I’ve got an interesting situation at one of our high sites.
We appear to have had the solar panels stolen and the radios are shutting down. That’s the short of it.
The longer version is as follows:
The high site is excellent. It’s one of the best in the Western Cape and gives me clear line of site to everything I need to see. It’s in a conservancy area. There’s obviously no electricity, and I couldn’t put up a wind turbine because the ramblers staying overnight in the hut nearby don’t want to hear “woosh woosh” all night long.
I had 6 x 55W solar panels charging 4 x 102Ah deep cycle batteries. We had a big storm last week. The solar panels either blew away (I find that had to believe as they were secured onto steel frames that were concreted into the mountain) or they’ve been stolen. Either way there’s no power coming from them. The site itself doesn’t have any paying clients connecting to it, but the 3 RB600’s all have XR5’s with large aerials on them. It’s a repeater site in the true sense of the word. It connects access points with our two NOCs and provides for redundant links.
Yesterday I started getting “voltage low” emails. I drove out there, but the track is too wet for me to go up. It may dry out enough for me to try on Tuesday or Wednesday.
We have a Land Rover Defender with a big V8, big mud tyres and diff lockers in the front and back axles that we need to drive for more than an hour in low ratio to get from where the tar ends to where the tower is - that’s when the track is dry. It’s much worse when the track is wet.
As things stand now, the batteries are down to 11.7V and it appears that some of the radios are no longer working.
wlan1 on each rig still works. wlan3 is dead. wlan2 works on one rig, but not on the other two.
Am I right in thinking that things will return to normal once I’ve got the batteries charged up?
You should do ok until the voltage gets below 10 volts. From personal experience, when the voltage drops below 9 volts, the unit will lose its mind, and then its license. No thing. Your dealer can help you with the license reinstall if that happens.
ADD: Are you certain the solar panels are gone? I had a solar charger fail before, and the results are about what you are getting. And you might want to check the huts that don’t like “whoosh whoosh” to see if they have your panels!
You will figure it out when you get to the site. I have been through some really bad storms (hurricane Opal as an example), but none have been strong enough to remove bolts or screws.
My solar chargers now have Low Voltage Disconnects (LVD). They disconnect the load at about 11 volts. They reconnect it at 12.5 volts.
Turning off a wind turbine overnight is very simple. If you have wind then wind energy is much cheaper than solar power.
How do you monitor the battery voltage and where?
Do you measure the voltage at the batteries or at the radios?
My experience is that RB411A routerboards + high power radios will go dark at somewhere around 8.5V to 9.5V, as SurferTim says.
The voltage was measured by a nearby RB450G.
At 11.6V, your radios should run perfectly fine.
If you are measuring the voltage at the batteries, then you are losing too much voltage to the wires - do something about it.
If that is the case, you are probably wasting over 30% of battery capacity on wire loses.
400 Ah should easily keep you online for 3 days. I can run 3 XR5s in 3 RB411A for 70 hours on 160 Ah from 100% to 0% charge.
Anyway, you should be just fine when you get the batteries charged.
We have a site where a solar panel is supplemented by a windmill but after a solid week of cut-outs and reboots every few minutes and “jan/01/2002 14:00:02 system,error,critical router rebooted without proper shutdown, probably power outage” reports in the syslog we turned the windmill off, since when all has been fine.
We’re still investigating the problem but current speculation is that the windmill, which locks the generator up to prevent the rotor turning when the batteries are fully charged, was spinning up with charged batteries in gusty weather and the ‘lock-up’ function was causing either a voltage drop or ‘shock’ through the system which either caused the regulator to cut off the power to the board (an RB532), or was actually causing the board to momentarily shutdown.
So if you’re thinking of getting a windmill be sure you understand how it’s going to affect the system.
If anyone else has experienced this problem we’d be interested to learn to solution.
I had pretty much the exact same problem with the Air X. But mine was worse - about 30% of the time the board would reboot, and the other 70% it would freeze.
Freezing is of course far worse, because it would be down until a manual reboot, not just 30 seconds.
I ended up getting a 12V UPS from http://www.powerstream.com/12V-backup.htm and attaching it to a small 4 Ah backup battery.
That got me from a crash every 1-2 days to a crash about once a week.
I then added a 4700uF capacitor in parallel with the load. Since then, 1.5 months of 100% uptime.
The problem may not be with the windmill per se. It’s connected directly to the batteries as it has its own controller but the solar panel is connected to the batteries through a solar controller and the wireless gear takes its 12v feed from the solar controller. The problem may be with the way the solar controller reacts to the battery voltage as it is affected by the windmill - it was very noticeable that the problem was worse at night. We’re still trying to nut it out, but the site is not very accessible which makes investigation difficult. We don’t want to go up there until we’ve at least some idea what’s going on and what the solution might be.
No, but until we know WHY what is happening is happening we won’t know how to stop it happening.
Your approach is a patch and it may be in the end the only solution for us but eben uses the same turbine without suffering the same issues which suggests the problem lies elsewhere in our system, and we’d rather fix the problem than patch over it.
My windmills are connected in the same way (ie direct to the battery banks), but I use Steca Solstum controllers as they are supposed to be the best.
My equipment is connected to the “out” on each controller. What happens when you connect the kit direct to the battery and only use the controller as a voltage regulator for the solar panel?
I got the same configuration of eben, with 3 windmill in the same site ( we are in a windy and sunny place, so we are plenty of power.)
No voltage issues nor disconnections.
The windmill is Air X too, and it should have his own charge controller (IIRC)
Windmills
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Batteries —> Equipment
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Solar Panels with charge controller
We’re using the Steca Solstrum too, and with the same configuration as you and Medianet but we’re getting problems and you’re not. Odd.
My vote would be to power the wireless gear direct from the batteries but I’m outvoted on the grounds that if both windmill and panel “disappeared” (to adorn someone else’s country estate!) we wouldn’t know until the equipment had drained the batteries, and as they are gell-cell 6v ones that could be damaging.
If the board cuts itself off if voltage drops below 11 this wouldn’t be so much of a problem, but I think that with the input via the jack-plug the RB532 can go right down to 6v and still work.
Now that the weather’s settled down (we were getting gusts of 140kph last week) we’re going to reconnect everything tomorrow to see what happens.
Why don’t you connect directly to the batteries and monitor the voltage with a EB433AH or RB450G?
If the voltage goes too low for your batteries, you can shut down the system remotely.
For us, losing a little battery life (by discharging it too much) costs much less than offline customers.
Hrmm, do you guys run a Solar controller that supports diversion ? For example the Morningstar TriStar 45 and 60 do, but the SunSaver range and most Steca’s do not.
You need to run a diversion load, e.g. a 12/24volt heater
According to the docs, a diversion-type charger would only be needed with an alternate charging source that does not have its own regulation. My supplier assures me the Air Breeze wind generator and any of the solar chargers they offer will work together. The Air Breeze has internal regulation.
Those little things have clever regulators. I have some that have very short cables and I have some that have LOOONG cables and no matter how long the cable, the correct voltage always gets to the battery.
