A good battery monitor required for my trailer battery

[zac]

Just fitted a 100ah lithium battery to my small car trailer (this powers the motormover and gps tracker) I am looking for a good bluetooth battery monitor. Need to be able to connect remotely via something like bluetooth via an app on the phone.

I am aware of the victron smart battery sense which I think would work but this only gives a voltage which I could then convert with guides on the Internet. Ideally I would like one that gives a percentage of power left in the battery.

Any one use anything that is reliable and accurate?

Only need it for monitoring as I will be charging via my ctek csone mains charger when needed.

All the ones I have found talk about shunts and mppt controllers which I have no need for in this situation.

Thanks in advance

 

[St3v3]

If you want to monitor the state of charge, you need a shunt.

Are you sure the battery doesn't already have a BMS that you can bluetooth to?

 

[zac]

If you want to monitor the state of charge, you need a shunt.

Are you sure the battery doesn't already have a BMS that you can bluetooth to?

No bms included it was just before they started including them in. When this was in the motorhome I used bmv702 with a shunt and the additional bluetooth dongle but that's not an option with this one unless I buy a new one but that's quite expensive just to monitor it.

 

[zac]

Maybe I will just bite the bullet and get one of these, seems to have bluetooth built in
Victron Energy SmartShunt 500 amp Battery Monitor (Bluetooth) Amazon product ASIN B0856PHNLXI don't need to know what's being used just what's left in the battery really

 

[autorouter]

Maybe I will just bite the bullet and get one of these, seems to have bluetooth built in
Victron Energy SmartShunt 500 amp Battery Monitor (Bluetooth)

Yes the Smartshunt has no display hardware like the BMV monitors, it displays via Bluetooth to a phone app. A simple voltage-based monitor (ie not a shunt) is not a good idea for lithium batteries. The voltage curve is very flat, which means it is difficult to tell the state of charge from the voltage level.

If you google 'shunt battery monitor' there are a number of less expensive shunt monitors. With a 100Ah battery it seems to me that a 100A shunt would be fine for your use. There is also one with a 'Hall effect' probe instead of a shunt, which fits around the wire and measures the amps by measuring the magnetic field that the amp flow generates.

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[zac]

Yes the Smartshunt has no display hardware like the BMV monitors, it displays via Bluetooth to a phone app. A simple voltage-based monitor (ie not a shunt) is not a good idea for lithium batteries. The voltage curve is very flat, which means it is difficult to tell the state of charge from the voltage level.

If you google 'shunt battery monitor' there are a number of less expensive shunt monitors. With a 100Ah battery it seems to me that a 100A shunt would be fine for your use. There is also one with a 'Hall effect' probe instead of a shunt, which fits around the wire and measures the amps by measuring the magnetic field that the amp flow generates.

thanks will take a look as the victron one is expensive for what I need

 

[berni109]

Cheap battery monitors work with lead acid type batteries by monitoring voltage. For lithium you are going to need something with a 'shunt'.
I am not sure you will find much that will work in an unprotected environment on a trailer.

 

[zac]

Cheap battery monitors work with lead acid type batteries by monitoring voltage. For lithium you are going to need something with a 'shunt'.
I am not sure you will find much that will work in an unprotected environment on a trailer.

the box is under a cover so not out in the open, no water can get in.

 

[berni109]

Have a look at a Chinese 'junctek' KL series. Need the right one for the amps drawn by the mover.
Mine works fine with bluetooth telling me more than I need to know. It's inside the van in the dry. Doubt it would last long in a moist/damp atmosphere.