Battery Separator (Isolator) Functionality?

[kite_rider]

Happy new year folks!

Does anyone know if a battery separator (isolator) will disengage and engage based only on the connectivity of the ground signal? More specifically, will it disengage the relay when the ground signal is disconnected 'floating'?

Like others I'm running into a problem where my lithium house batteries are keeping the bi-directional battery isolator connected to my chassis battery since their resting voltage is over 13.2V which is the magic number that connects the two battery systems.


This specific isolator is the Eaton / Sure Power 1315-200.

[hbn7hj]

You could consider changing it back to an isolator.

I have the same problem with a Xantrex Echo Charger. Only way to stop it is to turn it away from the lithium batteries and back to the LA. No more problem.

Looks like a switch needs to be installed somewhere or return to an isolator. Would be nice if you could change the switch point from 13.2 to 13.4 volts. Is there such a separator yet? Certainly there will be one someday soon.

A switch in the ground line would be ideal if it works that way which was your original question. Try it.

[lmittell]

The simplest solution for my coach, for a number of reasons I won't go into here, was to route the ground wire of the separator through the NO contacts of a small 12v relay, whose coil is energized by the chassis ignition switch. That way, the batteries are isolated with the ignition off, but connected with it on, once the chassis battery reaches the 13.2v threshold.

I could have done almost the same thing with a simple electromechanical relay-type isolator, but the route I took was less work and expense for me. Also, a simple isolator would no longer isolate the batteries at less than the threshold voltage, though I'm not sure how important that is.

Larry
2017 PW Lexor TS

[booster]

Originally Posted by lmittell

The simplest solution for my coach, for a number of reasons I won't go into here, was to route the ground wire of the separator through the NO contacts of a small 12v relay, whose coil is energized by the chassis ignition switch. That way, the batteries are isolated with the ignition off, but connected with it on, once the chassis battery reaches the 13.2v threshold.

I could have done almost the same thing with a simple electromechanical relay-type isolator, but the route I took was less work and expense for me. Also, a simple isolator would no longer isolate the batteries at less than the threshold voltage, though I'm not sure how important that is.

Larry
2017 PW Lexor TS

A lot of the benefit of using a separator is that most of them are now bidirectional, so that you can keep he starting battery charged when you are on shore power or solar. This can be important in storage so you don't need a separate trickle charger for the starting battery or on a vehicle that starts a bunch of timers or wakes up computers every time a door is opened or closed, which happens a lot when camped and can kill a starting battery.

[lmittell]

Originally Posted by booster

A lot of the benefit of using a separator is that most of them are now bidirectional, so that you can keep he starting battery charged when you are on shore power or solar. This can be important in storage so you don't need a separate trickle charger for the starting battery or on a vehicle that starts a bunch of timers or wakes up computers every time a door is opened or closed, which happens a lot when camped and can kill a starting battery.

I understand the benefit, but OTOH, if the batteries are permanently connected together, which is the case as long as the lithiums are north of 13.2v, why bother with a separator at all? Just hook 'em all together. This particular thought has bothered me for some time.

Larry
2017 PW Lexor

[booster]

Originally Posted by lmittell

I understand the benefit, but OTOH, if the batteries are permanently connected together, which is the case as long as the lithiums are north of 13.2v, why bother with a separator at all? Just hook 'em all together. This particular thought has bothered me for some time.

Larry
2017 PW Lexor

You can get most all advantages with an auto and manual separator like Blue Sea makes. In the auto mode it will work like a normal separator and connect when it sees "charge level" voltage on either side, but you also have connect or disconnect from a remote switch so you can turn it off or on when you want to over ride. This way you would still be able to get the starting battery charged, or jumped, if needed. They work well with lithium, I have heard as they have good versatility.



We opted for the manual only version of the same separator as it is better suited to being able to charge AGM batteries without overcharging if they are full when you start or get full, and save all the hassle of full battery output signal and relays being needed.

[avanti]

IMO the optimal configuration is to have a dumb isolation relay controlled by the ignition and a Trik-L-Start to get chassis-battery maintenance. Simple and robust.

[lmittell]

Originally Posted by avanti

IMO the optimal configuration is to have a dumb isolation relay controlled by the ignition and a Trik-L-Start to get chassis-battery maintenance. Simple and robust.

I'm convinced you're right. But I'm sticking with the Sure Power separator with the relay patch so I needn't figure out how to mount a different device. But I'll add a Trik-L-Start, as you suggest.

Larry
2017 PW Lexor

[kite_rider]

Great discussion. I just didn't know if the separator would function like a 'dumb relay' by switching the ground signal. Sounds like it will.

If this doesn't work out for some reason, the dumb isolation relay is the next step for me.

Thanks everyone!

[JohnnyFry]

A seperator is a relay and, as such, it needs both sides of the circuit to operate. It will not operate without a proper ground. An isolator, on the other hand, is a diode which allows current to flow in only one direction, it does not need a ground.

[MsNomer]

Yes to the original question.

Coincidentally, today we are installing two switches on the dash. One is the "jump-start" mode and the other is a kill switch in the ground. We have AGM's, so not your issue, but sometimes solar electrons are precious and we’d rather not share them if we don’t have to.

[reilym]

Originally Posted by kite_rider

Happy new year folks!

Does anyone know if a battery separator (isolator) will disengage and engage based only on the connectivity of the ground signal? More specifically, will it disengage the relay when the ground signal is disconnected 'floating'?

Like others I'm running into a problem where my lithium house batteries are keeping the bi-directional battery isolator connected to my chassis battery since their resting voltage is over 13.2V which is the magic number that connects the two battery systems.


This specific isolator is the Eaton / Sure Power 1315-200.

My Pleasure-Way uses the 1314-200, which is a one-way device. The batteries are isolated unless the chassis battery is at >13.6 volts. You can wire in a switch it to couple the coach batteries to the chassis for emergency starting.

-Mike
2016 Pleasure-Way Lexor TS

[Jill Ellis]

thanks for all of your nice feedback regarding this thread abut i'm little confused about the purpose of Battery Isolator. if anyone of you can clarify me it will be grate help.

[reilym]

Originally Posted by Jill Ellis

thanks for all of your nice feedback regarding this thread abut i'm little confused about the purpose of Battery Isolator. if anyone of you can clarify me it will be grate help.

The primary purpose is to make sure that the coach and chassis batteries are not connected to each other when parked so that you don't accidentally drain the chassis (starting) battery. They work by keeping the battery banks separated until a threshold voltage of about 13.5 volts is reached, at which point a high current solenoid closes to connect the banks. There are 2-way and 1-way isolators. With either, when the engine is running, the chassis battery voltage will rise above the threshold and the banks will connect so that the alternator can charge the coach as well as the chassis batteries. A 2-way isolator will also connect both banks if the coach battery is being charged and it's voltage is above 13.5 volts, allowing the chassis battery to also charge. A 1-way isolator like in my PW connects the banks only if the chassis battery is above 13.5 volts, which only happens when the engine is running. I think PW decided to use a 1-way because the LiFePO4 batteries in the coach are often above threshold voltage even when not being charged. This could result in the solenoid closing, allowing the chassis battery to drain on the coach battery. If lead-acid batteries are in the both the coach and chassis, a 2-way isolator would connect the banks only if one or both were actively being charged. Hope this helps.