Need Help with High Output System Problem

[Pete the Cat]

I need some help with my electrical system. I can't find the problem and wonder what is going on.

Here is the system that I have been using successfully for about 20 years;
High output alternator wired for external regulator (currently a Hitachi 80 amp)
External regulator (currently a Balmar ARS 4)
65 Watt shade tolerant solar panel working through a controller with a diode
All feeding into four golf cart batteries in two banks that total of 440 ah, but run as one bank most of the time (currently new and fully charged when put in this Spring).
All of this is monitored by a LinkLite battery monitor properly installed.


Here is the problem:
When doing my Spring commissioning, I ran the batteries down about 25 ah while flushing my water system. When I went to recharge the batteries, I noted that the charge rates from the alternator at the beginning of bulk charge were only about 10 amps to start and within 1 minute, tapered to 7 amps and within one minute was down to 5 amps and then down to 4 amps .....and within five minutes was at 2 or 3 amps. At this rate, it would take forever to get things back to 100%. I do not recall this happening before with this set up. Here is what I have done so far to chase this down:
Alternator was checked by an alternator shop and is working fine.
Changed the regulator to a spare and got the same result in outputs
Checked all the wiring and it checks out and cleaned contacts
Checked and tighted the belt.

Any ideas of about what is going on here? I am perplexed. Seems like the system should go to full bulk for at least a few minutes before tapering. And should not taper that much when things are cool and there is still a 20 amp deficit.

What am I missing??

[omgitsgela]

Could happen if one battery is healthier than another. Maybe the charge controllers are sensing 13 volts from one battery while the other is drained? Try charging each battery seperately.

[Zil]

As the only thing changed were the batteries, that suggests battery problem.

[Pete the Cat]

I am thinking that the issue might be that the solar charger (it has been sunny when I start the engine up) is making the battery voltage seem artificially high to the smart regulator and that, in turn, is limiting the bulk charge cycle and causing it to taper quickly even though the amp hours of the batteries are down, the smart regulator isn't that smart. Could that be?

[Paul Elliott]

It's an off-chance, but I had erratic charging on my batteries last year. Running the engine at very low RPMs gave me about 20A charging current (normal), but when I cranked the RPM up to 1500, where I would usually get up to 90A the current would spike up briefly, then drop down to virtually zero. The battery voltage was low enough that the regulator/alternator should have been putting out max current.

That was the symptom. The problem was that one of the wires to the external regulator had become corroded (at the crimp lug). At high currents the bad connection heated up and became even worse. Re-doing the connectors fixed the problem.

[Paul Elliott]

Originally Posted by Pete the Cat

I am thinking that the issue might be that the solar charger (it has been sunny when I start the engine up) is making the battery voltage seem artificially high to the smart regulator and that, in turn, is limiting the bulk charge cycle and causing it to taper quickly even though the amp hours of the batteries are down, the smart regulator isn't that smart. Could that be?

This is a possibility, if you are in the topping-off phase. Also be aware that Ah monitors are notorious for getting "out of sync" with the actual charge-state of the batteries. Could they already be fully-charged? Do check the battery voltage with no load after a rest period.

[Andina Marie]

Measure the voltage on the battery on charge when it is only accepting the low charging current both at the battery terminal and the output from the regulator.

If those are different you have a bad connection or cable in that circuit (don't forget to check the negative cable(s) too!)

If the battery voltage is less than about 13 volts the regulator should be putting out maximum current so that would indicate low output from the alternator, perhaps one or more bad rectifiers.

If the battery voltage is above 13.5 then the regulator(s) have cut back the current because the battery voltage looks like it is charged. That would indicate a bad battery.

[Pete the Cat]

Good suggestions, folks. I will do some more checking after limiting the variables. The Balmar guy says that there are a lot of bad new batteries out there (these were new last year and kept on trickle chargers through the off season), so that might be--I can split my bank and maybe that will tell me something. Also, battery monitor could be out of sync, as you suggest though the amperage used appeared to be right, the starting point might have been wrong--I might have set it to "full" with the trickle charger on--not sure if that would matter. Also, need to take the solar system out of the picture to see if that is having an effect and test the batteries for voltage and s.g. after a rest. Really appreciate this forum.

[smac999]

how do you have a linklite properly hooked up to a house bank that is split into 2? you would need 2 with 2 shunts. combine the bank into 1 permanently

2.

batteries charge well from 50-80%. charging from 80-100% takes longer. this is normal. you never run a gen or engine for sole charging purposes if you are over 80%. it's just a waste of fuel.

[Pete the Cat]

OK. I finally figured out what was going on. I offer the following to folks who might be as dumb as me. My system has essentially new golf cart batteries. I kept them on a trickle charger over the winter and up till the time I sync'd my Linklite when I hooked the system back up. In reading Living On Twelve Volts for the umpteenth time, I realized two things, I probably was able to overcharge these batteries and then sync the voltage at a high level--so the regulator would taper charge to a couple amps almost immediately because it sensed the high voltage feedback. Also, as some folks have mentioned, it takes a very long time, even with a smart regulator to get those last few amp hours stored in the bank. I am assuming most of us settle for 95% charge or have, as I do, a solar array that will keeping at a low rate over a long time.

I have had the same basic system for a decade and never really understood the limits of my instrumentation. FWIW.

I appreciate the help folks.

Ray
"Velera"