What's the big difference in a battery isolator, versus starter solenoid?
- Thread starter Carl2500
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Perfect Switch
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A conventional silicon diode isolator's voltage drop may not work well with a trickle charger.
A MOSFET-based isolator will work fine with a trickle charger because the voltage drop should be negligible.
A typical solenoid will DRAW more power to close the contactor than a trickle charger will output and is NOT a good solution for storage. If you run the trickle charger output directly to the battery(s), they you'd be good to go.
A MOSFET-based isolator will work fine with a trickle charger because the voltage drop should be negligible.
A typical solenoid will DRAW more power to close the contactor than a trickle charger will output and is NOT a good solution for storage. If you run the trickle charger output directly to the battery(s), they you'd be good to go.
Little off topics, but at a junk yard hunt I got a 95 amp isolator by sure power.
Like said the voltage drop to forward bias a diode prevents charging a the battery fully on internally regulated alts.
Now if the halfish volt drop is a problem what about jumping the main alt feed to the bat 1 connection but leave the 2nd battery through the isolator? That way only the 2nd battery is affected by the volt drop.
Like said the voltage drop to forward bias a diode prevents charging a the battery fully on internally regulated alts.
Now if the halfish volt drop is a problem what about jumping the main alt feed to the bat 1 connection but leave the 2nd battery through the isolator? That way only the 2nd battery is affected by the volt drop.
dwh
Tail-End Charlie
It would work. You'd just be bypassing the batt 1 diode.
Might not be needed though for that setup though.
If the voltage regulator is reading the voltage at batt 1, and batt 1 is fed through the diode and is .5v low, then the voltage regulator is going to keep the alt on for longer until batt 1 reaches proper voltage.
So, IF the voltage regulator reads the voltage at the battery, AND both batteries are being fed through diodes, then you wouldn't have the voltage drop problem (on either battery) because the voltage regulator would cause the alternator to keep running until the input (center) of the isolator was .5v (or whatever the exact drop is with that particular unit) high and the battery was where it's supposed to be.
Might not be needed though for that setup though.
If the voltage regulator is reading the voltage at batt 1, and batt 1 is fed through the diode and is .5v low, then the voltage regulator is going to keep the alt on for longer until batt 1 reaches proper voltage.
So, IF the voltage regulator reads the voltage at the battery, AND both batteries are being fed through diodes, then you wouldn't have the voltage drop problem (on either battery) because the voltage regulator would cause the alternator to keep running until the input (center) of the isolator was .5v (or whatever the exact drop is with that particular unit) high and the battery was where it's supposed to be.
Ok so it will work at least to prevent the ve drop on the service battery. My Ramcharger has the vr inside the pcm. ('89) If it goes, going to run an old style external vr and hook the sense wire up to the fuse block. I think I will run it and see if the isolator ve drop affects the battery any.
common words when shopping for this sort of stuff..
solenoid-simple, dumb, same as a starter solenoid(not really, but to keep it simple)
separator-smart solenoid, moving parts
isolator-smart, no moving parts
i run both a separator and a solenoid(40 amp relay) in two different vehicles.
the truck with the separator is using a surepower 1315-100. It is smart and just reads the battery voltage and determines when to connect. it monitors both batteries for charging voltage.
Example: main battery is being charged by the alt, when the voltage rises past 13.8 it will connect the aux battery. if the voltage drops below, then it disconnects(excessive load, no charging voltage). Now if the truck is off and there is a charger on the aux battery and the voltage rises past 13.8 it will connect the main battery and charge both. when the voltage drops below that number, it will disconnect. I can energize the separator using the voltage from the aux battery if the main runs low with a momentary switch to the left of the steering wheel.
in my poor mans camper, fullsize van, i have a much simpler setup. i use an aux battery to run my cabin accessories(fridge, dvd, inverter). I have a 40 amp relay that is wired to connect the two batteries when the key is on and disconnect them when the key is off. So the aux battery is charging when i am driving. With this setup, i cannot jump start, and if my main battery goes dead and i try to start the truck, it will blow the fuse in my relay circuit.
both system work for what i intended them for.
now with all the fancy talk about this stuff, there are also contactors and solenoids that are magnetic and only use voltage to switch positions. they are usually expensive.
if you are gonna use a simple solenoid, look for one that is continuous or constant duty. usually you can find those online for about $40.
i'm sure there are things wrong with my reply, and i'm sure some people here won't hesitate to correct me.....
solenoid-simple, dumb, same as a starter solenoid(not really, but to keep it simple)
separator-smart solenoid, moving parts
isolator-smart, no moving parts
i run both a separator and a solenoid(40 amp relay) in two different vehicles.
the truck with the separator is using a surepower 1315-100. It is smart and just reads the battery voltage and determines when to connect. it monitors both batteries for charging voltage.
Example: main battery is being charged by the alt, when the voltage rises past 13.8 it will connect the aux battery. if the voltage drops below, then it disconnects(excessive load, no charging voltage). Now if the truck is off and there is a charger on the aux battery and the voltage rises past 13.8 it will connect the main battery and charge both. when the voltage drops below that number, it will disconnect. I can energize the separator using the voltage from the aux battery if the main runs low with a momentary switch to the left of the steering wheel.
in my poor mans camper, fullsize van, i have a much simpler setup. i use an aux battery to run my cabin accessories(fridge, dvd, inverter). I have a 40 amp relay that is wired to connect the two batteries when the key is on and disconnect them when the key is off. So the aux battery is charging when i am driving. With this setup, i cannot jump start, and if my main battery goes dead and i try to start the truck, it will blow the fuse in my relay circuit.
both system work for what i intended them for.
now with all the fancy talk about this stuff, there are also contactors and solenoids that are magnetic and only use voltage to switch positions. they are usually expensive.
if you are gonna use a simple solenoid, look for one that is continuous or constant duty. usually you can find those online for about $40.
i'm sure there are things wrong with my reply, and i'm sure some people here won't hesitate to correct me.....
dwh
Tail-End Charlie
Was that a dare?
Only gotcha I see is:
"Now if the truck is off and there is a charger on the aux battery and the voltage rises past 13.8 it will connect the main battery and charge both."
Handy...just don't use a 3-stage charger on the aux battery when you do that.