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paulz
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# Posted: 9 Nov 2020 09:19am
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I need some help understanding this meter I'm going to use to monitor my battery capacity. The instructions show two wiring diagrams, one with 'independent power supply', as shown in the photo. Also a third with a relay, I don't think or know why I would need that. Only difference seems to be where the red wire enters the battery, and jumpering to suit. Can you make sense of this? If independent supply means a separate battery not connected to the system, it sure doesn't appear so.
Here is the online PDF of the instructions.
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ICC
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# Posted: 9 Nov 2020 09:35am
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The diagram 1-3 in the photo shows a separate battery power source connected where it says 10-60v. That is the schematic symbol for a battery.
The jumper is placed on a different set of pins compared to the diagram 1-2
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paulz
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# Posted: 9 Nov 2020 09:52am - Edited by: paulz
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Thanks ICC, I didn't know that was the symbol for a battery. Why the change in the red wire connection at load? It's still connecting to the + load connection in the top diagram, right? I see no reason to use a separate battery.
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razmichael
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# Posted: 9 Nov 2020 12:25pm
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Although the two connection options (1.3, 1.4 - no relay) look different that is just the way it is drawn. As ICC notes, 1.3 is if you want to power the monitoring system from a separate source - reason is to isolate the monitoring system from what is is monitoring (from a power perspective). Although the impact should be minimal normally, if your battery was low, the monitoring system might not have enough power to function properly. If you look at 1.4 (using a relay) it is shown only with this separate power source - in this case so that the relay will still function as it is set regardless of the main battery power level.
I would not generally see 1.3 being used in this case as it does mean an additional power source - great in a manufacturing or some other use case.
it looks like a nice unit (the Hall effect for current makes it easy as no shunt in needed) but no idea on overall quality.
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paulz
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# Posted: 9 Nov 2020 12:57pm
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Thanks raz. I'll go with no external battery as you suggest, not going to shut down any hospitals if my battery dies. I'm still wondering why the red wire on the bottom of that diagram (1.2) has it going into the side of the battery instead of the terminal, or the other red wire, as is 1.3. Any idea? I don't want to hook that up and fry it. Looks to me like it would have to go the terminal for it to power up.
These meters are about $25 online, from China of course. It came to me in the box of stuff that was thrown in with my SCC purchase off Craigslist. Might as well try it. Going back out there tomorrow, I left my Valence LFP battery hooked to the new solar, curious how it's doing.
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razmichael
Member
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# Posted: 9 Nov 2020 01:31pm
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The wiring is the same - just drawn differently . Should have a fuse as well.
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Fanman
Member
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# Posted: 9 Nov 2020 04:52pm
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I put one of those meters in our camper, works quite well. Only complaint is the text is hard to see but that's because I mounted it near floor level because that's where the battery wire is. I too didn't see the need for the separate battery.
The relay option is if you want it to automatically isolate the battery when it discharges to a certain point to protect it from overdischarge. I didn't do that either.
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razmichael
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# Posted: 9 Nov 2020 06:10pm
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Paulz, just to clarify, despite the way it is drawn, the red box labeled “Load†is not a battery. It could be a single light, a set of circuits for a bunch of DC things etc. it just represents whatever thing(s) the battery is providing power to. The meter is just one more thing that is being powered by the battery (as well as measuring the voltage). The Hall sensor is measuring current through the loop. I suppose you could look at the way the two are drawn that the second is not a load component as there is a separate battery - only a measurement lead, while the first is both a load and measuring. Does not change anything and since you are not using an independent battery it does not matter.
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paulz
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# Posted: 11 Nov 2020 12:32pm - Edited by: paulz
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OK thanks again. I was going to hook it up today but..
I left my solar hooked up to one of the Valence lfp batteries for the last coupe days, no load. Got to the cabin yesterday and it was, and still is, showing 13.0 volts. When I charge these at home on a grid charger they usually have 13.2 or 3 after charging.
Hmm, well I have terrible sun but I had SLA batteries hooked up a week ago, ran them down and they came back to 12.6 fairly quickly. I don't see a parameter for what the sitting voltage on the SCC, has all the other usual stuff, the boost set to 14.4. Right now under cloudy shade the PVs show 60v and 1amp charge.
So not sure what to do. I figured I need get it all the way charged before hooking up and programming the meter. I can do that back at the grid but won't do much good if it's not going to charge on the solar.
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ICC
Member
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# Posted: 11 Nov 2020 02:20pm
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Isn't there a reset button or a method to zero out the accumulated readings? There should be. That would permit you to install the pieces and then simply wait to when you have a full charge before resetting the meter to zero.
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paulz
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# Posted: 11 Nov 2020 03:22pm
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Yes I think so, there is some serious Chinenglish in the instructions, still studying.
The SCC is now showing 13.1v, 1amp charge and battery capacity at 100%, maybe that is all it will charge to.
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razmichael
Member
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# Posted: 11 Nov 2020 04:47pm
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I’m not 100% sure of the goal here but want to make sure you understand what a fully charged battery is. For fla a full charge is about 12.7volts. The charger will put out more than this during the charging process and any meter on the battery will show this higher number. Turn off the charger (or sun goes down) and the battery voltage will drop and slowly settle to its actual charge (hopefully fully charged at 12.7). With a solar CC you see this drop as the sunlight diminishes and the CC is finishing up. I’m really over simplifying everything here and measuring needs to be down open circuit/no load etc etc. if you really want to test your batteries (flooded lead acid) you need a hydrometer.
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Fanman
Member
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# Posted: 11 Nov 2020 07:38pm
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The battery the meter displays is based on the current flowing through the Hall sensor, not the battery voltage. You have to go into the OAH function and set it to the total amp-hour capacity of your batteries, then reset it once when fully charged. Thereafter it tracks battery capacity in percent based on the current flowing in or out.
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paulz
Member
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# Posted: 12 Nov 2020 09:12am
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OK will do. I'm going to make a larger gauge load wire before I hook this battery up to power the cabin.
Battery sitting at 13.1 this morning (it's the Valence lifepo4). Expecting sunshine today, if it doesn't go up I'll take it to the grid and charge it, see if it goes higher.
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Brettny
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# Posted: 12 Nov 2020 10:41am
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You will have to tell us how you like that battery monitor.
I have been eyeing this one for a few months.
https://www.amazon.com/gp/product/B07FGFFHC6/ref=ox_sc_act_title_1?smid=A3JXNUUKLASGK 0&psc=1
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paulz
Member
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# Posted: 12 Nov 2020 11:16am
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I have that exact one in my truck hooked to the two batteries that power my cabin now (that I am hoping to replace, or at least augment, with solar). There's some info on it in the last couple pages of the Valence thread, by someone who knows more about it. All I did was charge the batteries full, enter the AH rating and it tells me the percentage of juice remaining. I'm sure it does other stuff,and it has never done anything wonky.
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Brettny
Member
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# Posted: 13 Nov 2020 06:17am
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That's all I really want it for...to tell me the percentage left when theres a load on the batteries.
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paulz
Member
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# Posted: 25 Nov 2020 11:32am - Edited by: paulz
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Finally got the meter hooked up yesterday. Simple, pass positive battery cable through the sensor, two wires to battery terminals to power it. Looks like it belongs in airplane cockpit, with Chinese instructions. Got the AHs set but nothing showing on bar graph. Working on it.
One of the virtues of this thing expressly described in the instructions is the relay option. By hooking up a relay it has the ability to cut out or cut in what you hook up to the relay, based on over or under voltage or current. Don't see needing any of that myself, so far.
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razmichael
Member
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# Posted: 25 Nov 2020 02:53pm
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Making an assumption that you do not already have over/under voltage protection, I would keep the Relay option in mind going forward. As the smarts are in your meter already, running your load through a high capacity locking relay to protect your system from something going wrong, especially when you are away, would not be very expensive.
Example, a fuse goes in the solar side of things (so no recharging) but power is still being used from the batteries by something you left running, this provides a safety switch. I use a Stirling locking relay (includes the smarts) for the DC side of my system - the inverter is separate and handles over/under itself.
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Steve_S
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# Posted: 25 Nov 2020 05:41pm
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I agree with razmichael. Protecting your battery investment with a simple inexpensive setup like this is prudent. Things only have to go sideways once and you can be out big bucks.
I use a couple of these in my test rig and they work pretty well (but you have to verify the readings with a DVOM and compensate a little).
I also have a PeaceFair AC model similar to this to monitor the input from the Genset independently and in front of the Inverter (even though the Inverter {Samlex EVO} can display watts, amps & hours as well, this is easier for the "At a glance Quick View".
The Aili & Drok monitors like this are quite popular and do work as expected.
The PeaceFair products are more varied and many have options for BlueTooth, Wifi, RS485 etc for accessing the info as well and the price point is almost the same. That helps if you are integrating a monitoring / management system.
Having used an assortment, I like the DROK & Aili's but a slight step up to PeaceFair lines which have more options can be better as the systems get more complex.
Ref Link to PeaceFair.. Note most of their products are available on EBay/Amazon etc... just search for the part number. They are NOT expensive either, so shop it out.
https://peacefair.en.made-in-china.com/
NB: They are an OEM that supplies many vendors which often relabel or rebrand to their own marque. 1 piece "samples" can be bought direct if your willing to wait on delivery.
Here is a link to an Amazon.CA vendor which is also on EBay & Amazon US too.
https://www.amazon.ca/s?me=A2PMIWMSUTAYGS&marketplaceID=A2EUQ1WTGCTBG2
Hope it helps,
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paulz
Member
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# Posted: 26 Nov 2020 05:13am
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See, that's why I have you guys on my payroll. 
Excellent idea. According to the instructions, I need a separate battery, a relay and a switch at the battery cable. So which battery would be supplying the relay and how much current does it take?
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razmichael
Member
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# Posted: 26 Nov 2020 07:41am
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Before doing anything I would just play with the meter for a bit to validate how well it works. The diagram (as per the other ones) is not crystal clear (although the written instructions are very polite). The independent battery should not be needed (power from the main battery) as long as the
a. The system voltage matches the relay energizing circuit voltage, and
b. the relay energizing circuit voltage range will be wider than the low voltage cut-off you need.
So if your system voltage is 24 but you have a relay that actuates with 12v you need a separate 12v battery. Assuming 12v, If the relay actuator range is something like 10-16 volts then this will continue to work as the system voltage drops to the point of low voltage cut-off. In these cases you could power the meter relay circuit from the system batteries before the relay (with a fuse obviously).
The switch shown is really the relay - they just re-used the main diagram and added the dotted green line from the original relay box to the switch. The meter does not have a relay, just can provide power to a relay actuator.
You need to determine what capacity relay you need (and the activating voltage). The Relay/switch must be able to handle the maximum current. This can be very high if want to put the relay before an inverter - which is why i separated my Inverter (with it's own low voltage shut-off, from the DC side of the system (lights etc) which runs through a Sterling protection Relay.
I'm assuming your system has/will have all the required fusing and cut-out switches for safety.
One key value is the relay actuator power draw as this will be drawing power whenever the system is on. A locking relay can really reduce this but these are more expensive. Automobile relays tend to be power hogs as it is not really an issue in a vehicle with the engine running.
Depending on the overall design and how you use your system, you could include a small switch between the battery and the relay power in circuit on the meter which would act as a main off/on switch for the power.
Now the potentially bad news - if I am reading the instructions correctly, it looks like whenever the meter opens the relay for low voltage (or any of the other parameters that can be set), it must be manually reset - in other words, it does not power back on once the voltage gets back to normal. many systems will include (or automatically provide) a second parameter for each - example shut off at 11.3, back on at 12.5. This may not matter if you shut the power down when you leave anyway (so really providing protection if you forget to shut down and something goes wrong). If you need power when not there, using this meter to control a relay may not be the approach.
More to think about!
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paulz
Member
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# Posted: 26 Nov 2020 11:21am
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Thanks again raz. Lol, yes, always nice when the instructions start with Please. Unfortunately it's usually followed by "Connect where to regarding under position therefore.." Glad I have you to translate. OK I understand, I would just need to buy the proper relay.
Another item that came in the box of stuff with my Epever is this Victron battery protector. I went through the instructions first time this morning. Looks like it only consumes 1.5mA, maybe a better option? I don't see where it provides over voltage protection but the Epever does that I think.
You also bring up an important new point for me. As I've mentioned before, I've been running the cabin for several years from batteries in my truck that I recharge back at the grid. So when I leave, I unplug and there is no power at the cabin. This new setup has one Valence Li battery in the cabin, hooked to my solar panels and the cabin electrical. I can still unplug it when I leave but ultimately I should be able to leave it plugged in for clocks, night light or whatever. So then it would be possible for the battery to severely run down.
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Steve_S
Member
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# Posted: 26 Nov 2020 12:42pm
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Easy way to disconnect battery from gear and do it safely:
https://www.bluesea.com/products/category/11/41/e-Series
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razmichael
Member
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# Posted: 26 Nov 2020 05:26pm - Edited by: razmichael
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As Steve noted, the marine switches are really well suited for higher amperage battery switches. I used (recently modified) a Off/1/2/1&2) as my master - I could power up the dc side, the inverter or both. I think I have four of these in various models in my system. A lot of the Marine products can be really well suited although important to shop around.
Only took a quick look for the Victron manual - couldn't find it as it is an older model I suspect. Assuming it has decent Low Voltage parameters (or can be adjusted, I think it would be the easiest solution rather than try to add a relay to the meter (and you don't really need all the extra parameter settings available from the meter). Some devices with low voltage setting default too low so, by the time it cut off the battery, you have already gone below where you might want to go for a cabin solar system.
Just make sure the Victron is suitable for you total max amperage with room to spare.
Edit: noticed you are using a li battery so can safely be run down more than flooded so the concern about too low a cut-off is probably not an issue.
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paulz
Member
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# Posted: 27 Nov 2020 09:49am
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Thanks guys. This Victron battery protector is 100 amp and is programmable for voltage. So yes I will probably just use it.
And switches are in my future too I can see. I've been diligently unplugging the panels (via an MC connector) before disconnecting batteries as stated in the manual, even if there is no charging going on.
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