Dual battery monitor or not ?

I have a monitor and it's nice to know what the battery is doing...beats popping the bonnet and getting the meter onto it

I have the same set-up (DBE180S +DBM4). I use the monitor's low voltage cut-out in preference to the one built in to my Waeco.
The cut-out can be over-ridden if needed.
It just works:-)

Cheers
Glenn

Walter,

I've also got the DBE180S. I use a battery voltage/fridge temp monitor purchased from Jaycar. Doesn't auto cutout though.

I definitely recommend a battery monitor, low voltage cutout, discharge protector, or whatever other name they go by, which automatically cuts the battery supply if the voltage drops below 11.6 volts.

I am not familiar with the Piranha product, but you can get devices from around $30 for the Projecta discharge protector (ODP500) to $98 for an Engel Battery Monitor.

I notice the Piranha monitor doesn't cut out until the voltage has reached 10.5 volts and this is too low IMO, as 10.5 volts is FLAT.

The Engel has a selectable toggle switch of 10.5 (too low) or 11.5 (better).
The Projecta ODP500 is fixed at 11.6v (30% battery capacity) which is about where the supply should be interrupted before permanent damage may occur.

I think Derek from ABR (Advertiser on this site) also has a unit the same or similar to the Projecta device.

Thank you all for your replies and based on the general consensus a monitor with a low voltage cut-off is the way to go. I still have one query, I understand that too low a cut -off can cause permanent damage to a battery and I am currently running a AGM type deep cycle to run the fridge and some other minor accessories and was under the belief that this type of battery is designed for a deeper discharge. Am I wrong before I do any permanent damage.

Cheers Walter

# State of Charge
For longest life, batteries should be maintained above 50% State of Charge
Occasional drops to 30% & 20% are not harmful, but continual discharges to those levels will shorten battery life considerably.


S o C _ Voltage
100% __ 12.7
90% _ _ 12.5
80% _ _ 12.4
70% _ _ 12.3
60% _ _ 12.2
50% _ _ 12.1
40% _ _ 11.9
30% _ _ 11.7
20% _ _ 11.6
10% _ _ 11.3
0% _ _ _ 10.5

Mainey . . .