alternator wires

[kitchenman]

Hi, I want to wire up my leisure battery but not sure where the control wire is, by that I mean the wire that shows 12+ volts when the alternator is charging, the wire that turns off the charge light on the dash.

On my Peugeot Partner I run a wire from it to a relay which is energised when it get the 12+ volts & then makes the contacts to charge the battery.

So effectively the battery is not in circuit when the engine is not running.

The picture shows the wire I think I should come off the one with the short arrow from the right, your comments please gents:bow

 

[solarman216]

it is easy to tell, on most alternators with built in regulators there are usuall only two wires heavy battery/charging wire and the smaller one for the bulb, this is the one you want, if you have three wires then the third is for rev counter usually marked W, Rick

 

[kitchenman]

Hi Rick, thanks, there are only two wires I can see so I guess it is the one I marked, I will check it is at zero volts with engine off
Thanks for you help.
dave

 

[kitchenman]

Hi Rick, I managed to unplug the connector there are two wires locks like a blue[L] & white]R], but I am colour blind may differ, anyway picture attached, with the plug disconnected the battery/charge light on the dash is out, so I guess one of then is the wire I want.
With the ignition off there is 12 volts on the white wire & 0 volts on the blue, with the ignition on they both have around 12v

Do you know which wire I need to connect to the relay coil to energise it when the alt is charging, or should I just fit & Scotch block to each & see which has 12 volts when alt is charging? With the plug reconnected of course!

 

[solarman216]

the blue wire is the one you want, the 12v on it with ignition on is coming through the bulb, when it starts charging you get 12v out to the blue from the alternator = 12v on both sides of the bulb so it goes out and if you have a relay connected it will energize, Rick

 

[kitchenman]

Hi Rick, :thumb2
Thanks for the update, I was nervous about doing anything with out backup. 50% chance of using the wrong wire.

OK second minor question, as I am putting the leisure battery over the nearside wheel in the space similar to the current battery position, it seems sensible to me to take the 12 volts from the alternator rather than the battery. The terminal seems to have a rubber shroud over it, as it is looking down I cant see it, if I move the shroud will I be able to loosen the nut/fixing? or would you play safe & run the wire from the battery to the switch terminal on the relay.
I am thinking more problems with voltage loss & vibration/chaffing if I run from battery.
I am using a 40A relay, the same system works great on my Partner [Peugeot] that is.

I can do pictures if it may help others.
thanks, dave

 

[solarman216]

yes you can the the feed straight off the alternator, I would, with similar sized wire, not sure the 40 amp relay will be heavy enough, I guess it will depend on how flat your battery is, if nearly fully discharged it will pull more than 40 amps another point to remember is a car alternator never fully charges your battery, 14.8 volts is not enough but it is held this low to stop overcharging on long runs 15.1 (for a standard lead mix flooded battery) is the correct full charge voltage some are 15.2 or more, it is amassing how many more amp hours you get by charging to 15.1, Rick

 

[kitchenman]

Hi Rick :thumb2
Thanks for the relay size tip, I will get one of a higher rating, AIR I did burn one out on the partner.
I will be putting a 240 volts socket on the on the towbar for a charger. I have too many gadgets.

Thanks again, another example of the best tenner i ever spent:bow:bow

 

[rustic]

Hi Rick :thumb2
Thanks for the relay size tip, I will get one of a higher rating, AIR I did burn one out on the partner.
I will be putting a 240 volts socket on the on the towbar for a charger. I have too many gadgets.

Thanks again, another example of the best tenner i ever spent:bow:bow

If you are connecting 240 volts to the vehicle then you need a plug on the car and a socket on the free cable.


.

 

[kitchenman]

Hi Rustic,
You are right, I used the wrong word:doh:doh, I have a socket on my Parner plan to do the same on the Mav, thanks for pointing that out.:bow

 

[rustic]

Hi Rustic,
You are right, I used the wrong word:doh:doh, I have a socket on my Parner plan to do the same on the Mav, thanks for pointing that out.:bow

Not a problem, but on boats, it's amazing how some boaters get it wrong, and have live pins to plug into their boat.... They carry this plug over water to get to the boat as well.....

Fortunately there is an RCD device on the bankside post.
I would suggest that you fit one as well, if you are connecting/disconnecting wet plugs.
Also it is possible to forget to unplug it, and you might leave live wires on the ground.


The "Boat Safety Scheme " Inspector tests the boat every 4 years, and this is checked now, but they could have been using this for upto 4 years

 

[kitchenman]

Update

Hi all job done pictures follow

Views of leisure battery

Battery is sitting on a piece of 10mm thick tufnol
30 amp fuze in feed from alternator to protect relay & cables
Relay in small box with old voltmeter added, velcroed to wing​

The bonus is figuring out multi pictures on post

 

[Dynamics]

another point to remember is a car alternator never fully charges your battery, 14.8 volts is not enough but it is held this low to stop overcharging on long runs 15.1 (for a standard lead mix flooded battery) is the correct full charge voltage some are 15.2 or more, it is amassing how many more amp hours you get by charging to 15.1, Rick

Is there a way to "Adjust" the output of the alternator?

 

[rustic]

Is there a way to "Adjust" the output of the alternator?

The voltage has probably been chosen to suit normal driving, under normal or average conditions.

The ambient temperature affects the charge acceptance from a battery, and it can get quite warm under the bonnet of the car.

If you had a temperature sensor on the battery then you could have an electronic system that will give the correct voltage for the battery depending on its temperature. This way you could get that extra bit of charge in.

Also consider that at higher voltages, the bulbs would be taking a larger current and will become brighter, BUT their life will be reduced considerably, unless you have a voltage stabilisation on voltage dependent items.

So consider this before thinking about adjusting the alternator output voltage.


:nenau

 

[Deleted account DD]

quick question here.......................

why do you need the second battery?

 

[solarman216]

Is there a way to "Adjust" the output of the alternator?

yes there is but it is an add on unit and not specially cheap, it kids the alternator into thinking the battery is near flat and so delivers full output, which is then regulated by the add on unit, works extremely well on cabin batteries on a boat, fast charge in the shortest time, but as

rustic

says you will be over volt-aging your car equipment, Sterling Power Products are the company to watch, Rick

 

[Dynamics]

Great answers, thanks. Not thinking of doing it, just very interested in anything like this.

I'll get my anorak... :augie

 

[panelbeater]

on my pv powered caravan i have the regulator set to 15.2v for my 140ah batt.
due to the rise in volt during daylight all my volt sensitive things like tv hd recorder etc go through a 10a fixed reg stabiliser i also have a temp sender on the batt so the regulator adjusts acordingly. when my mains kettle is on through the inverter and the suns high up the pv panels have recorded 32amps,on my meters.
last season,upto jan 1st when i reset meters they put in just under 9000watts.