KAM
Well-Known Member
Anyone got any experience of these. The cheap ones on Amazon and EBay look like they will do the job. Can't see if the current monitor will indicate both charge and discharge. Does anyone know.
Cheap Battery Monitors
- Thread starter KAM
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Refueler
Well-Known Member
If you give us a link to the ones you are talking about ??
adamlang
Well-Known Member
I think I know the ones you mean though a link would help. One I bought to add to a test solar rig was very basic it didn't have any settings to change the capacity of the battery bank manually, and I think it couldn't tell the difference between current going in to the battery and coming out. It just seemed to add the flow together. Not very helpful beyond telling you the net current flow at any one time.
KompetentKrew
Well-Known Member
They're pretty popular on the 12v boating electrics group on Facebook or, at least, a while back when I was last using it there was a spate of posts on there about these cheap battery monitors.
If it has a shunt then it'll be able to show current, and it'll show both charge and discharge if you put it next to the battery with nothing in between.
Considering the cost of boating, however, IMO you might as well just buy a SmartShunt. Saves the hassle of cutting a hole to mount the display too, and of running the wire to somewhere where it'll be visible.
If it has a shunt then it'll be able to show current, and it'll show both charge and discharge if you put it next to the battery with nothing in between.
Considering the cost of boating, however, IMO you might as well just buy a SmartShunt. Saves the hassle of cutting a hole to mount the display too, and of running the wire to somewhere where it'll be visible.
KAM
Well-Known Member
KAM
Well-Known Member
Will it differentiate between charge and discharge
diverd
Active Member
I have the NASA one and an ebay cheapie. The Nasa one tells you time to charge, time to discharge and whats going on. The cheapie gives you all the values, and its up to you to work out the times. The nasa is on the yacht, where i need to know durations and discharge times, the cheapie is on the motor boat, where i just need to know whats going on.
andsarkit
Well-Known Member
I got one of these Battery meter.
It reads current in and out of the battery and an estimate of the percentage charge remaining. It seems reasonably accurate for the current and voltage readings. The capacity measurement will depend on you knowing the capacity of the battery which will have to be estimated unless you can measure it. Also you have to set the 100% level when you know that battery is completely charged, and will probably need to be reset regularly as any errors in the current measurement will accumulate the error in percentage of charge. I assume it makes an estimate of charge efficiency as some of the current going into the battery is lost in the charge and discharge process.
With all the possible errors I just use it as a guide to when I need to recharge the battery and for the fairly low cost it is fine as long as you do not expect too much from it.
It reads current in and out of the battery and an estimate of the percentage charge remaining. It seems reasonably accurate for the current and voltage readings. The capacity measurement will depend on you knowing the capacity of the battery which will have to be estimated unless you can measure it. Also you have to set the 100% level when you know that battery is completely charged, and will probably need to be reset regularly as any errors in the current measurement will accumulate the error in percentage of charge. I assume it makes an estimate of charge efficiency as some of the current going into the battery is lost in the charge and discharge process.
With all the possible errors I just use it as a guide to when I need to recharge the battery and for the fairly low cost it is fine as long as you do not expect too much from it.
KompetentKrew
Well-Known Member
A couple of previous threads:
- On this forum: Battery monitor
- On a motorhomes forum: Leisure battery monitor
William_H
Well-Known Member
That monitor does not seem to recognise that you will have a charge source. So only able to estimate power usage. Might be wrong of course. ol'will
oldharry
Well-Known Member
No. They had been fitted to my camper. One gives charge rate, the other discharge, achieved by reversing the shunt connectors. Once the current flow reverses, they just read zero. Accuracy is questionable too. Voltage seems accurate enough but amperage readings seem low. For example the 12v element on the fridge takes a measured (by me using a DVM) 8.5 amps, but the meter rarely shows more than 5amps, with all charging sources off. Maybe because the shunt leads are too long the way mine were mounted. But at least I know when the solar panel is keeping up with the load. The actual meter sensitivity is 75mv on the ammeter, so a few MV drop will affect the accuracy
