Batteries for 2010 RZ4

[IDBoating]

The problems come when a battery is over or under charged by a charger, while its NOT in use.

Right, but when the engine is running the alternator generally powers everything and the batteries are being charged. I presume the batteries don't know the difference between "being charged with the engine off" (wall charger) and "being charged with the engine on" (alternator). So wouldn't over- or undercharge would be a risk during normal operation unless something (an intelligent isolator?) knows the battery chemistry and controls the charge profile accordingly?

[ericinmich]

Alternators have a voltage regulator.... that senses voltage of the battery (actually of the wire at the alternator) and regulates the current (ie lowers the current when voltage goes up).

Here is a better description:
http://www.madelectrical.com/electri...witworks.shtml

A bad voltage regulator can cook a battery. In a car, a diagnostic light should indicate the fault.

Old 'dumb' chargers just put out a constant voltage (14ish volts) and since they are plugged into a wall, have 'limitless' power. The current will ramp down when battery SOC (state of charge) goes up, but they don't go to zero current and continue to push energy into the battery.

[chpthril]

Think of it a toilet. The water in the bowl (battery) flows out when there is demand and the water in the tank (alternator) replenishes until the demand is met. Flow is controlled by the float (regulator). Ok, i know that analogy was crappy As long as the system is in use, the regulated alternator will just replenish whats used, up to its capacity. If the toilet float hangs, water will keep filling the bowl, even though its demand (electrical load) is no longer there. With an alternator, it cannot be isolated from its loads. Like they say, dont disconnect the battery cable with the engine running or the alt goes full field. A regulator is a smart device so to speak. Its output is based on demand. so light load, light output, heavy load, higher output. The difference is, an alt is not a battery charger. They are not meant to recharge and maintain a battery at its proper level. Its designed to just keep pace with demand and replenish whats used from the battery. No way to to do what an actual charger is intended to do, while the battery is in use with fluctuating loads.

A quality smart charger with the correct profile, should not over charge a battery, but, it can leave one under charged, with the incorrect profile.

[IDBoating]

Flow is controlled by the float (regulator).

Yes, I fully understand voltage regulators at the component level. I've designed a few, in fact, for various projects. Both linear and switching.

What I DON'T know is whether the alternator-isolator-battery system in modern vehicles (land or water) have the intelligence to properly charge various battery chemistries, or if they just (blindly) apply a "higher voltage" to the battery to force a charging current into it.

A quality smart charger with the correct profile, should not over charge a battery, but, it can leave one under charged, with the incorrect profile.

What will today's standard alternator-isolator-battery system do? (As noted, a voltage regulator is not the same as a smart charger that monitors the battery's charge profile and modulates the voltage and current as appropriate for that chemistry.) Are they including what would effectively be "smart charger" intelligence in the recharge power path of modern vehicles?

[chpthril]

Yes, I fully understand voltage regulators at the component level. I've designed a few, in fact, for various projects. Both linear and switching.

What I DON'T know is whether the alternator-isolator-battery system in modern vehicles (land or water) have the intelligence to properly charge various battery chemistries, or if they just (blindly) apply a "higher voltage" to the battery to force a charging current into it.


What will today's standard alternator-isolator-battery system do? (As noted, a voltage regulator is not the same as a smart charger that monitors the battery's charge profile and modulates the voltage and current as appropriate for that chemistry.) Are they including what would effectively be "smart charger" intelligence in the recharge power path of modern vehicles?

No cause it couldnt work. It impossible to properly charge/condition/maintain a battery while its in use. All you need to do is maintain a safe operating voltage and enough current to meet demand.

[IDBoating]

No cause it couldnt work. It impossible to properly charge/condition/maintain a battery while its in use.

OK... but if the engine is running, the alternator should be powering things while recharging the battery. Technically, then, the battery would not be "in use" (since that's when vehicle batteries get recharged anyway).

Seems like one could design a marine isolator that recognizes this condition (alternator terminal is at a higher voltage than the battery terminal[s]) and properly modulates the recharging profile going to the battery as long as that condition exists (i.e. the onboard electrical systems are being powered by the alternator, not the batteries). Put a switch on the isolator to select the battery chemistry connected to each terminal (easy enough to accommodate differing chemistries as anticipated by this thread). Obviously the output power to onboard systems would have to be separate from the battery terminal(s), rather than in parallel like they're wired today.

Edit: A quick search reveals so-called "smart" marine isolators that use relays to selectively charge multiple batteries, so you can prioritize charging of the starting battery first, then the house batteries, etc. Not too far to add intelligent charge profiling to such a product.