Quick X Charge Question

[disco_al]

Morning all,

I finally managed to get the 2nd battery in place over the weekend, and hooked it up to the x-charge relay and ground, so it's ready to receive it's charge and be used for my auxialliaries

just a quick question though - which wire on the alternator does it need to attach to? i know it's the sensing wire for the dash warning light, but which wire is it as there are two (from memory) thin wires out the back of mine, one is obviously for the rev counter.

on is a bolted connection and one is a spade connection.

cheers

[FridgeFreezer]

Brown/yellow if the wiring is standard.

[mmgemini]

NONE!

If you do it that way with some alternators the alternator will blow.

Use a White ign live.

HTH

[FridgeFreezer]

If you do it that way with some alternators the alternator will blow.

Use a White ign live.

Does that not largely defeat the point of the split-charge though?

Admittedly the BMW alt we put on the 90 wouldn't switch a normal relay let alone an X-charnge, but didn't seem to suffer from the experiment.

[disco_al]

when i had it fitted on the v8 it didn't cause any issues, although the wiring was a bit easier to spot on that one due to the plug rather than bolted type connections.

[mmgemini]

No FF it doesn't, it works just the same.

As alternators are very expensive I don't like to see money wasted.

If you have a TD5 that is the only option.

[Retroanaconda]

It works the same except that if you have the ignition on but the engine off the batteries are still connected.

If you are worried about damaging the alternator, then I would use an oil pressure switch to determine if the engine is running or not, and switch the split charge relay with that.

[FridgeFreezer]

No FF it doesn't, it works just the same.

Erm, no it doesn't - the point of running it from the charge warning light is that if the alternator can't cope, the light comes on and the relay drops out, so you're charging the main battery and only charging the 2nd one if the alternator is happy. Running it from ignition switched live you're basically paralleling both batteries as soon as you turn the key.

[mmgemini]

Right FF You fit it your way and blow alternators.

I've had no problems but two trips one over six months with the fride working all the time don't mean anything. At £170 a time I suspect you must be able afford an alternator to last less than a second

I only give advice on any forum from what I've experienced.

I can only thank John_T for his help in this matter some years ago.

[Se7enUp]

It's mainly late 300tdi's and TD5's that have the problem with their alternators going pop and the split charging not wanting to work.

All is revealed here

[mmgemini]

It's mainly late 300tdi's and TD5's that have the problem with their alternators going pop and the split charging not wanting to work.

All is revealed here

Yes I agree but I wouldn't call 1994 builds late.

It's a pity that the alternators that don't allow a split charge to work off the alternator warning light can't be identified.

[rusty_wingnut]

I've done over 12k miles on my 1996 def with the setup as per the manual XEng provide (can't remember the config) and it's been fine.

[PaulMc]

Using a Voltage Sensitive Switch to control the X-Eng (or any other H/D) relay is a much better idea.

The Land Rover part (PRC4427) is readily available -

. . .

They can be picked up cheap on eBay (they're silly-money new )

A SmartCom Relay (12S towing electrics) from TowSure will also do the same job.

.

[FridgeFreezer]

Right FF You fit it your way and blow alternators.

Jeebus Mike, I'm not suggesting blowing up alternators, just pointing out that there is a good reason why the split-charge isn't just wired to ignition live, and the difference in behaviour could matter to some.

The voltage sensitive switch, as mentioned above, is an ideal alternative and provides the same function - if the ignition switched voltage drops, the split charge will drop out and remove the extra load from the system, allowing the vehicle to continue running & charging the main battery.

As an example, if your 2nd battery goes totally flat, or faulty, with the relay wired to ignition live as soon as you turn the key on you are connecting a massive load across the main battery. Depending on the situation, this could prevent you from starting the car and you could find yourself stuck with two dead batteries.

[mmgemini]

FF I agree the VSR is the way to goI just wish that they's been available at a sensable price when I did mine.

I might look at Pauls VSr before thas next trip. I believe the rear wiper uses one. Now that I've no rear wiper I wonder where I can find that VSR relay.

[Adam001]

Erm, no it doesn't - the point of running it from the charge warning light is that if the alternator can't cope, the light comes on and the relay drops out, so you're charging the main battery and only charging the 2nd one if the alternator is happy. Running it from ignition switched live you're basically paralleling both batteries as soon as you turn the key.

You are mistaken the relay will not disengage in that situation, alternators do not work in the way that if the alternator cannot cope the battery light will come on, that is not true, the battery light will always remain off regardless of load unless the alternator completely dies and the return to earth is completed. Or in other words it is possible to drain your battery while running without the light coming on if you put enough current across it. If you are in doubt as to the alternator you have, put in a manual switch.

As for X-charge, do it properly, get yourself a better version, the relay X-eng ues is not in my opinion equiped to deal with the tasks they suggest.

I have had a look at a kit and the relay is rated to 100amp and the wiring is a measly 16mm2, which are not sutiable for winching even with a peak load of 180amp

I made my own using 35mm2 cable and a 200amp continuous relay...cost me less than the X-charge kit and because it is stronger I have a manual switch on the relay I can leave them connected during starting.

Adam

[western]

FF I agree the VSR is the way to goI just wish that they's been available at a sensable price when I did mine.

I might look at Pauls VSr before thas next trip. I believe the rear wiper uses one. Now that I've no rear wiper I wonder where I can find that VSR relay.

it was for the rear heated screen, to turn it off if the engine/alternator was not running/charging, a way to prevent battery drain, if fitted look behind the instrument pack to the front right corner/behind the 3 rocker switch panel to right of steering column.

[simonr]

As for X-charge, do it properly, get yourself a better version, the relay X-eng ues is not in my opinion equiped to deal with the tasks they suggest.

Opinion - not fact!

We tested a twin battery setup with a single 8274 equipped with a 6.5Hp motor. At stall the motor drew 540A, but the cross-flow between the batteries was 180A.

Based on our testing, the winch motor windings will expire before the relay.

What is it suitable for?

Single winch, with uprated motor - Yes

Aux lighting, Inverters, Fridges and single winch - Yes

Twin motor winch - No

Twin or triple winch setup - No

I have had a look at a kit and the relay is rated to 100amp and the wiring is a measly 16mm2, which are not sutiable for winching even with a peak load of 180amp

The relay manufacturer sells them to us as being rated to 180A for 20 mins and 100A continuously. We have tested one at 1000A until the casing started to melt. It lasted 2 minutes before we disconnected it - and although the casing was a funny shape, it still worked once cool.

We also tried loading to 180A and after two hours - figured that was close enough to being continuous. At the end, it was still working fine. It therefore exceeds the manufacturers rating - but I guess it pays to be conservative.

I made my own using 35mm2 cable and a 200amp continuous relay...cost me less than the X-charge kit and because it is stronger I have a manual switch on the relay I can leave them connected during starting.

A typical Land Rover starter motor draws about 250A under load - so, same as above, your starter motor windings or battery will expire before the relay.

The 16^mm cables are only 60cm long. The rating of cable necessary is dependent on the length as well as the current. As is covered in the instructions, if the batteries are next to one another in the battery box, the supplied 16^mm cable is fine. If the batteries are further apart (such as on either side of the engine bay in a Disco / RR) we recommend 25^mm or larger.

Right FF You fit it your way and blow alternators.

I've had no problems but two trips one over six months with the fride working all the time don't mean anything. At £170 a time I suspect you must be able afford an alternator to last less than a second

Mike, do you have evidence of this - or is it urban myth?

I've tried damn hard to 'blow' an alternator by connecting it up like this - and have totally failed. Sure there are lots of ways in which you can 'blow' the regulator, but this ain't one of them. Even if you do, a new regulator is about £15 from Wood Auto Supplies.

In the instructions, (pointed to on the first line), it says (paraphrased):

Some vehicles, notably Land Rover Td5 and late 300Tdi use what is known as a battery sensed alternator.

If you connect your split charge, you will notice that the charge light will remain illuminated and the relay will not energise.

In this case, instead of connecting the orange wire to the alternator, it must be connected to an ignition live which does not go live while the starter motor is cranking the engine.

A good example of this is the ignition power feed to your radio - usually the radio remains off while cranking.

It may be that if you leave it connected permanently like this, it will damage the regulator. I have only tested it for a week or so without damage - so it's not definitive.

If you follow the instructions - your alternator will not be damaged.

The kit is covered by an unconditional 5 year warranty - so I'm pretty sure it is up to the job, so long as you follow the instructions!

Lastly, VSR's

In many circumstances these are a good solution for split charging. Unfortunately, even the one fitted to the Land Rover rear de-mist (not the rear wiper) circuit as a new part costs about £70. Sure you can pick one up at Sodbury for 50p - but you can't really base production around that. I can buy a suitable VSR board to drive the relay for about £30 - but would you want to pay another £30 for the kit?

The problem with VSR's is they are fine so long as they are mounted inside a nice cosy, dry dashboard. Split charge relays tend to be mounted in a wet, cold battery box or engine bay. The VSR contains electronic components which do not appreciate the wet. A VSR which has got wet and the switching voltage changed is worse than useless. So, if you are going to use one - put it somewhere dry!

Chris (GBMud) came up with a good idea which is to connect the earth of the relay to the 'A' terminal on your winch motor. While the motor is running, this rises from 0v to about 6v, which switches the relay off. The result is that when you are actually winching, the main battery is disconnected from the winch battery giving you much reduced cross-flow between the batteries.

Sure, the X-Charge is not suitable for every application but it was intended to be a simple solution - no computers, no electronics, no issues with getting wet - and to be low cost compared to most other solutions. Of course you can make it yourself for less money - but not everyone has the knowledge (or interest) in doing so. But then, that's true of most products we buy.

Si

[Gromit]

I do enjoy seeing the results of actual testing rather than hearsay purported as fact.

Thanks Simon.

[FridgeFreezer]

[disco_al]

anyway - it's fitted and wired upto the centre pole on the alternator connections, and my multimeter is showing that it is charging the second battery.

reliablity and recommendation were my key factors in purchasing this kit in the first place. i don't do winching, but am planning to run aux lighting and power connectors off the leisure battery fitted on the n/s, so for my useage it's fine.

thanks to all for the pointers, most helpful as usual.

obviously if you are going to use it for running multiple winches or anything that will cause a high current drain, then something bigger is obviosly going to be better.

i know (mainly from the folk on here) that x-eng test their kit to the maximum and beyond, and so they know it's limits - for that i am grateful (as are many others that use their kit), as it is IMHO top quality equipment - and best of all its British engineering.

[mmgemini]

Simon

Yes I blew my alternator through connecting my Lucas split charge relay to the warning light wire. I can tell you the brand new alternator didn't last a second when the engine was started. I think I was the first person to come across this when I changed an alternator. I knew John_T had had problems with his TD5 so I went the same route as he did.

That's why I say don't use that wire. Nothing to do with your relay set-up just using the warning light wire. You do say in your instructions that the later alternators shouldn't be wired that way.

The difficulty is knowing which alternator isn't suitable to use the warning light.

[errol209]

The difficulty is knowing which alternator isn't suitable to use the warning light.

If I follow this thread correctly, then the older ACR type machine sensed alternators (which have a 12V brown cable, a warning light wire and possible a tacho connection to the W terminal) are OK, but the battery sensed alternators (which have an additional thin wire from between the alternator and battery) are not.

Yes?

[mmgemini]

errol

Yes it appears so.

The relay was fine with the 65Amp alternator. It was only when I fitted the 100Amp from a Discovery I hit the problem.

[errol209]

errol

Yes it appears so.

The relay was fine with the 65Amp alternator. It was only when I fitted the 100Amp from a Discovery I hit the problem.

Aha, in that case the explanation is that the extra load of the split charge coil would have fooled the alternator regulator into thinking that the battery had about 8V in it and tried to compensate by increasing the output voltage until it blew itself up!

SimonR, a cure here would be to include a low current draw sensor for the ignition warning light line, which would in turn drive the split charge relay. I'm thinking a biggish transistor with a few protection diodes? You only need to source an amp or so to flip the split charge relay. The kit could then be fitted with impunity to anything.