How much damage does a battery suffer...

[RonD]

I got one of these, installing it today.

View attachment 29142

This is a battery disconnect switch, if you leave lights on or something else that drains battery down too far it will cut power on the positive side.

Which would allow you to restart IF(big if) battery wasn't too old

So back up to the Battery saver relay circuit in 1995 and up Rangers


I didn't read it all, curious what you need to do to reset it if it does Cut Power?

 

[Dirtman]

Some have a micro switch you press to re-connect the relay, the one I have you just hit the headlights or something and it senses the current change and turns back on.

Obviously if there is such a relay circuit already built into the truck from the factory it doesn't work. This is about the 10th time ive killed the battery by leaving something turned on.

 

[RonD]

Wouldn't be an electrical reset because there should be NO electrics with battery disconnected, so mechanical reset would be best guess, a button

 

[Dirtman]

The one I have, although it disconnects the truck from the battery the unit is still connected to the battery (notice the ground wire) so it can still detect a current. If it sees a drastic change in current (i.e. turning on the headlights) it turns back on.

 

[RonD]

I just finished reading about it

It has a voltage monitor and will disconnect battery positive if battery voltage drops to 11.7v for a minute or two, so won't disconnect on startup voltage drop to 10volts

It has a noise circuit that monitors if the engine is running or not, so if alternator stops working while engine is running it will not disconnect battery even when voltage drops to 11.7v so you can "make it home" on battery power

It uses a mechanical motor to open and close contacts to pass or cut power

Yes, if it does cut power you can reset it by turning on and off the head light switch, or the brake lights, or blower fan for a few seconds

 

[Dirtman]

Im gonna put my old crap battery in and leave the lights on to see if it works. Ill let you know in the morning.

 

[RonD]

If battery is bad it will just self discharge, the added unit can't prevent that

Install old battery and if it can start the engine then it should be OK, assuming old battery has been sitting on its own a few days not being charged

 

[Dirtman]

My "bad" battery can still start the truck but slowly self discharges. Im just throwing it in for the night to see how the relay gizmo works. I just wanna see if the relay disconnects when it should and if the battery will still have enough juice to start the truck. I have my multimeter hooked up to see exactly when the relay shuts off power. I don't wanna test it on my good battery.

 

[Dirtman]

Well I found out I have a 125 dollar peice of garbage. The priority start relay works and disconnects the battery but with one major flaw. It doesn't disconnect the battery at 11.7 volts, it disconnects at 9.7 volts. 9.7 volts is not enough to crank the engine so its useless. I guess it would still technically help save the battery itself from being drained to a damaging level, but I wanted it so my battery would still start the truck if I leave my lights or something on.


Live and learn. I took it off and after cursing for an hour because i can't return it I decided it may work for the auxiliary batteries on my boat. Those batteries dont need to crank the engine anyway.

 

[Bird76Mojo]

Well I found out I have a 125 dollar peice of garbage. The priority start relay works and disconnects the battery but with one major flaw. It doesn't disconnect the battery at 11.7 volts, it disconnects at 9.7 volts. 9.7 volts is not enough to crank the engine so its useless. I guess it would still technically help save the battery itself from being drained to a damaging level, but I wanted it so my battery would still start the truck if I leave my lights or something on.


Live and learn. I took it off and after cursing for an hour because i can't return it I decided it may work for the auxiliary batteries on my boat. Those batteries dont need to crank the engine anyway.

So you went out in to the woods and found it?

 

[Dirtman]

I didn't want my goats to find it and eat it.

 

[RonD]

Well I found out I have a 125 dollar peice of garbage. The priority start relay works and disconnects the battery but with one major flaw. It doesn't disconnect the battery at 11.7 volts, it disconnects at 9.7 volts. 9.7 volts is not enough to crank the engine so its useless. I guess it would still technically help save the battery itself from being drained to a damaging level, but I wanted it so my battery would still start the truck if I leave my lights or something on.


Live and learn. I took it off and after cursing for an hour because i can't return it I decided it may work for the auxiliary batteries on my boat. Those batteries dont need to crank the engine anyway.

That doesn't make any sense, no benefit at 9.7v, something is amiss.

The unit does have a "noise" detect circuit, so it won't disconnect if engine is running
So maybe that was being triggered, stopping it from disconnecting, I could see it disconnecting at 9.7v in that mode since running engine would die close to 9.5v in any case

Their instructions state to just have the head lights on to test disconnect voltage, not to use fan or other non-bulb devices, to drain battery for disconnect test

Can't return it?
Call and ask

 

[Dirtman]

I did some research and found many complaints on a bunch of different websites of this thing not disconnecting at the proper voltage. It's passed the return window for me to send it back to Amazon so im gonna call the manafacturer monday and see if they will do anything. At this point I don't even know if I'd trust it on my truck anyway.