so i purchased a new battery

Hello gentlemen, it's been awhile since ive been on here and i hope you are all doing well. Heres my story.. I have a 1995 honda civic and I recently replaced my alternator and got a brand new battery. During this process i was able to acquire another brand new battery. Now heres my setup.. i have a 1400W 4 channel amp just for my mids/highs. i have (2) component speakers in the front driver/passenger, and (2) 6 1/2's in my rear. Also on each channel i have a GLI installed. I have an 800W 2 channel amp, with a 3 farad capacitor( 1 farad and 2 farad capacitor in series) connected to it for my subs, which are 2 10". i dont remember the ohm rating on them. The entire system is Rockford Fosgate. My question is this. To make things easier im gonna call the battery under my hood (P), and my secondary battery (S). If i wanted to connect that other battery i had in my system, would it be simply a matter of connecting the positive from battery (P) to the positive of battery (S) and then connecting the negative on battery (S) to the chassis and then connect my system to the positive of battery (S)?. I will still keep the fuse i had originally which was connected on battery (P) for my system. Is there anything else i should add to it?, anything you guys would suggest/recommend? Will this harm the batteries? Any input would be greatly appreciated, thanks!.

A 1F & 2F cap in series is 0.667F, but I suspect you have them in parallel, hence 3F is correct. (If in series, your amp wouldn't even power up!) For the battery and system interconnection, essentially you are correct but there are other things to consider. BOTH batteries require a fuse (one at each end of the interlink). An isolator should be included. This could be automated, or a manual link when not being driven (ie, charged). Try searching hereon else googling "uibi" for threads that cover all the above. Maybe add "oldspark" to the search. Another issue is the caps. Your system is too small to require them (for battery protection), so if they add wiring complexity or extra battery to amp joins, remove them. [ That advice is only because you already have them. Caps are rarely required for audio systems. Their main function is extra income for their sellers, though apparently a bling market also exists (I just paint tins of Campbells instead). ]

ohh my apologies, i meant parallel thanks for clearing that up. Yes i will have a fuse on both +ve ends of each battery. Now i read up on ur other posts regarding battery isolators, very well informed i must say. My only question is what exact isolator am i looking for? Princess Auto has one thats 90A. Should that be enough for what im running? And im going to wire it up exactly like this other guy did but minus the T-blocks on both of them, i will just have a fuse going in between the battery and the isolator for both batteries. Am i heading on the right path here? lol well i always thought that capacitors were used to smoothen out the bass because it stores voltage that is easily accessible, almost like a filter. i do notice a difference when a cap is connected and when it is not, IMO especially when im pumping the bass on my subs. and i laughed pretty hard at the campbells comment LOL

You may not have read enough of my posts - there may be more explanation and comparison at mp3car.com. That Princess isolator is a diode type which IMO is exactly the type to avoid. Similarly for their equivalent MOSFET versions. The best IMO is the UIBI or alternator-controlled relay assuming you have some form of charging or not-charging indicator. That has none of the problems that voltage sensing isolators have, and of course is much cheaper. Otherwise a voltage sensing type. If of insufficient capacity, have it drive a relay of sufficient Amperage instead. PS - caps smooth out VOLTAGE no matter what it is. But so does a battery - it too is a cap, tho a battery can also self-generate additional current. A typical car battery is many thousands of Farads. As to being easily accessible, what difference is there? It's a few 100,000 km per second thru copper cable. [ And if arguing battery/chemical delays, then include the battery's surface charge and plate capacitance. Give me real waveforms to compare - it should be so easy to place a CRO across the amp terminals and yet no one has done that in what - over 30 years??! ] Besides, non of the cappers state how long the cap will hold up the burp. I find that rather amusing. The Campbell's can is a reference to a well known painting (LOL). I'm merely suggesting a tin can which is cheaper and lighter and probably as effective as a cap, but just paint it up like a cap so it can be shown off. Unless emptied first, it is also a good emergency ration in case the audio-depleted main battery leaves you a bit flat.

OHh i see. my fault then.. where would u go about purchasing a UIBI? And as it stands i noticed yesterday, that my passenger side front speaker started cutting out, then stopped working. Only the tweeter works.. i took the door panels off, checked the wiring and the speaker and everything seems fine, no loose or damaged speaker. Then about 3 hours later the front driver side speaker stopped working, Only the tweeter did... And sure enough an hour later both back speakers started cutting out and now they no longer work.. i checked the amp and connections, everything seems good.. i think my amp just went on me now ;s.. ugh if its not one thing its another.. the joys of having a car

Your fault?? I don't see how anyone trusting & buying commercial products etc is their fault. However I consider the bullsh that accompanies some products to be criminal - as do our Consumer Affairs agencies. I presume your speakers are cutting out because of a flattening secondary battery? If so, have you got the 2nd battery (S) connected to the main (P) battery? If it's not being charged, it will obviously flatten. And the less it is recharged (to replace lost charge) the quicker it will fail lifespan-wise. If you are using a diode isolator like the Princess, you may be experiencing the common problem with diode isolators (MOSFET types aren't as bad) - namely: - if you have a single-wire (D+) alternator, then your batteries will probably be undercharging by up to 1.0 to 1.5V depending on the load. At minimal load, they are probably ~0.6V less than the alternator output. - even if you have a 2-wire alternator with its sense wire direct to the main battery, the other battery will charge at a different voltage if their loads are not the same. If your system is 2200W RMS, then at full blast its demanding over 200A which would blow a 90A Princess. Hence I assume the amps are not RMS rated, or you aren't exceeding ~1/4 volume. Nevertheless, the amps may be using 50A-90A which is probably far more than your the normal current thru your main battery diode. Hence even if your main battery is at (say) 14.2V, the secondary battery will receive a lower voltage from the alternator. The UIBI is not a commercial package, it is merely a DIY solution that uses the existing charge-light circuit to energise an isolating relay. The relay is selected to suit the application (30A, 120A, 400A etc).    The one proviso is that the alternator's charge light circuit (D+ or L) has the capability of supplying the +12V current to the relay coil. Hence a small relay (eg, 30A; usually up to 250mA coil current) might be used to energise a large relay with 1A or higher coil current. Or a buffer circuit added to drive the relay(s). The alternative is any voltage sensing type isolator whether a cheap MW728 "battery protector" (~$20, but with some provisos) or the more expensive battery and "smart battery" isolators. In general you can use them to drive bigger relay of your choice if their current rating isn't high enough. (Or, like the UIBI, have them drive multiple relays for multi-battery installations.) But diode isolators - no way! And though newer MOSFET types overcome part of the diode voltage drop problem, relay types are generally the better and more versatile, and often cheaper. FYI:- On the commercial side, I was intending to build a UIBI-2 which is a simple solid-state (transistorised) buffer circuit to drive any relay from any alternator - ie, those that can't even power a 100mA-250mA relay coil, and newer CPU controlled alternator systems (DP etc types). There was also a UIBI-3 to supersede the UIBI-2 which was to be a programmable UIBI - including the option to use it as a typical "smart" or voltage controlled isolator but where the user can adjust the voltage switching levels and delays etc. The programming would be via a serial link from the user's PC or tablet etc. But the UIBI 2 & 3 are yet another of my "one day" projects though I might build a simple UIBI-2 (MOSFET buffer) today for a trip tomorrow.

haha i meant it as i read that wrong lol, thanks though. well alot has happened since my last post so ill give u an update my sisters battery ended up dying, so being the nice brother i am i ended up giving her my new one.. so as of now that whole second battery option is out the window.. BUT i will be saving this thread so when the time comes i can look back on it.. i appreciate the info.. i never ended up connecting the secondary battery so im not sure how the speakers were cutting out.. i have 6 1/4 component speakers in the front, and 6 1/2 component speakers in the rear. i checked all the channels on the amp to make sure it was not the amp, all the channels are fine and work. the only thing that works in the front is the tweeters thats it. I took my door panel off and checked the unit to see if it could be the component unit itself. all the wires were still connected and the tweeter still working.. i then connected a wire directly from the amp to the 6 1/4 and tested it, and nothing. no sound, no nothing.. that was the front passenger side, i couldnt test the drivers side cause it started to get cold and dark out. The 6 1/4 are rated at 4 Ohm 100 Watts RMS - 200 Watts Peak I noticed this when i took the speaker out         im not sure if this could be a factor or not, cause if it was wouldnt the speaker make a sound regardless once it was connected? and why would my drivers side cut out as well after my passenger side did?.. any thoughts ?? OH and oldspark ull get a kick outta this... i went to test my caps and see if they are holding voltage.. turns out my 2 farad cap was dead lol, when i measured it was at 1.45V while my other cap was 12.45V. lol

Sorry - I missed your last reply. The 2F cap may be ok, it depends how long since it was connected. They each have their own leakage but many have a self-discharge function else other leakage (maybe a voltmeter?). When connected to a battery, they will have the same voltage as the battery - eg ~12.6V. And - for the benefit of others! - NO, they do not magically have a higher voltage than that battery. However if the system is charging, it will still have the same voltage as the battery (eg, 14.2V) though if removed, the cap will have whatever ripple voltage was present at the time which may be higher or lower than the battery voltage (eg, 14.0V or 14.4V etc. When caps fail, they usually fail in short-circuit mode. Hence they can bring down the system voltage if bad enough, get so hot they flame or explode. They will also drain the battery (as will any such "leakage". I'm not a speaker expert, but that ding looks like a normal "something has hit it" thing - maybe a screwdriver tip whilst fitting, and IMO that should not cause problems. If perhaps EXTREME cone movement has hit something (but how & what?), then maybe that coil has been damaged - ie, cooked, hence shorting, hence overloads and cut out. You could test that by comparing their rear temperatures after running a similar program (music) thru them. If there is a difference, swap speakers with the same program to confirm. But the their volumes should be different, but volume varies less than their power and heat. Again, I am not an expert....