Batteries/solar not holding up, troubleshooting help please

[twvette]

I have no luck getting batteries to hold up it seems. Had a couple different RV's and different setups too (wet cell, lifeline golf cart, gel deep cycle batteries)and none have ever held up well.

Anyways, here is what I have now:
- Onan 5500 gen
- Iota DLS-45 converter
- Three Optima Bluetop D31M (less than a year old)
- Large solar panel (or maybe it is even two combined together?)
- Shell Solar RV 20 solar controller /monitor
- Only camp in AZ so almost always get great solar

Worked great in beginning but seem to be on downward spiral. I now can't get through even a mildly cold night (mid 40's) of heater use only without them dying. I have had to run the generator much more even with the solar system to get/keep them fairly charged whereas before the solar panel would generally give me full recovery from typical day and night use.

Here are some observations:
- I previously got 13.4 volts or higher when running the generator but now only see 13.0, and settles at about 12.7v a little while after shutting off generator
- When shutting off generator I never get much more than an "OK" status on my monitor whereas as before I would typically be at "GOOD" or a few LEDs above at least for a while
- Connected an automotive style battery charger after charging with generator for a while and it also claimed the batteries were fully charged.

Here are some questions/concerns:
- Is the solar system overcharging my batteries slowly killing them?
- I do not have the Iota IQ4 smart charge option as far as I can tell, perhaps this will help? Seems like a long shot as had this in previous RV and did not see any real improvement but maybe would prevent Onan 5500 from improperly charging gel batteries this time around?
- Generator/Iota DLS-45 issue in general? All my RV's have had this same setup
- Is the Shell Solar RV 20 junk or good? I did not purchase or install this system.
- Can anyone tell from pics below which solar panels I might have? I have no clue on make/model/output and no markings on them even underneath!
- Maybe I am leaking back power through the solar panels at night?
- Would putting an ammeter inline help figure this out? Maybe a Doc Wattson http://www.rc-electronics-usa.com/ammeters/rv-battery-monitor.html
- How to test my batteries to see if they are still good? Maybe only one battery is bad?







Thanks for any help!

[jrnymn7]

oops wrong thread 🙂

[pnichols]

jrnymn7 wrote:
That 11.9x volts; is that with or without loads, i.e; is that taking the peukert effect into account? And if so, how exactly does one determine how much peukert effect to account for, when it is an ever changing variable, based on actual soc?

That is with low loads, but I don't care if the actual intrinsic settled terminal voltage is 11.91 volts or 12.05 volts ... it's around/about/approximately time to charge with readings anywhere in that neighborhood - so I do it.

Remember, I've been doing this with these batteries for over eight years so subtle stuff like Peukert, over the long haul, is getting averaged out enough so as to be of no concern.

The most important thing I'm doing and didn't mention is that always - when in storage in our back yard - the batteries are kept on float except for very hot days. For long battery life it is of course very, very important that they be kept fully charged as much as possible. I can do this without solar in the RV because I'm not a long term no-generator drycamper so I travel with a couple of charging generators for varying situations, and have fast charging batteries (AGM, with low internal resistance) so that they also get brought up to full charge nicely by the alternator between campsites.

[jrnymn7]

smk, the point I was trying to make was no one can establish their charging/Ah needs without first paying attention to them.

[jrnymn7]

Just to clarify, I am not saying Ah monitors are the 'end all, be all' of battery monitoring and maintenance. But I am saying they can be very useful in establishing one's charging needs and performance. Mex has pointed out that the OP's needs must first be established, and I agree. I also believe suggesting more batteries, more solar, or more whatever, is a bass-ackwards approach to the situation.

Indeed, the OP needs to get something closer to real deep cycles, such as a pair of 6's, this much is clear. But the size of bank required is yet to be established. And he will likely need more solar; but again, that has not been established. It seems if one takes into account the OP's rough usage, location, and equipment (which may or may not be performing up to its potential), he may only need to make some minor improvements. Maybe the panels are fine, but need bigger cable, for example. Maybe the converter is performing intermittently, and needs replacement. Who knows? But first the OP needs to establish his needs, and work from there.

Does he use a microwave? If so, I would suggest a larger bank. Does he care about running the gennie for countless hours? If not, I suggest he doesn't park anywhere near me 🙂 Does he plan on doing some long term boondocking? If so, he should consider the need to keep the batts at near full at all times. I know I'm preaching to the choir here, but it appears these things bear repeating.

[time2roll]

jrnymn7 wrote:
Assuming any realistic historicity has been established.

If the batteries are new and inadequate then you need to double the battery capacity. Repeat until sufficient capacity is achieved.

[NinerBikes]

jrnymn7 wrote:
Based on realistic or unrealistic expectations? I'm guessing nobody expects to wake up to dead batteries, after having charged them all day.

But when you do, you fire up that generator, and do what you need to do to service, tender, water or replace the offenders that failed to provide juice when you needed it.

[jrnymn7]

Assuming any realistic historicity has been established.

[time2roll]

Based on historical performance with consideration of current conditions.

[jrnymn7]

Based on realistic or unrealistic expectations? I'm guessing nobody expects to wake up to dead batteries, after having charged them all day.

[time2roll]

jrnymn7 wrote:
Salvo, how does one who pays little to no attention to their batteries recognize when performance has declined? Does not monitoring Ah's help one see how the charging process is performing?

When you run out of power unexpectedly.
When the power should be there and it is not.... just get some new batteries.
With proper care it should have been 4 to 12 years since you bought the last set.
Not a huge deal.

[jrnymn7]

pnichols,

That 11.9x volts; is that with or without loads, i.e; is that taking the peukert effect into account? And if so, how exactly does one determine how much peukert effect to account for, when it is an ever changing variable, based on actual soc?

[jrnymn7]

Salvo,

No, the Trimetric's voltage readout does not go to 2 decimal places; something I have complained about several times on this forum. And I have pointed out there is a huge difference in Ah's between 12.2v and 12.12v on a 430Ah bank, and that the Trimetric rounds up; but then I'm told I don't need to know what my battery voltage is, and that I'm obsessing. I have also pointed out that single decimal place voltage meters are good enough for monitoring charge voltage, but not so good at monitoring battery voltage while in service, because of the peukert effect and the inaccuracy in terms of actual soc; to which I've been told it doesn't matter... just don't let them get below such and such a voltage... again, something I simply cannot do with any one decimal place readout that rounds up, unless I check it constantly.

So, for me, Ah monitoring is the way to go. Is it critical, no, but neither is having a 100% accurate fuel gauge, when one can always guess at how much gas they really have, and just fill up more often than needed. All I know is the Trimetric has been very accurate in regards to Ah usage, when compared to actual open circuit/resting voltages. So I use the Trimetric for monitoring Ah's, as well as charging current and voltage, and I use a handheld volt meter for monitoring resting soc; but this requires that I turn off all loads. I also use the handheld to monitor voltages across batteries, during both charging and while under load, to see if the four batts are sharing both the charge and the load equally.

But in the end, the Ah meter is the most accurate indicator of soc, on the fly, and does not require disconnecting the loads.

In your case, you are familiar with both your daily usage and batts, after so many years, but I think for many folks, an Ah meter can be very helpful in determining ones daily usage throughout the year, as their daily needs change, as well as becoming familiar with their batts and charging system.

[pnichols]

jrnymn7 wrote:
....how does one who pays little to no attention to their batteries recognize when performance has declined

I'm not Salvo, however:

I do a load test on my RV batteries periodically to determine if they're close to needing replacement due to permanently lowered capacity. For instance, my RV's battery bank is 200 amp hours so I recently loaded them with about a 17-20 amp load for five hours, then I let them rest for about one hour disconnected from any load, and at that point I checked the voltage on their terminals and it was around 12.3X volts. This meant they could still supply around 100 amps over five hours before showing a terminal voltage indicating that were getting close to one-half empty. Hence, they don't need replacing yet.

When camping, I can tell when the batteries are getting close to 90% - 95% full when being charged because the permanent ammeter in their circuit shows they're only accepting only around 3-5 amps. The ammeter shows zero amps when they're fully charged regardless of the voltage the charger applies to their terminals.

I do like Salvo does when camping to determine if they're getting close to needing a charge. I constantly monitor their output voltage with a voltmeter (permanently hooked up) that reads to one one-hundreth of a volt (i.e. a four place voltmeter -> XX.XX display). When their output voltage is around 11.9X volts or so, I charge them.

I've been doing this for a little over eight years with the same set of RV batteries.

[Salvo]

I monitor the batteries with a 4-digit panel voltmeter. You need 4-digits. Does the Trimetric have that? I can tell if performance declines when battery voltage at the end of the day gets to lower values.