Join Date: Aug 2010
I just took a look at the Bogart site and manual for the 203 solar controller.
The equalization is purely a manual operation, so that can't be it.
The controller does have a 4th stage of charging that can be turned on and off which takes the voltage to 15v+ at the end of the normal charge. This is getting to be a more common recommendation by some battery manufacturers, but IMO it should only be used on particular applications and situations. It is basically a mini-equalization at every charge cycle, which can be helpful if your charger doesn't allow you to control the charging based on the transition amps from absorption.
The fourth stage will be the most useful for wet cells, especially if they are being cycled and there is not enough time to always get them full. If the batteries are full, and on float like when not being used, I don't think I would use it, as it would put a couple of hours of overcharge on every day, using a lot of water in wet cells and dryout and corrosion in AGMs. For the wet cells, a manual equalization once month would probably be a good idea, and for AGMs, only if the capacity has started to slip. From the numbers they give, I think that it would run everyday if you got to the finish amps for absorb P2 %, if set correctly, as they are using the same amps for both settings on some batteries and 50% higher on others, and at 15v, you will have more amps so it will run. They are also picking P2 settings that are a bit high for at least some of the batteries, so in some cases the fourth stage may shut off right away, too. In either case, you may not get reliably full.
The actual amps to end absorb is not a fixed number percent, as it will change between brands, styles, and also as the batteries age. Lifeline recommends using .5% of capacity, where the Bogart chart says to use 2%, which will leave you undercharged. Our new Lifelines would actually go to .2% before the amps quit dropping, but as they age that will go up, and is probably why Lifeline says .5%. Getting totally full is essential, so that is a big deal to prevent capacity walkdown. The Trojans are listed at 2%, which is not too bad, as when we had Trojan GC batteries, they got down to about 1.2% for years. Trojan recommends higher at 3%, at least they used to, and that is about where they will be when they get old, or if the voltage is higher.
Sooo--how do you set the leave absorb amps. IMO, the best way is to do it is to set the % to a very low level, like .1% and let the batteries charge until they stop dropping amps for an hour or two. Calculate what % of capacity that is, and and add about .3% for new AGM batteries, and .5% for new wet cells. This will leave you a tiny bit short of charge, but testing we, and Marko, have done has shown float will finish off the rest well it appears. If you set the leave absorb amps this way, I would not use the 4th stage, unless you are cycling them every day when traveling and not getting a full charge off shore power or driving.
Once that setting is determined, it should be good for quite a while, as long as you are temperature controlled for the charging. A full charge to this point will often take 8-10 hours depending on depth of discharge, charger capacity, and battery bank size. It could be longer, or a bit shorter (not a lot shorter, though). If you find that your charge times stretch out a lot, or it never goes to float, it would indicate your batteries are aging, or possibly need an equalization. At that point you would increase the leave absorb % some. I do the setting test once a year, to see if it still correct, as it is very easy to do.
For batteries that are not getting run down much, and fully recovered every day, the 14.8v may be a bit high. Some manufacturers have started to recommend it that high, but I think it is to help cover charging that never reliably gets to the leave float amps. Trojan says use 14.7v for a "daily charge", which appears to mean like golf carts that are run very low every day, and have only a few hours to get recharged. For normal, periodic, charging from smaller discharges and enough charge time to get full, they say 14.4v range.
What battery type and brand are you running?