We’re just back from our travels, two small issues once we got back. I stalled it at the lights near home, sheer tired incompetence, but then found the battery was too flat to restart easily. I have a split charger that was showing good voltage on the motorway, I’m wondering if the big leisure battery was flat after running the fridge and lights on our last night camping, and was sucking up the charge from the alternator on the way home. The engine battery is fairly new and not much bigger than it needs to be, the leisure battery is huge. Maybe next time I might pull the fuse from the leisure battery for the run home. Issue number two is a high tickover, which I can adjust on the stop on the Butty’s Bits throttle lever, but with an occasional but persistent ‘pop’ from the exhaust. I reckon I need to check for an air leak or the timing moving a little. The van was running fine, though. Any informed opinion as opposed to my best guesses would be welcome.
If you've got a stock 55A alternator and two relatively run down batteries, the alt will likely have trouble keeping up unless you do a really long run in daylight. Give 'em a good charge up. Adjust idle speed on the carb, not anything else, certainly not the throttle linkage.
There’s a bit of blowage from the triangular flange where the exhaust goes into the back boxes, I’ll nip it up tomorrow and see if the pops stop.
If the leisure battery has got very flat then it will pull down the starter battery if all you are using is a split charge relay; because that just links the two batteries because the alternator is working.. If your alternator brushes are worn down, the max output from the alternator may be a lot less than 55 amps also. If you had a Voltage Sensitve Relay, it would have disconnected the starter battery from the leisure battery automatically in the situation you describe, and protected the starter battery witout faffing. If after a long run, with good indicated charging voltages like 14.1 volts, the batteries rapidly drop in voltage they are probably both knackered now..
As far as I know there is a straightforward split charge relay. The last night we were camping we just ran on the LB, using the lights and with the fridge on all night, no mains charge, so the LB will have probably been pretty low in the morning. We went up to County Durham with the fridge on, so that will have been taking power from the alternator all the time. On the return trip as well as a low LB, the weather was bad so we had lights, wipers, satnav, stereo and 'heater' blower all on at once. The engine battery is almost new, but the leisure battery has been there a while, and from what the PO told me, the van was stored for the last couple of years, which probably didn't do the batteries any good. I'm going to replace the leisure battery before our next mission, also I'm going to fit a battery isolator to the LB so I can 'turn it off' for journeys home when I don't need the fridge on anymore, because I've eaten all the bacon and drunk all the beer.
I would also swap to a VSR, and turning off loads on the alternator will help ( if you load it up enough it wont charge the starter battery properly as you found) .. Could be worth taking a look at the alternator brushes. A replaceable consumable item that cuts down the output of the alternator when they are nearly worn out.
I installed one of these on mine (think Mike was referring to this using VSR acronym). It will only charge the leisure battery when the main battery is over a certain voltage. Not sure if you have one on yours or not - but might be worth investigating.
Yes the eBay title for that VSR is full of search words including Voltage,Sensitive,Relay. It says dual sensing .. it should work both ways so that if you put a hookup charger or solar panels on the leisure battery, once it hits 13.8 volts, it connects the starter battery and charges that too. In addition to charging the other way with the engine running. And isolating both batteries as soon as charging stops.
Thanks I’ll order a VSR and try that before I replace the leisure battery. I’ll also check the alternator brushes. I had the alternator pack up on my 911 last year, they weren’t designed to last 40 years, a company called Electrostart refurbished it by return of post for not a lot of money, especially considering what car it was off.
@mikedjames i have a VSR that i bought many years ago and never got around to fitting itas the van already had a split charger fitted, as the split charger wires are very thin do i need to uprate to use the VSR? Cheers
Ideally for battery stuff, partic. wiring to the VSR, you want at least 4mm2 cable. You'd need to use tube crimps on the cable ends. Can get a suitable hydraulic crimper from fleaBay.
There's a 30A midi fuse in each of the battery +ve legs. You can just see the leisure battery fuseholder bottom centre in the pic. The VSR contacts are rated at 100A, but you're never going to see those kinds of currents. I recommend the "green label" VSR (can't remember the make), as the drop out voltage on them is such that they do actually drop out.
@snotty yes can see that now, had the unit a few years so not sure what make it is but it is rated at 100 A, Thanks for photo
My VSR arrived via Ebay, I'm going to swap it for the splitter this weekend if the weather plays ball. Also a new 20cm spring for the throttle arm to replace the stretched one.
