Topic: 24 Hr FARS Run time on stock batteries question?

[fkapp]

Question is what is the approximate run time for the 24 x 7 Fars before batteries run out of charge?

Batteries would be the stock 5000 Mha.

I am thinking up a modification to the DFARS conversion kit where I will have access to the batteries outside of the shield in a weather proof enclosure. In effect run longer leads soldered to the PCBA board. This would enable easy swap out of batteries if get into an extended overcast period.

I know going to hear AC fan, but that is not ideal for my setup and want to tinker with this approach and have some fun with it.
Just wondering how often will have to swap out batteries when get the winter drear conditions. If full charge, will that make it through an 10 hour winter night etc.

Appreciate thoughts/ feedback
Frank

[davidmc36]

I have an original 24 hour fan and a daytime I just upgraded to 24 hour. We just had a few days of good sun flowed but three straight days of rain. Never more than an hour of obscured sun each day.

Neither fan has stopped once. I do t see much issue for winter short days as long as there is some sun here and there.

[fkapp]

Thanks.  Going to go the battery route with long leads to have easy access in case need to swap out with charged batteries from ac battery charger.  Sounds like won't need to often

[azchrisf]

The AC fan mod might be something that interests you.

[fkapp]

It does but power to station is issue so going with a modified davis solar and battery approach.
Will send pictures once cooked up.

In future may relocate the radiation shield to near shed where power will be easier to run to, but that will entail another transmitter and shield which is not in the budget at the moment.

Also lose the THSW index unless Davis enables ability to select which transmitter to use for solar.
Meteobridge Pi I am going to setup end of this year will enable me to set this remote temp transmitter as primary to report to CWOP, etc.

As folks say on here, becomes evolving tuning approach for some

[davidmc36]

At 1.26 volts on stock NiCd cells the stock Davis fan motor pulls 100ma.

With the two 5000's on board you would have 100 hours if no charging at all was forthcoming.

That big panel must be able to put it back in at a fair rate? What about obscured sun, will any charge happen?

[fkapp]

Question on the dfars to 24 hr conversion.
Did you do the panel and pcba add and leave shield parts as is,  or did you add the shielded core when did conversion?
I have dfars and wondering if you added core is why ask
Thanks

[davidmc36]

I just put in the PCB and batteries. I used all the shield of the daytime unit. It seems to track temperature right along with my 24 hour unit.

[davidmc36]

So here this morning you see why a fan is good. With temp at 0.8 and DP Zero, there is lots of frost around. The original 24 hr fan and the daytime I modded are reading correct.

The non-aspirated unit reads 7 deg. That is what it was around 3 AM when the temp started to fall to 0.8 by about 6 AM. 

Quick look at the charts and I would say it shows average of 6km/h breeze.

[fkapp]

Thanks for all the tips and comparison to highlight difference.

2 more questions so can order parts.
Did you get the 24 hr solar panel or use the daytime one?
Did you order the hex spacers Davis 7350.015 – PRO2 Stainless Steel 24HR Shield Spacer   and   Davis 7350.787 – PRO2 24HR Standoff m/f #8-32 1.5 in hex 2.25 in?

Not sure if need the spacers for pcba board

Thanks again
Frank

[davidmc36]

I put the large solar panel for the batteries AND the Daytime Solar. I went to the back of Daytime Solar and re-soldered the leads to parallel the two halves and plugged in to SIM board.

I made all my spacers on the lathe. The 7350.787 spacer does not come in to play for me as it appears to be part of an actual 24 hour shield. You just need to space the rain base above the large solar panel so it can be brought forward and even with small solar, yet not interfere with attachment of ISS SIM enclosure. I removed the rain base, made the spacers on the lathe, just hollow "tubes" really, and re-installed the rain base with longer screws. I was just lucky that the screws from a non-aspirated unit were just the right length. These screws: 7350.258 – Vantage Pro2 Passive Shield 4″ Stainless Steel Machine Screw

I also fabricated the contacts and wiring for the batteries. The stuff is all available but I have the supplies and the day I went at it I wanted it "Done Now".

Which PCBA Spacers are you referring to?

[fkapp]

Thanks. The spacers were the davis parts I listed above, you answered that for me.

Interesting re using both the daytime and large solar panel.
I was wondering about that.
Do you mean you spliced the daytime solar wires into the ones from the large panel ahead of the pcba board connector?
If you could provide more details would appreciate it as dont want to waste the extra panel on the ISS cover if can connect this in.

Thanks
Frank

[davidmc36]

The daytime solar on the SIM enclosure has the double panels. One went to the SIM and the other ran the fan. I spliced them together and a single connector goes to the SIM.

The large solar panel of the 24 hour type, on the metal plate, now runs the fan and charges the batteries.

[davidmc36]

More like 2 deg

[fkapp]

Got it re the dfars panel and thanks for the info