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Split charge??


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Ive got 2 brand new, identical batteries for the D-Lander, is it really worth using a split charge to connect them, or should i just wire them in parallel without any charge control system?

Also whats the best way of wiring them, + feed and - earth to one batt and then linked over to the next or + feed to one, links across and - ve off the second battery??

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Unless they are specifically made for connecting together, then you need to run a split charge system. Never tried it, but have heard good reports about Simon's system: www.x-eng.co.uk

The reason being that there will always be discrepancies between the batteries so they will end up cycling charge from one to the other and back again. This will wear them out quickly. The ones that are made to be connected together are laser trimmed so that they are as close as possible to being identical.

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Guest diesel_jim
Unless they are specifically made for connecting together, then you need to run a split charge system. Never tried it, but have heard good reports about Simon's system: www.x-eng.co.uk

The reason being that there will always be discrepancies between the batteries so they will end up cycling charge from one to the other and back again. This will wear them out quickly. The ones that are made to be connected together are laser trimmed so that they are as close as possible to being identical.

^^^^^ but the x-eng split charge unit is just a relay that energises when the ignition is on (or alternator starts charging... depending on how you wire it) so all it does is link both batteries together...

use a blocking diode type split charge if you don't want them to drain into each other, but you'll lose 0.7 of a volt from each battery as the diode naturally takes this voltage across it's contacts.

an all singing all dancing electronic unit will give 100% voltage to each one if you want to spend the ££££

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I had a pair of 072 batteries in the lightweight for 5 years, wired together and never a problem. Perhaps I was lucky.

I also had a Maplins solar battery charger plugged in when not using it so perhaps that helped, 2 watts I think so not really a charger more a conditioner.

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Si's X-charge ties the batteries together when they're charging so the voltage can't shuttle, they're both pulled up to 13.7v from the alternator. When not charging, they're separate so they can settle at their own voltage. To my mind this means you could use totally dissimilar (12v) batteries, like a tractor battery for your engine and a moped battery for your spotlights, radio and fridge. Obviously the fridge wouldn't work for long but you would be able to starat the engine and recharge the smaller batt.

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I have been through all of this, and there are advantages of split charges, and yep Si R is VERY Good value for money, and yes the ££££s ones really are £££££££££££££££S :lol:

I have finally done the following

2x Optimas (matching)

Starter and gubins to BIG FIA Cut Off Switch

Other side of switch to Battery + Battery No 1,

Battery No 1 + to Battery No 2 +

Battery No 1 - to Battery No 2 -

Battery No 1 - to chassis

Battery No 2 - to other chassis mount

Then, disconnect cut out switch

When parked up connect Accumate (or smaller Optimate) Battery re conditioners (these are fanatsic bits of kit) to

Red lead to Battery 1 Positive

Black lead to Battery 2 Negative

And leave

this will fully charge up and test out BOTH Batteries at the saame time keeping them in tip top condiotion, you can (as I have) get a 2x wire and waterproof plug, so just "Plug in" the Accumate.

You can do each battery seperately but the links between obviously need to be disconnected. I have found the above is simple, and robust and works for me, and do bear in mind I am a fully qualified "EMC"

(Electrical Mumpty Cretin :lol:)

Nige

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I have, as have others

2x 096 batteries both connected together

never given a moments trouble even after 3 years and plenty of use.

batteries are a year different in age.

I run x1 100amp alternator.

cheap/easy.

mine are as per ^^^^ 2 x 092 bought together so same age and batch etc (£45 each).

wired in parrallel straight across.

and seems to cope well with 90A alternator off a 200tdi with a husky rear (Bowmotor) and 8274 front (4.6hp) been in there 2 to 2.5 yrs.

Sorry forgot to add - doesn't Si (X-Eng) do some batteries now as well at good ££££

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Ive got 2 brand new, identical batteries for the D-Lander, is it really worth using a split charge to connect them, or should i just wire them in parallel without any charge control system?

Also whats the best way of wiring them, + feed and - earth to one batt and then linked over to the next or + feed to one, links across and - ve off the second battery??

I have a National Luna split charge solenoid and dual battery monitor with alarm to sell, with full installation and user instructions.

For info see here - http://www.nationalluna.com/battery.html

It is in excellent condition £100 if you are interested. (New with the battery monitor they cost c£240)

PM me if interested.

John

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I have a National Luna split charge solenoid and dual battery monitor with alarm to sell, with full installation and user instructions.

For info see here - http://www.nationalluna.com/battery.html

It is in excellent condition £100 if you are interested. (New with the battery monitor they cost c£240)

PM me if interested.

John

I've had one of these before, was very good but a wee bit costly!

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Probably being a bit of a numpty here, but since I am looking to fit a winch in the near future I had better ask!

I had made the assumption that I would need to fit an additional battery when fitting the winch, and also assumed that it would be stand alone solely for the winch and fed via a split charge system.

Is this not the way to go?

Do you just connect the batteries in parallel, and thus pull power from both when operating the winch?

What are the pros and cons of each way of doing it?

Mine isn't a challenge truck, and only likely to see it used a few times a year to be honest, but it will need to work!

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fit an additional battery when fitting the winch, and also assumed that it would be stand alone solely for the winch and fed via a split charge system.

my Husky winch has a stanalone battery & kept up with the standard LR Defender split charge relay system, never given me any problems, my other battrey runs evrything else on my 110, the only additional thing I do is to rotate the batteries duty about every 6 months & occasionally put the mains charger on them.

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If you have a split charge connecting the two bateries together you can't say one is powering the winch and one is powering everything else. If they are connected together, either direct or with a split charge, then everything will draw power from both batteries (that's why you need a beefy split charge like the X-Eng unit if you are winching). The only way to have totally seperate batteries is to have two alternators and keep the two circuits seperate.

I just stuck in a single big 664 battery

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Guest diesel_jim
OK, so when I disconnect the start batt why does all the other kit except for the winch not work. noting that the split charge would obviously need a energising current.

Are you disconnecting the earth from the main battery? (as in, disconencting the lead that bolts to the chassis/gearbox and onto the battery.... if so, and it loops to the second battery, then you'd be disconnecting that second battery from the loop.

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OK Mark I can see what you are saying. I think

Does the split charge relay simply connect across the two positives of the batteries if engergised?

I had assumed that it was a bit more involved that that, more like diverting the power from the alternator to whichever battery needed it the most.

If that is not the case, then I can see the need for a heavy duty relay rather than a caravan shop accessory!

It sounds as if most of you have gone for the parallel battery option without the relay, would this be a fair assumption?

If this can stand perhaps an hours use while recovering then that would be the way for me to go I think - simple like me!

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Are you disconnecting the earth from the main battery? (as in, disconencting the lead that bolts to the chassis/gearbox and onto the battery.... if so, and it loops to the second battery, then you'd be disconnecting that second battery from the loop.

nope disconnected the live 12v terminal & nothing from winch batt when I try turning things on including ignition.

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Does the split charge relay simply connect across the two positives of the batteries if engergised?

Yes, so any load draws from both batteries and the alternator supplies current to both batteries. The split charge simply disconnects the batteries when not in use so they don't suffer the issues (that many people don't experience anyway) of having batteries permanently in parallel.

Ralph, if you disconnected the +ve terminal from the starter battery and this terminal had all the live connections for everything except the winch then only the winch would work as only the winch can see the +ve side of a battery. If you energised the split chage relay manually (from the winch battery obviously) then everything should work from the winch battery, assuming a common earth path, but starting the vehicle may blow the split charge relay as it would be taking 100% of starter current.

But if we're taking about a 'normal' situation of everything connected and split charge energised, ie vehicle running, then both 'winch' and 'starter' batteries will share all loads irrecspective of which battery they are directly connected too.

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We had a yellow top Optima for the main battery in the 90 to start with. But we got ARB in brisbane to fit a split charge system. The put anothe deep cycle battery

battery.jpg

But the best thing i like is the battery moniter as it tells you what is in each battery and what it is doing

With out car running

batteymetter.jpg

And with the engine running

batterymettercharge.jpg

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OK another numpty question.

Lets assume I go for the easier option of directly connecting the two batteries together, am I likely to have problems with the standard "Prince of Darkness ecu due to voltage drop?

The alternator is a standard RRC / 200tdi Discovery unit. Not sure what the output is.

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apologies if any of this has been mentioned before, i only skim read the post. hopefully different details/depth will be helpful.

National Luna et al are still a relay that gets closed,like Si's relay, the box just decides when that happens, like a VSR. there is nothing intelligent about them at all. They look at the voltage, and close and open the contacts when the batteries reach certain levels.

With, Si's relay, a VSR, and a 'national luna' style charger, once the batteries are joined they act as one, in terms of both charging and drains. they will remain acting as one until the relay is opened.

Proper 'intelligent controllers' control the voltage and current going to each battery independantly, quite often by actually controlling the alternator its self. they including cycling programmes to 'service' each battery. they are fitted mainly to boats and are proper money - often ££££.

The 0.7v drop across diodes means the batteries will never get properly charged with a standard 'machine sensed' alternator. fitting a 'battery sensed' alternator would allow the alternator to compensate for the voltage drop between it and the batteries.

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IIRC from the 101 forum, you can change a machine sensed alternator to remote if you are a dab hand with a soldering iron, but I have not seen the info on what is required.

Just been to Si's site and waiting for stock on the relays, but since I ain't home at the mo that doesn't matter. As long as they are in for some last minute Christmas shopping :-)

Does anyone know if during heavy winching ( not that I am planning that of course ) the alternator warning light would come on if the batteries were being dragged too low or should I fit a voltmeter?

Driving an auto, so bump starts aren't an option, hence my pre occupation with battery life etc.

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