Battery charger - equalization

As long as they clip on the battery posts they will be fine. If not you can just make something up you like better. Charging them separately or together in series is fine, either way, just not in parallel as you can’t guarantee the same charging current to both when they’re in parallel. Each battery has 3 series cells so set your voltages accordingly. Cruiser forum is a good site, unlike rver’s, cruising sailors have to keep their systems operating all the time, its not like they can run down to the Wally World and get a new battery if they have a problem. Have fun.

Exactly. Sensitive electronics. Of course, there is a switching PS in pretty much every piece of electronics in your house anyway, including all the compact battery chargers. Check the EMI specs on the PS if you’re concerned about it.

Up to you but you really don’t need both, the power supply can trickle charge just fine, just set it’s voltage at Trojan’s float voltage spec, 2.25 V/cell I think. Set the current limit on the power supply at 2A, voila, you have a regulated trickle charger that will maintain 13.5V and not exceed 2A. You are right that you don’t need to leave it on all the time but it won’t hurt anything if you did. Just keep an eye on the water level.

I think probably most anything reasonably priced you get these days will be switch mode, transistors being cheap and iron and copper being expensive and heavy.. Unless you have sensitive electronic gear next to the PS in your basement that should work fine for you.

Here is Trojan’s battery maintenance procedure for their flooded deep cycle batteries.

https://www.trojanbattery.com/tech-support/battery-maintenance/

They recommend equalization based on cell to cell specific gravity differences, which will typically be required somewhere between once a month and once a year. Equalization is performed at 2.7 volts per cell at 25C (temp compensated at -5mv per per cell per degree C) until cell sg’s stop rising.

How much of this procedure you do is up to you. But a hydrometer and bench power supply are inexpensive and can be used for other things. I wouldn’t use a crappy unregulated charger for anything, I’ve seen multiple sets of cooked batteries among my solar customers over the years. Not worth it.

I don’t buy the moving batteries don’t need equalization idea because that won’t do anything to change cell to cell sg’s. Automotive batteries don’t need as much aggressive charging as deep cycle batteries do because they use a different chemistry. That is the trade off, adding antimony to the plates in deep cycle batteries improves their tolerance to harsh cycling at the expense of more water consumption and more frequent equalization requirements.

Read this:


https://batteryuniversity.com/learn/article/lead_based_batteries

I think equalization is less needed in batteries that move. The physical movement will help agitate the electrolyte. It is only when they sit for months at an end that it would become an issue. For example, a battery bank in a fixed solar installation. There is no physical agitation there (unless there is an earthquake).