Battery Isolators, Separators, Switches & More (updated 2020)

[Scalf77]

Originally Posted by dhally

I found a new device online that combines some of these functions.

https://www.thornwave.com/collections/smart-products


It is a bluetooth logging net amp hour meter, and with an external relay can work as a battery seperator. It has an onboard shunt as well. Amazing what technology can do.

Nice find, that definitely has potential.

-greg

[BCam]

This looks like a similar device that I saw in a Winnieowners.com thread:

https://www.victronenergy.com/batter...-battery-shunt

[Scalf77]

The Victron device appears to just be a battery monitor with no display, it just uses bluetooth for a phone app, or connects to one of their GX devices. I nice unit, but it doesn't have the capabilities of controlling a relay like a ACR. The device by thornwave does appear to have that capability.

It is still a neat battery monitor option.

-greg

[ravensix]

This is a well written guide. Thank you!

[Scalf77]

So I added a diagram using the Thornwave PowerMon , which is a multi use device. It's major use is a s a battery monitor. It has an internal shunt, that will support lower current, and has a very programmable relay control. I used their external shunt PREMIUM 500A / 75MV SHUNT WITH MOUNTING BASE (0.25% TOLERANCE) $48.50 in the diagram and used the Defender series 404-1231-002 relay 200 amp $64.00. Add in the PowerMon $119.00 and you get a reasonable cost voltage motoring relay with a very accurate battery monitor.

The key is using the relay control to turn it into a unidirectional ACR. While it is not usual for battery monitors to have relay controls, the programmability of this relay gives you control of the disconnect and connect voltages. It has been a while since I looked at new battery monitoring option but I believe the Victron BVM 712 also would let you do this.

The other thing is that the PowerMon has bluetooth as default and a monitor as a option.



The shunt can also go on the ground line, but it appears the preferred location is on the Positive line.
-greg

[featherstone]

Thanks Scalf77. This thread is great. Saved the day for me replacing the separator in my van.

[nyyankees588]

This is an awesome resource - does anybody have a guestimation of the typical power draw used by a the 5.4L v8 econolines? I have a 2003 e250 and I'm trying to decide on what size B2B charger I should invest in when I transition to Lifepo4 house batteries. It looks like the 5.4l vans usually have a 115amp alternator, but I haven't been able to find any info on rough power draw while the vehicle is running to be able to know if I should get a 30amp or 60amp B2B charger.

Also curious if anybody has experience with the Lifepo4 isolator vs. the sterling/victron B2B chargers. I know that the isolator limits your application to only Lifepo4 batteries, but for $200 less, it seems like a reasonable deal.

[Scalf77]

Added a couple of more DC to DC charger options. The first are the Victron Orion-Tr Smart DC-DC Chargers. They support 12 to 12-30 amp, 12 to 24-15 amp, 24 to 24 - 17 amp non-isolated versions , they also have similar sizes and a couple of more like 12 to 12 -18 amps isolated versions.
The difference between isolated and non-isolated is if the grounds are tied together in the unit (non-isolated) or if the grounds are separated in the unit (isolated). For the most part in our environment the non-isolated version would be fine. If you have plans to measure current going into and out of the charger via shunts on the ground lines you would want the isolated versions.
All the units can be attached and viewed under you Victron connect app, you should note that it does not display current data to or from the unit. They all have automatic engine on detection, which can be disabled and also multiple remote on/off options.


you can also parallel multiple units together to increase the output. In this configuration it recommended that you disable engine on detection and use a remote option.


Another unit that has some promise is from Renogy the DCC50S 12V 50A DC-DC ON-BOARD BATTERY CHARGER WITH MPPT. While I am usually not big fan on Renogy products. This unit has some features that peak my interest. While some others do this , the unit has an solar charger also. If solar is available the unit can share 50%/50% with the alternator while the engine is running. Remotes sense for accurate charge voltage levels, Another feature is that solar can be used to trickle charge the starting battery once the house is charged. Add in Renogy BT-2 Bluetooth adapter and you get a unit with some respectable features.



-greg

[WeatherManVan]

I've had this on my van now for about 6 months and it has worked flawlessly, almost.

The labels on the + poles were reversed... Aux battery was crank, and crank was aux. It only took running it a couple times to realize, that and was an easy fix, but works like a dream now.

I have two optima yellow tops in the back, and one crank in the front. After hours of electronics running down the rear batteries, she starts every time.

https://www.amazon.com/Smart-Battery...NsaWNrPXRydWU=

[Beejmac]

Can I connect the SG-200 Smart Shunt Aux 1 positive (orange lead) to the starter van battery terminal of the Blue Sea 7622 to get starter battery volts? I would prefer this to running wire from shunt under gaucho to starter battery under hood.