KendallP wrote:
ktmrfs wrote:
Then I did a load test recomended by Mex, 20 seconds at 230A and record battery voltage. Some good and bad news from the load test. The "good" side is the Duracell only dropped to 5.75V while the Trojan's dropped to 5.48V. so it would appear that the Duracell has less internal resistance, and internal resistance is a big drawback to GC batteries. But that may also be the bad news. Since both weigh virtually the same and the same AH, what magic was done to reduce internal resistance??? first thing that comes to mind is maybe thinner plates but more of them. Drops resistance, but also is a drawback to long cycle life. The battery load cell was the same as used 12years ago with the Trojans as was the NIST traceable DMM.
Time will tell
Sounds like we all have the VEC1093DBD. BFL used to have a couple of lower amp Vectors back in the day... if he doesn't still have them. And my 25A version gave up the ghost several years back.
Is that 230A at 6V or 12?
And what load tester?
yes, I think we have the same charger. Mine is a B&D 40/20/10/2? A with equalize and desulfate.
For GC batteries load test at rated AH testing each battery individually, that is 6V applying the load for 20 seconds. Load tester is a harbor freight "carbon pile" tester, good for up to about 500A load.
NOTE: this test method is for GC batteries only. GC batteries are designed for long life, low load not high current draw so trying to do the typical X times CCA (which GC batteries don't have a rating for anyway) or X times AH is not useful.
But be sure to measure voltage directly at the battery with a good DMM, NOT the meter on the load cell. (1) it isn't very accurate and (2) w/o a four terminal measurement it will read low because of IR drop in the cables.
And I modified mine by cutting off the clamps and crimping on terminals that I can attach to the battery posts.
However a quick check of harbor freight doesn't show the load tester anymore. all they show is one good for 100A. But if you do a search for "carbon pile load tester" they pop up on amazon, ebay and others. Several look like the harbor freight unit. A decade ago I paid $50 at harbor freight. Today similar on Amazon are around $80
And in addition to the vector charger I have a cheap harbor freight 6V/12V charger that being cheap has the advantage that the 6V position is not automatic, just keeps stuffing current in letting the voltage rise so it is easy to equalize by monitoring the voltage and stopping at around 7.5- 7.75V on a 6V battery. And it current limits to 6A. And it also doesn't show up on harbor freight website anymore. But I bet lots are available at garage sales. Just look for old, old, old battery charger w/o any of the fancy stuff.
I treat the charger, the carbon pile load cell and el cheapo harbor freight charger like gold. they do not get loaned out.
