Club 80-90 Forums

I'll try to be brief!
Autosleeper 1.9 petrol. As far as I know the charge system is standard
2 new batteries only months old.
Just replaced the voltage regulator on alternator.
I have 2 voltmeters on the dash fitted by a previous owner.

I was aware the neither battery seemed to be getting any more than 13 volts. Replaced regulator and now the starter battery gets over 14 v (regulator has 14v stamped on it)

Leisure battery doesn't seem to be getting as good a charge? Rarely over 13 v? just had a long trip (600 mile round trip) and when driving with fridge on the voltage seemed to DROP! Switched off it doesn't get as high as starter battery.

The only other thing running off leisure battery is the stereo.

After a good 300 mile trip home, left for a few days and starter is at12.89v and leisure is t 12.4v (is this ok I have no idea of telling)

Any suggestions how I can get a better charge to the leisure battery? I feel the starter is getting all the charge when it's the other one that needs it more?

When the engine is running the 2 batteries are (should) be connected as if they were 1. This is done via the split charge relay. The fact that your leisure battery is getting some charge, but not as high as the main battery indicates a bad connection in the lead from the main battery to the relay, or from the relay to the leisure battery. Or possibly a slightly faulty relay (dirty contacts) or a dodgy fuse holder in that same wire.

A multimeter is your friend here. Those digital dash mounted voltmeters can often be WILDLY inaccurate Get your meter out and with the engine running, measure the voltage at the main battery, then trace the wire to the split charge relay and measure the voltage at the relay end = should be the same - then measure the voltage at the leisure battery feed wire side of the relay = should be the same - then lastly measure the voltage of your leisure battery = should be the same

Note 1 = "should be the same" means within .5 of a volt.
Note 2 = These tests should not be done if the leisure battery is below about 12.5 volts (if it is below about 12.5 volts it means it is in a partially discharged state and might best be charged with a domestic charger for a few hours before doing the above tests).
Note 3 = Make sure the fridge is off when doing these tests.


Check your test meter results on each battery with what it says on those digital voltmeters = I bet they are miles out

pi quattro wrote: and when driving with fridge on the voltage seemed to DROP!

That is quite normal, you will see the same when headlights and/or blower are on full. You are sucking 10 - 12 Amps with a fridge on 12v. Solution is to drive on gas. I never use 12v on mine, always just gas. (As do a lot of other people).

I do drive on 12v rather than gas (except when I forget to swap over). The alternator and split charge systems should (and do) easily cope with it and I really don't think it's a good idea pulling into petrol or LPG stations with a naked flame in your van; even more so if you have external cooling vents as well as an exhaust flue.

Just my tuppence worth

Just stick your hand behind you and turn it off - easy enough! You only have to do it at the entrance to the fuel station which is no trouble. If petrol were banned we wouldn't need to worry!
I have seen people on mobile phones and even smoking in the vehicle whilst it is being filled up.
My daughter is used to the routine in my Merc - she is ready to nip into the back as I pull in.

Just easier to leave it on 12v. I like easy and it is how it's designed to work....

pi quattro wrote: After a good 300 mile trip home, left for a few days and starter is at12.89v and leisure is t 12.4v (is this ok I have no idea of telling)

There in lies an age old problem ......two batteries of different capacities being charged off one alternator, the alternator 'SEES' one large capacity battery and charges accordingly only the larger capacity battery is never fully charged.
Look at it this way.....average out the two readings (12.4 & 12.89) you get around 12.65 volts, which to all intense and purposes is ONE fully charged battery...the alternator reduces it's charge rate to almost nothing leaving the larger battery only 50-60% charged.

There are a few things you can do......manually disconnect and charge the leisure battery separately.....before each major camping trip.
Fit TWO mains leisure battery charges...not as daft as it sounds.....each 'smart' charger will FULLY charge both batteries independently when on hook up...that might only be one in 4 - 5 camps but it will be enough to bring each battery up to 100%.
Or
Fit a very expensive Sterling battery to battery charging system.....fantastic bits of kit but a bit OTT for most users.

Martin

Thankyou for the replies.

I appreciate now how the alternator "sees" only one big battery. Both batteries are exactly the same though so no difference in capacity. I have had a nosey at tracing wires before and I think the relay may be in the engine bay to the near side? Should I be looking elsewhere? Two wires come out the battery box and go to engine bay. Only other wires are to the stereo and voltmeter.

I fully intend to fit a zig type charger and have been looking into it, waiting for funds to go ahead!

When I said the voltage drops I meant that it gradually and slowly brought down the voltage in leisure side over an hour. As if the alternator couldn't keep up? I had just been switching on for an hour or so then off for a bit then on etc. As I understand no thermostat works when in 12 v mode and it will just stay "on"

I just read an article in campervan mag today about split charging and it mentions that the leisure battery needs an earth strap just like the main battery? Do you agree? I don't seem to have an earth strap on the leisure side and have a spare to fit. This ties in with what ghost123uk says about bad connection? I'll stick on the strap tonight if you experts concur?

Are you saying that there isn't any terminal or wiring on the negative side of the battery? or just that you have wires coming off the terminal but they are going to the stereo/fridge/voltmeter but that there is not earth?

You MUST have the negative terminal going to the chassis or at least to the other batteries negative terminal which in turn must also be earthed.
No earth means consumers taking power from the batteries (plural with the engine running) but with the second battery unable to re-charge on the split charge relay (unless it is getting it's earth through one of the ancillaries) in which case that's an unsatisfactory state of affairs.
Put a good thick (50amp min) earth strap on it.

Martin

There are cables attached to both terminals but definitely not an earth strap.

Found the relay in engine compartment. Wires come out of the alternator and into what looks like the original wiring loom. One thin wire also comes from alternator to the relay. It works, can hear it switch or click.

There are 4 terminals on the relay. One from alternator, one earth and two red wires, one red one with a fuse. I checked the meters on the dash and they are spot on. With engine running checked that over 14 v going in to relay. Then pulled off the two red wires one at a time. Each time the volts drop to normal on the leisure battery? Starter battery doesn't budge at all. It looks to me like the starter battery is charged through the wiring loom?

I did clean all connections and saw 13.7 volts going over leisure battery. Am I right in saying that I should be seeing more volts going across the battery, irrespective of what the resting voltage of the battery is?

For reference, what voltage means a battery is fully charged and when camping off grid, what voltage is considered low?

Your tests and the results all indicate that things are pretty much correct and as they should be (the starter battery does charge via the long red wire that goes directly from the alternator to the battery). The only slight issue is the 13.7 volts to the leisure battery. This would be considered fine on many vans, but yours has a (nice)14 volt regulator and 14 volts is getting to the main battery so in an ideal world you should also see 14 volts at the leisure battery. That drop of (just) .3 of a volt is likely caused by a bad connection, a bad earth or (less likely) wiring that is too thin.

I would fit a sturdy earth from the leisure -ve to earth, it does not have to be an "earth strap" but as Martin says, it does have to be able to conduct a hefty ( ~50 amp ) current (occasionally). Mine is a 2 foot length of ~50 amp brown wire attached to a bit of bodywork with a nut and bolt (via a soldered on "ring" connector. Mind you, iirc you mention you had a spare std braided earth lead, so you might as well use that.

The fact that the fridge is pulling more than the battery is getting also indicates a voltage drop (caused by resistance) in the feed or earth circuit to the leisure. You could double check this by temporarily connecting another bit of wire from main +ve to leisure +ve and seeing if the leisure voltage rises to the 14 volts. If it does, then your wire or your relay is not up to the job.

To answer your last question = A normal leisure battery is considered flat when the voltage drops to 11.5 volts, a fully charged battery is 12.7 (or if using the latest "Calcium" types, 12.9). If ever you let any of these types of battery drop anything below 11.2 volts you have damaged it and it will never be as good as it was. If you do it more than twice it will be pretty much wrecked.

pi quattro wrote: I fully intend to fit a zig type charger and have been looking into it, waiting for funds to go ahead!

Just to say "I wouldn't bother" - There is nothing magic in a Zig unit. It's just a panel of lights and switches etc. With a suitable split charge relay (which you already have) and the usual switches for interior lights etc, you have everything you need. OK some of the fancier Zig units have a charger circuit for when on mains hook up, but a simple (Lidl) charger hard wired in will do that job much cheaper. Then of course you have all the faff of fitting it and wiring it all up. Nah, save your money for summat else

ghost123uk wrote:Your tests and the results all indicate that things are pretty much correct and as they should be (the starter battery does charge via the long red wire that goes directly from the alternator to the battery). The only slight issue is the 13.7 volts to the leisure battery. This would be considered fine on many vans, but yours has a (nice)14 volt regulator and 14 volts is getting to the main battery so in an ideal world you should also see 14 volts at the leisure battery. That drop of (just) .3 of a volt is likely caused by a bad connection, a bad earth or (less likely) wiring that is too thin.

I would fit a sturdy earth from the leisure -ve to earth, it does not have to be an "earth strap" but as Martin says, it does have to be able to conduct a hefty ( ~50 amp ) current (occasionally). Mine is a 2 foot length of ~50 amp brown wire attached to a bit of bodywork with a nut and bolt (via a soldered on "ring" connector. Mind you, iirc you mention you had a spare std braided earth lead, so you might as well use that.

The fact that the fridge is pulling more than the battery is getting also indicates a voltage drop (caused by resistance) in the feed or earth circuit to the leisure. You could double check this by temporarily connecting another bit of wire from main +ve to leisure +ve and seeing if the leisure voltage rises to the 14 volts. If it does, then your wire or your relay is not up to the job.

To answer your last question = A normal leisure battery is considered flat when the voltage drops to 11.5 volts, a fully charged battery is 12.7 (or if using the latest "Calcium" types, 12.9). If ever you let any of these types of battery drop anything below 11.2 volts you have damaged it and it will never be as good as it was. If you do it more than twice it will be pretty much wrecked.

Superb advice, many thanks!

I will fit the extra earth strap, see where it takes me, but perhaps try the wiring of the two positives together as a test first.

The wiring doesn't look original and isn't very thin, so I doubt that was the problem. I recall that when I checked the relay with the meter, 14v going in, but 13.7ish coming out. Suspect relay? Bit lost on looking for a replacement on that.... quick search found an intelligent one on JK for £70!

That's good to know about what voltages are considered "full" and "empty"

ghost123uk wrote:

pi quattro wrote: I fully intend to fit a zig type charger and have been looking into it, waiting for funds to go ahead!

Just to say "I wouldn't bother" - There is nothing magic in a Zig unit. It's just a panel of lights and switches etc. With a suitable split charge relay (which you already have) and the usual switches for interior lights etc, you have everything you need. OK some of the fancier Zig units have a charger circuit for when on mains hook up, but a simple (Lidl) charger hard wired in will do that job much cheaper. Then of course you have all the faff of fitting it and wiring it all up. Nah, save your money for summat else

Perhaps I should chosen a better description! I meant an intelligent charger fitted to the hookup that will charge leisure battery and has a float option so that I can use lights etc when on hook up and maintain the batteries in a good condition. I also intend to use over winter months when parked up to maintain both batteries. (I need to factor in a switch somewhere to divert to starter battery)

Have read a lot on here about great all singing and dancing units on here that cost an arm and a leg versus the cheaper aldi options. I had thought of the middle ground - Zig X70? hence I referred to a "Zig type" charger!

Cheers

My fault, I was assuming you meant a full Zig panel when you had stated "charger"

Relay, 14 V in and 13.7 out = not right

Split charge relays = Here and Here and Non auto type here(that one would be my choice) and Same here etc