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Topic: No generator charging while sun is out? (Read 3 times) previous topic - next topic
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No generator charging while sun is out?
Yahoo Message Number: 87964
I may be 100% wrong about this, that is why I'm asking.

Over Christmas, we had our first extended boondocking experience--4 days at Capinteria State Beach.

While we didn't need a lot of power, we did use the furnace some at night.  Based on the voltage display read from the solar charger, our batteries were declining from day to day.  With the short days and low sun angle, we didn't expect much from the solar panels.
 We tried running the generator some when allowed during the middle of the day.  However, that didn't seem to do much good.  Since we don't yet have a Link 10 (or similar) battery monitor, I don't have much data.

Here is my theory:  with the sun out the solar panels were reading around 14.5 volts but they were only producing a couple of amps.  The manual for the converter indicates that it switches over to trickle charging when the batteries reach around 13.5 volts.  I think the potential from the solar cells tricked the converter into not providing any generator charge to the batteries.

Is this believable?  If so, is there an easy work around?

Thanks,

Cliff Thomas 2007 26.5 RK  (Silver)
Re: No generator charging while sun is out?
Reply #1 –
Yahoo Message Number: 87967
Quote
I may be 100% wrong about this, that is why I'm asking.
Hi Cliff

I think you are pretty much correct. Also, even though you think your power usage is small, the furnace uses quite a lot of electrical energy. Thats why many of us who like to boondock use a catalytic heater such as the Wave series heaters.
 If you use more electricity than the solar system can replace, then you must use additional means of charging, as you are trying to do. If your charger is the one that came with the coach, it simply is not going to work for that purpose. It is a waste of generator time. You can get more electricity into your batteries running  your engine, and even that is not a good use of gasoline. The reason your charger will not work for this purpose is that it has no bulk charge ability. As soon as it starts charging, the battery voltage starts rising, and your charger starts cutting back on the charging current. It is called taper charging - your charging current tapers off as your battery voltage rises. It takes many, many hours to charge a moderately discharaged battery to full charge. The voltage on your batteries due to the solar panel, only makes things worse for the charger.

Your best solution is to replace your converter charger with a true
3-stage charger which is capable of bulk charging your batteries.
 Then if you use more electricity than the solar system can replace, you run your generator for a couple of hours in the early morning until the batteries are around 80% charged. The solar system should be able to bring them up to 100% charge by afternoon. It would be best if you had a battery monitor, but you can do it without one by just guessing at first and learning by experience how long to charge.

Tom Johnston, Red '99 TK, Whidbey Island, WA  40 degrees and light rain.
Re: No generator charging while sun is out?
Reply #2 –
Yahoo Message Number: 87968
...
 
Quote
Your best solution is to replace your converter charger with a true
3-stage charger which is capable of bulk charging your batteries.
 Then if you use more electricity than the solar system can replace, you run your generator for a couple of hours in the early morning until the batteries are around 80% charged. The solar system should be able to bring them up to 100% charge by afternoon. It would be best if you had a battery monitor, but you can do it without one by just guessing at first and learning by experience how long to charge.
Tom,

Thanks for the answer.

I've read that Andy and others have replaced their converters.  I spent most of a day on the kitchen floor wiring a surge protector into the existing power panel and transfer switch.  Is it possible to add some intelligence to the converter that I have?  Or, do I need to replace the whole breaker panel/converter assembly?
 I'm not an EE (Physics, Math, Computer Science) so I'm not sure that I understand how the three stage converter would be different.  If I understand correctly, the solar charger is wired directly to the batteries.  If that is the case, would the voltage from the panels confuse the 3 stage charger as well?
 I understand the AM Solar has an improved controller with some kind of on/off switch.  Would that allow me to disconnect the solar panels while running the generator?  Of course, there would still be the limitations of the factory charger.

Thanks

Cliff
Re: No generator charging while sun is out?
Reply #3 –
Yahoo Message Number: 87969
"If your charger is the one that came with the coach, it simply is not going to work for that purpose. It is a waste of generator time."
 I wouldn't go *quite* that far. Because your 2007 has a Magnetek 7345 converter instead of the fairly primitive 6345 model that came with Tom's 1999 rig, you're  a little better off.
 But Tom's right in saying that even your converter isn't particularly good at charging the batteries, and a more sophisticated one (as discussed here in the past) will make the most of your genset's power output.
 "Is it possible to add some intelligence to the converter that I have?"
 Unfortunately, no. As far as I know, the 7345 isn't upgradable, so any improvement would require a complete swap.
 "If I understand correctly, the solar charger is wired directly to the batteries.  If that is the case, would the voltage from the panels confuse the 3 stage charger as well?"
 I think it could, although I routinely leave my solar panels turned on while charging from the genset and haven't seen any particular problems.
 "I understand the AM Solar has an improved controller with some kind of on/off switch. Would that allow me to disconnect the solar panels while running the generator?"
 Yes, the HPV-22B controller will let you do that. As an alternative to buying a new controller, you could pull the solar charging system's fuse, which in most cases is a separate (but clearly labeled) inline fuse in your fusebox. I'd be reluctant to make a habit of that, though, just because for me at least, it would be too easy to forget to put it back in. ;-)

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: No generator charging while sun is out?
Reply #4 –
Yahoo Message Number: 87970
Quote
I've read that Andy and others have replaced their converters.  I spent most of a day on the kitchen floor wiring a surge protector into the existing power panel and transfer switch.  Is it possible to add some intelligence to the converter that I have?  Or, do I need to replace the whole breaker panel/converter assembly?
Is it possible? I suppose it could be, but I certainly don't think it's practical. For around $200 and a couple of hours install time, you get a higher capacity (say 60 amps or higher), you get bulk charging for a very fast charge, and you get genuine 3-stage charging capabilities.

Quote
I'm not an EE (Physics, Math, Computer Science) so I'm not sure that I understand how the three stage converter would be different.  If I understand correctly, the solar charger is wired directly to the batteries.  If that is the case, would the voltage from the panels confuse the 3 stage charger as well?
I don't really like to make specific recommendations, but I do recommend any RVr who wants to know something about his/her electrical system read "Managing 12 Volts" by Harold Barre, available at any CW. Yes, the solar system is wired directly to the batteries. Would the voltage from the solar confuse the 3- stage charger as well? I'm not sure. I'll have to think about that.
Perhaps someone with knowledge of the actual algorithms of the smart chargers would know.
Anyhow, that's why I said I would use the charger early in the morning before the solar was very active. Actually, I have the AM Solar controller with the switches, and I turn off the solar while using my charger just in case there is some undesired interaction. Which charger do you presently have?

Tom Johnston
 
Re: No generator charging while sun is out?
Reply #5 –
Yahoo Message Number: 87971
On Jan 6, 2008, at 6:41 PM, Clifford_Thomas wrote:

Quote
I understand the AM Solar has an improved controller with some kind of on/off switch.  Would that allow me to disconnect the solar panels while running the generator?  Of course, there would still be the limitations of the factory charger.
THe HPV-22B will do that yes, but there is no reason to turn off the solar panels, both sources will provide some degree of charge.
Running the generator will provide just as much charge capability as shore power (the generator is powering the same converter).  The 7345 is a voltage regulated power supply, and will pump out full power if the battery is slightly below whatever it is set for, usually somewhere around 13.5 V.  But it can only produce 45 amps, though. A quicker job will be done if you start the truck. (130 odd amps are available there)
 All charging sources are just connected together.  The one producing the highest voltage will prevail eventually. Usually that is the solar system, followed by the truck engine, then shore power or generator.
If you have the HPV-22B, the low setting ("shore power") is at the bottom of the list.