morningstars sunsaver duo (dual battery RV)

notsobright · May 2009

hello all, I just joined but have been reading and have leaned enough here to successfully install/operate my first PV charge system. thanks

my system is:

two Kyocera KC40T modules http://www.e-marine-inc.com/products/solar_panels/kc40.html
wired parallel

one morningstar sunsaver duo w/remote meter and temp. sensor
http://www.morningstarcorp.com/en/sun-saver-duo

one PowerTech 105ah AGM house battery

one Optima 34/78 AGM starting Battery

and all #10awg wire

In full sun with fully charged battery I had my small electric fan on and noticed it speed up and when I looked at the meter the charge was @ 15.8 volts.

from what Ive read this is too high for AGM batteries but it lasted only a minute. it does this occassionally (+14.7 volt spikes) but allways only for a minute or so and only when under a load (elec. fan) and in full sunlight.

without a load the highest voltage recorded on the meter was 14.5

should I be concerned? from my reading so far anything higer than 14.2 is too high for AGM batteries but my starting battery gets 14.8 routinely from the altenator.

at first I also had this in the system

http://powerstream.com/battery-isolator.htm

and was thinking it had something to do with the high reading so I removed it then observed the same behavior.

I like the idea of charging the house battery while driving so I will probably re-install it however I do have concern with the 14.7 volts output from my GM altenator, mabey I shouldnt be?

just wondering if anyone else is using the Sunsaver Duo controller and if you have similair behavior from it. Ive read that it is a brand new controller but not before the purchase.

seems to be the perfect controller for RVs but now I wonder.

I have other questions but not related to the SSD so I'll save them for later.

thanks

n3qik · May 2009

Re: morningstars sunsaver duo (dual battery RV)

The Optima 34/78 AGM starting Battery is good to 15.0 VDC.

http://www.optimabatteries.com/_media/documents/specs/34_78.pdf

During this peaking, where there any clouds out?

My charge controller (Xantrex C60) will over shoot the voltage during cloudy days or if a load is removed.

niel · May 2009

Re: morningstars sunsaver duo (dual battery RV)

i was thinking that the 14.7v from the alternator was unusually high, but as an afterthought i think it was done to have multiple batteries charging at the same time with the use of power isolation diodes that would drop the voltage by roughly 1/2v.
as far as why the controller is spiking that high i could only guess as i really don't know and i'm not familiar with that particular controller.

notsobright · May 2009

Re: morningstars sunsaver duo (dual battery RV)

the spike Im getting is only on the house battery, not the starting battery and sofar only in full sun with a slight load (only the fan on)

the sunsaver duo can be set to charge 50/50 or 90/10 house/starting batteries respectively. I have it set 90/10

the RV is a conversion van that I have added the extra battery to, the altenator is factory type (GM) and it has been successfully maintaining a flooded battery for a couple of years as it was before I changed it to the AGM. I never checked the output prior to installing the AGM but I have since checked it with a few different meters to be sure the 14.7v readings are accurate.

that was my concern before but now that Im seeing upwards of 15v from the controller itself its not so much.

is it true that anything higher than 14.2v into an AGM is bad?

how long would a voltage spike need to be before it hurts the battery?

it seems to be less than a minute that it spikes judging by how long the fan speed is increased.

thanks

icarus · May 2009

Re: morningstars sunsaver duo (dual battery RV)

Do you have temperature compensation? Is the battery cold when the voltage is that high?

Icarus

PS If it is only momentary I don't think I would worry too much about it,,, IMHO.

notsobright · May 2009

Re: morningstars sunsaver duo (dual battery RV)

yes, it has temp compensation and the battery is arround 85deg. F.

since my initial post here Ive searched over at least ten different RV forums for this controller and havnt even found as much as a mention of it which seems odd because it is the only controller Ive found designed specifically for RV applications.

I'll call morningstar tech support monday and see what they say about it.

its been a neat project so far and Im learning alot with it.

I plan to add a switch so I can also charge another external battery when both batteries are fully charged.

I may also add an outlet from the 100ah AGM and run an extension cord into the house so I can use its power for lighting when Im not using the RV. might as well, its free power at this point right?

dwh · May 2009

Re: morningstars sunsaver duo (dual battery RV)

I have been thinking of the SunSaver Duo myself, and I'm very interested in anything you have to say about this. I very much hope you keep us updated.

The Duo does look like an attractive package for an RV - charge the house and engine batteries from one controller, and it comes with the remote for a pretty good price (at least from WindSun, I haven't checked anyone else's prices and probably won't bother to).

The only drawback I see is that it seems to only support one temp sensor, which seems a bit goofy for a product specifically designed to charge separate batteries.

I have a van conversion RV that I bought not long ago, and it has pretty much the same setup yours had before you added the solar - except that the two batteries are connected by a dumb relay (looks like your powerstream without the electronics).

I'm planning to replace that relay with an actual isolator, and replace the marine/rv house battery under the hood with an AGM, as well as add another AGM (or two) in the cabin. I'm also going to stick some PV panels on the roof, and right now I'm either going with the Duo for the underhood stuff with a switch as you described for the inside bank - or a Duo for the underhood and another controller for the bank inside the cabin.

One reason I'm looking at two controllers, is that with the Duo I can have its single temp sensor on the house battery under the hood (and just take my chances that the engine battery will be okay), and have the temp sensor of the second controller on the battery bank inside the cabin.

dwh · May 2009

Re: morningstars sunsaver duo (dual battery RV)

notsobright wrote: »

I may also add an outlet from the 100ah AGM and run an extension cord into the house so I can use its power for lighting when Im not using the RV. might as well, its free power at this point right?

Keep in mind that battery lifespans are measured in cycles, so the more you cycle it, and the deeper you cycle it, the sooner you'll have to replace it.

notsobright · May 2009

Re: morningstars sunsaver duo (dual battery RV)

I called mornngstar tech support and they said that durring the float stage it is normal to have momentary spike upto 15v but anything higher is excessive.

also told me at anytime under the 5 year warranty I can exchange it. I may do that but told them I would keep an eye on it for now. I want to learn more about it before I exchange it.

today it spiked to 14.54v for about 10 seconds but that was it.

I will probably get the optional data link and software for it later after I have a better understanding of the basics.

I will continue to post my experiences with it here and hope someone else using one will chime in at some point also.

notsobright · September 2009

Re: morningstars sunsaver duo (dual battery RV)

I got the PC adaptor (thanks again NAWS)

I was very suprised to learn that the SSD has no logging capability as of this date but they have in their product info a note stating it is comming soon so hopefully a firmware update will take care of that.

another thing is that in order to connect the PC the SSD has to be dissconnected from all power then re-connected after the PC is running. a dissappointment, and now Im wiring switches in my system so I can do it without pulling 3 seperate fusses in three different locations which are not easily accessable.

other than those the SSD has performed well so far.

morningstars sunsaver duo (dual battery RV)

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