twin battery set up

Bump said:

another vote for 2nd alternator

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If only I knew someone who was good with vehicle electrics to help me wire it all in...

Mark L said:

If only I knew someone who was good with vehicle electrics to help me wire it all in...

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too far away for me im afraid

2nd alternator vs simple split charge addresses separate problems really.

Allow me to explain.

If you run two separate systems with 2 separate alternators that's great but you only get the benefit of 1 alternator and 1 battery, you dont join the systems.

If you run a split charge then you have the benefit of two batteries to sup from when winching but separate batteries when overnight camping etc.

You could run two alternators connected together so that you have 200 amps available when winching and two batteries to sup from, yet when camping you simply run off the one battery.

There is a possibility that running two alternators is a problem cos the regulator packs oppose each other and you get voltage/charging trouble.

This is something needing research.

Anyway, basically running two separate systems sorts the issue but then you don't get the benefits of when the batteries are connected.

Then there's the super idea of wiring 24v to your winch and 12v to your car but even I didn't persue that one because I wanted a simple life

if u run an upgraded 8274 even linking the batterys the tail of in power is very noticeable,,

I wouldnt entertain over volting my 8274,just feeding it correctly is the way I will be persueing.
the benefit of 2 alternators vs split charge if u run a single alt and it fails ya buggerd,running 2 if one fails its only a simple case of switching leads and you have power again

Is there no option to run a higher capacity single alternator? Not sure of there's an off the shelf part but it shouldn't be too difficult to make one off a different car fit?

Most modern alternators kick out loads more juice than a disco unit. Making the rev counter work could be an issue though.

Disco's usually run with a 100amp alternator instead of the 65amp ones fitted to defenders

phil540uk said:

Is there no option to run a higher capacity single alternator? Not sure of there's an off the shelf part but it shouldn't be too difficult to make one off a different car fit?

Most modern alternators kick out loads more juice than a disco unit. Making the rev counter work could be an issue though.

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I use a 300 tdi alt in me 200 disco that's 100amp output

I've had the same starting problems with mine in the cold even though I have cleaned all the earths fitted an 800cca battery etc ever since I bought it 4 years ago. Recently fitted another 800 cca battery and removed the airbox elbow and got some original battery leads from a broken disco and sent the positive to the original battery and negative to the block of the engine by bolting it to the dipstick bracket and can now start it before the glowplug light goes out even in sub zero temps, it would never start before this was done.

Very good shout on twin alternator for backup, better than relying on just the one.

I would like some kind of upgrade for my 3.5...

Mr Noisy said:

Just to let you know our 300tdi is a right sluggish starter when it's cold too.

Has been that way ever since and one does not seem to have identified a fault, yet nor has one looked for said fault

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I agree with Mr Noisy here, 300tdi's can be sluggish.

I had a iffy starting disco, new Bosch 2.5Kw high speed starter motor and my starting issues were a thing of the past.

I can now start it at -10° C with Bio in the tank without the glowplugs.

phil540uk said:

Is there no option to run a higher capacity single alternator? Not sure of there's an off the shelf part but it shouldn't be too difficult to make one off a different car fit?

Most modern alternators kick out loads more juice than a disco unit. Making the rev counter work could be an issue though.

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Yes you can get a 140 Amp alt for the 300tdi - to be honest though, it should be fine with a good battery, cables and starter.

I have a 100 Amp alt, 800CCA battery, and my big starter motor - perfect.

exjay9 said:

Hi
Since its got cold, my 300tdi auto is "reluctant" to start. The battery is only 6 months old & it and the alternator are ok (I took it back to eurocarparts and they tested it, 100% charged & 99% healthy)
It spins over faster and starts ok with a battery pack connected, so I think it needs either the more powerful battery or dual batteries.
What I would like to know is, if I put a second battery in, could I just connct the negative to the chassis and the positive directly to the existing battery?
I dont have a winch or extra lights, I just want more starting oomph!!
Thanks
Gary

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Had similar probs with mine .. When I bought my Disco the seller did say it'll probably need a new battery, so when it started to struggle to start I went out and got a new 1, couldn't use a bigger CCA one as it wouldn't physically fit because of the air con pipes . As I wasn't using my Disco very often it was still struggling after a couple of weeks without use with the new battery (been told the alarm takes it out of the battery) so I got myself a 12v 4w solar panel off Ebay ... so far so good starts like it should but suppose only time will tell especially now its getting colder

Just for reference here the minimum battery requirement for a disco is an 072 battery.

Obviously bigger is better but that's the smallest they can handle really.

Ok, this is fun, so its two batteries, two alternators, re-wiring, better starter and have I missed anything, split charging and a Solar Panel. Oh and check the glow plugs.

I like this thread

It will definitely be better if you fit everything

GreenHornet said:

For £24 you get a 200amp solenoid from Vehicle Wiring Products which you can switch from the ignition so you get both batteries on start and they both charge but they are separated when you stop the motor. Either use the ignition or use a simple switch on the dashboard.

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I like the sound of this. do you have a link (I've looked at VWP website, but don't really know what I'm looking for) and/or a wiring diagram??

the old 200 struggles a bit on start up when cold so the battery is isolated and she's on a permanent solar trickle charge when parked up now. I'd like to put a second battery in but cant justify the price of a second alternator or of those fancy systems advertised in LRO

JKx

Have a look in the FAQ section - madhatman 's post about splitcharges gives you all the info you could ever need

Here have a read : http://www.landyzone.co.uk/lz/f38/wiring-split-charge-relay-system-61268.html

Jay reKx said:

I like the sound of this. do you have a link (I've looked at VWP website, but don't really know what I'm looking for) and/or a wiring diagram??

the old 200 struggles a bit on start up when cold so the battery is isolated and she's on a permanent solar trickle charge when parked up now. I'd like to put a second battery in but cant justify the price of a second alternator or of those fancy systems advertised in LRO

JKx

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VWP - relays

R200R is the one you want £26.

My 200 never struggles although I do notice, as with my Zafira Diesel, that when very cold weather strikes they are slower to turn over but never struggle to start.

I decided in the end to try a bigger battery. The one I bought 6 months ago was listed as the correct one on eurocarparts site - it is a 031 70Amp 540cca, I think this one was a bit too weedy.
So I bought the other one they had listed, a 664 105Amp 760cca. I tried this morning, probably the coldest its been so far, I gave it 2 lots of glow plug, and it started after about 20 seconds of cranking.
Cured - I hope! (was a tight fit in the battery box though!)