Club 80-90 Forums

No it is extremely unlikely you have a mains charger with such a high output. If you look on the charger it will say.
Any mains charger rated at anything above 10 amps will usually "look the part" ie, it will be big and heavy !

ghost123uk wrote:No it is extremely unlikely you have a mains charger with such a high output. If you look on the charger it will say.
Any mains charger rated at anything above 10 amps will usually "look the part" ie, it will be big and heavy !

Thanks for the sanity check. I checked the ZIG manual and it quotes "up to 12 amps depending on battery state", so I'm safe in that respect. With my split charger in place, the alternator output should only reach the leisure battery via the split charger, but I'd like to leave the option to connect the two batteries through the ZIG (the "Touring" position). That would only be for emergency "on site" use if my leisure battery runs down, so the alternator current would only go through the LVD if I forget and drive off in this configuration. I guess a 15A fuse on the load side of the LVD will protect a 16A LVD against this scenario.

I'm in discussion with Neil at REUK, since he seems open to bespoke mods to his LVD. If I interpret his comment correctly I think a 'momentary' type switch to temporarily reconnect the load side of the LVD directly to the battery +ve will be sufficient. If the charger is on, a momentary reconnect (for 10 seconds) will bring the apparent battery voltage back above the cutoff threshold (due to the charging voltage), and the LVD can revert to automatic operation once the button is released. This seems like a nice safe way to override the LVD, since there's no way to accidentally leave it in the bypass position.

MidLifeCrisis wrote:Agree re those Smart Relays - I was always a little nervous of them (and also installed a guide light as you have) - I found them a little unnerving as after a drive they can often stay 'activated' for a while as the voltage decays on the main battery from the higher alternator voltage to the slightly lower battery voltage - so it often meant that I left the van with the relay still activated and had to 'hope' that it would eventually switch off (not very relaxing! although there is no prob real danger in the batteries staying connected when there is no drain on them ..... but it still made me nervous) I ended up switching it for standard relay(s).

So far the smart relay seems fairly reliable. Yes, it can take a bit longer to come on when there's a higher load (eg with main beam on), and it can take a bit longer to go off after a long run, but it does come on and go off reliably so far. Before I decide whether to switch to dumb relays I'm going to wait until I've replaced the voltage regulator on the alternator, so that I can work with thresholds that are further above the battery's natural voltage.

CJH wrote:alternator current would only go through the LVD if I forget and drive off in this configuration. I guess a 15A fuse on the load side of the LVD will protect a 16A LVD against this scenario.

Bit confused though here, the heavy cable that goes from the main battery to the leisure battery, via the split charge relay, should, as I see it, have nothing to do with the Zig or the LVD. That cable can conduct currents >40 amps for short periods, on start up, if your leisure battery is depleted somewhat, and goes directly (through the relay) from both battery +ve to +ve's (I use a HD blade fuse holder with 60 amp HD fuse)

CJH wrote:I'm in discussion with Neil at REUK, since he seems open to bespoke mods to his LVD. If I interpret his comment correctly I think a 'momentary' type switch to temporarily reconnect the load side of the LVD directly to the battery +ve will be sufficient. If the charger is on, a momentary reconnect (for 10 seconds) will bring the apparent battery voltage back above the cutoff threshold (due to the charging voltage), and the LVD can revert to automatic operation once the button is released. This seems like a nice safe way to override the LVD, since there's no way to accidentally leave it in the bypass position.

I was going to mention that. I find the REUK one does have a fairly long (>30 seconds on mine) time delay before it resets. This hysteresis is to prevent the relay oscillating as the voltage rises due to the load being removed.

ghost123uk wrote:Bit confused though here, the heavy cable that goes from the main battery to the leisure battery, via the split charge relay, should, as I see it, have nothing to do with the Zig or the LVD. That cable can conduct currents >40 amps for short periods, on start up, if your leisure battery is depleted somewhat, and goes directly (through the relay) from both battery +ve to +ve's (I use a HD blade fuse holder with 60 amp HD fuse)

For my first stab at the split charger wiring I've used 30A cable protected with a 25A fuse. If this proves to be troublesome I'll upgrade the cable and fuse, but the Smartcom relay fitting instruction even recommend just a 15A fuse. It's confusing I think because there are now two ways my leisure battery sees my alternator. One is through my split charger (which, thanks to the Smartcom relay, won't be connected until a few seconds after startup, due to the relay's threshold voltage), and the other is an option I'm keeping for emergencies which is through my ZIG unit (the 'Touring' position of the ZIG disconnects the mains charger and links the two batteries). On reflection, it seems like this second route has the potential for the leisure battery to be in the circuit during starting, which I thought was a no-no. Still, it's a standard feature of the ZIG - perhaps it's OK as long as a conventional starter battery is in the circuit too. The first option, via the split charge relay, will not go through the LVD, you're right.

Hi CJH, welcome to the club.

For those of us who live in or around Nottingham I can recommend Vehicle Wiring Products Ltd, based in Ilkeston for a wide range of electrical bits and pieces and other vehicle related goodies - good website listing available products.
PS I also have a Viking - might see you around

Cheers

keith2 wrote:Hi CJH, welcome to the club.

For those of us who live in or around Nottingham I can recommend Vehicle Wiring Products Ltd, based in Ilkeston for a wide range of electrical bits and pieces and other vehicle related goodies - good website listing available products.
PS I also have a Viking - might see you around

Cheers

Thanks Keith

That looks like a good website, and they're not too far from me so I may well use them. And yes, I'll keep my eyes open for other Vikings. I must admit I was quite blind to these vehicles before I started the search for a camper a few weeks ago, but now I'm much more tuned in to seeing them on the road. Getting used to the waves from fellow owners too.