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Re: More low cost Battery Monitors.

PostPosted:Thu Jul 25, 2019 7:56 am
by scubadoo
First numbers in and I am impressed with the results! Overnight use as at 7.45am this morning.
Juntek #6 on Neddy's list - 85% SOC - 45.847Ah used.
Votronic - 85% SOC - 255Ah remaining = 45Ah used.

Display unit draws 0.2W at minimum brightness - perfect for indoor use.
0.5W at full brightness - easily read in full sunlight.

Added bonuses.
Display battery or battery box temperature on screen with the supplied sensor. My seperate wireless thermometer can be reutilised.
The display unit can be turned off or removed while the shunt block keeps on counting data. Reconnect the display and carry on. :TU
I have ordered another unit. It will be interesting to see if I can display the battery details in 2 locations simultaneously from the same head unit.

Negatives so far.
Current readings reversed on my model. i.e. charging is displayed as a negative number and discharge as a positive. A black fine felt tip pen may just fix that. ;)

Re: More low cost Battery Monitors.

PostPosted:Thu Jul 25, 2019 7:51 pm
by Neddy
It will be interesting to see if I can display the battery details in 2 locations simultaneously from the same head unit.
I tried running two display units simultaneously (one wireless and one cable) but this confused the head unit to some extent. You can set up two display units, but one must be turned off for the other to work reliably. All you need to do is flick the 12v power supply from one to the other.

Negatives so far. Current readings reversed on my model. i.e. charging is displayed as a negative number and discharge as a positive
Right. A bit annoying but you get used to it.
Another idiosyncrasy is that the Charge and Discharge display labels have got their colours reversed. (Charge is RED and Discharge is GREEN). Go figure!

The wireless link is surprisingly effective. When testing the installation, I was able to take the Display unit into the house and monitor the van battery parameters from the warmth and comfort of our lounge - a distance of a bit over 10 meters.

I found that discharge levels exactly replicated those of a Votronic meter. Charge levels were a very different story, though, mainly because the Votronic unit signalled "100% Charged" well ahead of the Juntek unit which does not signal a "Full" charge until the battery really IS full (as confirmed by the Solar charger and/or the mains charger switching to "Float")

It will be interesting to see how well a Juntek meter copes with the very different charging characteristics of Lithium batteries.

Re: More low cost Battery Monitors.

PostPosted:Thu Jul 25, 2019 8:58 pm
by NeilV
Following this one as my switch to LifePo4 May outdo the current ‘very cheap’ model.

Might be worth making this a new thread specifically for the Junket model?

Re: More low cost Battery Monitors.

PostPosted:Fri Jul 26, 2019 12:39 am
by Mark
Neddy wrote:
Thu Jul 25, 2019 7:51 pm

The wireless link is surprisingly effective. When testing the installation, I was able to take the Display unit into the house and monitor everything from the warmth and comfort of our lounge - a distance of a bit over 10 meters.
Interesting.

I have had the Juntek running for a few months. The monitor is located no more than 2.5m from the head unit. I have found that the wireless connection on mine drops out intermittently. Maybe once every day or two, usually for only a few seconds, but sometimes (rarely) for a few minutes.

This has prompted me to consider moving the house battery from under the passenger seat to under the entrance step (in a Dreamtime) where there is a closer and more direct line of sight between the two. (Should allow me a higher capacity battery as well).

But in light of Neddy's experience, below, there may be something else going on with mine.

Re: More low cost Battery Monitors.

PostPosted:Fri Jul 26, 2019 10:12 am
by Neddy
If you have anything less than perfect wireless communication between the Shunt and Display units, Mark, you might like to consider cable connection. Juntek monitors use bog-standard micro USB cables that are readily and cheaply available in many lengths. I got a 5M one for less than NZ$10
https://www.aliexpress.com/item/3281213 ... 4c4dTLEJAk
Cable connection supplies the Display unit with power, offers a few more setup options, provides bullet-proof resistance to electrical noise and doesn't need any shielding.

Our van has several electric motors including rangehood, bed raising/lowering, waterpump, toilet flush, airbag compressor, vacuum cleaner, mains charger fan, fridge and diesel heater. Of these, only the last gives any interference at all, making the Amp readings jump about a little - but only when the heater fan is running full-bore during its initial warm-up sequence. This is probably because the heater and the Shunt are mounted right alongside each other. This causes no problems whatsoever, but if it ever did begin to annoy me, I have discovered that the van has a number of cable "rat-runs" built-in so I could easily run my 5M USB cable without it being visible anywhere at all - which we all know is the hallmark of any good wiring job.

Neville.

Re: More low cost Battery Monitors.

PostPosted:Fri Jul 26, 2019 1:00 pm
by Mark
There could well be "rat runs" in mine, too, Neddy, but I have not been able to find them. That was the main reason for going with the wireless one.

It hasn't been a biggie, so far, and if it gets no worse, I can live with it.

(@Neddy: No liaison with Nikki now: plans have changed :roll: )

Re: More low cost Battery Monitors.

PostPosted:Wed Jul 31, 2019 12:41 pm
by scubadoo

Re: More low cost Battery Monitors.

PostPosted:Fri Aug 02, 2019 5:48 pm
by NeilV
I’ve got two of the original ‘very cheap’ (#3 on this new list) and the AGM count seems very accurate, but with my ‘new to you’ lithium’s somethings really screwed up as I go from full (set to 90AH) and reset on the meter, to 10-15% remaining the next day.

Amp use seems reasonably accurate when on the ‘Amp in use’ but SoH and A/h remaining counters are both saying they on the last 10% by the morning even when the cells read 3.3v each and the total volts are 26.2 or 26.3 (LifePo4 makes that 30-70%?)

Any ideas on how I may have set this up wrongly?