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By Noodles
#100367
I keep seeing threads about the Himi losing charge, and am still experiencing it myself on two separate Himis and 4 batteries, all replaced under warranty.

The bike has been parked over winter and shock, it's dead again. My 1200 honda which has been parked up right next to it over a year started first time.

The current battery is(was) a known good one from Motobatt. I think the dealerships and Enfield just like fobbing the issue onto the battery as an easy fix which gets them outside the warranty period.

I've done a bit of research online, and there seems to be a few different components people have identified as a root cause.
Sources. https://www.advrider.com/f/threads/roya ... 0/page-102
and Youtube https://www.youtube.com/watch?v=IKbBRqtcw9s

1. Regulator/Rectifier diode leakage. Easy to diagnose
Unplug all but the 3 Phase and do a Diode/Continuity check in each direction on the DC to Battery connection. Should have a value in one direction and 0 in the other. More than zero = leak.

2. Starter Relay Diode leak.
Same test as 1, but across starter motor relay when disconnected from battery but connected to motor.

3. Bad cell in battery.
Next time you don't intend to use it for a bit, disconnect battery the and measure voltage, measure it again just before you use it. If it's losing voltage while disconnected there is a fault in the battery. Note: If you have a parasitic drain, it will ruin batteries over time, so finding a bad battery does not prove you don't have a drain somewhere else.

4. Leaky Capacitor across the alternator. There is a capacitor in the alternator to smooth the AC out but This should be a non issue if the regulator doesn't leak.

5. Wet battery
Battery compartment isn't water tight, if it gets damp enough in there you will get battery drain.
User avatar
By stinkwheel
#100373
The way i'd go about looking for a power leakage is to connect an ammeter set to measure milliamps in series with the battery positive. This will show the amount of current leaking. I'd then start unplugging things one at a time until it drops to nearly zero.

Remember, at no point should you turn anything on when measuring milliamps or you'll pop your meter. Keep the key in your pocket.

The cheapest and simplest way to deal with the issue would be to fit a battery isolator switch. Which would also act as an additional anti-theft measure. Only downsides are a) remembering you fitted it and b) If you have a clock, it'll reset it every time.
By RocketRR
#100454
As Rushour said fit the new lead from our host bestvthing I fitted to my Himmy no battery issues at all since

Brilliant way of doing it by switching the rectifier off thru the rear brake light circuit.
#100510
Simplest way I solved the problem was to fit an isolator switch. Ok so it means your clock is never going to be at the correct time, but as the screen is usually like a hazy kaleidoscope of moisture, you'll never see it anyway. Mine would drain the battery pronto if you parked it on the side stand and left it in gear.
Image
One of these connected to the earth and mounted discreetly, and accessible worked for me. I only switched it off if the bike was not being used for longer than a week.
User avatar
By Noodles
#100523
Call me a fool, but I prefer to fix the root cause than make the wiring loom more complicated by adding switches and relays.

I keep seeing people pushing Lithium as the answer, but it really isn't unless you only had a bad battery in the first place.
A good battery will drain just as quickly as a bad one if there is a current leak.

I can't edit the original post, but I have seen in forums another potential cause which is that the gear position sensor is always powered on the BSIV model.

This actually resonates with me, as After charging it back up without disconnecting my battery my gear position sensor stopped working until I disconnected the battery for 5 minutes. The only way that could have made a difference is if the sensor electronics needed a reset.
I think it crashed because it got fed 12V down to 0.1V during the discharge then straight up to 14 when charging but was never off.
By Andy C
#100524
Dont get me wrong I am not saying a Lithium battery is the solution to fixing battery drain, but is a solution when the OE battery gives up the ghost like mine did.

Clearly if there is a constant current draw on the battery with the ignition switched off something needs to be done to stop it, or hosts loom seems to be a simple solution however it works.
#100541
Noodles wrote:
Tue Mar 29, 2022 1:38 pm
Call me a fool, but I prefer to fix the root cause than make the wiring loom more complicated by adding switches and relays.

Interesting.comment.

On my bike there were there potential causes of current drain. Fitting an isolator switch got rid of all three, and allowed me to use the bike (my only transport) trouble free for over two years, when I decided to move it on. The "complications" you talk of, involved fitting a piece of wire, and a simple switch, which took all of 25 minutes and cost less than £20. Not having a barely legible clock set at the correct time wasn't even worth bothering about. Any bike I've owned over the past 30 or so years has had an isolator switch fitted anyway, as an additional safety precaution.

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