Charging circuit

[deliriousthun...]

My battery ran flat recently, while I was riding..

It is totally completely dead, and will not hold any charge at all.. No big deal, I can replace the battery, but I need to figure out why it's not charging..

So I borrowed a multimeter from a friend and today I tested the regulator/rectifier, (according to instructions in the owners manual), and theoretically it appears to be working..

I also tested the cable running from the reg/rec to the battery, and there was continuity, I then checked the resistance and there was none.. Don't know if that quite means the same thing, I thought maybe if the cable was slightly damaged there would be continuity but some resistance..

Anyway, according to the owners manual, the other thing you need to check is the stator coil.. It says to check that the resistance is 0.44 ohms +/- 15% at 20 deg C.. The meter I was using wasn't that accurate, but it was colder than that outside today and the resistance read at 0.5 ohms, so I figured that was ok..

So the next step was to jump start the bike from the car, which I did..

I then checked the voltage across the same terminals of the stator coil that I had checked the resistance from, (I'm assuming there should be between 14-15V there ), and there was no voltage at all..

So, what next? Any advice?

Thanks,
Thomas
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Tom

[stinkwheel]

1) What bike?

2) You can't test a reg/rec with a normal multimeter. The manual might say you can, but if it does, it's wrong. You can test them using a special type of ohmmeter which tests with a set current that triggers the internal diodes. A normal one doesn't do this.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

It's an SRX250, not exactly a common bike..

If it helps any, I have the owners manual in pdf form, or can just take screenshots of the relevant pages (i.e. circuit diagrams and "charging circuit" section)..

Yeah? All the manual said to do was check the continuity between the prongs in the connector block in a certain way, (i.e. there should be continuity between x and a, x and b, x and c, but not continuity between z and a, z and b, or z and c)

And since I jump started the bike, I had the engine running and should've been able to test the voltage being generated by the magneto, by testing the connector block where the stator coil runs into the wiring loom no

I just don't think I checked it the right way, (across 2 of the connectors), in hindsight I'm thinking that was really stupid and I could've broken the meter or possibly even part of the bike I'm thinking I should've connected the negative probe to something earthed, (or even to the point it would normally connect to the loom)..

Say I could get one of these ohmeters by the way, how would I know what to check?

Also, F.Y.I. this bike has had the same problem before, I phoned up the guy who fixed it last time, and he said there was a damaged wire and he had to replace the reg/rec, the battery, and fix the wire.. He made a good job of it because I can't find any evidence of a repaired wire
____________________
Tom

[stinkwheel]

Ahh, now.

I seem to recall the SRX has an odd charging system. Possibly a field coil alternator.

If it does, be careful, they can put out enough power to give you a nasty shock if it comes through unregulated.

You got a copy of the wiring diagram?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

I do, but I don't have any photo editing software installed just now so I'm afraid I had to copy paste from acrobat into paint, which seems to have streched the image..

Here it is anyway:

Number 11 is the Magneto, 12 is the reg/rec, and obviously 1 is the battery, 2 the main fuse..

https://i71.photobucket.com/albums/i126/deliriousthunder/chargingsystemcircuitdiagram.jpg
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Tom

[stinkwheel]

Fair enough, it's a normal charging system.

Unplug the rectifier box (12) and measure resistance between each pair of the white wires (you're not testing the box, test the wires as they come from the bike). It should be the same between each pair. There should be infinite resistance between each white wire and a frame earth.

If these are ok, your stator coils are pretty certain to be intact.

Measuring voltage between the red wire and earth, you should be getting battery voltage at all times. Between the brown wire and earth, you should get battery voltage only when the ignition is on. The black wire should be connected to earth.

That tests all the wiring to and from the reg/rec.

That leaves the reg/rec itself. You ought to be getting around 14V output when you measure between the two battery terminals.

By a process of elimination. If it is connected properly and the coils are intact and it still doesn't deliver charge to the battery, the reg/rec is dead.

Contrary to what dealers etc would have you believe, you can fit pretty much any reg/rec off a Japanese bike. The wire colours and terminal block shapes are different but the guts of the things do the same thing.

So, if you're happy to cut the terminal blocks off and replace them with seperate terminals, you can fit any old reg/rec. I'd suggest mid 1980's Honda ones as being among the best.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Ok, so I have been loathe to actually fork out for a new battery so far.. On the basis that until I actually get the bike fixed, it will be getting abused a bit with no charge being fed to it.. Sounds like the only easy way to diagnose it is going to be to buy a battery, charge it, and use it for testing?

My car battery obviously has a little higher voltage, almost 14v so I'm not sure if I should use it to check these things?

I have already checked the resistance between each of the white wires as they come from the engine to the loom, (not as they come from the loom to the reg/rec, which I'll check now), the resistances are all equal, but I never checked the resistance between each wire and a frame earth.. I'll check that after I make this post, but I'm assuming it'll be ok..

For measuring the voltage between red wire and earth/brown wire and earth does the engine have to be running? Or do you mean it simply has to be hooked up to the battery?

If it just has to be hooked up to a battery, is it ok to use a higher voltage battery (car battery is almost 14v) just to check that, without running the engine?

Also, this is probably a stupid question, but how do I check that the black wire is properly earthed?

I know that zero voltage is delivered to the battery when the engine is running, it was the first thing the AA man checked at the roadside..

So if the wiring is intanct it should simply be a case of replacing the reg/rec? And I can use any Japanese reg/rec I pick up off ebay? That's handy
____________________
Tom

[stinkwheel]

[deliriousthun...]

[deliriousthun...]

Ok, so I finally recieved the reg/rec, and fitted it today.. Just have a quick question..

I jump started the bike from the car (with the car engine not running), and, as you really have to do with this bike, left the choke on for a good few mins till it was properly warmed up [leaving the choke on forces the engine up to around 5k revs].. All the time standing at the car battery with a multimeter, monitoring the voltage..

Car battery voltage when not connected to the bike: 13.58v

Once the bike engine was running, the voltage across the battery terminals instantly dropped to about 12.4v, but gradually climbed upwards..

I stood there for a good five minutes, maybe more, as I watched the voltage climb slowly (by 0.01v every second or so), till it eventually hit 14.22v, by which point every rise in voltage was taking longer, so I removed the multimeter so I could do something else, and came back to it after about 30 seconds.. It was then reading 14.24~5 and going back and forth between them, no longer rising..

I was expecting the voltage to simply hit around 14-15v as soon as the engine was running..

So, is this normal?

Thanks,
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Tom

[stinkwheel]

I presume you disconnected the car battery once it was started and this 14.5V is across the terminals of the bike battery with the engine running?

The fact that the voltage rose means the charging system is putting power in. If the battery was flat to start with, it could well take some time to build up the potential difference in the battery cells (in exactly the same way as if you hooked a flat battery up to a charger). In short, sounds good .

A bit of a ride out with the lights off would be a good thing to get it fully charged up. The higher the revs, the more power it can potentially put out (because the alternator is turning faster), most bikes at idle will probably 'break even' in terms of power used and power generated. Obviously you don't want to sit revving it at a standstill or the engine will overheat.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Um, this might be stupid, but no, I didn't disconnect the car battery, I didn't even have a battery in the bike.. I had the car battery connected straight to the loom, treating the car battery as if it was a bike battery..

My bike battery was so knackered that a week long slow charge didn't have any effect on it whatsoever, so I have a new one, but I haven't put it together yet.. (as I can't understand the poorly translated instructions )

Still sound ok?
____________________
Tom

[stinkwheel]

Aye, that means it's charging the car battery, which takes a lot more doing.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Cool, thanks a lot

One more thing, any tips on getting this acid:

https://i71.photobucket.com/albums/i126/deliriousthunder/DSC00392.jpg

Into this battery:

https://i71.photobucket.com/albums/i126/deliriousthunder/DSC00395.jpg

And f.y.i, it came with this tube

https://i71.photobucket.com/albums/i126/deliriousthunder/DSC00394.jpg

Looks like it goes on the breather nozzle, but my bike has a breather hose to attach there anyway..

The only time I've put acid in a battery before, the acid came in a pack with 6 seperate compartments, each with their own outlet, I just clipped it onto the top of the battery, let it drain and charged the battery up...

This one looks like I'm going to have to fill each compartment individually

Can't see how to do that without getting acid everywhere
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Tom

[stinkwheel]

My internet router is on the blink so I can't see your pictures but I presume you have a big bottle of acid and a hose. You cut the end off the spout bit on the bottle, put the hose on the end of it and fill each cell through its individual cap.

The answer to your question is "carefully, while wearing gloves and goggles.". I usually use a big syringe to do the job. You can also get a thing that looks very much like a turkey baster to do the same job. Obviously, don't do it on the carpet. Wash any spills with LOTS of water
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Thanks

I did it last night though. I remember from Chemistry at school that acid (at least this kind of acid, relatively dilute sulphuric acid), don't react to any great extent, (or at any great speed at least), with plastics. So I just did it inside a plastic bag, and moved the acid container from one port to the next. There was slightly more acid than I needed in the container anyway so the very small amount that I spilled wasn't important. It ended up inside the plastic bag, which I will rinse out today. I'll probably use bicarbonate of soda or something to neutralise the acid first.

I left it standing overnight with the little yellow plugs loosely on, hoping to let any air rise to the surface. It seems that the level has actually risen overnight, I expected it to fall as trapped air left, or the acid permeated the plates

Now I just need to charge it I guess. In the past I've just hooked up to a charger and left it overnight, but the instructions say something about charging till it's bubbling Presumably that'll be giving off hydrogen gas then

The instructions are so difficult to understand Have you heard of/done that before

Thanks,
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Tom

[stinkwheel]

You technically ought to charge it before use (just as you'd charge a normal battery that had gone flat). In practice, I usually find they have enough juice in them to get the bike running once they've settled.

So I fill them, leave them to stand for a few hours then put them on the bike and go for a ride around with the lights off to get some charge into them.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Heh, yeah I would do that if not for the fear that the new reg/rec would break while on that ride

It's had 3 reg/recs and 3 batteries in the 6 months that I've owned it

Think I'll just stick it on charge and hope for the best. I'll be keeping a close eye on it with a meter every time I have the engine running till I sell the bike now. It's one thing to need to replace the reg/rec, but having to replace the battery every time is annoying. If I catch it early enough the battery won't die and I'll be able to save it
____________________
Tom

[stinkwheel]

Be handy if someone invented a simple device you can attach to your bike that shows a green LED when battery voltage is ok and a red one when it's not.

Oh, they have.
LINK
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[deliriousthun...]

Thanks

I'll recommend it to the next owner Not going to spend any more money on this bike unless I absolutely have to.

Thanks for all your help, I would've been pretty lost otherwise
____________________
Tom