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Sun Jun 02, 2013 10:23 am

does anyone know the full load amps for a starter on a 2.1 L wbx. i know they might be different for different brands but they should be close.

Mon Jun 03, 2013 7:01 am

I would expect 100 - 150 amps. This will bump your thread.

Mon Jun 03, 2013 7:09 am

According to RockAuto.com, the 2.1 starter is rated at 0.8KW which is about 67 amps.

However, this is steady state current draw. When spinning up the motor can draw several times this for a fraction of a second.

Mon Jun 03, 2013 8:06 am

67 amps under load or free spinning? Under load, that seems very reasonable and my number is way off. Sorry.

Mon Jun 03, 2013 8:59 am

That is the rated output of the starter (DC motors can pull much more than their rated output for several seconds).

Free spinning it will pull very little current. If the load on the starter is higher (lower rpm during operation), then it will pull more amps. 0.8 KW is a pretty small output. For example most nippon-denso starters are 1.0-1.4KW even for smaller engines around 2.0L.(higher compression than the WBX though)

The wiring to the starter is over-sized for the steady state current, but it is usually sized to reduce voltage drop when the starter pulls 200ish amps to spin the engine up to starting speed.

Mon Jun 03, 2013 9:23 am

i know go westy rates their new gear reduction starter at 1.4kw this would mean around 117 amps @ steady state. since the stater is basically a dc motor if you measure the armature resistance you can approximate the startup current I= volt/resistance = 12/r (i googled this). generally the start up currrent rule of thumb is 10 times the running current. this would take a pretty substantial battery. around 1100 cca (cold cranking amps). i am still wondering what anyone has measured on their starter?

Tue Mar 10, 2020 4:44 pm

Ok, I'm working on a kill switch and will be routing some amperage around the van. VW was stingy with their wires, that's pretty clear, but why do I get these ridiculous figures when I use wire gauge calculators? I don't see anyone routing 1/0 wire from their battery to their starter. Maybe I'm crazy, but I'm pretty sure I'm not.

I changed the 117A to 30 and it still said to use 6 AWG, which I think is overkill. I'm all for overengineering for safety, but come on.

Tue Mar 10, 2020 5:07 pm

VW doubled the size/gauge of the long battery cable stating in 86 models, as well as shortened it.
I would strongly consider buying the later version if you will be dropping the fuel tank for any reason.

Mark

Tue Mar 10, 2020 5:17 pm

I just put in a battery to starter cable on a project van I’m working on. I used 2/0.

Tue Mar 10, 2020 5:46 pm

The later cable is a metric size close to #2/0 AWG.

The early cable is close to #2 AWG, 3 sizes smaller than the later cable.

Mark

Tue Mar 10, 2020 5:56 pm

Well fair enough. I actually need to replace some of these wires as they're lookin old.

Mark, any guess as to what the starter relay kits would pull in terms of amps - not the starting circuit obviously, but the coil side. It'd have to be on the order of a few amps, right?

https://www.busdepot.com/wr1

Tue Mar 10, 2020 6:04 pm

That size of relay pulls way less than an amp, about a tenth of an amp.

Even the fairly massive "ford solenoid" type are under an amp.

Mark

Tue Mar 10, 2020 6:46 pm

Those calculations don’t reflect that the allowed voltage drop far exceeds 3%, it. Is more like 20% over a few seconds

Tue Mar 10, 2020 6:49 pm

jwallis wrote: ...why do I get these ridiculous figures when I use wire gauge calculators? I don't see anyone routing 1/0 wire from their battery to their starter...

One reason may be the 3% voltage drop you specified. Change that to a 5% acceptable voltage drop and the spec comes out as 2AWG.

Okay -- I see the latest post gets to the same point.

Wed Mar 25, 2020 10:59 am

Thanks yall, I need to do some reading on voltage drop.

Ok, I JUST realized something. In a stock van with no hard start relay, there is still - as with every car's starter - a solenoid slapped on the side of the starter, which acts as a "relay" in that it closes the circuit with the heavy wire from the battery to the starting motor itself.

So when we're saying 117A to the starter, that does not mean 117A through the starter switch on the steering column. The starter switch circuit is a lower amperage circuit that goes from the battery, through the starter switch to the solenoid.

Q1
Do we know what *that* amperage is? That's a 10 gauge wire that goes through the steering column. I've looked online and with other cars I found around 20A for a typical starter solenoid... does that sound reasonable in a Vanagon?

Q2
To be painfully clear: when we put a hard-start relay kit in a van, those 20A or so are now running through the hard-start relay, true? It looks like most of these bosch style hard-start relays are rated around 30/40A.

Thanks for letting me play catch-up :)

Wed Mar 25, 2020 11:59 am

jwallis wrote:
Do we know what *that* amperage is?
I recently read a post about a kill switch using the Neutral Safety Switch, and the Sambanista had measured this current. A quick search and you should be able to find it. If I had to guess, I'd say 7 amps, but don't quote me on that.

Wed Mar 25, 2020 12:01 pm

20A might be a tad high, but it's in the right ball-park. That's still a pretty hefty current for the small switch contacts. That's why an extra hard-start relay (whose coil may only take 200mA but whose contacts are good for 40A) is a Very Good Idea.

Wed Mar 25, 2020 1:03 pm

Crud, I searched but just tried "solenoid draw" and found this thread:
https://www.thesamba.com/vw/forum/viewtopic.php?p=7947951

Wed Mar 25, 2020 6:31 pm

jwallis wrote: Crud, I searched several times but just got the idea to try "solenoid draw" and found this thread:
https://www.thesamba.com/vw/forum/viewtopic.php?p=7947951

Thu Mar 26, 2020 6:04 am

I just measured two different vans, both of them were measured at right around 10 amps.