Setting up an inverter; shore/solar

[artro]

Yesterday I got the installed solars, two 85W
Kyoceras, an HPV-22 controller, Magnum remote
and 2012 2000W inverter. I'll be parked
at a CG with shore power for some months
but would like to conserve on the electric
bill. I have four 88 Amp/hour AMG batts
installed for the coach. I ran through the
setup for the inverter, which has me specify
battery type, a 'search' mode for the wattage
at which the inverter comes out of sleep mode,
Low Battery Cutout, amp/hour capacity, charge
rate and AC dropout voltage. I understand
everything but the dropout voltage, not
sure what to set that for. Also,
the controller has a voltage set point selector,
whose default is 14.3 V. The battery specs
say to use a float charge of 13.5 to 13.8.
My solar guru suggests that if I'm in
a campground with regular shore power,
that I set it to 13.6.

Can anyone enlighten me on 1. the proper
float charge setting and 2. how to manage
the alternation between shore and solar.
And 3. when the engine is on, do I have
some kind of switch or isolator that
prevents overcharge? I have a newmar Mountain
Aire, '98 on a P12 Chassis.
I'd like to leave the solars to charge
all day and only use the shore to run
AC or recharge in poor weather. The rest of
the time, I'll have shore power turned off.That is,
if I can get enough juice from this
relatively modest array. I apologize for
this somewhat technical question, but
figure someone out there can help.

thanks!

[artro]

Yesterday I got the installed solars, two 85W
Kyoceras, an HPV-22 controller, Magnum remote
and 2012 2000W inverter. I'll be parked
at a CG with shore power for some months
but would like to conserve on the electric
bill. I have four 88 Amp/hour AMG batts
installed for the coach. I ran through the
setup for the inverter, which has me specify
battery type, a 'search' mode for the wattage
at which the inverter comes out of sleep mode,
Low Battery Cutout, amp/hour capacity, charge
rate and AC dropout voltage. I understand
everything but the dropout voltage, not
sure what to set that for. Also,
the controller has a voltage set point selector,
whose default is 14.3 V. The battery specs
say to use a float charge of 13.5 to 13.8.
My solar guru suggests that if I'm in
a campground with regular shore power,
that I set it to 13.6.

Can anyone enlighten me on 1. the proper
float charge setting and 2. how to manage
the alternation between shore and solar.
And 3. when the engine is on, do I have
some kind of switch or isolator that
prevents overcharge? I have a newmar Mountain
Aire, '98 on a P12 Chassis.
I'd like to leave the solars to charge
all day and only use the shore to run
AC or recharge in poor weather. The rest of
the time, I'll have shore power turned off.That is,
if I can get enough juice from this
relatively modest array. I apologize for
this somewhat technical question, but
figure someone out there can help.

thanks!

["007"]

Congrats on your new solar setup sounds great
I can't answer your questions not into solar But AJ or Cruser will pick this up and give you the answers you need, like I said great setup enjoy. "007"

[Cruzer]

Hi Art,

I run four 110 watt Siemens panels, with a 50 amp RV Solar MPPT charge controller, four 6 volt deep cycle batteries and an Xantrex RS2000 true sine wave inverter/charger so I kind of have an idea what you're looking at. My next plan is to replace my flooded batteries with AGM batteries. That way I can add more battery capacity without having to worry about venting them.

To answer your questions:

Most 3 stage converters or inverter/chargers generally cut into float mode at 13.5 volts because this is where gassing occurs and you want to be able to stay under that point. However, AGM batteries are different. They're better because you can draw them down deeper and they accept a recharge faster than flooded. Plus, they're lighter and don't require vented compartments. The only drawbacks are that they cost more and they won't handle a severe overvoltage charge. If you ran your solar panels without the charge controller, the AGMs would be toast. But the charge controller will maintain them nicely. Same with the vehicle alternator, which is controlled by a voltage regulator and shouldn't go any more than 14.6 volts at the maximum and most of that will be buffered by the chassis batteries that are absorbing it.

You can set your float to 13.5 volts safely. There's really no reason to go any higher. The batteries don't need voltage, they want current flow (amps). You only need to supply enough voltage to overcome the resident voltage in the battery in order to push those amps into it. If the volts are less than the battery, the current flows out of the battery. That's why most MPPT charge controllers will drop the solar array voltage to "just enough". By reducing the voltage, the amps go up (amps times volts = watts) so a good charge controller can give you a 30% boost in solar output.

I don't have any problems with mixing my solar charge power, inverter/charger charge power, or vehicle alternator charge power. They all get along just fine without any fancy relays or cutouts so I wouldn't worry about it. Sometimes these engineers go a bit overboard on designing these systems.

As to the AC dropout voltage, that should be set to 90 VAC. That's the point where the inverter/charger will stop charging because the low voltage can damage the unit.

I think that your design goal of providing enough power to charge all day is probably pushing it and you will need shore power. I upgraded from 220 watts to 440 watts because 220 just didn't provide that much. I've found the biggest issue with dry camping is battery capacity. My 4 batteries give me 440 amp-hrs, and you can only draw batteries down to 50% without damaging them. My next plan is to swap them out with 6 AGM batteries, giving me 660 amp-hrs. That'll help run things through the night until the sun comes out the next day or we drive to the next place.

[artro]

Great reply, Mark. Very useful. After
a few days, I'll 'tune' the controller,
as it says to do. And you're in agreement
with my supplier, to set the float at 13.5 or
13.6. Cool! I know I don't have enough panels
but it would be great if I could go day by day
with the occasional replenish from another
source. Only experimentation will tell.

[ajbjrvers]

To; Arto and Cruzer;

Artro, as Cruzer posted, you may be hoping for too much from the battery set-up you have. You will note from the info in my signature that I have a boondocking set-up, but I just got it squared away over the winter and haven't put it to use yet in the outer world.the panels are keeping the batteries at 13.8 volts, all 10 0f them,so I do not need gen-set or engine to charge.
Use the settings the manufacturer states in maaual.


CRUZER=== Rather than go the AGM, $$$ route, why not use 8 , 6 volt. I found room for extra 4 in engine compartment,on the side, behind where a rubber barrier was installed,right behind, about 1' ,the factory 4, amp hours== 1,000 and about the same or less cost than the AGM's??

It took me 2 years to find place for added batts, I didn't want to put them in a closed bay and have to deal with venting.

Hope you can find space.

Hope this info useful, Aime=== AJBJRVERS