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24v Large Super Capacitors

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Topic: 24v Large Super Capacitors
Posted By: Phil B
Subject: 24v Large Super Capacitors
Date Posted: 06 December 2016 at 12:26pm
Ok so I have a problem that I can't work around.

On our solar rig we use a few large 240v class D smps amps ( FFa and C-Audio Pulse)  Usually not a problem with our new inverter. Loads of power available 3000 watt rms with a 6000 watt peak. All good and we never pull more than 1/4- 1/2 of the RMS capacity.

BUT it sends the inverter into a warning mode due to voltage ripple on the DC side. This is probably due to the fast & high current demand on bass notes which the inverter tries to pull out of the batteries. We have upped the cable size and made sure we have good tight connections at all times. It also seems to happen at 80% or less of battery charge state, which can catch us out when running hard from a full 100% start off.  And finally last weekend it tripped out during a gig.. very dull.

So would fitting some very big ( scary) 30v say 6-10 Farad caps before the inverter help things ? I'm beyond my skill level when talking about smoothing out DC ripple by introducing more capacitance before an inverter?? In theory it should work to reduce the ripple on the dc side of things but thought I better ask ! The inverter is one of these....CP 3000 24v

http://www.currentgeneration.co.nz/site/current/files/CombiPlus%20Manual.pdf" rel="nofollow - http://www.currentgeneration.co.nz/site/current/files/CombiPlus%20Manual.pdf  

Ta

.p.




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Replies:
Posted By: carlosdelondres
Date Posted: 06 December 2016 at 2:04pm
not 100% sure it's the same issue, but adding caps is a recognised solution for voltage ripple causing ESC (speed controller) failure - this thread at rcgroups might shed a bit of light https://www.rcgroups.com/forums/showthread.php?952523-too-long-battery-wires-will-kill-ESC-over-time-precautions-solutions-amp-workarounds" rel="nofollow - https://www.rcgroups.com/forums/showthread.php?952523-too-long-battery-wires-will-kill-ESC-over-time-precautions-solutions-amp-workarounds


Posted By: Sapro2
Date Posted: 06 December 2016 at 4:04pm
Have a chat with the guys from bimble solar:

http://www.bimblesolar.com/" rel="nofollow - http://www.bimblesolar.com/

They run the Bimble Inn at Glastonbury festival and a few other festivals. They also supply solar related gubbins but they also run a reasonably large solar rig in their festival venue. They sell those sorts of Caps and I am sure would be up for having a chat with you and should know their stuff.

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Splat Soundsystem
Baby Sham pram Soundsystem
Sapro - SoundCloud
https://soundcloud.com/sapro
DJ Sapro. West country free party DJ and Producer.


Posted By: snowflake
Date Posted: 06 December 2016 at 5:41pm
what batteries are you using? deep-cycle batteries might not be designed for high current but would have thought any standard car battery should deal with it.


Posted By: slaz
Date Posted: 06 December 2016 at 10:22pm
Originally posted by snowflake snowflake wrote:

what batteries are you using? deep-cycle batteries might not be designed for high current but would have thought any standard car battery should deal with it.


Don't know details of type .... but - big ones - lots of em AFAIK - pics of this rig were up on here a while ago. Wondering if a single battery (mebbe even one cell in one battery)  has degraded with high internal resistance could cause a voltage drop on heavy load.

Another thought - might be worth (if poss) trying a non switch-mode amp or two - see if behaviour is any different.



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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON


Posted By: mk2_ginger_biscuit69
Date Posted: 06 December 2016 at 11:21pm
im thinking that above, one cell having issues - its a problem with have with a 48V traction battery on a work forklift, trying to get the lease company to admit there is a problem is another matter. Try using much juice at once [say driving off whilst lifting a heavy load, and it trips out].

regardless, having a bigass capacitor bank would certainly help - but would have to be attached in a clever way. A softstart type resister circuit would need to be added for when they initially charge or you would risk a MASSIVE current surge which could screw your traction cells, blow breakers/fuses, and arc like a bugger when you connect the battery/flick the switch. You could of course have it 'on' the battery bank so its always charged, meaning you'd only have to 'soft' charge it on the initial run, but any short circuit would make a spectacular boom.... certainly have to be bloomin' careful with that kind of capacitance, its really dangerous.




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Posted By: ceharden
Date Posted: 06 December 2016 at 11:22pm
Adding some bulk capacitance close to the inverter is not necessarily a bad idea but I'm not sure you need to go for as high a value as you're suggesting.  Might not need to be Supercaps either, some decent high ripple current Electrolytics might also do the job.

Beware that if you do go for such high value supercaps that the initial charge current when you connect them across the battery will be massive, they'll appear like a short circuit.  You'd probably need to charge them slowly through some big power resistors, then short the resistors out once the caps have reached the same potential as the batteries.

Internal resistance of your batteries could be an issue as mentioned.  One option would be to use some high current starting batteries close to the inverter in parallel with your main deep-cycle storage ones.

That inverter looks really cool though, especially all the features to run in parallel with a current limited mains supply etc.  It's almost more of a UPS than an inverter.



Posted By: valve head777
Date Posted: 06 December 2016 at 11:51pm
As above,
Is there any way of loading the bank with a typical current load for test purposes? If you can rig this up and you have flooded cells, its relatively easy to spot a dying cell as it will gas before the rest. Imho if you are using big sealed batteries (vrla) they're not really suited for your application. In my experience vrla sulphate really quickly when in partial charge. They're only really good for applications where they get charged fully directly after discharge such as ups. At 80% soc, a good bank should hold its voltage under reasonable (related to ah capacity of the bank) current demand. Obviously diagnosing a weak cell on vrla is more difficult.


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Freedom of choice, choice of freedom.


Posted By: davey t
Date Posted: 07 December 2016 at 9:50am
Inverting to 240V then using AC amplifiers seems like the wrong way to do things. I would invest in some pro car audio class D amps. They are designed to run from batteries and have lots of energy storage built in. That said... most only go up to 14.4V DC. We have a 3.6k rms 12V rig which runs for ages no problem from 2 or 3 110Ah leisure batteries. Plenty of power. 

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Minirig portable soundsystem movement


Posted By: valve head777
Date Posted: 07 December 2016 at 2:17pm
Erm, 3.5kw is a 330ish amp draw. From 2x 110ah batteries?????

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Freedom of choice, choice of freedom.


Posted By: Phil B
Date Posted: 07 December 2016 at 9:47pm
Ok...thanks for some ideas there..

Firstly its not a voltage drop but a ripple. The inverter detects the ripple 

a) Davey T... not going to swap to car audio amps now, invested too much in 240v ones and we are adding more subs as well. Also we run 24v so would need a step down of some kind.

b) Snowflake ...batts are 12 x Yuasa 1100 amh SLA 2v cells. Came from a UPS system. Run in series to get a 24v bank.

c) Valvehead. We have tested all the cells a few months ago, getting voltage readings on resting cells over a 2 day period, none seemed to be low. They have always coped well up till now and spend 99% of the time at float resting. That's why I was thinking of the capacitors in-line with the bank to smooth out the peaks that the amps are demanding. The voltage under load can sag to 23.3 - 23.5 when about 80% of charge and a heavy load, thats when the voltage ripple alarm starts up. The low voltage shut off is set to 22v and we've never gone that deep.

d) Chris... yep like the starting battery idea, would do the same job as some big caps. Not sure how that would work with charging from solar though... At the moment we run 1.5kw of panels through a Midnight Solar 150.. means we can sometimes be pushing 40-50 amps @ 24v back into the bank? The equalise mode with a different type of battery would be all over the place.

Food for thought..

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: snowflake
Date Posted: 07 December 2016 at 10:03pm
Originally posted by davey t davey t wrote:

Inverting to 240V then using AC amplifiers seems like the wrong way to do things. I would invest in some pro car audio class D amps. They are designed to run from batteries and have lots of energy storage built in. That said... most only go up to 14.4V DC. We have a 3.6k rms 12V rig which runs for ages no problem from 2 or 3 110Ah leisure batteries. Plenty of power. 

or there are lots of amp modules that run on 24, 36 or 48V DC. converting DC to AC and back to DC it going to waste at least 25% of your power, possibly more.

if you are going to stick with the inverter just try a few odd capacitors and see if any of them solve the problem. if you think you might have a duff battery it will probably have a slightly higher temperature than the other ones after running for a few hours..


Posted By: valve head777
Date Posted: 08 December 2016 at 12:01am
@ Phil, do you equalize the banks? And at what voltage?
Im interested to know as i live off grid and use agm ups batteries.
I did wonder about voltage ripple. I still feel its the bank becoming weak. When charging i myself never let my system reach more than 27.8v as its gasing which will dry them out. The drawback is not really being able to equalize like you can for flooded, so very regular readings are taken and individual batteries charged. Tbn its a chore and makes me resent the lead acid technology. If only i could afford nife batteries.

Its sounds as if you should do a capacity test to get an accurate idea of how much capacity you actually have. Once below 80% original advertised capacity, performance drops quickly. In my experience the advertised advantage's of sealed don't bear out in reality. But they are reasonable safe (physically).

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Freedom of choice, choice of freedom.


Posted By: Phil B
Date Posted: 08 December 2016 at 8:39am
Originally posted by valve head777 valve head777 wrote:

@ Phil, do you equalize the banks? And at what voltage?
Im interested to know as i live off grid and use agm ups batteries.
I did wonder about voltage ripple. I still feel its the bank becoming weak. When charging i myself never let my system reach more than 27.8v as its gasing which will dry them out. The drawback is not really being able to equalize like you can for flooded, so very regular readings are taken and individual batteries charged. Tbn its a chore and makes me resent the lead acid technology. If only i could afford nife batteries.

Its sounds as if you should do a capacity test to get an accurate idea of how much capacity you actually have. Once below 80% original advertised capacity, performance drops quickly. In my experience the advertised advantage's of sealed don't bear out in reality. But they are reasonable safe (physically).

Hi

I think you've hit the nail on the head there. We changed over solar controllers recently and it does an auto Eq once a week up to 28.4. Time to turn that off ! Slipped through the net of new panels, amps and inverters. Also gonna check density for each cell but not sure we'll be able to get in/out easily without damaging the vents.

These are the batts.....

http://www.cyb.co.nz/content/industrial/telecommunications/batteries/uxl-specs/uxl1100-2.pdf" rel="nofollow - http://www.cyb.co.nz/content/industrial/telecommunications/batteries/uxl-specs/uxl1100-2.pdf


Thnx !

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: U.Viktor
Date Posted: 08 December 2016 at 8:51am
If you use 230Vac powered amp, use PFC amp only.
Please keep in mind that most of conventional (non-PFC) amplifiers may generates 5x -- 10x of current peaks due mains current distortion than PFC amps.
These sharp current peaks means like your 3000W amp would look like 30000W amp for the inverter!
It easily triggers the output current protection of the inverter periodically or permanently.


Posted By: Phil B
Date Posted: 08 December 2016 at 10:33am
Originally posted by U.Viktor U.Viktor wrote:

If you use 230Vac powered amp, use PFC amp only.
Please keep in mind that most of conventional (non-PFC) amplifiers may generates 5x -- 10x of current peaks due mains current distortion than PFC amps.
These sharp current peaks means like your 3000W amp would look like 30000W amp for the inverter!
It easily triggers the output current protection of the inverter periodically or permanently.

Yep well aware of all that and we swapped out our inuke 6000 for an FFa 6k to try help with PFC things. We are getting a ripple in the DC voltage though, the inverter can easily cope with the current draw so looking for ways to help the DC not AC side of things.

Ta

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: valve head777
Date Posted: 08 December 2016 at 2:13pm
Hi Phil, I've tried in the past to put a small amount of deionised water back into sealed bats but with no success. Once the mat is dry its dead batt time...
You use large cells. How do you charge them? Ideally you'll need a rate at a minimum of c15 which for your bank is around 100amps for bulk charging. If you are relying on the panels, 40 amps is only a trickle.

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Freedom of choice, choice of freedom.


Posted By: valve head777
Date Posted: 08 December 2016 at 2:24pm
In an ideal situation with all cells exactly the same in terms of voltage/capacity, 28.4 is ok (absolutely max) but in aging, cells become unbalanced so the weakest cell rises before the rest and begins drying out. This situation only gets worse over time. A lower voltage is a compromise but increases overall life. I hope your horse hasn't bolted just yet...

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Freedom of choice, choice of freedom.


Posted By: minaximal
Date Posted: 09 December 2016 at 8:26am
Hey Phil

Yeh i think equalizing SLA's will quickly kill them, unless it's possible to top up the water, or have a much lower eq voltage with temperature compensation.

Being off grid too, I had a very similar problem with our Victron Multi shutting down when battery voltage collapses with a heavy load, unfortunately it's normally a sign of cell degradation - lead paste falls off the plates over time leading to less capacity.

Best Bang for buck is still FLA forklift style cells, i wish we'd gone for them originally, and they're much better at coping with continuous cycling with heavy loads than SLA's

To get around it, lower the inverter shut down voltage, that's what i did, but i also added a http://www.smartgauge.co.uk/smartgauge.html" rel="nofollow - http://www.smartgauge.co.uk/smartgauge.html battery monitor and use that with relay output to tell the Victron when to shut down. It doesn't rely on voltage sensing alone, so it's a much more accurate way of knowing when SOC is low, and now i've set it so the batts can never get below 50% SOC, but it allows short term heavy loads which pull the voltage below 22v etc to pass through.

If the inverter can take an external relay input to tell it when to shut down or even the crude method to use a large contactor to disconnect it (only when SOC gets too low) and use something like the smartguage to trigger that, i think that's the best option without buying new batts or amps, and overall makes for a much more controllable and safe system.

What do you use to to know your batts are actually at <80% SOC when it happens, as it could be giving a rosier view of the batts, hence the voltage drop?

Whatever you do don't mix battery types! will be a world of pain and wasted money.

Really want to hear the system, i'll be over next year sometime...

Al

*Edit - As mentioned by Valvehead, if certain cells are less happy than others you could pull them out of the string and try to 'condition' / charge them seperately to bring voltage back up, but without a way to check SG of individual cells it's hard to tell whats happening. It could be worth exchanging cells at either end of the string for the central ones, as in a long string with cable resistances the cells at either end accept more charge and drain more quickly so 'wear out' more quickly.. lots of info on the smartguage website.





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Posted By: carlosdelondres
Date Posted: 09 December 2016 at 8:44am
Yep, we have ~1000 Ah 48 volt forklift battery, 5 years old now and still going ok despite less than ideal usage. Can pull 7kW from the motor without fuss, never had a problem with running system off our inverter either (studer xtender 8000). But the inverter has PFC and can handle 24kVA 2 minute peaks.

Bigger battery and better inverter in the longvterm i'd have thought. Though multiple low ESR caps in parallel is what people use for speed controllers in multirotors - the vrip can be high enough to overvolt fets and cause burnout. Rule is to add caps if your're lengthening the battery wires over what the mfr supplies. Talking 22 volt systems pulling 100 amps plus DC and switching to 3 phase ac so not a million miles off in alectrickal terms perhaps...


Posted By: Phil B
Date Posted: 09 December 2016 at 9:01am
Ok to answer a few questions...

Bank is charged by solar 99% of the time, we occasionally get a 240v feed into the Inverter / charger which I've limited to a 50 amp ( 24v) max. The solar charging is controlled by a midnite solar classic 150. The max I've seen is 47 amps so the batts aren't getting a huge amount and yes I know they can take 100amps but we haven't that many panels ( yet).

And Al ( hi fella) the midnite allows logging and using the Whizzbang shunt you can see real time system draw ( in fact almost all parameters). So I track SOC using a wifi router and a laptop.

And yep I'm hoping the horse hasn't bolted. I don't think it has, just using Class D amps has flagged something with the inverter. In all honesty I'd love to disable the ripple alarm and shutoff as the inverter can cope with the load fine, it's just an artifact of the way the amps draw that current!
I like the idea of a truck starting 24v batt in line to smooth things out. Not supposed to mix/ match but maybe we pop it in for gigs and charge separately afterwards?

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: carlosdelondres
Date Posted: 09 December 2016 at 9:10am
Won't the different internal resistances of the batteries mean the load is drawn unevenly then?


Posted By: Phil B
Date Posted: 09 December 2016 at 9:14am
Originally posted by carlosdelondres carlosdelondres wrote:

Won't the different internal resistances of the batteries mean the load is drawn unevenly then?

Maybe ? The truck batt might just take out the peaks that the amps are demanding, allowing the dc voltage across the bank to stabilize? 

And just to clarify...this is only when the system is maxxed out .. subs and low mids at -10 on the amps, limited by a multi band compressor. 

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: minaximal
Date Posted: 09 December 2016 at 9:23am
Hey Phil Smile

The Midnight has relay outputs i think doesn't it?

So just disable the inverter low voltage disconnect, (is that possible?) and use the midnight to trigger a big contactor to disconnect batteries at low SOC instead of the crude low voltage. Albright make proper contactors just for the job.

I can't remember how accurate the Whizzbang shunt SOC is, (think they're meant to be fairly accurate tho'?) hopefully it also uses Peukert calculations with a clever algorithm, as shunts logging just amps in and out don't tell the whole picture and go out of snyc.

If you do try adding odd batteries, treat them as expendable, and only connect them into the system for gigs, to make sure both banks get charged seperatley (properly)

The Navitron Forum has quite a few threads about battery mixing, and general consensus is it's a false economy.







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Posted By: carlosdelondres
Date Posted: 09 December 2016 at 9:24am
Maybe? Or drain one battery first until IR equalises, then one battery will try to charge the other depending on which drops more volts due to the peaks? Don't know, but it doesn't sound great for battery life...interested in the answer though!


Posted By: minaximal
Date Posted: 09 December 2016 at 9:27am
Originally posted by Phil B Phil B wrote:

Originally posted by carlosdelondres carlosdelondres wrote:

Won't the different internal resistances of the batteries mean the load is drawn unevenly then?

Maybe ? The truck batt might just take out the peaks that the amps are demanding, allowing the dc voltage across the bank to stabilize? 

And just to clarify...this is only when the system is maxxed out .. subs and low mids at -10 on the amps, limited by a multi band compressor. 

.p.

It's possible the internal resistance of the truck batteries is higher than the Yuasa's and in effect they don't discharge when needed..


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Subs + Barges = :)

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Posted By: valve head777
Date Posted: 09 December 2016 at 3:29pm
What a great thread. Shows how great SP is
I still feel that a high amp charge periodically is good as you want to pull the ions from deep within the plates.
Best of luck for the future dude.

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Freedom of choice, choice of freedom.


Posted By: carlosdelondres
Date Posted: 09 December 2016 at 4:58pm
Yep, deep cycle batteries need to be cycled to bring all the plate material into use. Our batteries sit at float all summer (even pulling 80 amps on the motor cruising all day, plus cooking on electric etc. they recharge in half a day or so on the towpath).

So in Dec/Jan when we're only getting half the power we need from the panels I let them draw down to 50%ish and then try to time the recharge day for a sunny one, only get 40amps of the wee genny so the extra 20 from the panels gives a worthwhile boost and hopefully gets deep enough to fully activate. First winter without a mains hookup though so will see how that goes.  Basically everything you do to lead acid batteries degrades them, trying to balance all the factors against each other and make practical use of them drives you mad...

Interesting read on battery chemistry here:

http://mathscinotes.com/wp-content/uploads/2012/12/lead_acid.pdf" rel="nofollow - http://mathscinotes.com/wp-content/uploads/2012/12/lead_acid.pdf




Posted By: valve head777
Date Posted: 09 December 2016 at 5:28pm
The Exon corporation successfully marketed a crystal making box. The game is to use electric charge to hinder the formation if crystal. Its a totally flawed chemistry if you view a battery as being able to store charge irrespective of charge level. They did this while sitting on technology that if developed would have provided an almost perfect battery which would have a life time of over 50 years.
But profit rules over real advances.

Rant over....

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Freedom of choice, choice of freedom.


Posted By: valve head777
Date Posted: 09 December 2016 at 5:31pm
Im referring to the humble NIFE battery. Also the least poisoning and most eco friendly option.

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Freedom of choice, choice of freedom.


Posted By: Phil B
Date Posted: 10 December 2016 at 8:21am
Originally posted by minaximal minaximal wrote:

Hey Phil Smile

The Midnight has relay outputs i think doesn't it?

So just disable the inverter low voltage disconnect, (is that possible?) and use the midnight to trigger a big contactor to disconnect batteries at low SOC instead of the crude low voltage. Albright make proper contactors just for the job.

I can't remember how accurate the Whizzbang shunt SOC is, (think they're meant to be fairly accurate tho'?) hopefully it also uses Peukert calculations with a clever algorithm, as shunts logging just amps in and out don't tell the whole picture and go out of snyc.

If you do try adding odd batteries, treat them as expendable, and only connect them into the system for gigs, to make sure both banks get charged seperatley (properly)

The Navitron Forum has quite a few threads about battery mixing, and general consensus is it's a false economy.

Hi Al

It's not a low voltage disconnect its a ripple alarm. The inverter has a lot of values to program but I can't find how to disconnect or disable the ripple alarm and shutdown. 

The manual is a delight to read...not !

  http://webbuilder3.asiannet.com/ftp/2249/Combi%203%20Inverter%20Charger.pdf" rel="nofollow - http://webbuilder3.asiannet.com/ftp/2249/Combi%203%20Inverter%20Charger.pdf

As far as I can tell you can't change the constant values. So the alarm is fixed at 1v dc. You can make it a pre-alarm which can go out of an aux relay to trigger something else but can't find how you disable it completely!

E1-17: Udc Ripple Alarm Select (When E1-18=0, ignore this setting) E1-18: Udc Ripple Alarm for ? sec 6-15 z If you want to switch on the Aux-Relay 1 when there is a battery voltage ripple alarm. This setting (E1-17) can be used to choose between pre-alarm or normal alarm. z As with other Aux-Relay 2, setting a delay value (E1-18) must be specified also. This can be done with Delay value for set Aux-Relay 1 ON when battery voltage ripple alarm (E1-18) setting.

Anyway we also are going to double up on our batt link cables just to make sure it's not an overall bank current flow problem. Pretty sure it's not as we have over sized cable all round.

.p.


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Mostly harmless.... except if catering is shut.

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Posted By: minaximal
Date Posted: 10 December 2016 at 1:27pm
Hmm, 

I'm not an electronics engineer, so can only guess, but can ripple be caused by high impedance on the DC bank connectors? So maybe do some resistance checking on the battery terminal connections I.E. could the negative links be at a much higher resistance than positive causing excess ripple.. could just need to get the multimeter out and clean up some terminals.. Or maybe the Inverter is chopping up the DC poorly and it's inherent in design / unable to keep up with the high power peaks at a nice smooth level? 

I'd Guess Capacitors could help, but maybe need to be quite specific.. Carlos(Charlie)? Maybe the Amp forum guys?




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Posted By: carlosdelondres
Date Posted: 10 December 2016 at 7:42pm
Don't know, details are definitely beyond  :). Based on the ESC analogy the issue could be helped by shorter cables between battery and inverter, with pos and neg runs as close as possible (thicker won't help, it's an inductance issue).  On the caps solution, voltage peaks could potentially go past the battery voltage so multiple overrated, low ESR caps, close as possible to the inverter... 

if the issue is the load the amps are presenting rather than something in the system being under spec for the job is there anything that could be done on that side of things to help? Perhaps a larger amp with more capacitance in the power supply, run at the same output level, would present an easier load for the inverter?


Posted By: valve head777
Date Posted: 10 December 2016 at 9:46pm
It really dosnt sound like a cable site issue . You would have figured that already via warm links etc.

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Freedom of choice, choice of freedom.


Posted By: valve head777
Date Posted: 10 December 2016 at 9:48pm
Remember the song, i know an old lady who swallowed a fly?

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Freedom of choice, choice of freedom.


Posted By: Phil B
Date Posted: 11 December 2016 at 6:25am
Originally posted by carlosdelondres carlosdelondres wrote:

Maybe? Or drain one battery first until IR equalises, then one battery will try to charge the other depending on which drops more volts due to the peaks? Don't know, but it doesn't sound great for battery life...interested in the answer though!

Yep thanks you lot for all the suggestions. So I think our plan is

a) A deep discharge and then flat out charge. The Inverter / charger can do up to 10 amps 240v input so I reckon we'll disconnect the solar and let that do a full on charge.

b) double up batt link cables to reduce resistance around the bank. At the moment the inverter leads are about 1m & 1.5m for Neg and Posi sides. But it is super thick AWG 0 (55mm2) welding cable ! I could double up on that as well but would be tricky at inverter stud end for room.

c) Prob buy a cheapo truck batt 24v and put inline. This I'm prob gonna do anyway for the next gig as we will be running all 4 of our 15" SS15 subs plus 2 x new keystone subs with B&C SW115-4's !! So a lot more sub demand. I have a feeling that it can't hurt the bank and it'll either work or it won't, not that fussed about buying a s/hand single batt.

d) Try get an answer from the inverter manufacturers of how to disable the ripple alarm / cut-off. Maybe also re-flash the firmware to make sure it's not a glitch.

e) disable the equalise function in the Midnite controller.

.p.




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Mostly harmless.... except if catering is shut.

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Posted By: valve head777
Date Posted: 11 December 2016 at 6:07pm
Cable size issue not site issue.
Welding cable is quite happy at 2-300 amp, and is expensive. Really do not think its that which is your issue. Try to stuff as many amps it
into your bank as you can initialy too. Maybe combine 240v inverter charge with your panels.. Also consider splitting the bank to 12v blocks, or if you can 6v blocks as you can compare which cells takemore/less time to charge. It seems like an expensive punt on copper to see if that makes a difference.

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Freedom of choice, choice of freedom.


Posted By: Phil B
Date Posted: 12 December 2016 at 10:30am
Originally posted by valve head777 valve head777 wrote:

Cable size issue not site issue.
Welding cable is quite happy at 2-300 amp, and is expensive. Really do not think its that which is your issue. Try to stuff as many amps it
into your bank as you can initialy too. Maybe combine 240v inverter charge with your panels.. Also consider splitting the bank to 12v blocks, or if you can 6v blocks as you can compare which cells takemore/less time to charge. It seems like an expensive punt on copper to see if that makes a difference.

Already have spare welding cable and loads of spare batt links so not an expensive option...just time consuming ! Smile

.p.


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Mostly harmless.... except if catering is shut.

Solar Sound System Shennanigans.. http://diyhifi.biz/" rel="nofollow - http://diyhifi.biz/


Posted By: valve head777
Date Posted: 12 December 2016 at 2:08pm
Cool man, let us know the outcome

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Freedom of choice, choice of freedom.


Posted By: Greg32
Date Posted: 13 December 2016 at 11:41am
Hi Phil, i would consider some low esr capacitors (the type used in smps etc) to help with the way your inverter draws power, if you have long leads to the inverter this may make the problem worse. if your inverter uses pwm in the sine wave converter it could run at 25khz or more for effieciency, that means your inverter will be drawing power at the same frequency and that gets problematic with long cables(high impeadence/inductance) regardless of their dc ability. just a thought Greg.
would love to see your rig it sounds well thought out.



Posted By: Phil B
Date Posted: 06 January 2017 at 11:26am
Well I did all the changes that I could...doubled up all the battery links, put in a 500amp isolator ( with the thick welding cable and proper 70mm lugs). And we set up for New Years Day gig.....

Well all I can say is that we now know the limit of the inverter and the system ! With our new Keystone subs ( B&C 18SW115 loaded) it would trip the inverter on about 3/4 volume. Seems the demand from the class D amps is very exponential. Chugging along at half volume we draw 7-11 amps @ 240 but turn it up very slightly and we saw peaks of 15-22amps which then overloads the inverter!

So in the end I don't know if we solved the ripple problem but now have an overall power problem We could run a second inverter for the keystone subs but we would be trying to pull 150-220 amps out of the bank continuously. Max input from the panels is 40-45 amps with direct full sun so we would be playing catch up all the time.

I think we will have to compromise with either SS15's or Keystones subs for stand alone events and ask for extra power if the whole system is needed. I have an idea about a hydrogen powered small genny ..but that's another whole can of worms !

.p.


-------------
Mostly harmless.... except if catering is shut.

Solar Sound System Shennanigans.. http://diyhifi.biz/" rel="nofollow - http://diyhifi.biz/


Posted By: Mark James
Date Posted: 06 January 2017 at 11:41am
weve also been looking into hydrogene fueling a genny [well atm just getting "A" engine to try run on it as an experiment before modifying a useful genny]
let us know how you get on as i would be very interested in this.


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: Phil B
Date Posted: 06 January 2017 at 11:50am
Originally posted by Mark James Mark James wrote:

weve also been looking into hydrogene fueling a genny [well atm just getting "A" engine to try run on it as an experiment before modifying a useful genny]
let us know how you get on as i would be very interested in this.

There's a mob here in Melb who are doing it on a regular basis, I'm gonna go pick their brains when I get a chance !

.p.


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Mostly harmless.... except if catering is shut.

Solar Sound System Shennanigans.. http://diyhifi.biz/" rel="nofollow - http://diyhifi.biz/


Posted By: minaximal
Date Posted: 07 January 2017 at 12:59pm
Solar panels are (relatively) cheap and don't explode or make lots of noise.. AFAIU Hydrogen extraction is still not very efficient or 'Eco'

More panels, bigger inverter, bigger Li Battery bank = More bass fun .. maybe less $$ though..

Hope NYE was fun though, got any pics?


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Subs + Barges = :)

http://www.metaacoustics.com" rel="nofollow - www.metaacoustics.com



Posted By: valve head777
Date Posted: 09 January 2017 at 5:01pm
Perhaps one vision of the future is using pv to extract hydrogen from water. Using an infernal combustion engine seems perverse tho. New polymer technology should make fuel cell technology progress...

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Freedom of choice, choice of freedom.



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