Not sure about the stability of attaching a diode on the + of each power supply, I have seen diodes go short circuit as opposed to the popular open circuit fault condition? However thanks for the suggestionJust stick two simple power supplies in paralel and connect PSU positive output via diode and you have redundant feature.
This is good news, can i ask have you have tried this method and works for you, thanksIf you not exceed Absolute Maximum Ratings it's very stable. Regading ralay devices all this devices have bad MTBF rate. And I am not use it for any serious application.
You say changed power supply from 18v to 24v, Are you now running all of your devices from one single 24v power supply,Since I cange all my 18V PSU to 24V I don't feel requirement for redundant power supply solution )
Has anybody tried this power supply redundancy method?Just stick two simple power supplies in paralel and connect PSU positive output via diode and you have redundant feature.
How many POE ports does it have and can i attach my 113AH deep cycle battery to this unit for time extension when running on a batteryHi why dont try a Restlesspowerbox?
You will love it, by its multiple features. And its from only 189 Euro.
You do not need second powesupply, because if the powersupply will fail the integrated batteries will power the router.
you will be informed about a failure by email and/or SMS (optional).
Give it a try!
sonny
http://www.citynetz24.de - http://www.retlesspowerbox.com
It has 4 POE ports. If you use 24V battery you can power the box with it.How many POE ports does it have and can i attach my 113AH deep cycle battery to this unit for time extension when running on a battery
I spent 30 years in electronics before wireless networking and this method does work. In this application, the diodes are called "steering diodes". It allows power to flow from each power supply through a diode to a common positive point to feed the load. If one power supply short-circuits, the diodes prevent power from the remaining good supply from flowing backwards and shorting through the failed supply.Has anybody tried this power supply redundancy method?Just stick two simple power supplies in paralel and connect PSU positive output via diode and you have redundant feature.
My plan is to use a inline fuse for each connected device, so if 8 devices connected and say load no 2 goes short it blows the inline fuse. and prehaps a led light on the load side of the fuse so this will indicate which fuse is goneI spent 30 years in electronics before wireless networking and this method does work. In this application, the diodes are called "steering diodes". It allows power to flow from each power supply through a diode to a common positive point to feed the load. If one power supply short-circuits, the diodes prevent power from the remaining good supply from flowing backwards and shorting through the failed supply.
If the load side short-circuits, there isn't much you can do, it will drag down both power supplies.
At present i have this battery attached to a UPS in place of the 2 batteries which came with UPSIt has 4 POE ports. If you use 24V battery you can power the box with it.
If the battery is discharging you can Monitor this and get informed by Email.
How are you charging your battery?
That is a single PSU there is no redundancyWhy not try a AD-55 or AD-155?
Examples here: http://tandem.ck.ua/ups_mt-eng.php
For important sites, I put a separate (redundant) power supply.That is a single PSU there is no redundancyWhy not try a AD-55 or AD-155?
Examples here: http://tandem.ck.ua/ups_mt-eng.php
This is exactly what happened to me!!the diodes prevent power from the remaining good supply from flowing backwards and shorting through the failed supply.
And with the diodes have you had any more problems since,This is exactly what happened to me!!
I had 2 48v 1amp power supplies connected in parallel, powering a rb 800.
The one power supply blew short after 2 years of operation and dropped the rb 800.
I have now subsequently put diodes in all my installations with parallel power supplies.
Well, considering competition in ISP market, it is rather hard to keep the costs down, when shelling out almost 200Euros per one end for just power supply backup.Hi why dont try a Restlesspowerbox?
You will love it, by its multiple features. And its from only 189 Euro.
You do not need second powesupply, because if the powersupply will fail the integrated batteries will power the router.
you will be informed about a failure by email and/or SMS (optional).
Give it a try!
sonny
http://www.citynetz24.de - http://www.retlesspowerbox.com
Yes - I use this power solution for some time and it's greatWell, considering competition in ISP market, it is rather hard to keep the costs down, when shelling out almost 200Euros per one end for just power supply backup.
My suggestion would still be - Meanwell 24v/5a psu + 2x12Ah/12v batteries + simple voltage monitor script in routeros, to get you notified and ready to respond if the power doesn't return.
The total would be around 100Euros and a bit longer backup time.
I came to this solution with these Meanwell power supplies few years ago. I don't know how you guys were successfully using it, but these power supplies aren't exactly compatible with lead-acid batteries used with them, especially AD-55B 24V model. These sealed maintenance free lead-acid batteries require constant-voltage/constant-current charging. The later one isn't that much important as CV, but it still counts. You have to charge them with at least 13,6V, which in case of two batteries would obviously be at least 27,2V. And according to battery manufacturers, 13,65-13,8V is the best voltage for float charging when this battery is used in cycle mode (which in this case it is). The problem arises that if you want to rise the voltage at battery terminals to 27,2-27,3V, you have to also increase the output rail voltage (that is the simple way), which then becomes ~28,1V which isn't what you want with most RouterBoards, since their specification tells you shouldn't apply more than 28V to them (and yes, I know about voltage drops in long PoE lines). This seems to apply less for 13.8V version of the PSU, there you could easily turn the pot to get the desired voltage at battery output terminals, since the voltage of output to the boards doesn't really matter in this case.Why not try a AD-55 or AD-155?
Examples here: http://tandem.ck.ua/ups_mt-eng.php
This a very interesting comment does it mean that to charge the batteries we are approaching the cut-off threshold (less POE cable loss) of routerboard ?I came to this solution with these Meanwell power supplies few years ago. I don't know how you guys were successfully using it, but these power supplies aren't exactly compatible with lead-acid batteries used with them, especially AD-55B 24V model. These sealed maintenance free lead-acid batteries require constant-voltage/constant-current charging. The later one isn't that much important as CV, but it still counts. You have to charge them with at least 13,6V, which in case of two batteries would obviously be at least 27,2V. And according to battery manufacturers, 13,65-13,8V is the best voltage for float charging when this battery is used in cycle mode (which in this case it is). The problem arises that if you want to rise the voltage at battery terminals to 27,2-27,3V, you have to also increase the output rail voltage (that is the simple way), which then becomes ~28,1V which isn't what you want with most RouterBoards, since their specification tells you shouldn't apply more than 28V to them (and yes, I know about voltage drops in long PoE lines). This seems to apply less for 13.8V version of the PSU, there you could easily turn the pot to get the desired voltage at battery output terminals, since the voltage of output to the boards doesn't really matter in this case.Why not try a AD-55 or AD-155?
Examples here: http://tandem.ck.ua/ups_mt-eng.php
The charging current control is also working a little strangely in these power supplies. It is supposed to charge the battery at around 640mA current after serious discharge (the relay should click), but it only applies the 0,16A charging after AC power is restored, which is ok for float charging, but not for restoring the battery.
I could of course be wrong about something, so your input is always welcome.
If this is a problem, it solved by the installation of a diode.The problem arises that if you want to rise the voltage at battery terminals to 27,2-27,3V, you have to also increase the output rail voltage (that is the simple way), which then becomes ~28,1V which isn't what you want with most RouterBoards, since their specification tells you shouldn't apply more than 28V to them (and yes, I know about voltage drops in long PoE lines).
The charging current is really nevsegda enough.The charging current control is also working a little strangely in these power supplies. It is supposed to charge the battery at around 640mA current after serious discharge (the relay should click), but it only applies the 0,16A charging after AC power is restored, which is ok for float charging, but not for restoring the battery.
How is this done, componet change or preset adjustment?The charging current is really nevsegda enough.
You can modify the AD-55 and increase the current up to 0,5 ... 0,6 A.
This, however, exclude the warranty on the AD-55.
We must not forget that the effective capacity reduced to 50 watts when charging the battery.How is this done, componet change or preset adjustment?
Up to 60ah but my plan as i have them to hand is 2 X 113ah deep cycle batteries in series, now how would i re-charge them if they ran down,Convenient and affordable solution for batteries up to 60 A * h.
P S C-60 - http://www.meanwell.com/search/psc-60/default.htm
This solves all problems.
....This is quite simple power supply and even simpler charge current limiter. You should simply replace the 20R resistor R50 & R51 in series to, let's say one 3.3 ohm 2W resistor, and you get enough current to charge your battery. I don't think your solution is good, because bypassing the diode almost eliminates it's purpose. I know it doesn't do much while the supply functions as it should (normally - relay open) To my opinion, it's cleaner to replace the existing resistors with appropriate ones. The only thing in this circuit to limit charging current is that double resistor (R50+R51). Whatever is your way, it is the point you'd want to consider first.
I'm attaching the circuit diagram for you to get the idea better. In my setup 3.3R resistor allows about 680mA of current to pass into the battery after complete discharge, afterwards it keeps dropping until it reaches float charging current of about 40-80mA. The voltage at open battery terminals is set to 27.3V (normally being 13.65V per battery), and with fully connected battery is 27.1V. This is the behavior I would expect from normally working battery charger. With 3.3R resistor, voltage output terminals read 27.6-27.7V. If it seems too high for you, or if you'd like to raise the charging voltage, simply adding one or two diodes in series makes it fine.
.......
At present i use 2 X 12v 7Ah and asked before what is the maximum capacity that can be used. You say this is "significantly shortening battery life operating it that way" does this also apply to deep cycle batteries. AC power supply outages are rare and usually the result of a storm and because of isolated locations there can be a delay in restoring the ac supply as it would be listed as a low priority, so it would be important to have long battery life to cover such a event.That zener there is a very simple overdischarge protection. 19V would mean that you're discharging your batteries to 9.5V per battery which is exactly the lowest allowed voltage specified by most battery manufacturers. You are significantly shortening battery life operating it that way. On the other hand, it won't do much harm if it seldom happens. Either way wouldn't it be wiser to simply use higher capacity batteries?
Check out these devices, they will be able to do it all. We use them for our sites and have never had any issues.Up to 60ah but my plan as i have them to hand is 2 X 113ah deep cycle batteries in series, now how would i re-charge them if they ran down,Convenient and affordable solution for batteries up to 60 A * h.
P S C-60 - http://www.meanwell.com/search/psc-60/default.htm
This solves all problems.
Could a seperate smart battery charger do and when charged have a relay to switch over the 24volt battery supply back to AD-155's, not sure if you can a seperate battery charger connected to the batteries while the ad-155 is also running
How much do they cost and how long have you been using them?Check out these devices, they will be able to do it all. We use them for our sites and have never had any issues.Up to 60ah but my plan as i have them to hand is 2 X 113ah deep cycle batteries in series, now how would i re-charge them if they ran down,Convenient and affordable solution for batteries up to 60 A * h.
P S C-60 - http://www.meanwell.com/search/psc-60/default.htm
This solves all problems.
Could a seperate smart battery charger do and when charged have a relay to switch over the 24volt battery supply back to AD-155's, not sure if you can a seperate battery charger connected to the batteries while the ad-155 is also running
http://www.snaptec.com.au/dc-ups-systems.html
For these batteries AD-155 does not fit.Up to 60ah but my plan as i have them to hand is 2 X 113ah deep cycle batteries in series, now how would i re-charge them if they ran down,Convenient and affordable solution for batteries up to 60 A * h.
P S C-60 - http://www.meanwell.com/search/psc-60/default.htm
This solves all problems.
Could a seperate smart battery charger do and when charged have a relay to switch over the 24volt battery supply back to AD-155's, not sure if you can a seperate battery charger connected to the batteries while the ad-155 is also running