Can dead batteries break a charger?

islandguy

The setup is ten golf cart batteries in five twelve volt banks. For a little over three years now they have been in place and working. Over the last six months the reserve capacity has been dropping to almost nothing,

At this point they are dead, being run down to close to ten volts overnight and so on. House load is less than 300 watts at use times and under 50 watts at off use times.

The first charger to go was a powermax 100 amp charger. the 6000 watt inverter charger has also developed problems.

Last night I wired in a smaller powermax forty-five amp charger and within five minutes it lit up, smoked sparked and died.

Any ideas on what is going wrong?

Thanks!

Blackcherry04

Re: Can dead batteries break a charger?

islandguy wrote: »

The setup is ten golf cart batteries in five twelve volt banks. For a little over three years now they have been in place and working. Over the last six months the reserve capacity has been dropping to almost nothing,

At this point they are dead, being run down to close to ten volts overnight and so on. House load is less than 300 watts at use times and under 50 watts at off use times.

The first charger to go was a powermax 100 amp charger. the 6000 watt inverter charger has also developed problems.

Last night I wired in a smaller powermax forty-five amp charger and within five minutes it lit up, smoked sparked and died.

Any ideas on what is going wrong?

Thanks!

A guess would be that your batteries are sulfated and are in need of the ability to Equalize them, if they are not to far gone already. The guy at Power Max seems to be a nice guy, e-mail him and maybe he'll send a new charger. The Power Max charger is well, not all that dependable. Try to work some kind of exchange.

If you ever get those batteries back up or a new set a Hydrometer would be a good thing to own, otherwise your guessing in the dark.

vtmaps

Re: Can dead batteries break a charger?

Welcome to the forum.

Part of the problem is that you have too many batteries in parallel.
read: http://forum.solar-electric.com/showthread.php?14674

You need to disassemble the bank and test one string at a time. Look for resting voltage and specific gravity. Try charging one string at a time.

When one cell goes bad, at first it is masked by the parallel strings. Then it pulls down the whole bank. Probably after charging the bank you had some strings discharging into other strings.

--vtMaps

Blackcherry04

Re: Can dead batteries break a charger?

The problem is a battery is made up of cells, any one cell goes bad your out of luck, it doesn't matter if the are in parallel or series.

islandguy

Re: Can dead batteries break a charger?

OK,
Thanks for the input about the banks. I do have them wired up so as to reduce the impedance. I'm still learning so I'll look into ways of reducing this type on install.

My real concern here is the equipment frying. I have a house ground and the bonding is tied into copper water pipes. The chargers are all case grounded as well as the ground prong. The Generator is at 119v and seems fine for output. The Powermax charger on the other battery bank is holding up fine so far.

This setup has been running ok for about a year now. The only thing that has changed is the condition of the batteries. That's why I am curious if dead or shorted batteries can fry the chargers and Inverters.

Thanks again!

vtmaps

Re: Can dead batteries break a charger?

islandguy wrote: »

That's why I am curious if dead or shorted batteries can fry the chargers and Inverters.

A high quality inverter or charger should not be damaged.

As battery voltage goes down the inverter will pull more amps, in an attempt to maintain power (amps X volts). Inverters usually have circuitry or over current protection to protect themselves from overly high current caused by low battery voltage. Perhaps your inverter's protection was not adequate. As for the charger, same thing, it must be designed to protect itself from low voltage.

--vtMaps

icarus

Re: Can dead batteries break a charger?

It is possible you have an AC/DC ground loop. I am no expert here on that subject, but I know that lots of things don't play well together with mixed AC/DC. Please describe in detail the battery, charger and load circuits and thier grounds and some one with way enter experience can chime in.

Tony

niel

Re: Can dead batteries break a charger?

tony,
it's possible he has the ac wired wrong all together. you are right that he needs to give specifics to try and nail down the potential problem(s).

islandguy

Re: Can dead batteries break a charger?

@niel thanks.

The system is overly complicated because of the reliance on generators.

There are two battery banks, one for house usage and one for the well pump.

The well bank has its own charger, PM3-55, and an inverter/charger from china delivering 220v 50Hz for the well pump. This set up is running fine.

The house has the ten Golf cart batteries in 5 12v banks. Wired to decrease impedance, +12v goes in the near side and -12v comes out the far side.

The first charging setup is when the diesel generator is running, this puts the Royal Power PIC6000 into charger mode and runs the house off the Generator. The well bank is charged by the PM3-55 at this point. The idea here was on days of running washing machines, gas dryer, vacuum cleaners etc. the diesel would handle the load and charge the batteries.

The second charging set-up is a small 2000w All Power America generator that just powers a smaller battery charger PM3-45, and the Chinese charger/inverter for the water bank. This load is kept below 900 watts. These are powered by what is essentially a hard wired extension cord with a ground at the Generator end and a ground into the house ground at the receptacle where the two are plugged in.

The original off-grid setup is over twenty years old and was allowed to deteriorate. The structures are a house and a barn, all off grid. There are a few people involved in this.

Everything is wired for 120v, SquareD panels etc.

The actual wiring for the house use and charging batteries is being upgraded. Currently there is a 5’ run of probably 00 cables from the 12v posts to the inverter. The inverter then supplies 120v to two panels, one is live all of the time and the other is live only when the diesel runs.

There is a house ground and a water pipe bond.

The chassis ground goes to the bonded part of the system.

The only other clue I have is that both the PM3-100 and the PM3-45 shocked me when I disconnected the chassis ground. The 12v was bleeding through to the metal outer case. Wiring looked good.

My background is in IT and currently working home Automation & AV projects. I’m looking forward to nailing the nuts and bolts of this system so I can start working on automating the systems and some custom software.

Cariboocoot

Re: Can dead batteries break a charger?

If there is proper over current protection in place even a dead short will not damage a good charger.

However, if you load one up too much so that its thermal cut-out trips (if provided) and then do it again and again and again ... that charge will eventually be damaged. Current = heat, heat = early failure of some component.

It sounds as though there may be more than one thing wrong with this system, starting with the multiple parallel batteries. The 'diagonal' wiring doesn't help much beyond two parallel strings.

12 VDC will not give you a shock. 120 VAC will.

The inverter then supplies 120v to two panels, one is live all of the time and the other is live only when the diesel runs.

That is a contradiction. If the inverter supplies 120 VAC to two panels, then both are live whenever the inverter is on. Perhaps you mean only one is active if the generator is running? Or only one panel switches to gen power?

You also mention having 220 VAC 50 Hz for the well pump. This is not compatible with 120 VAC, which is probably 60 Hz. As such the two systems should be entirely separate.

I'm afraid it's "disconnect and inspect" time. You need to:

1). separate all the batteries, charge and test (with hydrometer) each one individually to see which, if any, are still good.

2). isolate all AC feeds and loads. Consider each generator and inverter as a separate power source and be sure no two are ever feeding AC to the same load circuit at any time.

3). draw a schematic for DC, and another for AC. It may require more than one. You need to look at each power to load(s) circuit separately, and study carefully any point where they seem to interact including grounds.

islandguy

Re: Can dead batteries break a charger?

@cariboocoot
Thanks!

You are correct that the two systems are totally separate. The batteries for the well pump set-up are charged by different chargers. The batteries are also separate from the house bank. This design is simply to supply 220v to the well pump.

The panels in the house are also separate. With the Inverter supplying constant power to one load center. When the diesel runs it supplies power to the second load center with the inverter still supplying power to the first panel. At this point the inverter is in Charge mode and I assume running all house demand from the diesel.

The current Battery bank being replaced over the next couple of days. after three years I doubt any of them are worth trying to save.

Will draw up schematics. I am pretty sure that the only place there is any interaction is the ground. Will this cause a problem?

The latest charger to go was a PM3-45. It lasted less than five minutes. So there is something seriously wrong.

I haven't checked the Hz coming from the Generator, just the voltage. I should probably check that this evening.

thanks for the help!

Cariboocoot

Re: Can dead batteries break a charger?

A ground connection alone between two AC or even an AC and a DC system will not cause any problems.

However you might have an issue if there is also a neutral connection with N-G bond in the wrong place or more than one place.

But it sounds like the battery chargers are frying as a result of incorrect power input. Standard generators can vary quite a bit in RPM, and that will change frequency and Voltage of their output.

Whenever you come up against a problem like this you have to "strip back" to the power source, whether grid or generator or batteries, and check that it is within specs before examining anything else in the circuit.

islandguy

Re: Can dead batteries break a charger?

Cariboocoot wrote: »

However you might have an issue if there is also a neutral connection with N-G bond in the wrong place or more than one place.

As I rewire the buildings I am separating N/G wires.

The old load center, used to power the house from the inverter/charger, has neutral and ground wires combined.

Cariboocoot

Re: Can dead batteries break a charger?

islandguy wrote: »

As I rewire the buildings I am separating N/G wires.

The old load center, used to power the house from the inverter/charger, has neutral and ground wires combined.

There probably should be a connection between neutral and ground, but only one and only in the right place.

So check whether the generator(s) have N-G built in, and check the inverter as well. Usually an MSW type inverter should NOT have an N-G bond whereas a pure sine inverter can have one.

Typically you'd have this N-G bond and Earth ground connection in the main service panel. Since you have two panels there could be confusion on the configuration. The neutral and ground may be common throughout, especially if this is 120 VAC only. If the gen and/or inverter or loads have 240 VAC ability it can get even more complicated. I can envision a mix up causing 240 VAC going to your battery charger which would fry it in short order if it is designed to run on 120 VAC.

islandguy

Re: Can dead batteries break a charger?

The generators have Neutral, ground and a chassis ground. Not really sure if the chassis is technically a ground or a bond.

At some point I was going to post some questions on Grounding, bonding and lightning protection. Not a small topic from what I gather.

This setup has, a cinderblock generator shed with a ground rod, House with two mains and a ground rod, and a barn with a single mains and a ground rod.

I've been following the black and decker books on wiring.

The 220v set up is isolated from the rest of the electrical completely. I have a three wire plug into the Inverter that bypasses the pressure switch and supplies current directly to the well. the on=off switch on the inverter is wired into a 12v relay which is triggered by the pressure switch.

Since I wasn't sure if the generator load center was technically a sub-panel I wired it to the ground. With ground and neutral separate, on different bus bars.

My intention is to ground each power source, and mains at the local ground. There is however some confusion if multiple grounds, gen shed, house and barn, can cause lightning problems or other grounding issues.

In addition to testing the Hz tonight I'll see if I can detect any current off the neutral wires. My understanding of 120v is that there should be no, or minimal current, off the N wire.

Thanks again for the assistance.

Cariboocoot

Re: Can dead batteries break a charger?

islandguy wrote: »

The generators have Neutral, ground and a chassis ground. Not really sure if the chassis is technically a ground or a bond.

This is normal. The issue is whether it has its AC output ground bonded to the AC output neutral.

At some point I was going to post some questions on Grounding, bonding and lightning protection. Not a small topic from what I gather.

The understatement of the year.

This setup has, a cinderblock generator shed with a ground rod, House with two mains and a ground rod, and a barn with a single mains and a ground rod.

Right there is an issue: two ground rods at two different locations. There should be one, or the two rods need to be bonded subterranean, or there must be a long enough distance between them (debatable how much - depends on soil conditions) that there is no other conduction between the rods. Really difficult thing to work out.

The 220v set up is isolated from the rest of the electrical completely. I have a three wire plug into the Inverter that bypasses the pressure switch and supplies current directly to the well. the on=off switch on the inverter is wired into a 12v relay which is triggered by the pressure switch.

You use one pressure switch to trigger either 220 VAC or 12 VDC? I can see where there could be a problem there as you have to break both sides of the switch and you need a switch that can handle both currents @ operating Voltages.

Since I wasn't sure if the generator load center was technically a sub-panel I wired it to the ground. With ground and neutral separate, on different bus bars.

Most of the time that will be the correct way to go. Usually neutral and ground are "pass through" wiring between main and sub panels, with the N-G bond and Earth ground connection in the main only. Having an N-G bond built in to the generator or having an MSW type inverter or having GFCI on either AC source can change this.

My intention is to ground each power source, and mains at the local ground. There is however some confusion if multiple grounds, gen shed, house and barn, can cause lightning problems or other grounding issues.

You are looking at electrical safety ground wiring. Do not confuse with lightning protection. Map out one function at a time.

In addition to testing the Hz tonight I'll see if I can detect any current off the neutral wires. My understanding of 120v is that there should be no, or minimal current, off the N wire.

No, neutral on 120 VAC has the same current as hot. Ground has zero current. With 240 VAC the current is between L1 and L2 with no current on neutral. Make sure you don't get the Voltages and wiring terminology confused! It's too easy to do!

islandguy

Re: Can dead batteries break a charger?

Very helpful.

First, the generator was cycling between 119 and 220 Hz or so. So i,'m guessing that's the culprit. Voltage was steady but the Hz was all over the place.

The water pump has a 12v powered relay. It is in Normally Open configuration. When the well pressure switch trips the 12v side of the relay gets power and puts it into a closed state that turns on the 220v inverter.

Thanks again, very informative site.

Cariboocoot

Re: Can dead batteries break a charger?

islandguy wrote: »

First, the generator was cycling between 119 and 220 Hz or so. So i,'m guessing that's the culprit. Voltage was steady but the Hz was all over the place.

Gaa? I don't know how that would even be possible. It's 2X+ normal frequency. What sort of generator is this? Usually a fixed RPM generator would be pretty dead-on frequency +/- maybe 10%. If this is an inverter-generator it's obviously fried. If it has an electronic Voltage regulator it's probably fried too. Are you sure about those frequency readings? Completely out of whack!

islandguy

Re: Can dead batteries break a charger?

Wen 3500
I tested the meter at work in an outlet, 59.9 hz off the PIC6000 inverter it was around 59

Off the Wen it was going crazy. I tested a few times because i didn't believe it either. I'll Check again in the morning before I call wen.

Edited to add voltage was a steady 119v

BB.

Re: Can dead batteries break a charger?

Some Generators have very poor sine wave output (may look OK with light loads, and have several peaks with heavy loads, etc.)... If the sine wave has multiple voltage peaks, the Kill-a-Watt may not count accurately. Here is a website with some pictures of various less than good sine wave output from generators:

http://www.screenlightandgrip.com/html/emailnewsletter_generators_ext.html

The generator output frequency should be a function of the engine RPM (typically 3,000 RPM for 50 Hz and 3,600 RPM for 60 Hz on light weight/portable gensets). I doubt that your generator is out of RPM spec. by 2-3x times.

-Bill

Cariboocoot

Re: Can dead batteries break a charger?

BB. wrote: »

Some Generators have very poor sine wave output (may look OK with light loads, and have several peaks with heavy loads, etc.)... If the sine wave has multiple voltage peaks, the Kill-a-Watt may not count accurately. Here is a website with some pictures of various less than good sine wave output from generators:

http://www.screenlightandgrip.com/html/emailnewsletter_generators_ext.html

The generator output frequency should be a function of the engine RPM (typically 3,000 RPM for 50 Hz and 3,600 RPM for 60 Hz on light weight/portable gensets). I doubt that your generator is out of RPM spec. by 2-3x times.

-Bill

You know Bill, they'd really have to work hard to make a generator so bad its frequency was 2X normal. But I don't doubt they could do it.

islandguy

Re: Can dead batteries break a charger?

Well, Checked again this morning. Engine RPMs were cycling and the Hz were cycling up to over 200.

Took the same meter and checked the output from the PIC6000, results were 59.2

Checked the Xantrex and the Hz was 59.9

The meter is a true RMS meter. A no name but up to now it's been believable.

The Generator is a WEN 3500 that has been allowed to run down on oil till the low oil shutdown kicked in. .

Cariboocoot

Re: Can dead batteries break a charger?

Mechanical flaw in the gen wouldn't do it: if the engine runs it will run at the correct speed more or less and so the gen head should output the correct Voltage and frequency. I'd hazard a guess that the thing has electronic controls that have gone haywire* allowing the output to be whatever happens instead of regulating it.

Sounds like new generator time.

*Trivia time! The term "haywire" meaning something going wrong originates from farming, where bales of hay were sometimes fastened with twine and sometimes with wire. To get at the hay, the twine/wire had to be cut. The twine would just go limp, but the wire under the tension of the bale would spring open with a "twang" and often go in an unpredictable direction (like into the farmer's face). Hence: go haywire meaning to do something other than what is desired.

islandguy

Re: Can dead batteries break a charger?

Ordered a new Wen last night when I got that reading. Additionally I have digital voltage and digital Hz meters that I was planning to mount on the wall for each generator.

Might need to change the priority on that project.

Called Wen a couple of times and the guy there was as surprised as everyone else. He couldn't think of anything that would cause those kinds of results. He was going to contact the Chinese Engineers and see if they had any ideas.

Since I have damaged three pieces of hardware, inverter and two chargers, my goal now is to prevent this from happening again.

@BB thanks for the link on generators. Very informative. Thanks for all the input!

solar_dave

Re: Can dead batteries break a charger?

Cariboocoot wrote: »

*Trivia time! The term "haywire" meaning something going wrong originates from farming, where bales of hay were sometimes fastened with twine and sometimes with wire. To get at the hay, the twine/wire had to be cut. The twine would just go limp, but the wire under the tension of the bale would spring open with a "twang" and often go in an unpredictable direction (like into the farmer's face). Hence: go haywire meaning to do something other than what is desired.

Just like those slot machines with the same name, something always goes wrong, they take my money.

BB.

Re: Can dead batteries break a charger?

You may also have a fault in the wiring/alternator windings/etc... If you plug in an electric lamp, a induction motor, etc... Does the line voltage remain stable at ~120 VAC, does the light/motor work OK, etc.?

There is no way that a 3,600 RPM genset running at (x 200 Hz / 60 Hz 12,000 RPM would sound "normal". If anything, you would be running away for your life with wife/kids/pets.

There is something wrong with the AC wave form (checking frequency with no load vs loaded may also affect the wave forms and give you a more stable frequency reading).

A broken neutral connection can cause 120 VAC appliances to see anywhere from 0-240 VAC -- Depending on what loads on the other 120 VAC circuit (think center tapped transformer--If you don't have a neutral connection to the 120 VAC loads, then the loads are in series connected to 240 VAC and that, usually, the appliance with the heavier current draw will tend towards zero volts while the smaller appliance/load will tend towards 240 VAC).

Measuring 120 VAC frequency with an open neutral will be iffy. If you have a 240 VAC reading DMM with a frequency counter, you might try checking the 240 VAC frequency (should be stable 60 Hz even with a bad neutral).

-Bill

Cariboocoot

Re: Can dead batteries break a charger?

In theory you should be able to put a 100 Watt incandescent bulb on the 120 VAC output and stabilize the gen for accurate frequency and Voltage readings. The wild frequency should have no effect on a resistive load.

I suspect there is a short in the windings that is causing them to behave like "double windings" and the AVR (if it has one) is trying to compensate, making it put out the right Voltage at ridiculous frequencies. To say this would be hard on the wiring would be an understatement, and eventually the whole thing will fry.

In short form, it's hooped.

mike95490

BB. said:

Re: Can dead batteries break a charger?

Some Generators have very poor sine wave output (may look OK with light loads, and have several peaks with heavy loads, etc.)... If the sine wave has multiple voltage peaks, the Kill-a-Watt may not count accurately. Here is a website with some pictures of various less than good sine wave output from generators:

http://www.screenlightandgrip.com/html/emailnewsletter_generators_ext.html

The generator output frequency should be a function of the engine RPM (typically 3,000 RPM for 50 Hz and 3,600 RPM for 60 Hz on light weight/portable gensets). I doubt that your generator is out of RPM spec. by 2-3x times.

-Bill

The lighting & grip website has been revamped, but I found the generator page.  It's basically talking about cheap inverter generators having square and mod sine output, and that even PSW inverter and conventional generators, seeing strangely reactive loads instead of "old style" restive loads, are unable to provide sine waves and the loading distorts the waveform (much as I have experienced with my new small robin/subaru/hatz genset)  it's very interesting and should be required reading.
http://www.screenlightandgrip.com/html/emailnewsletter_generators.html#anchorSquare Wave Generators