# Help needed Low Voltage cut off or alarm for deep cycle 12 v

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Hello Professionals and like mined Hobbyist, Im new to this area and could really use some smart-ish advise that hard to find...

I have a Crown deep cycle battery 31HDC130 is has 4 posts 2 screw type and 2 slide on, my 1st question is can I hook up a low voltage battery alarm to the screw in posts while using the slide on for current powering a devise or will it damage the low voltage alarm ?

The low voltage alarm I have in mind is only rated for 12 volts and 30 amps but Im new to this area and think the rating could be off...

I will save my next question when I get a solid answer of my 1st to keep the thread clean and usable for others researching.

Thank you for your time, it is much appreciated !

#### crutschow

Joined Mar 14, 2008
27,232
1st question is can I hook up a low voltage battery alarm to the screw in posts while using the slide on for current powering a devise or will it damage the low voltage alarm ?
No problem at all to do that.
The low voltage alarm I have in mind is only rated for 12 volts and 30 amps but Im new to this area and think the rating could be off..
What's the maximum current you will need from the battery?

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Hello and thank you for your time, I will most likely never use 30 amps probably maybe max 10 amps mostly just for led lights and maybe a work radio box...

Im looking for a low voltage alarm or even cut off that is adjustable so I can have it set to 11.5 or 11.2 and never 10.5...

Here is the adjustable low voltage alarm Im looking at but it seems I might have to run a load through it for it to work, this is ok would rather have one that is not on a load I dont trust these ebay items at high amps 30 amps is past my comfort zone...

https://www.ebay.com/itm/30A-Batter...ule/192034308347?_trksid=p2485497.m4902.l9144

This is the another option only 10 amps and it states for lithium batteries but I think that is only due to the adjustable voltage cut off being so low & high ...
https://www.ebay.com/itm/12V-Batter...ard/171825454690?_trksid=p2485497.m4902.l9144

Thank you for you help it is much appreciated !

#### crutschow

Joined Mar 14, 2008
27,232
The ebay 30A one looks like it should work.
It's 30A rating is based on the relay contact rating.
The relay cuts off your load when the battery drops below the set voltage.

Don't know what you mean by "would rather have one that is not on a load".
The load is whatever the battery is powering.
Do you not want to cut off the load when the voltage drops?

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Thanks again Im new to relays though have wired them before in my Jeep but they were a bit larger so glad you cleared that up I feel safer now...

Im just a bit tight with my hard earned money and the more affordable the better so having one that uses the 2 spare posts with no load is the most affordable way if I where to ever need to run power tools that had a higher draw at least I would get a buzzer alarm warning.

Another more likely scenario is boosting a vehicle and with 750 Cold cranking amps I have no clue if they even make Low voltage cut offs that high and if so way above my spending.

The Cut off is best option though, like I said I think 30 amps is way more than I should ever need and money well spent.
I only wish it had a digital read out of the settings so far only could find the 10 amps with read out but I have a way around that using my ebay step down converter they are cheap and should do the job.

I ordered both and using the 10 amp for my 18650s as that is what the add stated it was for ( Lithium ) but see no reason why I couldnt use it for the lead acid, from my understanding voltage is voltage and its just the charging and also the amp draw and or how fast they can discharge those amps that makes batteries different and possibly dangerous. Am I correct in that statement ?

Again thank you for your time, knowledge is such a safe feeling :]

#### crutschow

Joined Mar 14, 2008
27,232
Another more likely scenario is boosting a vehicle and with 750 Cold cranking amps I have no clue if they even make Low voltage cut offs that high and if so way above my spending.
It's not clear to me what 750 cold cranking amps has to do with a low voltage cutoff.
You would not want to cutoff a battery when it is starting an engine since the battery voltage likely drops below 10V during the start.
voltage is voltage and its just the charging and also the amp draw and or how fast they can discharge those amps that makes batteries different and possibly dangerous. Am I correct in that statement ?
Basically, yes.

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Thank you good to know, you probably just saved me some head scratching and beer drinking....

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
My 2nd question is do I need a shunt for a digital meter that is only 10 amps ?

This is the one I purchased https://www.ebay.com/itm/Mini-0-56i...var=472323764194&_trksid=p2057872.m2749.l2649

I have two 30 amp shunts but not sure if they will work with a 10 amp meter and online all I can find are equations I havent had the passion to figure out yet...

Thank you again for your guidance crutschow and have a great week !

#### JMW

Joined Nov 21, 2011
134
Hello Professionals and like mined Hobbyist, Im new to this area and could really use some smart-ish advise that hard to find...

I have a Crown deep cycle battery 31HDC130 is has 4 posts 2 screw type and 2 slide on, my 1st question is can I hook up a low voltage battery alarm to the screw in posts while using the slide on for current powering a devise or will it damage the low voltage alarm ?

The low voltage alarm I have in mind is only rated for 12 volts and 30 amps but Im new to this area and think the rating could be off...

I will save my next question when I get a solid answer of my 1st to keep the thread clean and usable for others researching.

Thank you for your time, it is much appreciated !
You can buy them on ebay for under 10 bucks

#### DrewStupid

Joined Nov 28, 2018
64
You can buy them on ebay for under 10 bucks
Why a alarm ? Solar contrloller will disconect battery anyway at low voltage.

#### KeithWalker

Joined Jul 10, 2017
1,789
Thanks again Im new to relays though have wired them before in my Jeep but they were a bit larger so glad you cleared that up I feel safer now...

Im just a bit tight with my hard earned money and the more affordable the better so having one that uses the 2 spare posts with no load is the most affordable way if I where to ever need to run power tools that had a higher draw at least I would get a buzzer alarm warning.

Another more likely scenario is boosting a vehicle and with 750 Cold cranking amps I have no clue if they even make Low voltage cut offs that high and if so way above my spending.

The Cut off is best option though, like I said I think 30 amps is way more than I should ever need and money well spent.
I only wish it had a digital read out of the settings so far only could find the 10 amps with read out but I have a way around that using my ebay step down converter they are cheap and should do the job.

I ordered both and using the 10 amp for my 18650s as that is what the add stated it was for ( Lithium ) but see no reason why I couldnt use it for the lead acid, from my understanding voltage is voltage and it`s just the charging and also the amp draw and or how fast they can discharge those amps that makes batteries different and possibly dangerous. Am I correct in that statement ?

Again thank you for your time, knowledge is such a safe feeling :]
A solution would be to power your normal load with the cut off circuit (as shown in the flyer), attached semi-permanently to one pair of battery terminals and use the other pair of terminals for occasional heavy loads.