2 leisure batteries
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- timthetrader
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2 leisure batteries
As my leisure battery is under the passenger seat and its not really a leisure as there is limitted space I,ve wired a second one via the zig unit so when I'm driving Im charging 3 battieries. Ive put a in line fuse on all the batteries. Has anyone else tried this and does anyone know of any probs I,m likely to have?
VW 1990 autohomes
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OK. Maths.
In an ideal world.
According to my information 45 Ahr and 65 Ahr alternators were origionaly fitted. Some folk have fitted uprated 95 Ahr units.
Batteries are complex beasties and dont charge in a linear fashion.So the following is a very rough approximation.
A 65 Ahr battery should take an hour to charge with a 65 Ahr alternator (running at 2500 + revs)
To charge 2 110Ahr batteries + a 45 Ahr starter battery ( 265 Ahr)
will take over 4 hours.
Now as said batteries dont play simple math so you are looking at about 6 hrs of driving.
So when you start up the alternator will start supplying current to the batteries, the flatest will take the most, leaving your starter battery weakend.
If your batteries are old or the alternator worn then the charging times will increase dramatically.
T
In an ideal world.
According to my information 45 Ahr and 65 Ahr alternators were origionaly fitted. Some folk have fitted uprated 95 Ahr units.
Batteries are complex beasties and dont charge in a linear fashion.So the following is a very rough approximation.
A 65 Ahr battery should take an hour to charge with a 65 Ahr alternator (running at 2500 + revs)
To charge 2 110Ahr batteries + a 45 Ahr starter battery ( 265 Ahr)
will take over 4 hours.
Now as said batteries dont play simple math so you are looking at about 6 hrs of driving.
So when you start up the alternator will start supplying current to the batteries, the flatest will take the most, leaving your starter battery weakend.
If your batteries are old or the alternator worn then the charging times will increase dramatically.
T
There are 10 kinds of people. those who understand Binary and those who dont
- timthetrader
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Well all seems fine! The main probs with autohomes the leisure battery is under the passenger seat and as your limited for space the is normally a car battery not a leisure and as such only lasts a night/day in the winter if your running a heater (propex) so by George I think we,ve cracked it!
VW 1990 autohomes
- kevtherev
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tonytech wrote:OK. Maths.
In an ideal world.
According to my information 45 Ahr and 65 Ahr alternators were origionaly fitted. Some folk have fitted uprated 95 Ahr units.
Batteries are complex beasties and dont charge in a linear fashion.So the following is a very rough approximation.
A 65 Ahr battery should take an hour to charge with a 65 Ahr alternator (running at 2500 + revs)
To charge 2 110Ahr batteries + a 45 Ahr starter battery ( 265 Ahr)
will take over 4 hours.
Now as said batteries dont play simple math so you are looking at about 6 hrs of driving.
So when you start up the alternator will start supplying current to the batteries, the flatest will take the most, leaving your starter battery weakend.
If your batteries are old or the alternator worn then the charging times will increase dramatically.
T
very useful stuff there mate thank you...
uprating the alternator to 90A/h and good batteries would help the charging speeds?
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- "WEAZLECHIN"
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- ringo
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I've got three leisure batteries and one engine battery. Had them for about two years.
I must say i've never had a problem with the batteries charging at all.
However, mines a diesel and the engine battery is in the engine bay - this makes a difference...
Due to the length of the wires to the liesure batteries from the split charge relay, there is a considerable voltage drop to the liesure batteries - the leisure batteries charge at 12.8 volts, as oppossed to 13.6 on the engine battery. This difference means that the engine battery gets topped up faster.
Some of the more up to date electrically guys on here (Irish Dave for one) have recommended a diode in the split charge circuit. This takes care of such volt drop (0.7volts for a silicon diode).
Theres loads on this subject...
I must re-read this thread when i have a moment..
http://forum.club8090.co.uk/viewtopic.p ... sc&start=0
HTH
Ringo
I must say i've never had a problem with the batteries charging at all.
However, mines a diesel and the engine battery is in the engine bay - this makes a difference...
Due to the length of the wires to the liesure batteries from the split charge relay, there is a considerable voltage drop to the liesure batteries - the leisure batteries charge at 12.8 volts, as oppossed to 13.6 on the engine battery. This difference means that the engine battery gets topped up faster.
Some of the more up to date electrically guys on here (Irish Dave for one) have recommended a diode in the split charge circuit. This takes care of such volt drop (0.7volts for a silicon diode).
Theres loads on this subject...
I must re-read this thread when i have a moment..
http://forum.club8090.co.uk/viewtopic.p ... sc&start=0
HTH
Ringo
Now driving a big bad VW LT Florida.
- "WEAZLECHIN"
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Batteries work as a sum of their parts. If you've got a bad battery in a three battery system then you'll only effectively have 2 1/2 batteries but the duff battery won't drag the others down.
That is unless it's shorted across all its cells and then you'd have bigger problems than just one bad battery....
Dave
That is unless it's shorted across all its cells and then you'd have bigger problems than just one bad battery....
Dave
- "WEAZLECHIN"
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but its not going to be good while charging, if the duff battery is replaced with a new one the other 2 batteries will recieve an equal charge, at the moment the problem is that his leisure batteries wont charge. same problem that i recently encountered. my leisure battery was always half flat but was new and my engine battery was old and failing so i replaced the engine battery(because it was taking all the alternator charge) anyway both batteries are now always fully charged. unless ive been using 240v gadgetry through the inverter.