that is exactly the system i built into my bus,
i have a 30amp 12v PSU under my passenger seat, when the hook up is switched on at the distribution box, the power supply powers up, which switches the relay to power everything 12v from the power supply unit.
A battery charger lives next to the power supply under the passenger seat, which when hook up is switched on, charges either the leisure battery OR the main vehicle battery depending on where the charging control switch is switched to........... easy and effcient..... when i am on hook up everything 12v - all lighting, all radios, all aux sockets ebber spacher all work from the PSU while the battery is charged........
plug in the electric hook up at home?
Moderators: User administrators, Moderators
-
Mocki
- Membership Admin
- Posts: 17255
- Joined: 29 Sep 2005, 09:27
- 80-90 Mem No: 428
- Location: Mansfield Notts
- Contact:
[img:698:413]http://www.club80-90.co.uk/techhelp/hupsuswitch.jpg[/img]
Steve
tel / txt O7947-137911
________________
1989 2.1LpgWBX HiTop Leisuredrive Camper
1988 2.1 Auto Caravelle TS TinTop Camper
tel / txt O7947-137911
________________
1989 2.1LpgWBX HiTop Leisuredrive Camper
1988 2.1 Auto Caravelle TS TinTop Camper
-
irish.david
- Registered user
- Posts: 54
- Joined: 31 Jul 2006, 04:14
- 80-90 Mem No: 3347
- Location: Belfast
Sorry Mocki but I'm going to have to disagree with you here.
I can see what you're saying. When you're on hookup you have the 12v leisure hookup stuff being powered by a mains power supply and your batteries being charged separately using a mains charger but the whole lot seems a little overcomplicated to me.
Most people when they're on mains hookup are going to be there for a while, at least overnight. It seem simpler and more economical to just fit a decent mains battery charger that can supply 7 amps or more and then run everything off that. From now i'll assume the max output of my charger is 7 amps.
When you're hooked up (normally after a drive which would have topped the batteries up anyway) any item hooked up to the 12v leisure system would be fed from the battery charger until the total load reached a current equal to the max output current of the charger. After that only the additional load over the first 7 amps would be fed from the battery.
The beauty of this system is that the battery acts like a buffer for anything that the charger can't handle and whenever the load on the 12v system drops under the 7 amp mark the battery is being charged. Because of the battery this system can cope with huge loads for a short period of time without dropping off and as long as you don't have big loads on your 12v system for long periods you'll still end up with fully charged batteries.
Dave
I can see what you're saying. When you're on hookup you have the 12v leisure hookup stuff being powered by a mains power supply and your batteries being charged separately using a mains charger but the whole lot seems a little overcomplicated to me.
Most people when they're on mains hookup are going to be there for a while, at least overnight. It seem simpler and more economical to just fit a decent mains battery charger that can supply 7 amps or more and then run everything off that. From now i'll assume the max output of my charger is 7 amps.
When you're hooked up (normally after a drive which would have topped the batteries up anyway) any item hooked up to the 12v leisure system would be fed from the battery charger until the total load reached a current equal to the max output current of the charger. After that only the additional load over the first 7 amps would be fed from the battery.
The beauty of this system is that the battery acts like a buffer for anything that the charger can't handle and whenever the load on the 12v system drops under the 7 amp mark the battery is being charged. Because of the battery this system can cope with huge loads for a short period of time without dropping off and as long as you don't have big loads on your 12v system for long periods you'll still end up with fully charged batteries.
Dave
-
Mocki
- Membership Admin
- Posts: 17255
- Joined: 29 Sep 2005, 09:27
- 80-90 Mem No: 428
- Location: Mansfield Notts
- Contact:
you may be right, but i have radios that draw 25-30 amps on transmit, and the battery charger wont substain that, and a charger wont be able to keep a leisure battery fully charged running a ebber , dvd, stereo water pump and lighting ...... there are no mains operated equipment in my van other than the fridge and possibly a fan heater on occasion, everything is 12v only......
i am only describing whats in my van.
take it or leave it, but i know my battery gets a real charge when i stop for hook up, which is only maybe once every 3-4 nights away, when other site facilites are needed.........
and whilst i realise most people dont have radios drawing that much power to consider, a 10mp PSu and a charger are still cheaper than a 3amp Zig and its poor excuse of a unregulated power supply/charger .
i am only describing whats in my van.
take it or leave it, but i know my battery gets a real charge when i stop for hook up, which is only maybe once every 3-4 nights away, when other site facilites are needed.........
and whilst i realise most people dont have radios drawing that much power to consider, a 10mp PSu and a charger are still cheaper than a 3amp Zig and its poor excuse of a unregulated power supply/charger .
Steve
tel / txt O7947-137911
________________
1989 2.1LpgWBX HiTop Leisuredrive Camper
1988 2.1 Auto Caravelle TS TinTop Camper
tel / txt O7947-137911
________________
1989 2.1LpgWBX HiTop Leisuredrive Camper
1988 2.1 Auto Caravelle TS TinTop Camper
-
powelly
- Registered user
- Posts: 136
- Joined: 21 Jan 2008, 13:01
- 80-90 Mem No: 4653
- Location: Manchester
- Contact:
irish.david wrote:Sorry Mocki but I'm going to have to disagree with you here.
I can see what you're saying. When you're on hookup you have the 12v leisure hookup stuff being powered by a mains power supply and your batteries being charged separately using a mains charger but the whole lot seems a little overcomplicated to me.
Most people when they're on mains hookup are going to be there for a while, at least overnight. It seem simpler and more economical to just fit a decent mains battery charger that can supply 7 amps or more and then run everything off that. From now i'll assume the max output of my charger is 7 amps.
When you're hooked up (normally after a drive which would have topped the batteries up anyway) any item hooked up to the 12v leisure system would be fed from the battery charger until the total load reached a current equal to the max output current of the charger. After that only the additional load over the first 7 amps would be fed from the battery.
The beauty of this system is that the battery acts like a buffer for anything that the charger can't handle and whenever the load on the 12v system drops under the 7 amp mark the battery is being charged. Because of the battery this system can cope with huge loads for a short period of time without dropping off and as long as you don't have big loads on your 12v system for long periods you'll still end up with fully charged batteries.
Dave
Would it simply be a case of connecting the battery charger to the positive and negative of the leisure battery?
Also cold you connect a solar charger at the same time, or would you need to switch between the two chargers depending on if you had mains or not?
-
irish.david
- Registered user
- Posts: 54
- Joined: 31 Jul 2006, 04:14
- 80-90 Mem No: 3347
- Location: Belfast
The good news is that the whole battery charging thing can be as easy or complicated as you want it to be. Although i don't agree with some of what Mocki is saying i can see where he's coming from, but more on that later. We'll start with the simplest charging system.
Assuming you've got a empty van with one starting battery and one leisure battery with both -ve terminals connected to chassis ground and the alternator output connected to the starting battery. When the engines running you want both batteries to charge. So you start the engine and connect a jump lead between the +ve battery terminals and both charge. When you stop the engine, you remove the jump lead and then you can run the leisure battery empty and still start the engine. But soon this gets to be a pain in the ass, so you install a split charge system. You run a wire between both +ve terminals and put a relay in there. The relay is switched on the alternator output so it only switches when the alternator is active (ie engine is running) so you can do away with the jump lead and everyone is happy.
So now you get a bit older and get sick of camping out in the back of beyond and start to look at campsites with hookups. First thing you do when installing a hookup is fit an RCD on the 240v input and then run it to a fusebox. Through the fusebox you can run 240v supplies to plugs, fridges and other things but anything that runs off 12v only still comes from the battery which still needs the engine running to charge. To get round this you can fit a battery charger.
The first problems you have are how can i charge both batteries at once and can i leave the battery charger permanently connected to the system.
As far as the first problem goes, you need to figure out if charging both batteries is important. For most people, when they pull up to a campsite both batteries will be charged so when the engine stops and the starting battery and leisure battery are disconnected you don't need to charge the starting battery as it won't get drained while parked up. While this is true, there are a number of things that could drain your starting battery while parked up and because the starting battery is so important my personal feeling is that the starting battery should be charged at the same time as the leisure battery. For people with a ZIG system this is pretty much what your stuff does. More than that i don't know as i've never worked on or used a ZIG system before.
The way to make this happen is to fit a relay with a 240v coil in parallel with the split charge relay. The relay coil is connected to the 240v input of the battery charger and this way, when the battery charger is connected to a 240v input the relay closes and both batteries are charged by the battery chargers output.
The second problem depends on the battery charger (this includes all battery chargers, including solar, wind, nuclear or whatever). Chargers designed to be hookup chargers are designed to be left connected to the battery at all times. This design means that the batteries won't discharge THROUGH the battery chargers over time. If you leave anything permanently hooked up to both battery terminals you could be draining you battery through it depending on it's internal resistance. Chargers designed to be hookup chargers will have an insanely high internal resistance so the battery will discharge insanely slowly. I have no experience with regular battery chargers or solar chargers so the best thing to do is to measure the discharge current using a multimeter with the charger inactive and if the current is really really low then you haven't got a problem. If you're measuring anything over about 50mA then let me know and i can probably come up with a simple circuit to disconnect it when it's not in use.
The main issue i have with a separate 12v PSU is that it adds complexity and actually reduces the ability of the system to handle high current applications. I'll explain why using an example using a system with a separate 30 amp PSU and one using a normal £30 10amp battery charger connected into a system as described above.
If you're in the van running the stereo (5A), the eber (1.5A) and a few lights (1A) and you want to transmit on your CB. If the CB draws 25A then the total draw will be 32.5A .
A system with a separate 30A PSU will go into overload and reduce it's output voltage to keep the current at 30A. In practical terms the lights will dim briefly before the stereo cuts out and the eber trips on undervoltage.
A system with a 10A charger connected directly to the batteries will behave differently. Running the stereo, the eber and the lights the charger will supply the 7.5A and the remaining 2.5A will be left to charge the batteries. When the CB starts to transmit however the current draw on the charger max's out and the voltage starts to drop. Difference is that when it the voltage gets to about 12.5 volts the batteries take over and supply the remaining 22.5 amps and the voltage holds at 12.5v. All you'll notice is a slight dimming of the lights.
Now, obviously the batteries are discharging every time the CB transmits but unless you're running a pirate radio station they'll spend their majority of time charging. Also, you may have noticed that using my setup the batteries are only charging at 2.5amps. What you have to remember is that is with the stereo, the eber and the lights running. At night when you're sleeping the stereo and the lights are off so you'll get at least 8.5 amps for battery charging. As long as this went on for about 10 hours, in practical terms, that would be enough to fully charge 2 very empty 63 amp/hr batteries.
I hope this hasn't come across as pretentious or argumentative but the whole battery charging thing seems to still be one of the great unsolved mysteries of the whole camper scene and i think if people understand the mechanics of it it'll help them find the best solution for their situation.
Dave
Assuming you've got a empty van with one starting battery and one leisure battery with both -ve terminals connected to chassis ground and the alternator output connected to the starting battery. When the engines running you want both batteries to charge. So you start the engine and connect a jump lead between the +ve battery terminals and both charge. When you stop the engine, you remove the jump lead and then you can run the leisure battery empty and still start the engine. But soon this gets to be a pain in the ass, so you install a split charge system. You run a wire between both +ve terminals and put a relay in there. The relay is switched on the alternator output so it only switches when the alternator is active (ie engine is running) so you can do away with the jump lead and everyone is happy.
So now you get a bit older and get sick of camping out in the back of beyond and start to look at campsites with hookups. First thing you do when installing a hookup is fit an RCD on the 240v input and then run it to a fusebox. Through the fusebox you can run 240v supplies to plugs, fridges and other things but anything that runs off 12v only still comes from the battery which still needs the engine running to charge. To get round this you can fit a battery charger.
The first problems you have are how can i charge both batteries at once and can i leave the battery charger permanently connected to the system.
As far as the first problem goes, you need to figure out if charging both batteries is important. For most people, when they pull up to a campsite both batteries will be charged so when the engine stops and the starting battery and leisure battery are disconnected you don't need to charge the starting battery as it won't get drained while parked up. While this is true, there are a number of things that could drain your starting battery while parked up and because the starting battery is so important my personal feeling is that the starting battery should be charged at the same time as the leisure battery. For people with a ZIG system this is pretty much what your stuff does. More than that i don't know as i've never worked on or used a ZIG system before.
The way to make this happen is to fit a relay with a 240v coil in parallel with the split charge relay. The relay coil is connected to the 240v input of the battery charger and this way, when the battery charger is connected to a 240v input the relay closes and both batteries are charged by the battery chargers output.
The second problem depends on the battery charger (this includes all battery chargers, including solar, wind, nuclear or whatever). Chargers designed to be hookup chargers are designed to be left connected to the battery at all times. This design means that the batteries won't discharge THROUGH the battery chargers over time. If you leave anything permanently hooked up to both battery terminals you could be draining you battery through it depending on it's internal resistance. Chargers designed to be hookup chargers will have an insanely high internal resistance so the battery will discharge insanely slowly. I have no experience with regular battery chargers or solar chargers so the best thing to do is to measure the discharge current using a multimeter with the charger inactive and if the current is really really low then you haven't got a problem. If you're measuring anything over about 50mA then let me know and i can probably come up with a simple circuit to disconnect it when it's not in use.
The main issue i have with a separate 12v PSU is that it adds complexity and actually reduces the ability of the system to handle high current applications. I'll explain why using an example using a system with a separate 30 amp PSU and one using a normal £30 10amp battery charger connected into a system as described above.
If you're in the van running the stereo (5A), the eber (1.5A) and a few lights (1A) and you want to transmit on your CB. If the CB draws 25A then the total draw will be 32.5A .
A system with a separate 30A PSU will go into overload and reduce it's output voltage to keep the current at 30A. In practical terms the lights will dim briefly before the stereo cuts out and the eber trips on undervoltage.
A system with a 10A charger connected directly to the batteries will behave differently. Running the stereo, the eber and the lights the charger will supply the 7.5A and the remaining 2.5A will be left to charge the batteries. When the CB starts to transmit however the current draw on the charger max's out and the voltage starts to drop. Difference is that when it the voltage gets to about 12.5 volts the batteries take over and supply the remaining 22.5 amps and the voltage holds at 12.5v. All you'll notice is a slight dimming of the lights.
Now, obviously the batteries are discharging every time the CB transmits but unless you're running a pirate radio station they'll spend their majority of time charging. Also, you may have noticed that using my setup the batteries are only charging at 2.5amps. What you have to remember is that is with the stereo, the eber and the lights running. At night when you're sleeping the stereo and the lights are off so you'll get at least 8.5 amps for battery charging. As long as this went on for about 10 hours, in practical terms, that would be enough to fully charge 2 very empty 63 amp/hr batteries.
I hope this hasn't come across as pretentious or argumentative but the whole battery charging thing seems to still be one of the great unsolved mysteries of the whole camper scene and i think if people understand the mechanics of it it'll help them find the best solution for their situation.
Dave
-
chippieshaun
- Registered user
- Posts: 137
- Joined: 16 Jan 2008, 19:55
- 80-90 Mem No: 4640
- Location: london 4640
-
rugchucker
- Registered user
- Posts: 322
- Joined: 11 Oct 2005, 17:07
- 80-90 Mem No: 1605
- Location: Andover Hants
Hi Irish David & Mocki
What a great thread!! This has totally de-mystified the requirements I have and saved me loadsa dosh too!!
Just one question, I notice the ZIG unit and my battery charger get pretty warm in operation, how much space around them is needed and how well ventilated? OK thats 2.
What a great thread!! This has totally de-mystified the requirements I have and saved me loadsa dosh too!!
Just one question, I notice the ZIG unit and my battery charger get pretty warm in operation, how much space around them is needed and how well ventilated? OK thats 2.
If you can't weld it try bostic!!
Member No:1605
Member No:1605
Hi Irish David & Mocki,
I'll second that(the great thread and writing a book
)
"The way to make this happen is to fit a relay with a 240v coil in parallel with the split charge relay. The relay coil is connected to the 240v input of the battery charger and this way, when the battery charger is connected to a 240v input the relay closes and both batteries are charged by the battery chargers output. "
Any chanceof a wireing diagram simple enough for a numpty like me to follow,showing how to do this?
Is this the relay I would need?(top one)
http://www.maplin.co.uk/Module.aspx?Mod ... lay%20240v
Thanks
I'll second that(the great thread and writing a book
)"The way to make this happen is to fit a relay with a 240v coil in parallel with the split charge relay. The relay coil is connected to the 240v input of the battery charger and this way, when the battery charger is connected to a 240v input the relay closes and both batteries are charged by the battery chargers output. "
Any chanceof a wireing diagram simple enough for a numpty like me to follow,showing how to do this?
Is this the relay I would need?(top one)
http://www.maplin.co.uk/Module.aspx?Mod ... lay%20240v
Thanks
-
Westy.Club.Joker
- Registered user
- Posts: 484
- Joined: 18 Sep 2006, 19:37
- 80-90 Mem No: 2863
- Location: Sunny Lancs. 1988 1.6TD Westfalia Club Joker pop-top
Irish Dave did a great thread on this with pics a while back, shows how to wire up a modern 3 stage charger into a Westy to replce the OE unit, but the principle is still the same, just connect to your leisure batt, and main starter batt if you need to and you`ll be charging
Keep it real.
Search first - ask second ;>}
Search first - ask second ;>}
-
irish.david
- Registered user
- Posts: 54
- Joined: 31 Jul 2006, 04:14
- 80-90 Mem No: 3347
- Location: Belfast
Hi Mig,
Technically the one you mentioned would work but you normally only need one set of contacts and 10A is probably a little low. You always have to bear in mind what would happen if, for some reason, one battery was very low and the other was fully charged. You plug in your charger and suddenly the relay closes and the charges on the batteries try to equalise and you get quite a bit of current flowing initially. In this case you want the highest rated contacts you can get on the relay to deal with this scenario. The relay i used in my system can be found on this link:
http://www.maplin.co.uk/module.aspx?ITA ... y=8m4#spec
The same logic can be applied with split charge relays but in reality these contacts should be rated even higher than the 30A relay in the link above. This is because most people don't have hookups when they park up and normally run their leisure battery flat before starting the engine. Another factor is a lot of people run a bigger capacity leisure system (ie two batteries) than their starting system. Take these together and you can get a very high sustained current through a split charge relay in the above set of circumstances.
On a side note to people with Westies : Do not add capacity to the leisure system without upgrading the split charge relay (and preferably the cable between the starting and leisure system). The split charge relay in mine was only rated at 10A which was barely sufficient for one battery. Also when replacing the relay a reverse biased freewheeling diode
needs to be added across the relay coil. The original westy one has it built in. This is not as complicated as it sounds; just google it and you'll see
Ginge : As far as that ebay item goes, i'm really not sure. It does a similar job to the relay mentioned above but costs £45 more. It also limits the current to 5A and if you've got a drain on your starting battery (like if you leave the side lights on) you'd end up with two flat batteries. This means no camper van trick of connecting a jump lead between the +ve battery terminals and using the leisure to start the van. I'd just get a relay and spend the £45 on getting the best charger i could.
On another side note for Westies : Never do the jump lead trick described above without upgrading the puny earth strap on the leisure battery for a proper one. The original earth wire can barely take a tenth of the current needed for starting the van.
Hope this helps.
Dave
PS : I'll try and do a basic wiring diagram for the 240V relay a bit later on tonight. Can't do it now ; watching the footy
Technically the one you mentioned would work but you normally only need one set of contacts and 10A is probably a little low. You always have to bear in mind what would happen if, for some reason, one battery was very low and the other was fully charged. You plug in your charger and suddenly the relay closes and the charges on the batteries try to equalise and you get quite a bit of current flowing initially. In this case you want the highest rated contacts you can get on the relay to deal with this scenario. The relay i used in my system can be found on this link:
http://www.maplin.co.uk/module.aspx?ITA ... y=8m4#spec
The same logic can be applied with split charge relays but in reality these contacts should be rated even higher than the 30A relay in the link above. This is because most people don't have hookups when they park up and normally run their leisure battery flat before starting the engine. Another factor is a lot of people run a bigger capacity leisure system (ie two batteries) than their starting system. Take these together and you can get a very high sustained current through a split charge relay in the above set of circumstances.
On a side note to people with Westies : Do not add capacity to the leisure system without upgrading the split charge relay (and preferably the cable between the starting and leisure system). The split charge relay in mine was only rated at 10A which was barely sufficient for one battery. Also when replacing the relay a reverse biased freewheeling diode
needs to be added across the relay coil. The original westy one has it built in. This is not as complicated as it sounds; just google it and you'll see Ginge : As far as that ebay item goes, i'm really not sure. It does a similar job to the relay mentioned above but costs £45 more. It also limits the current to 5A and if you've got a drain on your starting battery (like if you leave the side lights on) you'd end up with two flat batteries. This means no camper van trick of connecting a jump lead between the +ve battery terminals and using the leisure to start the van. I'd just get a relay and spend the £45 on getting the best charger i could.
On another side note for Westies : Never do the jump lead trick described above without upgrading the puny earth strap on the leisure battery for a proper one. The original earth wire can barely take a tenth of the current needed for starting the van.
Hope this helps.
Dave
PS : I'll try and do a basic wiring diagram for the 240V relay a bit later on tonight. Can't do it now ; watching the footy
