integrating a battery into a system?

[.Seth.]

Alrite, well I do installs here and there and I have never done one w/ another battery, (besides the one thats hooked up to the electrical system, so wat all would I have to do? I doubt if I actually do it but I would like to know for a reference if I have a friend that wants me to do a big system install for him.....

Thanks for the help in advance, rep for ppl that help

[Notladstyle]

use a high current relay to isolate the positive terminal from the front battery or pay me to install it

[.Seth.]

^:lol:


fuck u Dalton!

LET ME LEARN! :lol:

[Notladstyle]

:p i gave u the answer

[Skittle]

Chck into Battery Isolaters.

[the727kid]

Just got + to + and ground the other battery to the frame.

[.Seth.]

^alrite cool! thanks, thats wat i was thinking but i didnt wanta fuck anything up lol

[Notladstyle]

^alrite cool! thanks, thats wat i was thinking but i didnt wanta fuck anything up lol

directly connecting the batteries directly will eventually drain both batteries.

[.Seth.]

^lol thats why i was asking! you tell me then!! lol

[jriggs]

^lol thats why i was asking! you tell me then!! lol

he did lol you toss the high current relay between the positive's (ok i think thats what he said i'm sure i'll be corrected if thats wrong)

[Notladstyle]

^lol thats why i was asking! you tell me then!! lol


connect the relay between the two points - connect the turn on lead for the relay to the ignition output.

[.Seth.]

ahh, got it! lol thanks Dalton!

[the727kid]

directly connecting the batteries directly will eventually drain both batteries.

I still disagree with this, I've had different batteries hooked up for a while, all still sit around 12.95

[TJElite]

How about an 'adding an extra battery' greatest hits sticky? This has come up many times before, and no one seems to want to search.

I'll sum it up...

Dalton, as well as a large portion of the car audio world says use a high current relay between the two batteries.

727 kid as well as an equally large portion of the car audio world says you don't need the relay, just hook them in parallel and be done with it.

Another portion of the audio world says use an isolator (sorry, don't know the proper TR FanBoy for this faction).

Oh yeah, TJElite says that these all work, they all have pluses and minuses, and there are at least 3 other ways to do it, as well. Scooters, chevy's, 4x4's and Bentley's will all get you to the mall.

Just make sure you use the right wire, run and fused properly, and make good grounds.

Toby

[the727kid]

^^ Good point.. I would also like to say mine is the cheaper method :)

[.Seth.]

How about an 'adding an extra battery' greatest hits sticky? This has come up many times before, and no one seems to want to search.

actually TR seach FTL, b/c i tryed it.

but thanks for all the info

[Notladstyle]

I still disagree with this, I've had different batteries hooked up for a while, all still sit around 12.95

I specifically said "eventually" because it is a certainty they will drain eachother eventually. they may work for a "while" but they will drain eachother within some point before the end of the useful lives of both batteries. Of course, gell and dry cell batteries have a much lower parasitic drain and will take longer to show signs of equalization.

even identical lead acid cells do not age identically, if only because one is exposed to much greater heat from being in the engine bay.

[TJElite]

I specifically said "eventually" because it is a certainty they will drain eachother eventually. they may work for a "while" but they will drain eachother within some point before the end of the useful lives of both batteries.

hmmmm, maybe...but probably not. Yes, due to the different ESR's (and some other things) the two batteries will 'fight' each other, and discharge. And yes, if left long enough, they will both go to zero (or close enough too it). But, as long as they are recharged regularly (like through daily running of the engine), I don't think this will ever be a problem.

Technically, each of these discharge and recharge cycles subracts from the batteries effective life, but only slightly more so than the standard discharge and recharge cycle of a car battery due to things like parasitic drains, vehicle computers, radio memories, etc.

For practical purposes, only 'deep cycles' are counted against battery life. In the case of a regular cranking battery, this is anything below about 11.3 volts for any length of time, and for a deep cycle battery, it is anything below about 10.5. This is when things like sulfation and acidity distribution become issues (and these are what kill batteries). As long as the vehicle is driven at least every other day, and there are no other drain issues, the parallel connected batteries will never see these levels.

In a normal street driven setup, I don't think the relay will provide any longevity benefits over the non relay system.

Toby

[djgizmo]

Will a relay / isolator though provide better battery protection from system shorts / overloads?

[03AcuraCLTypeS]

i have had an extra battery in my car for almost 3 years now never had a problem with them at all still over 12 volts i dont remember the exact voltage and they are run without an isolator or relay

[TJElite]

Will a relay / isolator though provide better battery protection from system shorts / overloads?

An actual diode isolater will act like a high current fuse, so it will provide some protection, and can eliminate the need for the front fuse between the batteries (assuming one is under the hood, and one is in the rear). But, they are usually more expensive than a fuse, and have other drawbacks, like voltage drop.

I don't see how a relay will provide any real protection. In fact, when subjected to overload, relays tend to stick closed.

Toby

[IdriveAbucket]

Do batteries have to be identical?or is it just ideal to have them the same?Thanks

[Notladstyle]

Do batteries have to be identical?or is it just ideal to have them the same?Thanks

with an isolator, they just have to both be 12v.

If you plan on connecting them together with no isolation, they need to be identical.

[TJElite]

I submit that as long as the vehicle sees regular charging, and all batteries are 12v, automotive type, that you won't see any measureable difference in life, or anything else for that matter, using an isolator or not.

Sure, it would be better if they were 'identical' even though that's technically impossible.

Toby