# 7 Amp Solar charge regulator



## Rick (May 10, 2002)

http://www.harborfreight.com/7-amp-solar-charge-regulator-96728.html

Can anyone advise on how 115 Amp hour "Deep cycle" Marine batteries would last using this 7 amp Solar charge regulator instead of a 3 stage charge controller? We have a trio of these batts in a secondary system, charged by 3 old 35 Watt ARCO panels. That system was on a CC for 2.5 years, and has been kept going the last 2.5 years by our diverting the voltage when needed. The batteries are still holding a good charge after this less than perfect conditioning.

Any thoughts?


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## wy_white_wolf (Oct 14, 2004)

Just to make sure I'm reading this correctly. You have 3 - 115AH batteries for a total of 345AHs that you are trying to charge with 3 - 35 watt panels for a total of 105 watts.

I don't see it making much difference as your barely generating enough to cover the self discharge rate unless the 3 stage is MPPT, but then such a small system wouldn't justify the cost.


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## Rick (May 10, 2002)

A better qustion might be what is the benefit of 3 stage charging VS Voltage regulationN

Could be wrong about the 35 Watts. No docs on the Arcos they are 35 Years old and I googled them 6 years ago when we bought this place. There are 33, 4 inch dia. Cells on 3 panels, total of 99. When they see good sun the battery voltage will hit close to 16. I charge various items using 60 to 80 watts for a couple hours and then I cut the voltage to 13.5 as needed. Then at night we can use 60 watts for 5 hours or so w/o draining the batts.

Thanks


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## 12vman (Feb 17, 2004)

4"x4" cells are ~ 3.5 amps @ .5 volts. I'll figure them at @ ~ 35-40 watt panels (Vmp @ 12-13 volts)

Those real old Arcos were designed to charge without a controller. They relied on the internal resistance of the battery to hold the voltage down. The open circuit voltage should be only ~ 16-17 volts. The voltage isn't going to get high enough to use a 3 stage charge controller.

You would have better luck using an MPPT type charge controller and connecting the three panels in series and charging @ 12 volts. This way you would achieve the higher voltage needed for 3 stage charging.


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## 12vman (Feb 17, 2004)

_"A better qustion might be what is the benefit of 3 stage charging VS Voltage regulationN"_

Voltage regulation only allows the voltage to rise to a determined level (~12.5-13 volts max) 3 stage allows the bulk voltage to rise a little above 14 volts and hold this voltage for ~ an hour or so to boil the electrolyte and mix it up. (IF the battery isn't run down too much to reach that level) Flooded cells needs this to happen now and then. 13 volts doesn't allow a battery to boil very much.

Using voltage regulation will cause the electrolyte to stratify (separate) over time because they can't boil enough to keep them mixed up.


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## cmcon=7 (Mar 7, 2010)

I just gave the last of my arco's to my brother, but they were the 36 cell model, the best I could get out of one was 1.5 amp into a battery.
with only 4.5 amps into such a large battery bank I would just use a blocking diode and disconnect them if I was going away for a few days


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