PS Reports $^\copyright$

Published by Ample Technology Manufacturer of Ample Power Products

Volume 2 - Issue 2 July, 1998

Revisiting the Regulator Test

About a year ago, we published a Volume 1, Issue 2 of this series, which is available on our web site, That publication reviewed an article published by Practical Sailor1 If you've read the test, you may recall that we observed in their data, a taper in current from the alternator that was never explained. The same current decline affected all the regulators tested ... even before the absorption setpoint was reached, alternator current was much less than what could be expected.

If it had been just one of the regulators, we would have immediately nodded our head and smiled because there is an aspect of regulator design that can cause premature current decline. That is, alternator current declines as the absorption setpoint is approached. Because the taper effect showed up on all three regulators tested, we just assumed that Practical Sailor had some sort of faulty configuration ...that may still be the case.

We know that Ample Power regulators do not exhibit the taper shown in the Practical Sailor article. And, despite wanting to put together a test situation where we could demonstrate performance, other chores kept pushing that project aside.

A Doubting Thomas

The caller was at first a little beligerent. He had been installing the `competitions' equipment for many years, and now he had a customer that was unhappy with the charge performance of his recently installed regulator. Furthermore, he'd seen our graphs that showed what to expect from a true high performance regulator. The caller made it clear he considered all the regulators to be more or less the same. Just why did we think ours was better.

We're not in the habit of giving away trade secrets over the telephone, but if any competent person is ready to do a comparison test, we're ready to help. After listening to the performance he was observing with the `other' regulator, and asking him enough questions to learn that he was well informed about electrical systems, we told him we would guarantee better performance. He was working against a departure deadline for his customer, and was clearly frustrated with the situation, and kept wanting to know why our regulator would improve charge rate. In the end we kept our secrets, of course, but sent him a Next Step Regulator that was his to keep if it didn't do a better job. All we asked was a copy of the test results.

The System Configuration

The house bank consisted of four Group 31 gel batteries. They were being charged with an Amptech alternator which was rotating about 5000 RPM. He had already made numerous tests where the batteries were taken down to about the 50% point and then recharged. He made one more while waiting for the Next Step Regulator to arrive.

Besides a built-in battery monitor, he also had a Fluke digital voltmeter and a clamp-on Ammeter ...required tools for any marine electrician. He didn't have a way of automatically recording information, but his results show diligence with paper and pencil.

Figure 1 - Next Step Performance

Next Step Performance

Shown in Figure 1 is the results using the Next Step Regulator. At the start, batteries have been discharged about 180 Amp-hours. You may wish to compare this graph with the one we presented in Volume 1, Issue 2. In that test, charge current is 17-18% of battery capacity, where in this test, battery current is about 25% of capacity.

At the start of charge, battery voltage takes about ten minutes to reach 13.7 Volts. During that same period, Amps fall from about 110 to about 100 Amps. This is to be expected as the alternator gets hot. Amps decline a little more as the test proceeds, some or all of which may just be due to the hot alternator.

For 10-15 minutes, the voltage on the battery is fairly constant, and then a slow rise begins to take place. A little after an hour into the charge, current is still almost 100 Amps when the voltage approaches 14.2, the absorption setpoint. At that point, battery current declines at their absorption ability. The regulator has done all it can do the charge process is all up to the batteries.

About 50 minutes after reaching the absorption setpoint, battery current has fallen below 10% of battery capacity and the test was terminated.

Many similiarities can be found between this graph and those shown in Volume 1, Issue 2. The initial voltage surge, (nose), on the voltage scale is absent, but because readings were taken by hand at intervals, a short duration surge in voltage may have been overlooked. The batteries had not been rested after the deep discharge, so no hardening of sulfate could take place.

Even without the pronounced voltage surge in the beginning, you can still see that voltage declined between 10 and 15 minutes into the charge cycle.

Other similiarities are the long slow voltage climb that accelerates as the absorption setpoint is approached, and the relatively sharp fall off in current once the regulator hits the absorption setpoint. The test was terminated before battery current falls into the final plateau, so the decline looks more like a straight line rather than exponential as we'd expect.

Other Regulator Performance

Shown in Figure 2 is the voltage and current obtained with the other regulator. It's pretty easy to see why the owner was not happy with charge performance, and yes, we have a new dealer that nows knows what we mean when we say ``a fast, full charge''! The Next Step Regulator was shut off before the batteries were full, but in less than two hours it had returned about 160 Ah of capacity.

The test with the `other' regulator was also terminated before the batteries were full. After two and a half hours, the absorption setpoint had yet to be attained. In ten minutes, battery current was about 70 Amps, and it was all downhill after that. This performance is remarkably close to what Practical Sailor observed! Perhaps the tapered current they reported is in fact a similiar problem with all the regulators they tested!

In the same time frame that the the Next Step Regulator returned 160 Ah to the batteries, the Other Regulator returned 110-115 Ah. This translates to a relative performance of only 69-72% of the Next Step Regulator performance.

Other Regulator Performance

What do you do to make a regulator act this bad? What are they missing that the Next Step Regulator has? Right now we're nodding our head and smiling because the answer is a single four letter word, and it's not even nasty. We've got it, and they don't!


It's rare to hear from customers unless there is a problem, so when the proud owner of the Next Step Regulator took the time to send a fax some thousands of blue water miles later, we were pleased to read ``that's a helluva regulator''.

With the right marketing, even poorly designed products can be sold. Any mall has reams of evidence to that truism. The sad part is, you don't always get what you pay for. If you want a fast, full charge, you can only get it with an Ample Power regulator! Given the performance documented above, the Next Step Regulator would be a bargain at ten times the cost of the `other' regulator, considering engine wear and tear as well as fuel costs incurred by an ``incomplete, slow charge''.

Ample Power products are manufactured by Ample Technology, 2442 NW Market St., #43, Seattle, WA 98107 - USA