Is 13.7 volts enough

[ChrisTriple]

When my vans running I only get 13.7 at the battery but 14.1 at the alternator. Is that enough or should I get more and if I need more where could I be loosing it?

[bigherb]

No you a minimum of 13.8V at the battery.
There should not be any significant voltage drop from the the alternator to the battery You need to check and clean all the connections from the alternator to the starter motor and the gearbox earth strap and the battery earth strap.

[Oldiebut goodie]

I lost 0.5v between the alternator and battery on mine - horrendous considering the length of the cable is around 1 foot! The cause was corrosion in the factory crimped terminals, replaced with soldered ones and normal 14.3v was at both ends. ( Ignore the thread where people are saying that crimped terminals are best - this is proof that they are not )
I would look at any terminal and replace any one that is exposed, they do suffer not always visibly.

[Mocki]

Petrol engined T25s suffer really badly with the lead that comes from the alternator to the starter motor , it's not big enough, and it gets hot and cold every time you run the engine , it rots internally , going high resistance
It is the first place I look for battery and charging issues . Visually it may look ok, but electrically it's almost always not

[ChrisTriple]

Ok thanks guys, I'm getting 13.76, I have next week off to spend time on the van, refitting the interior and little jobs like this.

[lodgey62]

Your multi meter could be 0.1 out either way couldn't it?

[ChrisTriple]

Your multi meter could be 0.1 out either way couldn't it?

It could indeed, i get 14.45 volts from the alternator. The blue wire crimp is in a bad way would that make the difference? At the battery?

I'm going to connect the split charging wires tomorrow, I'm sure I used to get 14.2 before the restoration.

[CovKid]

Seconded on soldered terminals. All my main cables are soldered to help seal cable ends and stop the ingress of condensation. The problem even extends beyond alternator and battery with a not untypical voltage at the headlights of 10.5v due to the barely adequate cable feed. If you look in the WIKI I wrote a series of articles on improving connectivity and reducing voltage drops - which can be substantial on a stock vehicle. The cable lengths involved don't help either.

If you check out my photo above, I only have one connection to the battery to avoid the clutter of extra cables that you can end up with by using HD junction boxes, with every cable lug soldered, shrink tubing, then bolted together.

There are alternator regulators available that provide an extra 0.5v, and even adjustable regulators but this is really compensating rather than fixing the problem. By far the biggest cause of loss is due to old or failing cables. Once they start fraying or corroding, their capacity is much reduced. The drop you're seeing sounds about right.

https://club8090.co.uk/wiki/VW ... ain_cables" onclick="window.open(this.href);return false;

https://club8090.co.uk/wiki/VW ... ry_to_dash" onclick="window.open(this.href);return false;

https://www.youtube.com/watch?v=cEIkGpC72GY&t=2s" onclick="window.open(this.href);return false;

If your main harness is original, it will already be carrying less voltage than it once did, and it wouldn't have been that great in the first place. These days vehicle manufacturers use much thicker cables than they did in the 1980s. Its not a perfect analogy but even plumbing systems become furred up after so many years, restricting the flow of water and reducing efficiency.

[nicq]

Prey tell me the logic of the terminal block as I see it you are adding 2 more connections in the system

[ChrisTriple]

Thanks Ralph

I have access to wire, just need to know what size I'll need. I can get my hands on anything from 2AWG to 26AWG. I was thinking I could replace the old earth straps with 6awg stuff and maybe 10awg for other hi load areas

[CovKid]

Ofcourse, but I no longer have umpteen cables going to the positive battery terminal now. I'm not actually adding any, they were already there but running all over the place (split charge etc).

I've seen so many campers where cables are crammed together at battery and its far too easy to short against underside of seat. It gets worse if you find yourself having to remove the battery often as wires can easily start breaking away. Much less messy this way and better connection as theres only one cable going to battery positive clamp. The alternative would have been to run my new thicker cable direct to battery and then on again but thats just not practical given the reduced flexibility of the thicker cables needed and the limitations of battery clamps

Prey tell me the logic of the terminal block as I see it you are adding 2 more connections in the system

[nicq]

I am waiting for somebody to make a decent bat clamp built like a bus bar so several outputs can be taken off directly. So cables can run over the bat top.

[nesty]

I have the underseat leisure battery and Trojan tractions.

I use car audio power block. One cable from the split relay going into 2 block thus to power the leisure underseat and the Trojan (2x6V).

Then their output power cables going from them into a 2 into 1 car audio block which then has a single cable going to my extra installed auxiliary busbar fusebox (located above the VW orignal one).

Basuically about 4 cables, but they all fit ok. No real issues. I plan to tidy the install up even more this year.

My system does look DIY and you lose some floor space behind passenger seat though beats ever having to pay for pick up, which I have never done since 2009!

[Oldiebut goodie]

This was a better solution but I can't remember the make or where I obtained this one.




Looking on ebay there are some 4 terminal - 2 post / 2 stud ones available.

[CovKid]

Thats what the junction box does. The fact one cable from junction goes to batt is neither here nor there since its so short. The advantage is its under seat, out of sight and more importantly, insulated. Not that anyone would use that many but you can stack eight cables in that thing.

I have the underseat leisure battery and Trojan tractions.

I use car audio power block. One cable from the split relay going into 2 block thus to power the leisure underseat and the Trojan (2x6V).

Then their output power cables going from them into a 2 into 1 car audio block which then has a single cable going to my extra installed auxiliary busbar fusebox (located above the VW orignal one).

Basuically about 4 cables, but they all fit ok. No real issues. I plan to tidy the install up even more this year.

My system does look DIY and you lose some floor space behind passenger seat though beats ever having to pay for pick up, which I have never done since 2009!