Battery isolators: What does everyone use?

[MJRW]

I've been looking for the right isolator for my van (2017 Ford Transit 250). The alternator is listed as 150 amps. I like the "smart" isolators on Amazon but can't find any rated higher than 140 amps. What is everyone else using? New to this and need recommendations. [My "house" batteries will be 2 agm 125 amp]

 

[picopat]

I'm not using it but this one is rated 150A peak:

https://www.amazon.com/WirthCo-20092-Battery-Doctor-Isolator/dp/B0058SGDFK

Your batteries won't accept current that quickly anyway - their max charging current is probably around 30A each. So if you only have a fan and fridge running, and some devices charging while you're driving the house electrical system probably won't draw more than 80A.

My opinion - the 140A version isolator will probably work for you. Just make sure to put a 125 - 140A fuse in-line and use wire gauge appropriate for the current.

Best!
Patrick

 

[speedhighway46]

I have been using an ArgoFET battery isolator on my Peterbilt Motorhome conversion for the past ten years. Mine is a three battery bank 200 amp model. This unit utilizes a field effect transistor instead of diodes, resulting in practically no voltage drop from input to output.

They are available on EBay from several different suppliers, and from Amazon. They are around $150.

 

[LoupGarou]

If you’re going to mix battery types, consider a DC-to-DC Charger.

 

[highdesertranger]

I prefer solenoids over isolators. stick with a brand with a good name, Blue Sea and Cole Hearse are 2 good ones off the top of my head. keep in mind you can't use just any old solenoid it must be rated for contentious duty. highdesertranger

 

[Zork]

I prefer solenoids over isolators.  stick with a brand with a good name,  Blue Sea and Cole Hearse are 2 good ones off the top of my head.  keep in mind you can't use just any old solenoid it must be rated for contentious duty.  highdesertranger

Continuous duty is good, too.   

 

[B and C]

There are two types of solenoids, starter and continuous duty. The continuous duty ones we use are usually wired into the electrical system where they are only energized when the ignition key is on. Others like to use a regular switch but could lead to a dead starter battery if you forget to flip the switch when you stop.

 

[makenmend]

I have been using this JayCorp 12V Dual Battery Isolation Kit with 140A Smart Battery Isolator (VSR Voltage Sensitive Relay) for Auto/Boat/RV , in my Transit T350 since 2016. I installed it to charge my house battery (200 amp hour) when my vehicle battery reaches 13.2 volts it energizes to charge the house battery.
I did this until I could afford buying my solar setup, couple of months latter that was done ( 320 watts ), a pleasant by product of this setup is that when the van is not running and the house battery reaches 13.2 volts the relay energizes to keep my vehicle battery topped up. The kit came with every thing to install except fuses.
3 years now, trouble free and happy.

 

[MJRW]

If you’re going to mix battery types, consider a DC-to-DC Charger.

Very good video. I'm going to look into this further. Expensive, but a very important part of my van conversion. A plus is that if I upgrade to lithium batteries, I can still use it.

 

[Reducto]

I tried using that Wirthco on my van with 150 amp alternator and 2 golf cart batteries. It worked fine when the battery was above 50% but when I let it get any lower I ran into the current limit. Those were the times I REALLY needed to be able to charge off my alternator.

I switched to this and am very happy:
https://www.amazon.com/gp/product/B001C7CJHC/

 

[highdesertranger]

hahahaha oops. highdesertranger

 

[makenmend]

''hahahaha oops. highdesertranger ''

?????

 

[LowTech]

I have been using this JayCorp 12V Dual Battery Isolation Kit with 140A Smart Battery Isolator (VSR Voltage Sensitive Relay) for Auto/Boat/RV , in my Transit T350 since 2016. I installed it to charge my house battery (200 amp hour) when my vehicle battery reaches 13.2 volts it energizes to charge the house battery.
I did this until I could afford buying my solar setup, couple of months latter that was done ( 320 watts ), a pleasant by product of this setup is that when the van is not running and the house battery reaches 13.2 volts the relay energizes to keep my vehicle battery topped up. The kit came with every thing to install except fuses.
3 years now, trouble free and happy.

Link?

 

[LowTech]

I prefer solenoids over isolators. stick with a brand with a good name, Blue Sea and Cole Hearse are 2 good ones off the top of my head. keep in mind you can't use just any old solenoid it must be rated for contentious duty. highdesertranger

I've had solenoids feel that way also, more often it's my truck. ;-]

 

[MJRW]

Thanks everyone for all the input. I just ordered the DC to DC charger someone mentions earlier (Renogy DCC50S 12V 50A DC On-Board Charger with MPPT). Pricey, but if I ever upgrade to lithium batteries, I can still use it. Simple installation. It also doubles as a solar panel controller, so when I add my panels I'll be spared some cost there.

 

[makenmend]

Lowtech  https://www.amazon.com/gp/product/B00400D6WU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[chris84]

I use a sterling 60 amp battery to battery charger. Why? Glad you asked

1. I have a sealed starter battery, lead acid battery chemistry. My house battery is lithium ion. They need different charging voltages and needs.
2. My battery bank can handle massive charge rates, that my alternator would never be able to handle and would likely fry if it tried. I don't have the capability to feed it that much but a 600 amp charge rate would not be a problem for my 600 amp hour battery bank. If the alternator tried to provide anything near that, there would be something fried somewhere. The most I have pushed through the system is 120 amps off my inverter on shore power.

A simple solenoid would be my choice if my batteries were the same type and not so large as to fry my alternator. If your house batteries are different chemistry or much larger (mine are both) then a battery to battery charger is a wise choice.

 

[chris84]

Update, my Sterling battery to battery charger fried its input terminal. I suppose this is better than the alternator or batteries.
my battery started the 3 1/2 hour drive at about 30% charged, so it would take amost 400 amp hours to get to full. But I do not feel compelled to have it full.

unless the fuse is bad, the current never exceeded 80 amps into the charger and I am running 4 gauge wire.
Looking at the input terminal (it get hot enough to unsolder and remove itself) it attached to the main circuit board with 4 small pins. I am wondering if this has been an issue for anyone else, I hope to talk to someone from their US service department soon.

 

[maki2]

I prefer solenoids over isolators.  stick with a brand with a good name,  Blue Sea and Cole Hearse are 2 good ones off the top of my head.  keep in mind you can't use just any old solenoid it must be rated for contentious duty.  highdesertranger

contentious duty is indeed a very amusing spelling error,  a great job and relationship description that many of us have experienced at one time or another. It is a keeper to put into my lexicon of frequently needed humorous phrases. So thanks for that one highdesertranger.