DIY split charge - Page 2

rayf3262 · 23-07-2013, 00:00

Schottky diodes,...
typically exhibit a forward voltage drop in the order of one third of a normal PN junction diode.
Available from the likes of RS components etc...

These can be a sensible no moving parts option, been used on boats and leisure craft a lot. Commercial products produced by Victron, Sterling etc..
eg.
http://www.victronenergy.com/battery...ery-isolators/

This is an informative read on split charge options:
http://highfields-arc.co.uk/vehicles/auxchg.htm

96terrano · 23-07-2013, 00:19

Quote:

Originally Posted by rayf3262

Schottky diodes,...
typically exhibit a forward voltage drop in the order of one third of a normal PN junction diode.
Available from the likes of RS components etc...

These can be a sensible no moving parts option, been used on boats and leisure craft a lot. Commercial products produced by Victron, Sterling etc..
eg.
http://www.victronenergy.com/battery...ery-isolators/

This is an informative read on split charge options:
http://highfields-arc.co.uk/vehicles/auxchg.htm

Nice, I wanted to go with a relay as I know how to wire them up, never wired a diode before and have no experience with them

rayf3262 · 23-07-2013, 00:33

The main reason the diode method was preferred on small boats and the like was due to persistent high humidity and condensation.
Damp gets everywhere on a small boat and it is difficult to locate sensitive parts where they will not eventually be affected by it. Add to that the possibility of salt water and everything has to be pretty much hermetically sealed!
Solid state devices have proven far more reliable in this environment than even the best "sealed" relays.
Unless you are constantly drowning your vehicle the relay method will be fine, but there is some elegance in eliminating the moving bits!

96terrano · 23-07-2013, 00:35

Quote:

Originally Posted by rayf3262

The main reason the diode method was preferred on small boats and the like was due to persistent high humidity and condensation.
Damp gets everywhere on a small boat and it is difficult to locate sensitive parts where they will not eventually be affected by it. Add to that the possibility of salt water and everything has to be pretty much hermetically sealed!
Solid state devices have proven far more reliable in this environment than even the best "sealed" relays.
Unless you are constantly drowning your vehicle the relay method will be fine, but there is some elegance in eliminating the moving bits!

Interesting that, the relay on this will probably be mounted either under the dash or under the boot floor with the battery

96terrano · 23-07-2013, 00:56

What would be the best amp cable to use? I was thinking about 30?

rayf3262 · 23-07-2013, 01:38

Quote:

Originally Posted by 96terrano

What would be the best amp cable to use? I was thinking about 30?

1) what is the max current the cable is required to carry?
2) what is the length of the cable?
3) what is the acceptable voltage drop at maximum current?
4) what is the mean temperature of the cable?

With the answers to these questions you can calculate the correct size (CSA) of the cable you require.

Note, it will be helpful if you think of this piece of cable as a resistor.

kitchenman · 23-07-2013, 02:33

Ryan, if you are fitting the battery to a car like mine there is a good place over the n/s front wheel under the bonnet. I have pictures
You would need a hell of a thick cable to go all the way to the back,
dave

bry · 23-07-2013, 05:32

Quote:

Originally Posted by Deano400

I've used something like one of these in the past. Much simpler and better in my opinon.

http://www.ebay.co.uk/itm/HIACE-SELF...item2a2e062217

Good link mate,cheers

Barrbeast · 23-07-2013, 14:50

One of the reasons I'll be fitting a split charge to my Troll is because I want to fit a winch at some point, am I right in thinking that the relay will need to be a bit beefier than the one in the eBay link, ie. rated higher than 40A, like a T-Max or X-Charge system?

Should I be looking for slightly higher than the rating of the alternator (iirc 90A) minimum? I'm guessing a winch will likely draw more out the aux battery than that if it's working but surely the most that will go through the relay will be the max output of the alternator?

Fez_uk · 23-07-2013, 15:03

I'd personally go for the bigger relay type. Winch can draw like 300amps depending on speed and weight it's pulling.

Winch will draw as much it can from the alternator then seek the rest of the amps from the batteries.

But I know plenty of people who run just one bigish battery for winching without issue, Unless your doing winch challenge stuff a 2nd battery with splitcharge is not really needed.

So a lesser amp relay won't be too bad on a overland style vehicle where the 2nd battery is more for running stuff when the engine is off.

Banshee · 23-07-2013, 15:45

Probably going off topic a bit and probably a very crude question but how do I incorporate a relay into electrical wiring I'm adding to the car?

How do I know which one I need and how would I wire it in the example of say Spotlights

96terrano · 23-07-2013, 16:09

Well, zenka and bought a split charge kit for the Hyundai, was £10, a nice maypole system, I only had £8

Banshee, you want this diagram,

simple 4 pin relay used for almost any simple circuit, pin 86 goes through a switch and then to the +ve feet to the relay, pin 30 will go to you're spotlights, this is daigram for a fuel pump, but just the same to wire up anything with a relay

I'm running 4x 552 roof lights on mine and use a 30 amp relay....more than enough

96terrano · 23-07-2013, 17:18

IMAG4647.jpg

96terrano · 23-07-2013, 17:28

bigger pic so you can see details

Barrbeast · 23-07-2013, 17:37

Can't see Ryan's pic (work email doesn't always like posted images) so he may have done something similar, but assuming the switch for the lighting is going to be inside the truck I would take the live feed for it from one of the ignition wires that way the switch will only be live with the ignition on.

That's what I did with the manual pre-heat for my old Shogun (the glowplug ecu has a habit of going fizz and is £££ to replace). Switch was connected to the glowpug relay which had the added bonus that the switch wasn't being overloaded by the draw from the glowplugs (previous owner had just ran a wire direct from the +ve side of the battery to the busbar... I only discovered this on a very cold morning when the switch got hot, melted and burnt my finger

!)

23-07-2013, 00:00	#16
rayf3262 Senior Member Join Date: Nov 2009 Location: Norfolk, Poringland NR14 Vehicle: Terrano 3.0 SVE 2002 Posts: 1,549	Schottky diodes Schottky diodes,... typically exhibit a forward voltage drop in the order of one third of a normal PN junction diode. Available from the likes of RS components etc... These can be a sensible no moving parts option, been used on boats and leisure craft a lot. Commercial products produced by Victron, Sterling etc.. eg. http://www.victronenergy.com/battery...ery-isolators/ This is an informative read on split charge options: http://highfields-arc.co.uk/vehicles/auxchg.htm __________________ Remember what the dormouse said: Feed your head....

23-07-2013, 00:33	#18
rayf3262 Senior Member Join Date: Nov 2009 Location: Norfolk, Poringland NR14 Vehicle: Terrano 3.0 SVE 2002 Posts: 1,549	The main reason the diode method was preferred on small boats and the like was due to persistent high humidity and condensation. Damp gets everywhere on a small boat and it is difficult to locate sensitive parts where they will not eventually be affected by it. Add to that the possibility of salt water and everything has to be pretty much hermetically sealed! Solid state devices have proven far more reliable in this environment than even the best "sealed" relays. Unless you are constantly drowning your vehicle the relay method will be fine, but there is some elegance in eliminating the moving bits! __________________ Remember what the dormouse said: Feed your head....

23-07-2013, 15:45	#26
Banshee Moderator Join Date: Jul 2012 Location: West Midlands Vehicle: 04 2.7 SWB Terrano II Van Posts: 13,526	Probably going off topic a bit and probably a very crude question but how do I incorporate a relay into electrical wiring I'm adding to the car? How do I know which one I need and how would I wire it in the example of say Spotlights __________________ Moderator 04' Terrano II SE 2.7 TDi SWB Commercial in Silver - Project Thread Toyo Open Country M/T 33's on 10J Steels, Super Strong Steering Job Navara D22 Snorkel, Front LOKKA, Maunal Hubs, EGR Blank TunitII ECU Chip, 3" Body Lift, 2" Suss Lift, Heat Exchanger Black Interior, 3.0 Borg&Beck Clutch, Eckes Heated Fuel Filter 99' Y61 Patrol GR SE 2.8 TD6 LWB in Blue/Silver - Project Thread Engine Transplant - In Progress!!!

23-07-2013, 00:56	#20
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	What would be the best amp cable to use? I was thinking about 30?

23-07-2013, 02:33	#22
kitchenman Senior Member Join Date: Jan 2011 Location: Essex Wescliff Vehicle: maverick 1994 2.7 TD Posts: 1,278	Ryan, if you are fitting the battery to a car like mine there is a good place over the n/s front wheel under the bonnet. I have pictures You would need a hell of a thick cable to go all the way to the back, dave

23-07-2013, 14:50	#24
Barrbeast Senior Member Join Date: Mar 2013 Location: Dundee, Scotland Vehicle: 1990 4.2 SWB Safari Posts: 2,615	One of the reasons I'll be fitting a split charge to my Troll is because I want to fit a winch at some point, am I right in thinking that the relay will need to be a bit beefier than the one in the eBay link, ie. rated higher than 40A, like a T-Max or X-Charge system? Should I be looking for slightly higher than the rating of the alternator (iirc 90A) minimum? I'm guessing a winch will likely draw more out the aux battery than that if it's working but surely the most that will go through the relay will be the max output of the alternator?

23-07-2013, 15:03	#25
Fez_uk Senior Member Join Date: Sep 2010 Location: Mid-Wales Vehicle: Maverick 2.7 - Patrol 4.2 Posts: 5,645	I'd personally go for the bigger relay type. Winch can draw like 300amps depending on speed and weight it's pulling. Winch will draw as much it can from the alternator then seek the rest of the amps from the batteries. But I know plenty of people who run just one bigish battery for winching without issue, Unless your doing winch challenge stuff a 2nd battery with splitcharge is not really needed. So a lesser amp relay won't be too bad on a overland style vehicle where the 2nd battery is more for running stuff when the engine is off.

23-07-2013, 16:09	#27
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	Well, zenka and bought a split charge kit for the Hyundai, was £10, a nice maypole system, I only had £8 Banshee, you want this diagram, simple 4 pin relay used for almost any simple circuit, pin 86 goes through a switch and then to the +ve feet to the relay, pin 30 will go to you're spotlights, this is daigram for a fuel pump, but just the same to wire up anything with a relay I'm running 4x 552 roof lights on mine and use a 30 amp relay....more than enough

23-07-2013, 17:18	#28
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	IMAG4647.jpg

23-07-2013, 17:28	#29
96terrano Senior Member Join Date: Jun 2010 Location: Dumfries and Galloway, Scotland Vehicle: Nissan Terrano 2.7TD LWB Posts: 8,024	bigger pic so you can see details

23-07-2013, 17:37	#30
Barrbeast Senior Member Join Date: Mar 2013 Location: Dundee, Scotland Vehicle: 1990 4.2 SWB Safari Posts: 2,615	Can't see Ryan's pic (work email doesn't always like posted images) so he may have done something similar, but assuming the switch for the lighting is going to be inside the truck I would take the live feed for it from one of the ignition wires that way the switch will only be live with the ignition on. That's what I did with the manual pre-heat for my old Shogun (the glowplug ecu has a habit of going fizz and is £££ to replace). Switch was connected to the glowpug relay which had the added bonus that the switch wasn't being overloaded by the draw from the glowplugs (previous owner had just ran a wire direct from the +ve side of the battery to the busbar... I only discovered this on a very cold morning when the switch got hot, melted and burnt my finger !)