Spare battery!

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uclarge
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Spare battery!

Post by uclarge »

hiya guys, for some period now ive been considering for my project morris a second battery, the primary will run stuff like the "lights, engine" etc... but my secondary battery could run my ice which will be installed, i.e. cdplayer, amplifier, speakers, 6"9's, and anything else i decided 2 install at th time! now how do u reckon i cud do this? have 2 alternator leads? one to the primary and one to the secondary? also itd be good becos if my primary goes flat i cud use the secondary 2 get going then flick a switch back 2 th primary, what do you guys think? any advice, itll have 2 be done tho sum way or th other.... charly
Cam
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Post by Cam »

I did this many years ago (about 10 ish) with a Mini when installing a 1715 watt stereo system consisting of 17 speakers (inc 1 x 10" and 2 x 12" subs) and 5 amps. Plus CD multi-changer, graphic equaliser etc.

I used a large alternator and 2 batteries wired in parallel. there was no need for split-charging or anything fancy, just a LARGE capacity. I also used 2 Mini (4 fuse) fuseboxes for the stereo system and LOTS of thick cable for power and speakers.

Mind you, I could flatten both batteries with the stereo on full with the engine running!!! :lol:

Now I just have a little cassette player in my moggy......... amazing how you change over the years!!! :wink: :lol:

It all depends on how far you want to take it. You might get away with a single large battery and uprated alternator....
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Post by wanderinstar »

17 speakers in a MINI, where on earth did you put them all.
uclarge
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Post by uclarge »

cheers, but the alternator kit for a morris? would that be enough to charge both units? i planned to keep them spperate (the batterys) from each other, but both being able 2 charge, c what i mean, thats crazy but almost the same amount as im going 4 as music apart from mechanics is one of my best hobby! i just wanted 2 gather sum advice from sum1 who may have already done it, i.e. u cam!, cheers buddy, if u have any further advice, however lame, daft, how did you wire it up? etc, charly (i do this just so i dont blow myself up)
>Charly, 20yrs Chichester.
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Post by Peetee »

17 speakers in a MINI, where on earth did you put them all
Easy. He took ALL the seats out and towed it behind the MG.
CAM - BLING MEISTER!
Older and more confused than I could ever imagine possible.
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Post by Cam »

Peetee wrote:CAM - BLING MEISTER!
:evil: No mate! That was well before Bling! :wink: :lol: and they were (almost all) hidden under black speaker cloth. You could not tell from the outside.
wanderinstar wrote:17 speakers in a MINI, where on earth did you put them all.
Well........

1 x 10" sub in middle of rear parcel shelf.
2 x 12" sub behind rear seat back.
2 x 6x9 full range in pods on rear parcel shelf.
2 x 5 1/4" midrange in each rear parcel bin (2 per side - 4 in total)
4 x 6 1/2" midrange under rear seat.
2 x tweeters mouted on top of dash.
2 x 6" full-range in front doors.

All housed in thick MDF and acoustic wadding.

1 amp bolted vertical behind rear seat back (next to subs).
1 amp under driver's seat
1 amp under passenger's seat
1 amp at bottom of rear parcel bin (under the two 5 1/4" speakers)
1 amp at bottom of rear parcel bin (under the two 5 1/4" speakers)

CD multichanger under driver's seat staggered and spaced from amp. Head unit & graphic equaliser in dash.

AND you could still carry a 2 passengers in the rear and one in the front + SOME luggage in the boot (not much though).

Everything was wired up individually and separately fused. As long as you are methodical you should be OK.

I would not attempt it now as I don't want to anymore.......... BUT there is more space internally in a Mini than a Moggy! Much more space!

So, uclarge, what sort of system had you in mind? Also bear in mind that it cost a fortune to do. I tried to get a lot of stuff 2nd hand and bought the cabling from an electronics supplier not a stereo shop!!! :lol:

I guess it still probably cost over £1000. and that was 10 years ago.....

You could fit 2 alternators (seen that done) and wire them in separately (one to each battery) but you have to be careful with that so I would not really recommend it unless you know exactly what you are doing.

If you are hell bent on two separate batteries (which I don't really see the point of) then you could get a leasure battery and split-charging sytem from a caravan/motorhome specialist.
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Post by bigginger »

Well, I bet the neighbours loved you, Cam...
Well.......... I never switched it on at home or anywhere near. You see if the local 'boys' had got wind of it then it would disappear VERY quickly! :lol:

All they have to put up with now is grinding, welding and hammering noises........ :lol: but at the weekend you can usually hear a couple of grinders going round here anyway........ :D
:wink: BTW!
Got that! :wink:
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Post by ColinP »

Charly,

I think the best way is to go to your local caravan dealer. They will sell you a device ("diverter"?) that allows the alternator to charge the spare battery without the standard one being affected.

It's designed so that the caravan's 12v High capacity battery can be charged while towing. It also avoids the problem whre one battery has a low charge. Connecting both in parallel at that point will cause the "good" battery to discharge rapidly to equalise the voltages (and IIRC the internal resistance of a 12v battery is a fraction of an ohm = LOTS of current - lots of heat = melted wiring!).

Cam's idea works (obviously) because both batteries are charged/discahrged at the same rate (but if one starts to fail, the other will be killed as well).

Colin
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Post by uclarge »

wo! never thought of a caravan idea... how much do u believe one of these would cost colin? i never thought i could melt everything, thas quite a scary thought! thank god u voiced it/well typed it, cheers charly
>Charly, 20yrs Chichester.
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Post by Alec »

Hello Uclarge,

The easiest but not cheapest is to put two physically small but high capacity batteries in parallel, but you will also need a high capacity alternator to match and suitably sized cables to carry the charging current.
If you are intent on splitting the batteries into two systems you will need a diode in the charging cable to prevent the supplementary battery discharging into the main car circuits. I.e. it will be charged by the alternator (you will still need a large capacity alternator) but cannot feed the starter\ etc.

Personally I think it's crazy, as cars are abysmal places to have a hi fi installed, but it's your car.

Alec
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Post by bigginger »

bigginger wrote:
Well, I bet the neighbours loved you, Cam...
Well.......... I never switched it on at home or anywhere near. You see if the local 'boys' had got wind of it then it would disappear VERY quickly! :lol:

All they have to put up with now is grinding, welding and hammering noises........ :lol: but at the weekend you can usually hear a couple of grinders going round here anyway........ :D
:wink: BTW!
Got that! :wink:
Is it just me, or has my message (from which Cam quoted) disappeared?I'm starting to think my 'puter's haunted, with messages changing order as well...
a
BTW, just noticed that Cam's meesage appears to have been written by me too... ???
Last edited by bigginger on Sun Jan 23, 2005 7:47 pm, edited 2 times in total.
Cam
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Post by Cam »

Alec wrote:Personally I think it's crazy, as cars are abysmal places to have a hi fi installed, but it's your car.
:lol: Agreed!!

It is fairly crazy and you are NEVER going to get high fidelity reproduction in a little tin box of an awkward shape but I don't think that's your aim is it?? :wink:
ColinP wrote:Connecting both in parallel at that point will cause the "good" battery to discharge rapidly to equalise the voltages (and IIRC the internal resistance of a 12v battery is a fraction of an ohm = LOTS of current - lots of heat = melted wiring!).
Well....... that depends on the wiring. If you use starter motor type cable to join them together (like I did) then it's fine as you don't melt your jump-leads do you when you connect one dead battery to a good one do you?

To be honest for your needs, either one large capacity battery or 2 smaller ones in parallel is the way to go.
Cam
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Post by Cam »

bigginger wrote:Is it just me, or has my message (from which Cam quoted) disappeared?I'm starting to think my 'puter's haunted, with messages changing order as well...
Looks fine to me mate. It's all still there........
bigginger
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Post by bigginger »

Jhst my 'puter then - very queer...
Cam
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Post by Cam »

Using all my computing expertise I would say I have to agree with you and come to the conclusion that it's haunted! :lol:

Who you gonna call?? :lol: :lol:
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Post by bigginger »

Rentaghost, of course, not those horrid Americans.. :)
Image
a
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Post by Multiphonikks »

Heh... got the themetune for that somewhere... :)
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Post by bigginger »

Well, at your next party, be a smarty - and play it! :)
a
Cam
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Post by Cam »

Multiphonikks wrote:Heh... got the themetune for that somewhere... :)
:lol: me too! Blimey it's been a while since I've seen that!! :lol: Fab! :D
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Post by guydenning »

i'd managed to wipe that from my traumatised childhood memory... until now

fred mumford eh? where is he now?

what's that behind you? your acting career mate
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