BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorThe Bonneville ShopBritBike Sponsor
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments.
Buy BritBike staff a coffee
Buy BritBike's staff a coffeeStill here since 1996 serving BritBike enthusiasts..
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Member Spotlight
Posts: 360
Joined: December 2001
Show All Member Profiles 
Newest Members
Mark Chapman, JacksMacnLE, Argos parts, Mr. Bean, rudi
10864 Registered Users
Top Posters(30 Days)
franko 167
DavidP 69
reverb 59
NickL 53
Popular Topics(Views)
1,019,866 mail-order LSR
a word from..
Forum Statistics
Forums34
Topics67,804
Posts680,446
Members10,864
Most Online14,755
May 5th, 2019
Who's Online Now
66 registered members (1958superrocket), 694 guests, and 890 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Measuring Charging Voltage Across Battery #783256 09/02/19 7:48 am
Joined: Oct 2003
Posts: 3,858
D
dave jones Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,858
When I try to do this my digital meter flickers all over the place. Should I be using an old fashioned moving coil meter or is there something wrong?

Dave

Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK
British motorcycles on e-Bay North America
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783258 09/02/19 7:54 am
Joined: Jan 2014
Posts: 375
N
NickL Offline
BritBike Forum member
Offline
BritBike Forum member
N
Joined: Jan 2014
Posts: 375
Using an analogue meter is easier, your digital one will probably be picking up all sorts of rubbish, HT etc.
If you want to use your digital one, try putting a 100uf and a 0.1uf 25v caps across the leads and see how you go.
Keep the leads away from the coils and maybe try twisting them together.

Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783291 09/02/19 4:47 pm
Joined: Oct 2003
Posts: 3,858
D
dave jones Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,858
Ok, thanks.

Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783296 09/02/19 6:08 pm
Joined: Jan 2017
Posts: 817
T
TR7RVMan Offline
BritBike Forum member
Offline
BritBike Forum member
T
Joined: Jan 2017
Posts: 817
Hi Dave, It depends upon the digital meter you have. The meter must have internal damping to not go crazy.

My cheapo digital go crazy like yours. My better ones read fine as you'd want.

Problem is I don't know what the cost/specification factor is that assures good reading from that particular meter. Seems here in USA when you get to the $50 range they work.

Of course if you have an old analog needle meter, they work good.

If you have a needle type, your good to go. But if you need a digital I'd ask UK users what digital works for them so you'll be assured of a meter that will meet your needs so you don't purchase one that still doesn't work on our bikes. Maybe ask on Triumph RAT group also if you don't get UK owner's response here.
Don


1973 Tiger 750
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783302 09/02/19 6:53 pm
Joined: Jun 2007
Posts: 6,455
HawaiianTiger Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Jun 2007
Posts: 6,455
For some reason, my digital meters don't work on my bikes in a random way. For example, my meters works fine on my Norton with zener and solid state rectifier, but not with a Podtornics unit installed.
It's baffling. On my Triumph with Podtronics, no problem. Honda, no issue.
Cheers,
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Black Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783316 09/02/19 10:12 pm
Joined: Jan 2014
Posts: 375
N
NickL Offline
BritBike Forum member
Offline
BritBike Forum member
N
Joined: Jan 2014
Posts: 375
Bill, if you remember there were a couple of chaps having problems with the Pod units and certain electronic ignitions.
The bikes would misfire etc. I suggested putting a couple of caps across the feed to the ignition units. John Healy
actually replaced the units with the type having the integral capacitor and the problem went away. It seems apparent
that the units use a gated oscillator arrangement to trigger the thyristors, the frequency of which was causing the
transmitted problem. Most digital meters have a very high impedance input so are sensitive to any electrical noise.
The simple way to enable use of a digital meter is to just put something like 100uf and 0.1uf across the meter leads.
I had to do the same thing with the miniature digital voltmeter i have fitted to both my bikes, works fine.

Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783339 09/03/19 5:59 am
Joined: Oct 2008
Posts: 5,698
DavidP Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Oct 2008
Posts: 5,698
Even my Fluke goes a bit nuts when checking a running bike without resistor plug caps. I use an analog voltmeter with alligator clips to check voltage while the bike is running.
BTW: The readings given for the alternator test in the workshop manual assume that you are using an analog meter.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
Re: Measuring Charging Voltage Across Battery [Re: NickL] #783412 09/04/19 7:39 am
Joined: Oct 2003
Posts: 3,858
D
dave jones Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,858
Thanks for all the new replies.

NickL- When you give the two capacitor values do you mean try one at a time, or two in series or parallel (between the probes)?

Maybe you mean a 100nf / 0.1 uf single capacitor?

Thanks,
Dave

Last edited by dave jones; 09/04/19 4:40 pm.
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783566 09/06/19 1:04 am
Joined: Jan 2014
Posts: 375
N
NickL Offline
BritBike Forum member
Offline
BritBike Forum member
N
Joined: Jan 2014
Posts: 375
No, the combined pair gives a better solution for the required frequency range, so both in parallel. 100uf+0.1uf.

I'm not going into the 2 pi FC thing..........


Last edited by NickL; 09/06/19 1:07 am.
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #783588 09/06/19 7:17 am
Joined: Oct 2003
Posts: 3,858
D
dave jones Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,858
Thanks, Nick. I don't know much about electronics.

Re: Measuring Charging Voltage Across Battery [Re: dave jones] #784950 09/21/19 12:02 pm
Joined: Oct 2003
Posts: 3,858
D
dave jones Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,858
I had a go at this with the two capacitors etc. The reading was quite a bit less flickery this time. Anyway, the battery is no good so it showed a bit under 11 volts. When I started the engine the voltage actually dropped down to a bit under 10 volts. When I let it warm up a bit and revved it up at 4000 rpm it showed a about 13.5 volts. I didn't rev it higher but should have I suppose but wasn't sure if it was good for it as not fully warm. Probably 5000 rpm is my road max.

Why did the voltage drop when I started the engine. Is that just because of the draw from the ignition? Also, with a new battery the voltage will show a different value at 4000 rpm?

Dave

Last edited by dave jones; 09/21/19 5:38 pm.
Re: Measuring Charging Voltage Across Battery [Re: dave jones] #784969 09/21/19 4:16 pm
Joined: Aug 2001
Posts: 3,954
KC in S.B. Offline
BritBike Forum member
Offline
BritBike Forum member
Joined: Aug 2001
Posts: 3,954
Anyone interested. That Battery Tender co. Offers a very small volt meter that plugs right in to the tender pig tail. It's really a handy piece. It can be used to monitor the charge while running, and shuts off after a period of no activity. I have used it while riding to check stuff. Best for a quick plug into the stored bikes to see if all good! I have even made a short pig tail with clips that it will attach to, and can carry it as a voltmeter in the tool kit, or glove box.

https://www.batterystuff.com/all-pr...om6ji5AIVRtbACh0hdwPnEAQYCSABEgJlgfD_BwE

I buy my AGM batteries from these guys, can't beat the price and free shipping. BUT<........ I refuse to put anything wireless on my bikes, besides my Butt that is. :~/

https://www.batterystuff.com/batter...r-wireless-battery-monitor-081-0172.html

Last edited by KC in S.B.; 09/21/19 4:24 pm.

Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
1 '65 XLCH on the way to Japan!

Moderated by  John Healy 

Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.3