Author Topic: Electrical charging question.  (Read 2453 times)

Offline ComfySofa

  • SOHC Expert
  • Posts: 268
    • View Profile
Electrical charging question.
« on: February 02, 2025, 06:21:50 PM »
Was in the garage earlier balancing (or at least trying to) balance my carbs....which is a whole other story (one day ill get "the knack") but so far it eludes me...

Anyway, last week, when i started balancing them (or trying not as well) - i ran out of battery....which did surprise me. Just as a bit of background my 400 has got a completely replaced wiring loom. Its got a Lithium battery and an aftermarket reg specifically for a lithium driven system.

Put it back on the optimate last week and fast forward today. Balancing didnt take as long (its as good as i can get it). So, as a last check i put a meter on the battery as the engine was running which was showing about 12.4-5 volts....if i hold the throttle open slightly it goes up to 12.6v.

Ive got a few reasonably modern bikes (one of which is a z1000 gen4) - i seem to remember that charging about 13 to 13.3 or so. Should the 400 charge at that rate or is 12.6 ish about the right voltage...wondering if its because its a smaller bike, older generator etc etc....

Thanks to anyone that takes a punt at it.

Andy

Offline taysidedragon

  • SOHC Master
  • Posts: 1619
    • View Profile
Re: Electrical charging question.
« Reply #1 on: February 02, 2025, 06:28:01 PM »
Your charge voltage seems low. It should be up around 13.5 -14 v with engine running.
Gareth

1977 CB400F
1965 T100SS

Offline ComfySofa

  • SOHC Expert
  • Posts: 268
    • View Profile
Re: Electrical charging question.
« Reply #2 on: February 02, 2025, 06:40:47 PM »
Righty...ok..so having the meter on the battery is the correct place to take a reading?

Edit: well - sounds like a new problem....figures as its been about a year to sort out the carbs..!
« Last Edit: February 02, 2025, 06:52:12 PM by ComfySofa »

Offline Bryanj

  • Grogu
  • *
  • Posts: 11747
    • View Profile
Re: Electrical charging question.
« Reply #3 on: February 02, 2025, 07:15:50 PM »
Depends on the regulator, i am old school and dont like lithium batteries or the complicated regulator they need, what is the battery voltage with lights on and running at 3500 rpm?

Offline ComfySofa

  • SOHC Expert
  • Posts: 268
    • View Profile
Re: Electrical charging question.
« Reply #4 on: February 02, 2025, 08:50:24 PM »
Ill have to get back to you..! (back in the house now for the night) probably wont be able to get back to it til friday night....stand by!!

Many thanks for the reply back.!

Offline Alexrayz

  • SOHC Associate
  • Posts: 59
  • 1976 CB400F- Just making my way through the galaxy
    • View Profile
Re: Electrical charging question.
« Reply #5 on: February 03, 2025, 07:44:33 AM »
Hey man I had a similar issue with my bike, wouldn't charge, or at least the charging voltage was super low.
In my case it was one of the alternator coils that fried. The regulator was fed with two phases instead of three. As a result the rectified voltage was about the same as what you have.

Normally, at 3500 rpm, you should get 14V max. 12.5V means it is not charging.

I didn't do anything to find that out, my mechanic did this time, so can't really help ya with the research process.

Good hunting and looking forward to read your findings.

Cheers, ride safe!
If it aint broken don't fix it

Offline ComfySofa

  • SOHC Expert
  • Posts: 268
    • View Profile
Re: Electrical charging question.
« Reply #6 on: March 02, 2025, 02:22:07 PM »
Hi there - its been a while since ive had the chance to get back to the Honda to test it...ive started with testing the stator resistiance and im getting about 0.7 across the 3 yellow wires....is that a bit high?

Edit: Just opened the Haynes manual and found it should be 0.61 to 0.69 - not sure how critical that number is?
« Last Edit: March 02, 2025, 02:28:24 PM by ComfySofa »

Offline McCabe-Thiele (Ted)

  • Grogu
  • *
  • Posts: 8160
    • View Profile
Re: Electrical charging question.
« Reply #7 on: March 02, 2025, 02:30:41 PM »
IMHO I would not worry about 0.01 Ohm taking into consideration the accuracy of your meter plus the connection you used.

Also worth cleaning up the contacts in the connector block by method of your choice.
« Last Edit: March 02, 2025, 02:39:35 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline ComfySofa

  • SOHC Expert
  • Posts: 268
    • View Profile
Re: Electrical charging question.
« Reply #8 on: March 02, 2025, 03:10:40 PM »
Cheers - thanks for that. Well, its a whole new electrical system - the Reg/Rec is specifically for Lithium batteries. Ill make a start on cleaning and checking connections....as i say it seems to be steady at 12.6/7 volts....

Offline Sesman

  • SOHC Master
  • Posts: 2305
    • View Profile
Re: Electrical charging question.
« Reply #9 on: March 02, 2025, 03:10:51 PM »
Agree with Ted. Did you null your connection cables? I’d say you are mighty fine for coil resistance value. The charging voltage is a problem though..obviously.
« Last Edit: March 02, 2025, 03:12:29 PM by Sesman »

Offline Oddjob

  • SOHC Jedi
  • Posts: 4497
    • View Profile
Re: Electrical charging question.
« Reply #10 on: March 02, 2025, 03:32:22 PM »
I'd advise doing a really simple test first.

Get a screwdriver, turn on the ignition and put the screwdriver against the rotor badge area, if it gets pulled onto the badge then the field coil is working, if it doesn't then it isn't. Most failures these days seem to be field coil related, either it's buggered but more often the 2 spade connectors are corroded and failing to make a good contact. The field coil becomes a big magnet when the ignition is on, no magnetism, no charge.

It's a quick and very easy test and should always IMO be the first test you do when suspecting a charging problem, mainly because it requires almost no tools and it's so easy to do.

Carbs PD or the more normal 550 carbs? PD carbs are harder to balance in my experience as they have one which isn't adjustable, be thankful it isn't a GL1000/1100, those are impossible to balance until you know the knack.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline McCabe-Thiele (Ted)

  • Grogu
  • *
  • Posts: 8160
    • View Profile
Re: Electrical charging question.
« Reply #11 on: March 02, 2025, 03:41:51 PM »
Good tip Ken, I'll save that one for future use.

I've read something about lithium batteries being sensitive to over voltage thus shortening their life?
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline K2-K6

  • Grogu
  • *
  • Posts: 5720
    • View Profile
Re: Electrical charging question.
« Reply #12 on: March 02, 2025, 09:25:29 PM »
I'd see the fixed "reference" carb as an assest which prevents arbitrary setting of all slides to inappropriate overall positioning relative to the throttle operating mech.

In essence, it prevents a distortion of slide to operating mech by having that single one fixed. Just means that you only have to match the other three to that one.

It's a method used on some car twin carb setup too. Stops people wandering off track to get everything completely out of synch, not with each other but intended installation of overall throttle "system" etc.

Offline K2-K6

  • Grogu
  • *
  • Posts: 5720
    • View Profile
Re: Electrical charging question.
« Reply #13 on: March 02, 2025, 09:30:41 PM »
Cheers - thanks for that. Well, its a whole new electrical system - the Reg/Rec is specifically for Lithium batteries. Ill make a start on cleaning and checking connections....as i say it seems to be steady at 12.6/7 volts....

Original spec (albeit for 750 system) is regulator to cut @ 14.5v with most common system being similar.  Most of the cars and bikes I check are similar at approx 13.9 to 14.7v generally. 

Didn't think lithium was ordinarily targeting less than that.

Is there data for target output of lithium system  you've used?

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal