Parasitic draw.

[tim0409]

Hi

Hoping for some help with the following; my bike’s battery was draining after a couple of days and after a lot of investigating I found that the relay that powers the ignition/fuel pump was wired incorrectly and was always on, which meant the draw was around 170mah. I re-wired the relay and checked the parasitic draw (multimeter in series with the negative terminal and lead) and it had dropped to around .06mah, which is fine.

I thought it was fixed so I didn’t plug the maintenance charger in for a couple of days and noticed the battery had dropped from 12.6v to 6.8v. I’ve re-checked the parasitic draw and it’s still .06mah, so what could be causing the drop? The obvious answer would be a bad battery but it’s a fairly new replacement. I’m currently monitiring the old battery for voltage drop, and will try that and see how I get on, but in the meantime am I missing anything?

Thanks in advance.

[snagzie]

No alarm fitted right? Sorry to state the obv

[Mr Squarekins]

My first thoughts were alarm or tracker, but I guessed you'd already thought of those.

[paddy1970]

Even though your battery is fairly new, it could still be defective. Some batteries can develop issues such as an internal short or a bad cell, which could cause them to lose voltage rapidly. A load test on the battery would help determine if it can hold a charge properly under stress.

[black-k1]

If the draw when everything is switched off is .06mah then you've really only got 2 possible causes:

1. there is something that periodically puts a bigger draw on the battery and isn't "on" when you've tested. I've no immediate suggestions as to what that might be.

2. The battery is failing.

[tim0409]

Thanks for all the comments; I’m going to refit the older battery (which I replaced as I mistakenly thought was faulty) and see how I get on. There is no alarm fitted, but if it isn’t the battery I will have to monitor it to see what is intermittently drawing current. It’s a very simple bike so not sure what that could be. I have Oxford grips fitted but I have installed a relay so they shouldn’t really be causing an issue.

[black-k1]

tim0409 said:

Thanks for all the comments; I’m going to refit the older battery (which I replaced as I mistakenly thought was faulty) and see how I get on. There is no alarm fitted, but if it isn’t the battery I will have to monitor it to see what is intermittently drawing current. It’s a very simple bike so not sure what that could be. I have Oxford grips fitted but I have installed a relay so they shouldn’t really be causing an issue.

Can I suggest completely disconnecting the grips? I can't see why they should be a problem but having them disconnected will 100% eliminate them from the list of possible issues.

[snagzie]

What K1 says, but also might be worth taking the relay out of the equation completely and wiring the grips so they are connected to the switched live on a permanent basis. I was recommended to do this by my garage and makes sense.

Also stops scrotes turning the grips on if its parked in the open.

[black-k1]

snagzie said:

What K1 says, but also might be worth taking the relay out of the equation completely and wiring the grips so they are connected to the switched live on a permanent basis. I was recommended to do this by my garage and makes sense.

Also stops scrotes turning the grips on if its parked in the open.

I assumed that the switching side of the relay was fed by an ignition switched feed. Is my assumption wrong?

[tim0409]

black-k1 said:

I assumed that the switching side of the relay was fed by an ignition switched feed. Is my assumption wrong?

I took a feed from the rear light for the relay. I added a relay as the grips were meant to shut off when they detected a drop in current, but not long after I fitted them I came back an hour later and they were still switched on.

Good plan; I will disconnect them and see what happens.

[stu67]

Just throwing it in here, I had a USB port doing similar on a previous bike nothing plugged into it, just Chinesium rubbish.

[snagzie]

black-k1 said:

snagzie said:

What K1 says, but also might be worth taking the relay out of the equation completely and wiring the grips so they are connected to the switched live on a permanent basis. I was recommended to do this by my garage and makes sense.

Also stops scrotes turning the grips on if its parked in the open.

I assumed that the switching side of the relay was fed by an ignition switched feed. Is my assumption wrong?

Yep the relay is directly connect to the battery in "as instructions" use. The relay is off at 12v, but switches on at 14v (approx values) when the alternator is charging the battery

[tim0409]

I’ve just checked my multimeter and the 250ma fuse has blown, so I think my readings are a bit suspect…..will update when I have replaced it.

[Gladers01]

tim0409 said:

I’ve just checked my multimeter and the 250ma fuse has blown, so I think my readings are a bit suspect…..will update when I have replaced it.

Another thing you could check is the coil resistance of the relay that has been added, if this is around 200 ohms the current draw will be about 60 ma when energised (divide 12v by 60ma for the resistance value). Also you could try reading the current draw on the positive side of the battery, it shouldn't make any difference but worth a try.

What would be acceptable as a parasitic draw for this type of bike? 60 ma doesn't sound overly excessive

[OutInTheShed]

The meter is reading 60 micro-amps, 0.06mA.
Which sounds low.

A lot of vehicle ECUs will draw some current for a certain period after turning off the ignition.
Some go through a few phases shutting down.
My bike goes into a deeper sleep after a day or so.

So readings can be a bit confusing without model-specific knowledge.

I use a Ctek charger adapter which flashes green for good, orange for 'find the charger' and red for 'oh bugger'.

[tim0409]

OutInTheShed said:

The meter is reading 60 micro-amps, 0.06mA.
Which sounds low.

The reason I suspected my meter might an issue is because I measured 0.06mA on the main lead, and exactly the same for the feed to the grips, which didn’t feel right. I’ve swapped the battery and will keep and check it tomorrow when my new meter arrives (the only next day prime fuses were £9 and a replacement meter was £9.95!)

[KTMsm]

Once a battery has been discharged below around 9 volts, generally they're dead

They can be charged up but they don't hold many amps

So the previous issue could have killed the original battery and the new battery

I recommend the £20 CCA testers on eBay, they're not 100% but they're probably 95% reliable on a battery's condition

[tim0409]

Thanks KTMsm, that had occurred to me. I will check again once I get my meter but a new battery wouldn’t be that expensive.

[tim0409]

I checked the draw again with my new meter and it looks like it’s caused by the grips.

The reading for the bike less the grips -



And the grips on there own (through the relay, which is where the issue will be) -



Both batteries have been run completely flat with this issue so for the sake of £32 I’ve ordered a new one, and a new relay for the grips (will check the wiring at the same time).

Hopefully that will fix it!

[OutInTheShed]

100 to 200mA is about the current for a relay coil.

Where is the grips relay wired?

What does the grips system consist of?
On my bike ,there is a relay, a controller which adjusts the power to the grips and the grips themselves.
This Oxford Hotgrips from ten or so years ago.

The coil of the relay should go from a switched live to ground. So the relay comes on whenever the ignition is on.
And, importantly goes off when you turn off and take out the key
I think mine is powered by the feed to the horn button. It was a long time ago!

The contacts of the relay connect battery +ve to the grips controller. Via a fuse.

So unless there is live to the horn button, there is no power to the relay coil.
That means the ign must be on for any power to be drawn.by the relay
No power to the coil, no power out of the contacts.

On a more modern bike there might not be a live feed to the horn button, could all be canbus mumbo jumbo.
But you should find a switched live somewhere?
Maybe you have chosen an unswitched live which the ECU uses in sleep mode or something?
Sorry if I've simplified it to 'trying to explain nuclear fusion to my Gran' levels.