need help

[Tonycamco]

where can i find battery isolator for 210 popular 2004 rt
thanks tony

[cruising7388]

Originally Posted by Tonycamco

where can i find battery isolator for 210 popular 2004 rt
thanks tony

Are you looking for a dual isolator mounted on a heat sink or a relay operated separator?

What problem are you experiencing?

[Tonycamco]

dual isolator 4 wire

[cruising7388]

Originally Posted by Tonycamco

dual isolator 4 wire

http://www.cooperindustries.com/cont...ST_180012q.pdf



https://allbatterysalesandservice.co...utput-1202-3ad

[Nic7320]

You'll get better results with a "smart isolator."

The problem with dual diode isolators is the voltage regulator that controls your alternator only knows about the battery voltage on one side, that is, it's only connected to one of the two batteries; so if your house battery is low and the engine starting battery has a normal voltage, the regulator will stop charging both the house battery and starting battery until the starting battery is low enough for it to need more charge. The house battery is, in essence, just along for the ride, it is not part of the voltage regulator control loop; so it's quite common for the house battery to not get topped off with enough charge when driving.

The smart isolator eliminates this control problem, it cross connects both batteries after a set delay time, and it also reduces the voltage drop across the isolator because it uses a relay rather than silicon diodes.

You can find them on Amazon:

https://www.amazon.com/s/ref=nb_sb_n...smart+isolator

[avanti]

The other alternative is to just use a "dumb" isolation relay controlled by the van's "engine running" signal plus a Trik-L-Start.

[cruising7388]

Originally Posted by Nic7320

The smart isolator eliminates this control problem, it cross connects both batteries after a set delay time, and it also reduces the voltage drop across the isolator because it uses a relay rather than silicon diodes.

I think this needs some clarification. Isolators are diodes, i.e. passive semi-conductors. They are unidirectionas devices and there is no way to make them smart. The use of a device with solid state or mechanical relays to control battery paths may indeed be a smart device but it it can't be correctly described as a smart isolator because it doesn't use any isolators at all. It's typically described as a separator .

[Nic7320]

Not to quibble, but a relay is indeed an 'isolator' when in the off-state (when it is disconnected). It's more isolation (infinite ohms) than the off-state of a diode.

The 'smart' isolator has a control circuit that isolates the two batteries until the vehicle battery is partially recharged, and then closes the relay to cross connect the two so they both get the same voltage level.

If the relay is not delayed (by a 'smart' controller) it is possible that a dead house battery will sufficiently drain a good starting battery and leave you without enough charge to start the vehicle. Without the delay, you can get stuck.

And as long as we're not skipping the details, the two batteries will get the same voltage but NOT get the same current; the current sharing is determined by the intrinsic internal battery voltage and internal resistance, plus any wiring resistance, and the relay IR drop. So a faulty battery with high internal resistance won't get much of a charge with either type of isolator.

And on Amazon, they use the descriptor "Smart Isolator."

[cruising7388]

Originally Posted by Nic7320

Not to quibble, but a relay is indeed an 'isolator' when in the off-state (when it is disconnected). It's more isolation (infinite ohms) than the off-state of a diode.

The 'smart' isolator has a control circuit that isolates the two batteries until the vehicle battery is partially recharged, and then closes the relay to cross connect the two so they both get the same voltage level.

If the relay is not delayed (by a 'smart' controller) it is possible that a dead house battery will sufficiently drain a good starting battery and leave you without enough charge to start the vehicle. Without the delay, you can get stuck.

And as long as we're not skipping the details, the two batteries will get the same voltage but NOT get the same current; the current sharing is determined by the intrinsic internal battery voltage and internal resistance, plus any wiring resistance, and the relay IR drop. So a faulty battery with high internal resistance won't get much of a charge with either type of isolator.

And on Amazon, they use the descriptor "Smart Isolator."

I appreciate that there is stuff marketed as smart isolators. I just think that this label promotes confusion. Isolators don't require any intervention but what is described as a smart isolator is actually an ACR or separator which requires intervention, i.e. something to activate and deactivate a relay. Functionally, it may provide isolation but I think it's confusing to describe them as isolators which conventionally refers to a diode.

The relay "delay" you refer to is more complex than what you describe because it has to distinguish between potentially opposite conditions, i.e. a charged house battery with a discharged engine battery or conversely, a discharged house battery with a charged engine battery. For example, when a typical separator aka smart isolator like the Sure Power 1314/15 gets a signal from the start/run terminal on the ignition, it examines the condition of both batteries. If it determines that the engine battery is more discharged than the house battery it immediately parallels the batteries. If it determines that house battery is more discharged than the engine battery, it will not parallel both batteries until engine starting is completed.

[cruising7388]

Originally Posted by Nic7320

The problem with dual diode isolators is the voltage regulator that controls your alternator only knows about the battery voltage on one side, that is, it's only connected to one of the two batteries; so if your house battery is low and the engine starting battery has a normal voltage, the regulator will stop charging both the house battery and starting battery until the starting battery is low enough for it to need more charge. The house battery is, in essence, just along for the ride, it is not part of the voltage regulator control loop; so it's quite common for the house battery to not get topped off with enough charge when driving.

With conventional dual isolators, since the alternator voltage forward biases both isolator diodes how can the alternator deliver suds to only one battery?

[avanti]

What is all of this complexity intended to accomplish?

I am not a fan of charging hose batteries using the vehicle charging system. But if I were to do so, I am fuzzy about what all this "intelligence" accomplishes over a "dumb" relay. Is the idea to give the chassis battery priority over the house battery?

[Nic7320]

Originally Posted by cruising7388

With conventional dual isolators, since the alternator voltage forward biases both isolator diodes how can the alternator deliver suds to only one battery?

When the alternator's field winding is energized, both batteries do get some charge. But once the starting battery is fully charged, the voltage regulator shuts down the field winding and both batteries no longer get charged -- regardless whether the house battery is topped off or not. Since the voltage regulator does not even know the house battery is there, it often doesn't fully charge the house battery.

This problem is exacerbated when that long wire to the back has enough resistance to limit the charging current to the house battery while the regulator is charging. The house battery will get some charge, but not enough to top it off and keep up with all the demands of RV electrical use, such as a 12V fridge.

[Nic7320]

The 'smart' circuitry keeps you from killing your starting battery by paralleling them too soon. It lets the starting battery charge first, before energizing the relay to charge the house battery.

[cruising7388]

Originally Posted by avanti

What is all of this complexity intended to accomplish?

I am not a fan of charging hose batteries using the vehicle charging system. But if I were to do so, I am fuzzy about what all this "intelligence" accomplishes over a "dumb" relay. Is the idea to give the chassis battery priority over the house battery?

Isolators and dumb relays are limited to paralleling batteries during charging and separating them during discharging. Smart relays permit assigning which batteries have priority during a charging sometimes from multiple sources and additionally can decide to keep batteries paralleled or separated during engine starting depending on their respective SOCs.

I think OEM alternator charging used to be an effective way of charging house batteries until canbus controlled alternator regulators and lithium batteries got into the act requiring secondary alternators and multistage regulators to properly charge batteries.

[avanti]

Originally Posted by cruising7388

Isolators and dumb relays are limited to paralleling batteries during charging and separating them during discharging. Smart relays permit assigning which batteries have priority during a charging sometimes from multiple sources and additionally can decide to keep batteries paralleled or separated during engine starting depending on their respective SOCs.

I guess...
But, Sprinters (at least) have an "engine running" signal that only comes on several seconds after the engine is successfully started. Back before I got my second engine alternator, my system had three components:
1) A dumb relay driven by "engine running"
2) A Trik-L-Start, and
3) A manual "boost" switch to close the relay in the event of a weak chassis battery.

That seemed to cover all the bases that I cared about.

Multiple charging sources are a different topic.

I think OEM alternator charging used to be an effective way of charging house batteries until canbus controlled alternator regulators and lithium batteries got into the act requiring secondary alternators and multistage regulators to properly charge batteries.

Agree.

[cruising7388]

Originally Posted by avanti

I guess...
But, Sprinters (at least) have an "engine running" signal that only comes on several seconds after the engine is successfully started. Back before I got my second engine alternator, my system had three components:
1) A dumb relay driven by "engine running"
2) A Trik-L-Start, and
3) A manual "boost" switch to close the relay in the event of a weak chassis battery.

That seemed to cover all the bases that I cared about.

Multiple charging sources are a different topic.

Sure, I can see how that would meet all your requirements. It's just that the more sophisticated separators (aka ACRs and "smart isolators) can do that all in one module and the bidirectional ones made by SurePower, Blue Sea et al, in additional to supervising alternator charging will let the shoreside charger maintain the engine battery after completing house battery charging without requiring a separate trickle start unit.