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Topic: Batteries, Oh No, not again (Read 14 times) previous topic - next topic
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Batteries, Oh No, not again
Yahoo Message Number: 144647
So after installing two Trojan T145 a few days ago I decided to try and educate myself further on the proper use of them.

One of the things I noted was Trojan's literature stated that the daily charge voltage should be 14.8V or in other words two times 7.4. I know that the AMSolar HPV 22b is factory set at 14.4 and so I wondered if it should be raised.

I contacted Trojan and AMSolar. Both said that there was not a problem in raising the voltage set point. However, the guy at AMS indicated that I should be sure to keep an eye on voltage as the temperature compensation thingamajig in colder weather could raise the voltage to 15 or even 15.5 volts and some of the 12v devices in the rig might not like that.

So, this leads to my first question. What devices would have a problem and at what voltage.

If my internet research is accurate you can get a full charge with a set point of 14.4 but it would take several hours at that voltage, which you may not have, especially in the winter.

I would like to get some input on solar. We have three 100w panels from AMS. They are wired in series. If I understand, when a shadow is cast on a part of any one panel it diminishes the output from all three panels. Would using a combiner box to wire them make that a parallel connection and thus reduce shadowing issues to only panels that are in shadow?

Of course the gauge of the wiring impacts this and I don't know off hand what my set up is in that regard. I know what the wiring on the roof is. But LD installed the two original panels and placed the controller above the dinette in our 30' LD on the drivers side. Our batteries are on the passenger side just behind the entry door under the fridge and the converter is under the sink on the driver side.

Over the past 5+ years of fulltiming we have increased the amount of time that we spend boondocking and I would like to make the most of our system.

We don't have the tilt function for the panels and I am considering adding that and need to relocate the two original panels to a better position in the process.

Final question. These batteries replaced our two 7 year old T105's which seemed to be fading although oddly they seemed to have higher voltage readings on the controller in the evening when we shut things off and in the morning when we first get up than we are seeing on the T145s. Hopefully, that is just a reflection that the new batteries aren't yet reaching full charge for long enough this time of year.

Oh yeah, I know I need a battery monitor. Another thing on the to do list.

Any answers that use crayons and a coloring book to keep it simple will be appreciated.

Jim C
Re: Batteries, Oh No, not again
Reply #1 –
Yahoo Message Number: 144648
Hello Jim

I can help with a small part of your question. LD uses a 10 gauge wire leading from the panels. Both Discount Solar in Q and AM solar said they would not add my third panel unless I also went with a #8 wire. Don't recall the exact reason but they were both very clear on that point.

Enjoy Q. Wish I was there with you.

Ed
Re: Batteries, Oh No, not again
Reply #2 –
Yahoo Message Number: 144649
So after installing two Trojan T145 a few days ago I decided to try and  educate myself further on the proper use of them.

JimC


The 2005 batterys in my MH bit the dust last fall. Lost one of the T105 Trogans. They were oringal bat. It has a bad center cell.
Do you recall what you paid for the new T145 and are they AGM or the kind that you need to add water. What store did you get them.
Re: Batteries, Oh No, not again
Reply #3 –
Yahoo Message Number: 144654
You can charge the batteries at 14.8V, but I would turn off every electronic consumer in the rig while you do it. That includes such as propane detector, fridge controls, furnace controls, multimedia, etc, unless you independently confirm for each appliance that this voltage is in the acceptable range. Generally, 14.4V is at the upper end of operational acceptability.
 Also, Your MPPT charge controller will simply put out the maximum current possible into whatever voltage currently appears across the battery terminals, and that is determined by the state-of-charge. E.g., a discharged battery will only show about 12V, even if charging at 22A. As the charge is replaced, the battery voltage will rise. When it reaches the voltage setpoint - say 14.4V, meaning close to full charge, the controller output current will drop off as the voltage is clamped. Setting that setpoint up to 14.8V will have little effect on charge times for your batteries, while increasing the risk of damage to your electronics.

Steve
2004 FL
2013 Honda Fit
Re: Batteries, Oh No, not again
Reply #4 –
Yahoo Message Number: 144655
Thanks Ed. When I installed the 3rd panel I ordered wiring from AMS and it was #8.

Wish you and Carol were here and sorry we missed you by a day.

Jim
Re: Batteries, Oh No, not again
Reply #6 –
Yahoo Message Number: 144658
Hi Jim,
 Yes, you really need a battery monitor. We have a Xantrex         Linklite, would not leave home without it. We run 145's, and         have not adjusted the voltage on the solar controller. They just         silently do their job and continue to work well after four         years. I was not aware of this voltage requirement, and I'm not         going to change it either. If you do adjust the voltage, you may         end up adding more water. As far as shadows, I can't keep track         of my own, let alone collector shadow ;)

My opinion, worth price charged.

Chuck @ Hartford, IA OAT 3F.
1997 RB
Re: Batteries, Oh No, not again
Reply #7 –
Yahoo Message Number: 144666
Thanks Steve. I haven't come up with all of them yet but so far everything I have checked has maxed out at either 16V or 18V.

Not sure if anyone here is familiar with this site. Handy Bob's Blog. I have found it interesting regarding batteries if it is factually accurate.

http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/

To quote him:

"VOLTAGE: For the sake of simplicity, I am only going to talk about the requirements of standard flooded wet cell lead acid batteries, which is what most of us use. The major points apply to all types of batteries, but the actual numbers will vary. It is very important for you to research the charging requirements of your batteries if you are using any other type and make sure that your charging system provides what they need, or you could end up damaging them by over charging or never getting them fully charged, which will also damage them. Battery manufacturer's specifications say that a standard 12 volt wet cell battery needs to be charged to between 14.4 to 14.8V and then held there for some time before it will be fully charged. The Trojan Battery company says 14.8V daily charge (at 77 degrees F) and Interstate will tell you over 15V. Trojan's 2010 Users Guide has a new chart that shows you should actually vary the voltage depending on the amps you supply for charging and even higher voltages are recommended. Of course they recommend temperature regulation. So all of those out there who are telling you 14.8V is too high do not know what they are talking about. How long it takes to get the charge in depends on how far it was discharged. Trojan says to keep charging until a hydrometer test shows that the battery is charged and not one charger available today can do this. The best chargers can do a reasonable guess at state of charge by providing constant voltage and watching the amps taper as the battery fills to tell them when the battery is full. However, they rely on whatever the designer or programmer gives them for guidelines and are only as good as that data. Many do no work worth a hoot.  A fully charged battery can be maintained at a full state by applying a 13.2 - 13.6 volts "float" charge. All of the talk about how many amps a charger puts out means nothing. It is the volts (pressure) that you need to push the amps (volume) into a battery.  VOLTS, VOLTS, VOLTS!! Also, the amps pushed into a battery at a higher voltage contain more power than those at a lower voltage. Remember, volts times amps equals watts, so amps pushed at 10% higher volts give you 10% more watts. Therefore, the power stored in the upper range of a battery's charge is greater, so it is very important to get a full charge. Low voltage DC is not easy to get through wire without losing power due to voltage drop or resistance. It is huge problem in an RV.  Use big wires and short wiring runs to get around this. It is good practice to use one or even two sizes bigger wire than recommended to limit voltage drop. This charge voltage has to actually reach the battery, not just the output terminals on a charger. If you cannot get your batteries up to 14.4 volts (14.8 is better & faster) with whatever charging system you have and then keep them there while pushing amps in for more than an hour or two, your batteries will never be full."
 
Re: Batteries, Oh No, not again
Reply #8 –
Yahoo Message Number: 144677
If Bob is not exactly on the money, he's awfully darn close.
Particularly, when he says bigger wire.  Don't get carried away, but  don't scrimp.
Use the 12 volt wire size charts, and don't forget to figure round trip  distances.
 As Bob says, IIRC, the most important wiring is between the controller and  the batteries.  Then the batteries and the load.
Search          12 volt wire size chart 3% drop        or  something similar.
 https://www.google.com/search?q=12+volt+wire+size+chart+3%25+drop&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=fflb 
RonC

1b  Re: Batteries, Oh No, not again 

Tue  Jan 21, 2014 2:14 pm (PST) . Posted by:

Thanks  Steve. I haven't come up with all of them yet but so far everything I have  checked has maxed out at either 16V or 18V.
 Not sure if anyone here is  familiar with this site. Handy Bob's Blog. I have found it interesting  regarding batteries if it is factually  accurate.

http://handybobsola r.wordpress. com/the-rv- battery-charging -puzzle-2/

To  quote him:
 "*VOLTAGE: * For the sake of simplicity, I am only going  to talk about the requirements of standard flooded wet cell lead acid  batteries, which is what most of us use. The major points apply to all types  of batteries, but the actual numbers will vary. It is very important for you  to research the charging requirements of your batteries if you are using any  other type and make sure that your charging system provides what they need,  or you could end up damaging them by over charging or never getting them  fully charged, which will also damage them. Battery manufacturer’ s  specifications say that a standard 12 volt wet cell battery needs to be  charged to between 14.4 to 14.8V and then *held there* for some time before  it will be fully charged. The Trojan Battery company says 14.8V daily charge  (at 77 degrees
F) and Interstate will tell you over 15V. Trojan’s 2010 Users  Guide has a
 new chart that shows you should actually vary the voltage  depending on the amps you supply for charging and even higher voltages are  recommended. Of course they recommend temperature regulation. So all of those  out there who are telling you 14.8V is too high do not know what they are  talking about. How long it takes to get the charge in depends on how far it  was discharged. Trojan says to keep charging until a hydrometer test  shows that the battery is charged and not one charger available today can  do this. The best chargers can do a reasonable guess at state of charge  by providing constant voltage and watching the amps taper as the battery  fills to tell them when the battery is full. However, they rely on whatever  the designer or programmer gives them for guidelines and are only as good  as that data. Many do no work worth a hoot. A fully charged battery can  be maintained at a full state by applying a 13.2 – 13.6 volts “float”  charge.
All of the talk about how many amps a charger puts out means nothing.  It is the volts (pressure) that you need to push the amps (volume) into  a battery. *VOLTS, VOLTS, VOLTS!!* Also, the amps pushed into a battery at  a higher voltage contain more power than those at a lower voltage.  Remember, volts times amps equals watts, so amps pushed at 10% higher volts  give you 10% more watts. Therefore, the power stored in the upper range of  a battery’s charge is greater, so it is very important to get a full  charge.
Low voltage DC is not easy to get through wire without losing power  due to voltage drop or resistance. It is huge problem in an RV. Use big  wires and short wiring runs to get around this. It is good practice to use  one or even two sizes bigger wire than recommended to limit voltage drop.  This charge voltage has to actually reach the battery, not just the  output terminals on a charger. If you cannot get your batteries up to 14.4  volts (14.8 is better & faster) with whatever charging system you have  and then keep them there while pushing amps in for more than an hour or two,  your batteries will never be full."