the dick talking in the background.

[flash width=480 height=385]http://www.youtube-nocookie.com/v/WkKRqaNPIBE.swf[/flash]

[Bugsta]

Actually royce, measuring cable by its diameter is pretty standard. See post by Moag.

And anyway, just havin a bit of fun.

[royce]

got_bar_work wrote:

37A on 2.09mm2
Voltage drop much
Auto electrical indistury is so dogy

Do you know what JASO means?

[royce]

Bugsta wrote:

Actually royce, measuring cable by its diameter is pretty standard. See post by Moag.

And anyway, just havin a bit of fun.

Actually, you are so stupid you dont even realise your post makes you look even more stupid, no cable is identified by its OD ever, its always the cross sectional area of the the conductor, which is exactly what Moags chart is telling you

[whincup]

royce wrote:

No it doesnt, batteries will equalise voltage, doesnt matter a pinch of shit what their capacity is, they all rest at teh same voltage.

I know this cause I have a 7ahr and 80ahr joined all the time and its big one isnt flat and the little one doesnt glow in the dark

If you have a battery that is buggered and wont hold 100% charge, then all batteries will discharge to the level it can hold

well i only did high school physics, but my first thought was 'where does that power go? it doesnt just disappear, and its obviously not going into the smaller battery... unless your battery really does glow

Bugsta wrote:

Good point Shayne. I'm not sure if mine is any taller, but I didn't take the chance. I place a piece of 3mm rubber arcoss the top and tuck it down at each end.

old push bike tube works perfect. tight fit, hard to get it over the terminal, but all good once on...

[Bugsta]

Pretty sure I didn't say OD.

But all I can say is WOW. Do you have trouble with hats?

[got_bar_work]

Not really as I'm in Australia so i work off as 3008
2.5mm2 is only good for around 20 a in most conditions
They got some cool superconductors in japan that I don't know of or something

[royce]

Bugsta wrote:

Pretty sure I didn't say OD.

But all I can say is WOW. Do you have trouble with hats?

I dont know which post to quote here, the one where you said OMFG that is 3.5cm across like a Substation or the one where you said they are measured in diameter, is diameter and OD different in your little world?

[shep]

if the battery's are isolated correctly then it doesn't matter what size the battery's are.

my dads paj has been running 1 x n70, 1 x n52 and 1 x n105 battery's for 5 years with no issues.

[royce]

got_bar_work wrote:

Not really as I'm in Australia so i work off as 3008
2.5mm2 is only good for around 20 a in most conditions
They got some cool superconductors in japan that I don't know of or something

I cant find the standard for free anymore but the rating is more about insulation not melting than voltage drop, remember your average automotive cable length is a lot shorter than a house or building too

[got_bar_work]

I know it is but in a 12 v system voltage drop is alot more of a problem then at 240 v
Any more then 0.5v drop on a 12 v system is not acceptable i think
U also have to remember that as the temp goes up so to does the voltage drop . So cable running in the engine bay can't carry as much as cables in the cab

[got_bar_work]

As for the batt discharging it's due to the internal resistance of the battery
Wet cells are pretty high in internal resistance so they self discharge pretty fast

[Bugsta]

There is such thing as OD and CD, but WAIT... they are both quoted in Moag's nice conductor listing anyway so I'm not sure what your point is.

My litte world might seem little to you but its based in reality.

And royce, as I've already stated, my reference to got_bar_work's post was all in a bit of fun so you're just puffing smoke. I don't see him gettin his panties in a twist.

If you can't be civil in your responses on an open forum weather the person you are respondoing to is right or wrong (according to you of course), perhaps your interpersonal skills really need some work.