Blue Sea Battery Isolator Questions

capnkurt · 09-19-2016, 04:03 PM

Hey all,

I've currently got a surepower isolator hooked up and am looking to switch to a bluesea separator instead. My goal is to ultimately install two lithium batteries to replace my current dual, (group 27) wet cells. In order to do this I have to be able to shut off charge to the house batteries after they get a full charge. Charging them via the alternator is perfectly acceptable, and according to the supplier, the batteries have a built-in overcharge shut off. However, if you repeatedly allow it to continue sending charge after they're full, it will eventually reduce their life-expectancy. I will also need to change out the intellipower charger/converter that I'm currently using in favor of a lithium compatible version.

So, my question is, will any of the bluesea separators allow me to remotely (via a switch on the dash) shut off the alternator's connection to the house batteries? I'd rather not have to hook up any relays to get this functionality and was hoping one of their products could do what I'm looking for.

Thanks,

capn

Scalf77 · 09-19-2016, 05:11 PM

If you don't count the BlueSea 7622 as a Relay (it is a magnetic latch relay), it will do the job just fine as long as you install the supplied switch.

see video on this post for a run down of features.http://www.sportsmobileforum.com/for...2-a-16340.html

You could also use one of their 7713 to disconnect the battery, it has a switch also.

-greg

capnkurt · 09-19-2016, 06:44 PM

Hi Greg, thanks for the information. It looks as though I could wire in a 7713, leaving my system as-is with the surepower isolator and the 7713 would simply be my method of shutting off charge to the house batteries - is this correct?

I watched your video, but honestly I'm still stumped by all of the capabilites of the 7620/22 magnetic latches. Specifically, I'm not understanding the connection/disconnection scenarios. I understand that the surepower isolator sends power to both the house and starting batteries while the vehicle is running (are they considered "connected" at this time?) and then when the vehicle is shut off, the two are then isolated ("disconnected"?) from one another. So with the 7620/22, I see that it is not as simple as that. It seems that the separator senses voltages and then connects/disconnects based on whether one or the other is higher/lower voltage. I don't really understand the need to do anything other than charge both while running/driving and then disconnect them when shut off. Is the separator able to independently send charge to whichever battery needs it while the vehicle's engine is running, but then automatically disconnect them while the vehicle is shut off (or even while running, it seems?) And if this is the case, is there a way to set it up so that I never have to worry about the batteries being connected to one another when the engine isn't running (I don't plan to ever use the ability to connect house and starting batteries to start the vehicle in a situation where the starting battery is dead - mainly because I'm guessing that you can't connect lithium house batteries up with a wet cell, due to the slightly different voltages).

Sorry for all the questions. I'm really trying to wrap my head around this stuff, but it's tough.

capn

arctictraveller · 09-19-2016, 10:45 PM

You can call Blueseas and talk directly to a tech support engineer who will spend as much time as needed to explain your options. 800.222.7617

Flux · 09-19-2016, 10:58 PM

It isolates at start and then combines when it sees the right voltage. If either battery suffers an under or overvoltage, it will isolate it so it can't hurt the other battery. You can manually control it as well.

It's a darn good piece rated for high amps. The operation is explained well in the upper right hand corner

https://www.bluesea.com/products/762..._-_12V_DC_500A

Scalf77 · 09-20-2016, 06:44 AM

Quote:

Originally Posted by capnkurt

Hi Greg, thanks for the information. It looks as though I could wire in a 7713, leaving my system as-is with the surepower isolator and the 7713 would simply be my method of shutting off charge to the house batteries - is this correct?
capn

capn,
you are correct, the 7713 is pretty much like the 762X without all the automatic voltage monitoring function. It only needs 12 volts to it's control line to close, take away the 12 volts and it opens up. This can all be done with a switch that they supply.

You could also use the 7700 which will draw zero power when off. The 7713 will use some minimal operating current. So actually the 7700 would be the better choice.

All three are magnetic latch relays ( which means that power is used to switch the relay open or closed, but not while it is in either state. A continuous power relay needs some amount of current to keep it closed.

The 762X and 7713 both use some amount of power to keep the their monitoring circuits alive.

-greg

Scalf77 · 09-20-2016, 07:58 AM

Another option outside of Blue Sea would be this 100 amp magnetic latch relay by intellitec. https://www.amazon.com/Intellitec-Ba.../dp/B00KPR8QAO

It does not come with a switch, you will need a Momentary DPDT switch (on)-off-(on), it would be a cheaper alternative to the Bluesea.

-greg

capnkurt · 09-20-2016, 11:08 AM

Thank you all for the information! I've got a lot to digest here, and I'm definitely going to look into those products you mentioned, Greg. Thanks again guys!

capn

MountainBikeRoamer · 09-20-2016, 12:16 PM

Okay Capn, my turn to thread-hijack

(ok not really, this is related....)

I have a (perhaps naive) question about the various isolators, separators etc and the overall "coach (rv) battery" vs. "underhood engine battery" charging circuit. Capnkurt and I were discussing this offline this morning.

Where the question comes from:
As I understand it --- regardless of how the Coach and Underhood (Van) battery are isolated or separated while the engine is *off*, they will be connected (effectively in parallel, I understand) and both charging off the same under-hood vehicle alternator while the van's engine is running.

So my question is.....
How is the available charging-voltage regulated (or modulated....or effectively "divvied up") between the two batteries? (Coach and Van)? At any point in time while they are both being charged, do they each see the *same charging voltage* applied to their terminals, or is there a component (or electrical principle at work) that varies the charging voltage to each battery, such that the "more full" battery gets less, and the "more empty" battery sees more?

It seems that the Coach battery would almost always be the most "hungry" for charge voltage...so it would be requiring high alternator voltage. And yet the Underhood Van battery would probably not need much topping off at all, most of the time (as it has no real demands made of it while the van is parked/camping somewhere) --- and wouldn't want to have too much charging voltage applied to it while the Coach battery is being brought back to charge.

Is there a provision in the circuit that automatically sends correct, specific and individual/unique amounts of available charging voltage to each of the two batteries? Or.....as I'm picturing it.....is it a somewhat crude "one voltage fits all" situation, and thus the Underhood Van battery is therefore frequently subjected to a potential "overcharge" condition during the period of time that the House Battery is being brought back up from a state of deeper discharge?

(If so --- in a van that sees its House battery regularly deep-discharged and recharged via the van's alternator circuit, it seems that perhaps the Underhood Van battery could see its lifespan shortened (or that it would frequently need its water levels checked, to be sure it didn't overheat and vent off water when it was being temporarily overcharged, during those frequent instances when the House battery was being brought back up to charge.))

Still trying to digest all of this as well, I'm curious if the more sophisticated separators do the function of "intelligent, individual-battery specific charging voltage allocation" as I'm imagining would be ideal....or if it's a non-issue....or if even my "old school" 1990's Sportsmobile Isolator/Charging circuit is already as sophisticated as it gets, as far as applying correct charging voltage to each specific battery in the system (House vs. Underhood Van.)

(*** Thanks for the ongoing electrical enlightenment, btw...hope that these threads benefit a good number of others in the same position going forward. I've read a good number of the sticky-posts on a number of the related topics, but somehow this particular question I'm not sure I've found addressed.)

Scalf77 · 09-20-2016, 02:41 PM

It is effectively divided up by the load that is on each system.If you are using a isolator and have a overly large drained House Battery, then it is possible that the alternator won't keep pace with the load.

On the ACR or relay based smart system, you would disconnect the two battery systems as the voltage dropped below the specified low voltage threshold. This is common to happen with a heavy house load when you stop at a light and are in idle. If you are running a 6.0 I would definitely go with ACR versus the isolator. You can offset that by getting a bigger alternator.

If you want to turn your alternator into a better charger you could look at items such as a Battery to Battery charger Sterling Power USA Battery to Battery Chargers - DC powered, onboard, on the run charging solution

or an alternator to battery charger

Sterling Power DC Input Alternator to Battery Chargers, 12v & 24v DC powered battery charger

There are also specific regulators that you can purchase to turn your Alternator into a smart charger.

Next Step Regulator, NS2

the above is just a sample of some solutions off the top of my head, there are others.

In short, if you are using your alternator as is to be the primary or sole charging source of your house battery, then you would be compromising the life span of the battery.

-greg