Topic: Electrical vs. Battery question

[Duluoz]

WARNING:

Noob post! 


I have a 1975 Honda cb750 super sport.  When I first got the bike the battery was next to toast (the previous owner jumped the battery with a car battery to get it road worthy).  It ran but the start button did not work, the horn did for a few honks but it shortly stopped working, and it was a weak sound that came from those honks.  The key when turned to the on position would produce nothing, no lights, and no kick start (I fiddled with the wires that connected to the ignition and it worked).  The battery ended up just plain dying 2 days later, SO, I went and got a new battery filled ALMOST all of it with the acid stuff all but the one chamber on the positive side only got 1/4 the way full.  Charged it, let it sit for 2 hours as it instructed, installed it and presto it all worked the horn still sound like poop but the start button started the bike and the key when turned gave a positive response (most likely due to me fiddling with the wiring behind the ignition).

Then...

The next day it all went back to the way it was before start button no longer started the bike (it turns the head light off when I push the start button), horn pooped out a sound a few times then died and now the ignition system in not producing if I move the bike too much (obviously it is loose or faulty wiring that I need to fix) but what about the other things?  Is it still the battery or is it a wiring short?

Thanks in advance.

[oldbiker]

That sounds as though there is a partial short that is draining the battery while it is switched off. Partial or intermittent shorts are the most difficult to find so if you are not fairly competent in dealing with electrical cicuits, I suggest that you check with your biking friends to get a little help. Also do not leave one cell of the battery partly filled as that will allow the top of the plates to dry out and lead to early death.

[TwoTired]

You did good getting a new battery.  Not so good with the acid filling.  There are 6 cells working in series.  The current has to flow though all six and if one is deficient it severely reduces battery output.  At best, you only have 5/6 of a battery and with one cell only a 1/4 full, you may actually have 1/4 of a whole battery power.

You may still have other electrical issues with the bike, but it is pretty much pointless to work on those without battery power.
Your bike will not run without a battery.  The alternator won't work without battery power to getting it intiially excited no matter how much you kick the starter lever.  And, the coils won't fire the spark plugs without electrical power either.

So, get the battery properly serviced and charged, then move on to checking out the bike electricals.  You are probably going to need a meter to sort things out.  Digital ones can be had for under $10 these days.

If you or the previous owner at any time reversed the polarity of the jumper cables while getting power from a car, at least part of the charging system has been damaged, for certain.  And, this may explain the battery drain over time.
There is information in the FAQ to help you examine and correct faulty charging systems.

Cheers,

[Duluoz]

You did good getting a new battery.  Not so good with the acid filling.  There are 6 cells working in series.  The current has to flow though all six and if one is deficient it severely reduces battery output.  At best, you only have 5/6 of a battery and with one cell only a 1/4 full, you may actually have 1/4 of a whole battery power.
You may still have other electrical issues with the bike, but it is pretty much pointless to work on those without battery power.
Your bike will not run without a battery.  The alternator won't work without battery power to getting it intiially excited no matter how much you kick the starter lever.  And, the coils won't fire the spark plugs without electrical power either.

So, get the battery properly serviced and charged, then move on to checking out the bike electricals.  You are probably going to need a meter to sort things out.  Digital ones can be had for under $10 these days.

If you or the previous owner at any time reversed the polarity of the jumper cables while getting power from a car, at least part of the charging system has been damaged, for certain.  And, this may explain the battery drain over time.
There is information in the FAQ to help you examine and correct faulty charging systems.

Cheers,

The reason I only put 1/4 of the acid in the battery was because it was all the gave me...  Live and learn.

Can I put the acid in and not have to recharge the battery...  Or should I start again?

[TwoTired]

You should always float charge a wet cell battery after the introduction of electrolyte to the battery.

Fill the low cell, float charge your battery.  The sooner you do this, the better the survival chances of the battery.

Cheers,

[Duluoz]

You should always float charge a wet cell battery after the introduction of electrolyte to the battery.

Fill the low cell, float charge your battery.  The sooner you do this, the better the survival chances of the battery.

Cheers,

Cheers to you sir!

That will do it until I have another noob question.

[BobbyR]

You did good getting a new battery.  Not so good with the acid filling.  There are 6 cells working in series.  The current has to flow though all six and if one is deficient it severely reduces battery output.  At best, you only have 5/6 of a battery and with one cell only a 1/4 full, you may actually have 1/4 of a whole battery power.

You may still have other electrical issues with the bike, but it is pretty much pointless to work on those without battery power.
Your bike will not run without a battery.  The alternator won't work without battery power to getting it intiially excited no matter how much you kick the starter lever.  And, the coils won't fire the spark plugs without electrical power either.

So, get the battery properly serviced and charged, then move on to checking out the bike electricals.  You are probably going to need a meter to sort things out.  Digital ones can be had for under $10 these days.

If you or the previous owner at any time reversed the polarity of the jumper cables while getting power from a car, at least part of the charging system has been damaged, for certain.  And, this may explain the battery drain over time.
There is information in the FAQ to help you examine and correct faulty charging systems.

Cheers,

To put waht TT said in simple terms the battery can only be as good as it's weakest cell.
One quick and dirty method for find out if you have a short draining your battery is tio take a 12V bulb with two leads attached.
Place lead #1 and on the ground side of the battery.
Touch lead #2 to the frame or engine .
You have both leads attached to what are supposed to be grounds. If the bulb lights to any extent, you have a short to ground somewhere.
This will not tell you where the short is, that you will have to hunt down.
It would probably be in the headlight bucket since wires are jammed n there pretty good.
Your horn may also be crapped out also and has nothng to do with the battery.

[Slim_SLC]

okay, I'm the previous owner.  In my defense, I am a noob as well.  The 750F was my first bike, which I sold to rusty in a money desperation move.  The bike ran just fine for me the whole time I had it and I was shocked when he came to pick it up that the battery was dead.  We tried jumping it from a car at the advice of his friend.....I didn't, and apparently he didn't know there was anything wrong with doing that at the time......I've since learned that can fry the regulator.  I for sure did not cross the polarity on the battery.  I think we found that the ignition switch plug was loose and now that problem seems to be addressed.  I think a full charge on the battery would fix the charging issue......plus I think a lot of the problem is short trips which never allow the battery to fully charge after starting.  The horn works when the battery is fully charged.   I just got a 78 550k, so I'll be working with rusty on getting the 750 in top shape so we can go riding together. 

thanks for all the help on the board, everyone.

[Bodi]

Here's this myth about jumping a bike from a car again.
Jumping a 12V bike from a 12V car will do no damage. The regulator won't be damaged. The rectifier won't be damaged. The wiring won't be damaged
Jumping from a running car to a bike with a dead battery can possibly damage the bike battery, the charge current will be much higher than it is used to. This shouldn't usually be trouble especially for a short time but there is a small possibility of damaging some batteies. That's all.
The entire wiring harness is made for the normal voltage on any 12V car battery. Nothing is different.
If the jumpers are placed directly on the battery, there's no bike wiring involved in the jumpering. If you connect to the frame or starter stud, already defective ground or battery wiring might be overstressed as there'll be a lot of current flowing, but not much more than the starter itself draws so good wiring should be fine.

[Slim_SLC]

okay, so much for frying the rectifier then as we only connected to the battery on the bike.  the car was running, but any damage to the battery is a mute point as that battery was trash anyway and has since been traded in for the new one.  Sounds like we need to just get the electrolyte filled up correctly and let it have a good charge on the tender before installing it in the bike.  fun times.