ProducerBill Posted March 13 Share Posted March 13 My 1981 Suzuki GS550L was having trouble keeping the battery charged. It would go from fully charge off the battery charger to not enough power to start the bike and even barley light the turn signal indicator in under 30 min. I checked the AC output from the stator. All three lines showed greater then 24 vac. However, the reading at the battery at around 5k rpm was ~9.8 vdc. So I replaced the regulator. After installing the new regulator the voltage at the battery is now greater then 13 vdc. Sadly this didn't seem to resolve the issue. At best it has extended the run time to 60min. In the process I have replaced the headlight with an LED light to reduce the load. The original H4 would draw 65 watts. The new LED maxes out at 45 watts. So not really sure what direction to head in. Could the battery be damage? If so the charger bad battery light isn't lighting. If its parasitic I am not sure what is could be as there is nothing like power for phones or anything. If anyone has any ideas I would grateful to have them. Quote Link to comment
coombehouse Posted March 13 Share Posted March 13 13 volts is not enough, it should be within the range 13.9 to 14.7 volts. Have you hard wired the 3 wires from the stator directly to the reg rectifier & the remaining wires direct to the battery, not through the old wiring loom? 1 Quote Link to comment
TonyGee Posted March 13 Share Posted March 13 how old is the battery ? might be time for a new one. Quote Link to comment
ProducerBill Posted March 13 Author Share Posted March 13 1 hour ago, coombehouse said: 13 volts is not enough, it should be within the range 13.9 to 14.7 volts. Have you hard wired the 3 wires from the stator directly to the reg rectifier & the remaining wires direct to the battery, not through the old wiring loom? The voltage might have been higher. I will double check. All I can be sure of right now is that it was better then the old regulator. Quote Link to comment
ProducerBill Posted March 13 Author Share Posted March 13 33 minutes ago, TonyGee said: how old is the battery ? might be time for a new one. The battery is less than a year old. However over the winter as I worked on the bike it was drawn down to the point that it was unable to turn over the engine. Also now that I am riding it around it is being drawn done to a point it can't even really like a tiny bulb. So drawing it down to that point over and over can't be good for it, but if it has been 50 times do you think that could damage it? 1 Quote Link to comment
bunk Posted March 13 Share Posted March 13 Have you inspected electrical connections for corrosion? Quote Link to comment
Arttu Posted March 13 Share Posted March 13 A couple of notes: -24VAC from the generator wires sounds low. Usually the spec is something like over 50VAC @ 5000rpm. It might be a good idea to verify this. -If the battery voltage is always over 13V when the engine is running you can't drain the battery empty while riding. So apparently voltage drops lower at some conditions. Quote Link to comment
Gixer1460 Posted March 13 Share Posted March 13 New or old, if a battery is goosed - its goosed! I managed to kill a brand new battery between work and home approx 30 miles - mainly motorway and lights on, to the point that it was misfiring 1 or 2 miles from home - a duff regulator / rectifier will do that for you! I'd say the battery is deffo suspect as they don't like deep cycling, and maybe the genny as Arttu says the AC output is low! Quote Link to comment
TonyGee Posted March 13 Share Posted March 13 1 hour ago, ProducerBill said: The battery is less than a year old. However over the winter as I worked on the bike it was drawn down to the point that it was unable to turn over the engine. Also now that I am riding it around it is being drawn done to a point it can't even really like a tiny bulb. So drawing it down to that point over and over can't be good for it, but if it has been 50 times do you think that could damage it? a drop test on the battery after a full charge would probably tell you if its ok or not, but for the price of a new one I'd just replace it anyway. Quote Link to comment
Fazz711 Posted March 13 Share Posted March 13 Agree with others the AC seems low. If you have a good battery charger and you are fully charging the battery it should run ok for a while. Worth trying to check if you have something draining the battery. Run an clip on amp meter if you can on try running multimeter in line set on amps I also suspect you have now got a duff battery. Quote Link to comment
ProducerBill Posted March 13 Author Share Posted March 13 1 hour ago, TonyGee said: a drop test on the battery after a full charge would probably tell you if its ok or not, but for the price of a new one I'd just replace it anyway. Completed drop test per NIST Handbook 44-2020 subsection 3.40. Now I have acid burns on my arms, face and genitals. According to expected results it passed. And the worst thing of all is my bike still will not start. Quote Link to comment
ProducerBill Posted March 13 Author Share Posted March 13 2 hours ago, Arttu said: A couple of notes: -24VAC from the generator wires sounds low. Usually the spec is something like over 50VAC @ 5000rpm. It might be a good idea to verify this. -If the battery voltage is always over 13V when the engine is running you can't drain the battery empty while riding. So apparently voltage drops lower at some conditions. Thank you I will double check the ac output. Quote Link to comment
TonyGee Posted March 13 Share Posted March 13 20 minutes ago, ProducerBill said: Completed drop test per NIST Handbook 44-2020 subsection 3.40. Now I have acid burns on my arms, face and genitals. According to expected results it passed. And the worst thing of all is my bike still will not start. !!!!!! what was the exact Volt reading at the battery at 5000rpm ? you said it was over 13V, also i remember doing a geny test on a GS750 years ago and im sure the AC was over 70 on all 3 wires which was right. i would of thought yours would be similar, 25AC seams low ???? 1 Quote Link to comment
ProducerBill Posted March 18 Author Share Posted March 18 Well I am the big dumb-ey on this one. After reading the comments I went back to the start and re-measured. After testing everything at 5k rpm I found stator output was almost 100vac but DC at the battery was still at 11 vdc and going down. Thank god for my buddy who asked the question "Is the rectifier grounded?" Bingo! My dumb ass had used the rectifier mounting screw as a ground. One continuity check later and no connection to chassis ground was found. After relocating the ground to a better suited location and bang we are online. DC voltage at 11.5 and going up. Thank you all for your help and thoughts. Someday my dumb ass phase will pass, but at 42 I am starting to wonder if that will ever happen. 1 Quote Link to comment
TonyGee Posted March 18 Share Posted March 18 1 hour ago, ProducerBill said: Well I am the big dumb-ey on this one. After reading the comments I went back to the start and re-measured. After testing everything at 5k rpm I found stator output was almost 100vac but DC at the battery was still at 11 vdc and going down. Thank god for my buddy who asked the question "Is the rectifier grounded?" Bingo! My dumb ass had used the rectifier mounting screw as a ground. One continuity check later and no connection to chassis ground was found. After relocating the ground to a better suited location and bang we are online. DC voltage at 11.5 and going up. Thank you all for your help and thoughts. Someday my dumb ass phase will pass, but at 42 I am starting to wonder if that will ever happen. ive seen reg/rec earth wire mounted to the electrical plate which is rubber mounted from the frame before is the battery flat ? should be more Volts than 11.5 though Quote Link to comment
ProducerBill Posted March 18 Author Share Posted March 18 1 hour ago, TonyGee said: ive seen reg/rec earth wire mounted to the electrical plate which is rubber mounted from the frame before is the battery flat ? should be more Volts than 11.5 though Battery reading was 11.5VDC and heading up. We had been starting and stopping the bike so I guess I just accepted that it might be below 12VDC. Quote Link to comment
TonyGee Posted March 18 Share Posted March 18 21 minutes ago, ProducerBill said: Battery reading was 11.5VDC and heading up. We had been starting and stopping the bike so I guess I just accepted that it might be below 12VDC. put it on charge for a while then you can do a proper charge test when running Quote Link to comment
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