A shot in the dark. Lame batteries.

System · January 2008

Hey, hi. This is clumsy, by way of an introduction -- but I was shopping here for stuff to solve my current crisis, noticed there was a forum, and thought why not give it a shot. I'm not going to puke out an exhaustive list of all my system's parameters and stuff, the way I probably ought, because I just don't have time right now.

This is the gloomy part of the year here in Minnesota, when one has got themselves stuck with a solar powered house. So I'm used to having to fire up the generator often during this part of the winter over the last 15 years or so we've lived this way.

But this winter has been worse, and seemingly without adding a whole lot more power use. First, I replaced the 7-year-old set (4, set up for 12V) of Trojan L16-H's that were starting to need lots more charging than they deserved. I got the equivalent (?) Interstate batteries only because I was in a hurry and there was a place in Fargo where I could buy them and bring them home the same day.

I hooked them up the same way the old ones were. From the very beginning, I've been disappointed with performance. I've never had fancy metering or monitoring equipment/techniques, so I have to go sort of by "feel," mostly just watching the voltage. It seems they just drop too much overnight. Much more than they ought to, much more than I'm used to, with the little bit of use before bed and the minimal overnight loads.

Does anybody know a straight-out reason why a battery that's seeming fully charged at 10PM, would show 12.3, even down to 11.9 volts, come 7AM? Without, you know, falling asleep with the TV on? ;-)
I assumed the performance across different brands would be similar, on account of physics.

They might just be defective in some way, see -- and the warranty is getting older. I don't want to haul all 500 pounds of them back to Fargo in our little Subaru and find out what's wrong is something at my end. They seem to charge right up when I shoot the generator at them -- it's just that they show such a horrifyingly low voltage come morning. I wouldn't be fussing, except that it seems so different from what I got used to.

My current thinking is to hook up a proper disconnect and shunt, that everything has to pass through (currently I have separate wiring and metering for the inverter and the 12V loads) which I never did when I started out sloppily doing this, so I can do things like switch back to a pair of my old batteries for the night and see how the new ones fare after being totally off-line overnight. Also, I can measure absolutely the current going out, to make sure something else hasn't gone wonky at the same time just on account of pure Murphy.

Thanks for anybody who shows interest.

rplarry · January 2008

Re: A shot in the dark. Lame batteries.

David
It sounds like you have been off grid for quite awhile, so you probably know what your batteries should do and they are not doing it. I would find, borrow, or somehow commandeer a battery load tester and test each battery indvidually. You can also use a hydrometer but that usually just shows state of charge, a load tester will show you each batteries ability to sustain a load. Good luck with them.
Larry

westbranch · January 2008

Re: A shot in the dark. Lame batteries.

have you ever 'equalized the batteries? what is the SG on each cell after charge and in the morning before use?
there are a number of things that could be going on here.
I think you are also on the right track by investigating a phantom load/ short but the above questions will give the board more info to work on your problem..

cheers

Eric

BB. · January 2008

Re: A shot in the dark. Lame batteries.

I too don't have any magic answer... I would do the standard of using a good DVM (calibrated) and check the voltage of each battery (at the posts) and checking voltage drop of cabling/connections (when under load--charging or discharging). Looking for bad/open connections. If you have sense leads (remote wires for battery charger used to accurately measure battery voltage), make sure they are properly connected. Also, if you have a battery temperature sensor--check it (cold batteries require higher charging voltages).

Also check the temperature corrected charging voltage at the batteries (should probably be around 14.5 to 15.5 volts maximum).

And use a temperature corrected hydrometer to check your specific gravity (confirm batteries are fully charged, and find out how discharged they are in the morning). Normally, you would only check one cell per battery--but you should check all cells at least once to make sure that there are no shorted cells/other issues that may indicate you have a bad battery in your bank.

Lastly (only because they are not cheap), a good battery monitor to accurately measure how much current you pump in/remove. Short of constantly measuring your specific gravity to get a snap shot of your bank's current state of charge, a battery monitor will keep track of the bank's state of charge and if your nightly loads have somehow been getting larger over the years (more loads, appliance problem, something left on, etc.). As you know (you have much more solar experience than I), measuring battery voltage under load/charge is not a good way of estimating the battery's current state of charge.

-Bill

crewzer · January 2008

Re: A shot in the dark. Lame batteries.

David,

We could use some additional info about your battery charging protocol and related information:

1) What’s the generator brand, model and size?
2) What’s the charger brand, model and size?
3) Assuming you’re using a 4-stage charger (bulk, absorb, float, EQ), that’s the target absorption voltage?
4) How long is the battery bank held at the target absorption voltage?
5) What’s the battery equalization voltage and schedule?
6) Are your batteries cold, and are you using temperature compensation?
7) Are you familiar with Trojan’s on-line battery maintenance manual? See: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx
8 ) Are your batteries connected correctly? Check the “Connections Diagram” in the following link and verify that your batteries are connected per the right-hand diagram. The “diagonally” opposite connections for the main (+) and (-) cables in important. See: http://www.trojanbattery.com/Tech-Support/TechnologyLibrary.aspx
9) Here’s a link to Interstate’s charging instructions (such as they are): http://www.batteries-faq.com/activekb/questions.php?questionid=33

HTH, and more later,
Jim / crewzer

niel · January 2008

Re: A shot in the dark. Lame batteries.

i agree to seperate and test all batteries here. if you have more bad batteries then they could drag down the good ones to their level of bad. barring a small phantom load, what you describe is battery failure or exhausted batteries. when you find a few bad batteries in a bunch you have to keep in mind the rest is questionable and even if shown to be good, the lifespan is apt to be soon over on them and can happen at any time. it may have been a mistake putting those new batteries inline with the old if you failed to detect all of the failed batteries or those with much reduced capacity that are soon to fail. hopefully you have caught it in time so as to reduce the damages to the new batteries, but in any case it sounds as if the whole bank may have been needing replaced.

System2 · January 2008

Re: A shot in the dark. Lame batteries.

Wow. That's a bunch of replies in a hurry. Thanks for your thoughts, folks. And my-- what a lot of questions too. Whew!

Let's see...

Larry: I too was wondering about a load tester. My guess is that's what they'd do to check them if I hauled them back to the store. Any idea what sort of defect or damage would make the battery seem to take a charge, show a good state of charge -- but just have radically lower capacity?

Eric: Equalizing? Yes, all the time. I've never messed with measuring SG before, but I have a hydrometer and I'll try to force myself to do that measuring sometime this weekend.

Bill: good tip about testing for voltage drop across the connections - that's not something I'd have thought of. And yes, I've long dreamed of having a good battery monitor. ;-) Perhaps I'll finally be allowed to get one out of this problem. I do realize that voltage isn't the best state-of-charge indicator... but when everything's been working fine it has served well enough.

Jim ("crewzer"): I realize it's kind of tricky to track down a problem like this without a clear idea of what the system looks like. I was really looking for general "what might do this to a battery?" sort of thoughts--mostly hoping this particular problem sounded familiar to somebody, really. Or a few specific things to check -- rather than this long list of guesses I've been nursing.

I don't see how the make and model of the generator would be relevant, and I'm not familiar with the term "target absorption voltage." The charger is a Heart Interface Freedom 20 inverter, and its bulk charge phase tops out at 14.4V, which I think it does for like maybe 3 hours, and then floats at something like 13.5. It's fed by a 5kW NorthStar gas generator. Batteries are near room temperature, and there's no control over that anyway, beyond a DIP switch voltage setting for "warm/cold." Equalizing I pretty much do casually, on the fly, whenever I think it's been a while, or whenever they've been operated kind of chronically low for a while. I'm not a particularly rigorous solar power guy.;)

The main thing, really, is that the system is set up the same as how it's been working well (well, okay) for many years - only with new batteries. And I just can't decide whether this is normal January combined with somewhat higher consumption, or if I have an actual complaint here. I feel like I'm being punished for not sticking with Trojan.;)

Thanks for the links to the instruction manual -- I'll keep the bookmark handy, but yes that's how I've had them hooked up.

And lastly, "NIEL-N3GHX": I may have been unclear. I totally replaced the set of 4 L-16's with 4 new ones. What I mean is, I still have the healthier pair of the old Trojans sitting around, and my plan is to temporarily hook them back in with the 2-bank switch so I can still have power while I experiment.

By the way, can anybody tell me what limits the wire size to 4/0 on this switch? http://store.solar-electric.com/basw1300amp.html
I'm assuming it's just a matter of how far it stands off from the mounting surface, but I can't find a picture of the back of the thing. I was guessing I could get a fatter wire back there by using some spacers.
Oh, wait - are the "#x/0" sizes backwards from regular AWG? Is #4/0 bigger than #2/0? I forgot.

Holy cow, that got to be a long post. Sorry. Thanks for the interest, guys.
David

System2 · January 2008

Re: A shot in the dark. Lame batteries.

Ha-ha. I just realized that I totally forgot to mention any information about the PV side of things. That's a measure of just how irrelevant it is this time of year in Minnesota. ;-)

niel · January 2008

Re: A shot in the dark. Lame batteries.

to quote you:
"And lastly, "NIEL-N3GHX": I may have been unclear. I totally replaced the set of 4 L-16's with 4 new ones. What I mean is, I still have the healthier pair of the old Trojans sitting around, and my plan is to temporarily hook them back in with the 2-bank switch so I can still have power while I experiment.

By the way, can anybody tell me what limits the wire size to 4/0 on this switch? http://store.solar-electric.com/basw1300amp.html
I'm assuming it's just a matter of how far it stands off from the mounting surface, but I can't find a picture of the back of the thing. I was guessing I could get a fatter wire back there by using some spacers.
Oh, wait - are the "#x/0" sizes backwards from regular AWG? Is #4/0 bigger than #2/0? I forgot."

david,
yes, i guess i should've read it more closely and now i understand that you replaced them all. the basics of what i said still holds true as it still sounds like battery failure if you find no other causes like a small short or load still on. it is not impossible to have a battery go on you even if new and that battery could drag down the rest of them so individual battery testing is vital. i am of course assuming they are getting their proper charges as you had indicated.
as to your question a #4/0 is a very large wire and is larger than a #2/0. don't confuse them with #4 or #2 as it goes generally like this:
#4, #2, #0, #2/0 or 00, and #4/0 or 0000. there are sizes between them, but these are more common and that order was small to large wire diameters.

crewzer · January 2008

Re: A shot in the dark. Lame batteries.

David,

OK; here are some assessments, comments, and suggestions:

Equalizing? Yes, all the time.

Equalizing I pretty much do casually, on the fly, whenever I think it's been a while, or whenever they've been operated kind of chronically low for a while.

These comments seem a bit contradictory to me.

I don't see how the make and model of the generator would be relevant…

OK. I won’t disturb you any further on this matter.

“Target absorption voltage” is the voltage at which the bulk charge stage “tops out” and the charger switches to absorb stage. Interstate’s target absorption voltage value for their deep-cycle batteries appears to be 15.5 V for two- to four hours (assumed at 77 F). Trojan’s value is 14.8 V (at 80 F). Based on research done at Sandia Labs, Morningstar uses 15.0 V (ref 77 F) for their TriStar controller’s special L-16 battery setting. EQ voltage recommendations from all three sources fall in the range of 15.3 V to 15.6 V, with suggested (inferred) time periods ranging from two- to three hours.

I’m unable to locate a Heart Interface Freedom 20 inverter/charger manual on-line. Manuals for similar products (i.e., Marine Freedom 20, and Freedom 458 20-12) suggest the absorb voltage setting wet-cell batteries is 14.3 V to 14.4 V, that the EQ voltage is 16.3 V. and that the charger includes temperature compensation.

See: http://www.xantrex.com/web/id/50/p/161/pt/7/product.asp
And: http://www.xantrex.com/web/id/49/p/155/pt/24/product.asp

So, assuming that your new Interstate L-16 batteries require an absorption voltage of about 15 V or so, the Freedom’s 20’s absorption voltage of ~14.35 V is too low, and the batteries won’t fully charge. This sort of “deficit charging” eventually robs a battery bank of its capacity and useful life.

Conversely, assuming an EQ voltage of ~15.45 V is required, the Freedom 20’s EQ voltage of 16.3 V is too high, and if/when the battery bank is EQ’d, it’s probably venting off a lot of water in the form of oxygen and hydrogen gasses. In sufficient concentration, hydrogen gas is flammable or even explosive. Accordingly, flooded-cell batteries should be vented to the outside.

See: http://www.solarseller.com/battery_box_power_vent_by_zephyr_industries.htm

Based on the info you’ve provided and on available technical specs, it would appear that your battery bank is being abused as a result of regular undercharging (“deficit charging”; absorb voltage too low), occasional excessive EQ voltage, and perhaps not charged for long enough (absorb period plus EQ period = ~five hours). The typical result from this scenario would be poorly performing batteries, aka “lame batteries”.

If the Freedom 20 includes a “warm / cold” temperature selector, then switching it to cold should raise the charge voltage by ~0.4 V. I’d recommend you do this to increase the charger’s absorb voltage to something in the ~14.75 V range, which would be closer to the target discussed above. For the time being, I’d limit EQ charges to once a month for no longer than one hour due to the high voltage. Battery cell electrolyte level should be checked before and after the EQ cycle per Trojan’s instructions.

My assessment is that Freedom 20’s specs indicate it’s not an appropriate charger for your battery bank. You may need to rely on your solar charge controller for the correct absorption- and EQ voltages, and/or you may need to consider an different inverter/charger with programmable target voltages.

Another possibility is that one battery may be bad. However, I believe my assessment above would still be applicable.

The battery switch you asked about is the Blue Sea model 9001e. I suspect that the 4/0 wire (aka 0000 AWG) limit is space related, i.e., distance between lugs. Here’s a link to full specs for the switch, including drawings: http://bluesea.com/category/1/products/9001e

HTH, and good luck!
Jim / crewzer

System2 · January 2008

Re: A shot in the dark. Lame batteries.

Quote:
Equalizing? Yes, all the time.
Quote:
Equalizing I pretty much do casually, on the fly, whenever I think it's been a while, or whenever they've been operated kind of chronically low for a while.

These comments seem a bit contradictory to me.

Aha! You got me! You are far too clever for us naughty people! ;-)

(I do it moderately-frequently, perhaps approximately monthly - but just not on any kind of schedule. Is that better?)

So, assuming that your new Interstate L-16 batteries require an absorption voltage of about 15 V or so, the Freedom’s 20’s absorption voltage of ~14.35 V is too low, and the batteries won’t fully charge. This sort of “deficit charging” eventually robs a battery bank of its capacity and useful life.

To repeat and emphasize: I am not expecting anybody to figure out, redesign, or troubleshoot my entire system for free, over the internet. I'm only looking for tips as to how to evaluate whether these *brand new* batteries might be defective. I have been at this for some time, and I'm fullwell aware there is *plenty* I do that isn't consistent with ideal practices. But -- all else remaining equal -- these *brand new batteries* seemed to be working much-less-well than their aged predecessors, right off the bat.

( Question: what if anything might be wrong with my brand new batteries? They don't seem to work as well as the old ones.
Answer: You need a different charger. ) :-(

I got 7 years, almost exactly, out of the previous set, using this same hardware and connections and practices, which is within their expected lifespan according to the Trojan rep I talked to. So even the old ones don't seem to have been all that terribly "abused as a result of regular undercharging" -- and the new ones, the Interstates, seemed disappointing within the first week of use. I haven't even had time to abuse them yet.

Don't get me wrong -- this is all interesting and useful information as I go forward with this stuff, and I do appreciate the input. I just have a hard time seeing how it explains the current crisis (if it is one) we're having.

"I’m unable to locate a Heart Interface Freedom 20 inverter/charger manual on-line."

Not terribly surprising, as the thing might be about 15 years old, or more. It was already used when I got it. You may well be correct that it's not ideal-- but it (and the rest of this setup) has given adequate service for a long time and there's simply no funding for upgrades in the near-to-medium future. One thing I'm curious about is why do you suppose, if the batteries are all rated for higher charge voltages, does so much equipment go to the 14.3-.4 level? Are they being cautious? Are they matching vehicle regulator settings for RV applications? Do they get a cut of replacement battery sales? Oh well. I *can* actually turn my PV controller up to the higher value... which may be useful if we ever see the sun again here...

"In sufficient concentration, hydrogen gas is flammable or even explosive."

Oh? Really? You don't say. :-| I don't know how I've lived with deep cycle batteries in my house for all these years, and read all those owner's manuals... without anybody ever mentioning this before. ;-P

Thanks for the link to the BlueSea page on the switch! That's *exactly* the picture I was looking for! Of course, now that I've been reminded that my 2/0 wire is smaller than 4/0, it's moot. I don't know why it didn't occur to me to go straight to the manufacturer -- I guess Google Image Search has atrophied my resourcefulness...

Manuals for similar products (i.e., Marine Freedom 20, and Freedom 458 20-12) suggest the absorb voltage setting wet-cell batteries is 14.3 V to 14.4 V, that the EQ voltage is 16.3 V. and that the charger includes temperature compensation.

According to my manual, the only compensation is this setting on the DIP switches on the back of the control box:
"Battery Type - warm gel cell, cool gel cell, warm wet cell, cool wet cell."
And the specs page says that corresponds to a 13.8v for warm and 14.4 for cool. I do have it set for 'cool'. There's no separate sensor wire or anything like that, if that's what you mean.

Now if you'll excuse me, I have to go start the generator. :-(
David

Brock · January 2008

Re: A shot in the dark. Lame batteries.

I think we are all just trying to get the "big picture" because it doesn't make sense that the batteries are failing this early and we are trying to figure out why.

My guess, and it is just that, a guess, is that the Trojan batteries are a much better battery and the Interstates are not true deep cycle and are just failing rather quickly. Again because the Trojans could take a deeper discharge without damaging them and the Interstates are not holding well to that kind of loading.

My second guess is the top end charge voltage doesn't want to be as high for the Interstates and this may be damaging them.

I can say for certain, with the last two banks I had they behaved exactly how you described at the end of their lives. That is they would charge up quickly and discharge quickly. It didn't matter what the state of charge was or what the hygrometer said; they just acted like smaller and smaller batteries as time went on until I replaced them.

Hope this helps.

mike95490 · January 2008

Re: A shot in the dark. Lame batteries.

I think the idea here, is that the older batteries, from a different mfg, had a chemestry pacage that was happy with your charger's voltage.

The NEW batteries seem to require a higher charge voltage, and the charger does not seem to accomadate that.

crewzer · January 2008

Re: A shot in the dark. Lame batteries.

14.4 V is a popular absorption voltage for flooded-cell hybrid "marine/RV" deep-cycle batteries.

Trojan used to recommend an absorption voltage of 14.6 V for their 12 V batteries. I don't know if they changed their battery chemistry, their charging protocol, or both. Your inverter/charger's spec was probably "close enough" to realize decent service from your bank of older Trojan batteries.

The new batteries appear to require an absorption charge voltage higher than the charger can deliver. This may very well be the cause of the "lame" performance.

Jim / crewzer

System2 · January 2008

Re: A shot in the dark. Lame batteries.

All this stuff I've been reading today is very interesting -- and it's not one of the few hypothesis I had thunk up, at all. If Trojan's absorption voltage is lower, plus perhaps their batteries being just a bit more rugged... perhaps that was just enough to let me get away with the built-in limitations of my inverter, but isn't anymore.

( An interesting coincidence, maybe, is that *all* of my previous experience is with Trojan batteries -- so if this really is what's going on (insufficient charging due to low charger voltage), it could make sense that it was just now appearing when I changed brands. Huh. )

Trouble is, there really isn't new inverter money lying around here. And there's so SUN, either! Rats!

One hopeful possibility I just realized I have up my sleeve: I have an old Trace 2012 inverter/charger in the closet, a hand-me-down I was saving for when the Heart finally melts down. I'll have to dig out its manual tomorrow and see if it allows more options for charge voltage settings.
...I *was* planning to re-wire some anyway, for that switch. And I have the cables for it...

So, what do you folks think? Are there different diagnostics I should try first? Or should I just jump (if possible) to charging the Interstate batteries at a higher rate, and see what that does?

Dude. I really don't want to lift these batteries again, so soon.

Incidentally, my experience with the old Trojans I just replaced was much different from Brock's. Rather than charging quickly and then discharging quickly (just as if they were a smaller battery) -- they got so they'd charge and charge and charge AND charge before seeming to get to a reasonably full state... and then, yes, discharge fairly quickly. And this, the knowledgeable and helpful fellow at Trojan said, sounded just like what he'd expect from batteries reaching the last 20% (as I recall) of their usable life. Something to do with the internal resistance increasing, and more and more of the charge current just going to heat? (and yes, my cases did tend toward the warmish after all that charging). Hmmm...

(...thinking, and more thanks...)
David

Brock · January 2008

Re: A shot in the dark. Lame batteries.

Ya I stated that incorrectly. Say I drew 100 amps out of them (1000amp bank) and they looked dead voltage wise, I would then have to stick 120 amps back in to get them to the top voltage and they would fall off all by themselves. The 1000 amp bank with no loads would need 20 amps a day to stay charged. So what you described was more like what happened to me. My main point was that they acted like smaller batteries then what they were and were taking more and more power back in vs. out to recharge them.

I was down at 80% correction to get them full with my Trimetric meter, imagine my surprise when I installed my big AGM,s and 98% was a bit conservative, WOW

crewzer · January 2008

Re: A shot in the dark. Lame batteries.

David,

A quick scan of the Trace 2012’s manual(s) suggests it might provide a greater degree of flexibility in customizing the charge voltages for you new battery bank. The 2102 appears to have been available in several different versions; here’s a link to three manuals: http://www.xantrex.com/support/docdisplayarchive.asp

Some other ideas to consider, in no particular order:

1) New batteries do not initially operate at their rated capacity. Various manufacturers suggest that it can take anywhere from 15 to 50 discharge/recharge cycles before the batteries achieve full capacity.
2) There might be other/different problems with the new batteries, including one or more with bad cells. you might try using Trojan's instructions to test the SG of each battery cell (yep, all 12 of 'em) at the end of some typical charge cycle to see if there's any gross mismatch.
3) Measure the voltage for each battery at its (+) and (-) terminals while all four batteries are still interconected and being charged in bulk mode (relatively high current). Ideally, the voltage for each battery should be the same (i.e., ~7.15 V). Gross differences could indicate a bad/weak battery, a bad cable, or a bad connection between a cable and a terminal. Any of these problems could contribute to poor performance.

HTH,
Jim / crewzer

System2 · January 2008

Re: A shot in the dark. Lame batteries.

Jim / crewzer wrote:

A quick scan of the Trace 2012’s manual(s) suggests it might provide a greater degree of flexibility in customizing the charge voltages for you new battery bank. The 2102 appears to have been available in several different versions; here’s a link to three manuals: http://www.xantrex.com/support/docdisplayarchive.asp

Hey, thanks. I have two of these units, and they're slightly different. Perhaps this reference will help me sort out which version(s) I have.

I did find the original paper manual for it, though (VERY early vintage: looks to have been printed on an old dot matrix printer and xeroxed and stapled, and written in a rather conversational style too [*]). It does look like it'll do what I need. Or nearly enough, anyway. Apparently you can set a maximum charge voltage from 13.1 to 15.7 in .3-.4V steps, and a charge rate from 2 to 120 amps.

1) New batteries do not initially operate at their rated capacity. Various manufacturers suggest that it can take anywhere from 15 to 50 discharge/recharge cycles before the batteries achieve full capacity.

Good point. But these are probably about at the 65 cycles point now. But of course, if they were never getting a full charge any of those cycles...

2) There might be other/different problems with the new batteries, including one or more with bad cells. you might try using Trojan's instructions to test the SG of each battery cell (yep, all 12 of 'em) at the end of some typical charge cycle to see if there's any gross mismatch.

I swear I'll get on that soon -- both that, and your #3 about measuring the individual voltages under charge. But one thing at a time. I figure before I do anything else, I owe it to them to at least try to get a real charge in there first.
Delightfully, there have actually been two somewhat-sunny days in a row, and I took advantage of them. Not really enough, but at least it raised my spirits a bit.

I set the maximum volts on the PV controller to 15.5, and then ran the inverter in "equalize mode," so as to get the steady bonus 20 amps. They did get up to that voltage, and stayed for a couple hours, but it still took a total of about 30 amps to hold them there and I'm still looking at around 12.2 volts when I get up in the morning. What I really need to do is hook up that Trace and get them to where I can try a serious equalizing.

Thanks again for your interest in my predicament. All these years, it had never occurred to me to reexamine the designed behavior of the equipment that I started out with.

David

= = = =

[*] -- This Trace manual is definitely an artifact from the Old America. It's pretty clear no lawyers were invited to check it over. Check out this passage:
"BATTERY CONNECTIONS - THIS INVERTER IS NOT REVERSE POLARITY PROTECTED. This means that if the positive terminal of the battery is connected to the negative terminal of the inverter and vice versa the result is the instantaneous failure of nearly every power FET. To compound your misfortune, we can tell what has happened and it's not covered under the warranty. So, pay attention when making the battery connections."

I love it.

westbranch · January 2008

Re: A shot in the dark. Lame batteries.

Dave, again, you neeed to take those SG readings.
Even though you have not fully equalized the batteries , the SG readings can give you an indication of a poor cell(s) so that you can watch them after EQ is comppletely doone.

Have fun,
Eric

A shot in the dark. Lame batteries.

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