DIY split charge

[96terrano]

ok so split charge kits are £40 to £65 ish, so just simply googled DIY split charge and this came up, would this diagram work? i've got a 100amp relay and everything else....or will i need a proper kit? thing is, this diagram looks too low amps :doh

thinking of this for the little Hyundai since i'll be using it for holidays

http://www.freewebs.com/carawagon/Split_charge_relay.gif
http://img.photobucket.com/albums/v103/75bus/split202.gif

[kitchenman]

error

[96terrano]

Hi Ryan,
The top diagram is the one I use, works fine, I use a 45 amp relay,

there are two thin wires from the alternator, I think you need the blue one, just put a fuse big enough to protect the wires in series at both battery and load ends

ahh ok, so charging a battery doesn't pull many amps?

[kitchenman]

Hi Ryan,

I run the alternator wire to the relay with around a 30 amp fuse both sides, alternator will pump out loads of amps to a flat battery
The thin blue wire on the alternator is the one I use to hold in the relay, on my Mav anyway

My first post was a wrong you saw it before I changed it.

[96terrano]

Hi Ryan,

I run the alternator wire to the relay with around a 30 amp fuse both sides, alternator will pump out loads of amps to a flat battery
The thin blue wire on the alternator is the one I use to hold in the relay, on my Mav anyway

cheers, i'll just copy the top diagram then, thing is, im wanting to run a inverter and so on

[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-SWITCHING-VOLTAGE-SENSING-SPLIT-CHARGE-RELAY-12V-30-AMP-/181160780311?pt=UK_Campervan_Caravan_Accessories&hash=item2a2e062217

[96terrano]

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-SWITCHING-VOLTAGE-SENSING-SPLIT-CHARGE-RELAY-12V-30-AMP-/181160780311?pt=UK_Campervan_Caravan_Accessories&hash=item2a2e062217

Not bad that:thumb2

[Fez_uk]

It's easy enough to work out without a diagram. Just use relay, fuses and cable thats rated appropriately.

[96terrano]

It's easy enough to work out without a diagram. Just use relay, fuses and cable thats rated appropriately.

Yeah, just wanted to double check

[kitchenman]

Depends on the output of the inverter remember watts =voltsXamps so if you want to run a power saw at say 500 watts, that's around 2 amps at 240 volts or over 40A at 12V
I am sure solarman will correct me if I got it wrong
dave

[kitchenman]

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-SWITCHING-VOLTAGE-SENSING-SPLIT-CHARGE-RELAY-12V-30-AMP-/181160780311?pt=UK_Campervan_Caravan_Accessories&hash=item2a2e062217

I would go for one of them if I was starting from scratch
dave

[96terrano]

I would go for one of them if I was starting from scratch
dave

they seem easy to wire up:)

[makeitfit]

I would go for one of them if I was starting from scratch
dave

Top news I was just about to spend out £££s on a split charge thingy.
Now I'll buy that for my camper project , cheers guys :thumbs

[solarman216]

All I can add to the issue is a relay will charge the 2nd battery to full vehicle charge (not full battery capacity) as opposed to a diode which will only charge to a lesser capacity due to the voltage loss involved, Rick

[96terrano]

Top news I was just about to spend out £££s on a split charge thingy.
Now I'll buy that for my camper project , cheers guys :thumbs

Going to buy one fir my Hyundai too:thumb2

[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-isolators-and-combiners/argo-diode-battery-isolators/

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

[96terrano]

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-isolators-and-combiners/argo-diode-battery-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]

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]

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]

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

[rayf3262]

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]

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]

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-SWITCHING-VOLTAGE-SENSING-SPLIT-CHARGE-RELAY-12V-30-AMP-/181160780311?pt=UK_Campervan_Caravan_Accessories&hash=item2a2e062217
Good link mate,cheers:thumbs

[Barrbeast]

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? :nenau

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? :confused:

[Fez_uk]

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]

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]

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

Banshee, you want this diagram, :thumb2 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:thumb2

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

http://forums.rennlist.com/rennforums/attachments/928-forum/561892d1314343542-fuel-pump-electric-diagram-fuel_pump_wiring_drawing-1-.jpg

[96terrano]

4248

[96terrano]

bigger pic so you can see details

https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=a36db6a220&view=att&th=1400c4b6041f4137&attid=0.1&disp=inline&realattid=1441368127902318592-local0&safe=1&zw&saduie=AG9B_P8z5TO7gcgNTFmIHdWrjaTD&sadet=1374596249366&sads=eBt97X-7f9786vp-lvJFJUv-8d8&sadssc=1

[Barrbeast]

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 :eek: !)

[Barrbeast]

... and now the work internet decides to show the picture and I see it's a pic of the split charge system Ryan bought rather than the relay set up for lighting, damn technology! :doh

[Barrbeast]

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.

Cheers bud :thumbs So if I get this right my choices are:-

A) Another full size battery with on a split charge with a beefy relay to take the max draw from the alternator. Winch is connected to second battery.

-or-

B) Swap the Troll's main battery for a slightly larger one and use the old one (or a new normal sized battery) as the auxiliary one on a split charge to the larger battery via one of the smaller amp relays. Winch is connected to the main battery.

Think I'll go for go for A and leave my main battery doing it's normal thing with the auxiliary handling all the extras like the winch. Plus I like the extras on the T-Max like being able to link the batteries etc.

[96terrano]

Think I'll go for go for A and leave my main battery doing it's normal thing with the auxiliary handling all the extras like the winch. Plus I like the extras on the T-Max like being able to link the batteries etc.

think that's the best bet tbh, leave the original battery be:thumb2

[96terrano]

4249

[solarman216]

4249

What amps can it carry, does not look like many, Rick

[96terrano]

think the split charge unit i bought is for charging a caravan battery, as its got a fridge hookup too, will have to see if i can change it slightly for charging a on board battery, as the battery will be mounted under the boot floor, the instructions go on about 12 N and 12 S towing sockets:doh

[96terrano]

What amps can it carry, does not look like many, Rick

30 amps

[96terrano]

will be fitting a tow bar so might work alongside that

[Barrbeast]

think the split charge unit i bought is for charging a caravan battery, as its got a fridge hookup too, will have to see if i can change it slightly for charging a on board battery, as the battery will be mounted under the boot floor, the instructions go on about 12 N and 12 S towing sockets:doh

Yeh, reckon your right as 6, 4 & 2 (numbering on the relay) are the +ve pins on a 12 S socket.

[96terrano]

Yeh, reckon your right as 6, 4 & 2 (numbering on the relay) are the +ve pins on a 12 S socket.

In thinking of just connecting the outlet on the relay that's supposed to go to the 12s socket, straight to the leisure battery in the boot?, might work that way

[rustic]

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

Banshee, you want this diagram, :thumb2 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:thumb2

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

http://forums.rennlist.com/rennforums/attachments/928-forum/561892d1314343542-fuel-pump-electric-diagram-fuel_pump_wiring_drawing-1-.jpg


Who drew this diagram?
Not following any electrical convention is it?
What is -12 volts? unless they are running the system on 24 volts.

TUT TUT TUT

NOT IMPRESSED!:doh

[elty001]

Who drew this diagram?
Not following any electrical convention is it?
What is -12 volts? unless they are running the system on 24 volts.

TUT TUT TUT

NOT IMPRESSED!:doh

I would say that they are the earthing points.

never let your kids draw the wiring diagrams for you:lol:lol:lol

[bry]

"never let your kids draw the wiring diagrams for you".Had me in stitches Lol.

[elty001]

no offence meant by it:loli just couldn't resist.

[96terrano]

Who drew this diagram?
Not following any electrical convention is it?
What is -12 volts? unless they are running the system on 24 volts.

TUT TUT TUT

NOT IMPRESSED!:doh


what's wrong with it?? dunno who drew it tho, here's the original page

http://forums.rennlist.com/rennforums/928-forum/651659-fuel-pump-electric-diagram.html

[briggie]

yes , - 12v sounds interesting :augie , not sure the battery will like that :augie