charging system problem

[rb20035]

i have a 1990 gl1500 i replaced the battery and alternator and just replaced the pulse generator i can go about 60 miles at 65mph and the battery goes dead i've checked to see if it was recharging the battery and it was not last year we went on a 4000 mile road trip with no problems this year nothing but problems anyone have any ideal whats going on

[MikeB]

Sounds like the alternator is not working. It should be maintaining battery voltage as you ride.

[rb20035]

this is the second alternator i've put on both alternators have done the same thing i've fully charged battery and checked to see if it was charging everything checked out ok then on the ride battery would go dead engine even sounded like it was going to flood out or coils where weak not firing on all cyclinders

[MikeB]

... checked to see if it was charging everything checked out ok ...

I understand that you have replaced the battery and you expect it to work but, it could still be bad or the installation was incorrect. A broken or intermittent wire at the connector that plugs into the alternator could be causing your issue.

What was the battery voltage reading at the battery terminals before you started the bike?
What was the barter voltage reading after the bike was started and idling, and then again at about 1500 RPM?

Battery voltage should be approximately 13 volts at idle. If your battery voltage did not measure between least 13.5 and 14 volts at 1500 RPM, the alternator is not charging.

[rb20035]

before i started motor at the battery it was at 11.5 volts then after it started it was at 13.7 volts

[MikeB]

before i started motor at the battery it was at 11.5 volts then after it started it was at 13.7 volts

What was the battery voltage when when you were having the problem? Did you check the alternator output when you are having that problem?

[rb20035]

what can cause the alternator to go out again

[Andy Cote]

Welcome to the forum. Where are you from?

What brand battery? Alternator?

[MikeB]

what can cause the alternator to go out again

The alternator has not necessarily gone bad. The connector that plugs into the back of the alternator might have come out. Or the wire in that connector might have come disconnected.
Check your connectors to make sure everything is secure.
Initially you said that the battery went dead. Was the battery actually dead and what was the voltage?

[rb20035]

the last alternator i but in was a LR140-708 Hitachi and the battery is a Everstart ES50N18LA3 when battery went dead it was at 8-9 volts

[rb20035]

i'm from frankfort indiana area

[Swagonmaster]

Since the battery has been discharged that much it needs to be thoroughly charged or it will be damaged. A really slow charge of maybe 1 amp for 5-6 hours up to overnight or 2 amps for half that time and float charger would be the best as it can be hooked up indefinitely without any damage to the battery. After it's charged it should test at 12.7 volts or higher, then let it sit for a day or at least overnight and recheck the standing voltage and it should be a minimum of 12.6 volts. If it's not you either have a drain on the battery or the battery is defective. If you can rig up a volt meter to use while riding you can keep an eye on the charging ability of the alternator, voltage should stay above 13 but might fall a little under that at a stop with the brake lights on. Having said all that the comments on checking all of the battery/charging system connections are definitely in line, the best system in the world won't keep the battery up if it's only partially able to do it's job.

[rb20035]

i'm looking at a wiring diagram of charging system for it can the problem be a bad relay it show it in section 17-4 of the service manual number 6 relay that may cause the alternator to go out

[DenverWinger]

Check main 55A dogbone fuse, charging current from the alternator has to pass thru that fuse to reach the battery. Fuse may be old and corroded.

[rb20035]

sorry everyone went out of town for a couple days got back on the 5th installed a new alternator and relay and then me and the wife went on another bike ride went chattanooga Tn then up to Chicago Ill and back home i would say we went around a thousand miles no problems i think my problems with it not recharging was reley in the 35 dollar relay in charging system

[WingAdmin]

sorry everyone went out of town for a couple days got back on the 5th installed a new alternator and relay and then me and the wife went on another bike ride went chattanooga Tn then up to Chicago Ill and back home i would say we went around a thousand miles no problems i think my problems with it not recharging was reley in the 35 dollar relay in charging system

If you paid $35 for that relay (Relay 6) which controls the alternator field coil (among other things), then you got ripped off: G8MS-H30 Relay

[jbaviera]

With all this, I just recently started having problems with my charging system again as well. When I picked up my 95 in 2017, the alternator decided to quit (voltage readings went wild), I installed an "in dash" volt meter (viewtopic.php?f=14&t=36120). Voltage fluctuates wildly between 13.2 and 14.8. While I normally have a little fluctuation at startup (0.2-0.4 volts for a couple minutes), it hasn't done that since the last alternator change. What could possibly kill the voltage regulator?

[Swagonmaster]

To Kill An Alternator, that sounds like a story that should be written. But as to the story at hand, basically any defective part in the alternator itself or a very high very fast excessive load that gets to the alternator before the dogbone fuse can burn through. Or we could just go with a more mundaine reason being a constant high load over time that overwork the alternator's abilities. Since the original 40 amp alternator isn't overcome with excess capacity a lot of electrical gadgets drawing power can take out a good unit long before it's time. Before you give up and reach for your wallet take a look at the 55 amp dogbone fuse by the battery to make sure it's good as all of the juice goes through it.

[jbaviera]

To Kill An Alternator, that sounds like a story that should be written. But as to the story at hand, basically any defective part in the alternator itself or a very high very fast excessive load that gets to the alternator before the dogbone fuse can burn through. Or we could just go with a more mundaine reason being a constant high load over time that overwork the alternator's abilities. Since the original 40 amp alternator isn't overcome with excess capacity a lot of electrical gadgets drawing power can take out a good unit long before it's time. Before you give up and reach for your wallet take a look at the 55 amp dogbone fuse by the battery to make sure it's good as all of the juice goes through it.

Actually, I changed the dog-bone fuse when I replaced the alternator (didn't want to take chances(bought a spare too)) The alternator currently installed is a 90amp from DB Electric, and is the one "acting up". All lighting is LED, and the few accessories I have are USB powered (SAT Radio, GPS, cell phone charger), with the exception of the volt meter. I went so far as to disconnect the ALL accessories, and connected a multimeter to the battery(did this before removing acc. to verify). Still having the same issue. Have to wonder if it just may be a "cooling" issue for the alternator, and maybe excess heat is taking out the regulator.

[Swagonmaster]

In that case it could be something like what happened to me last year, I got a new 90 amp alt and several months later a part inside came loose and ruined my day (the alt was warranty but I had to call family to bring out the trailer and load me up).The replacement is working fine but any of them can have a random failure. Also check to see that none of the wires leading to the alt (or anywhere else I guess) are pinched or rubbing something sharp, that could be the cause of the fluctuating voltage.