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Author Topic: Off gird battery voltage  (Read 7559 times)
billi
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« Reply #45 on: September 18, 2015, 10:35:22 AM »

yep , i know , but  i cannot recommend  an offgrid system without a charge controller ....   batteries need proper care

i accept  the fact that one can  attach  some  non regulated power sources to a battery bank to a limited extend   , but certainly not,  as a general rule,  to work with out any charge control

there are so many aspects to consider  and  i am  pretty sure , there is a reason why my battery is  already  12 years old ..., and she wouldnot  be a live today , without a charge-controller

the midnite classic lite 200  as an example , can manage 5 panels in series or about 160 volt mpp and 4000 watt of panels  for  430 pounds ... 

there are surely  ways to reduce costs , and we all love that hunting for the best value for dollars , but  we have to  consider that  over a long period , its not just a pizza we eat in 10 min and shlte out after an hour

billi


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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
camillitech
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« Reply #46 on: September 18, 2015, 10:51:53 AM »

but  we have to  consider that  over a long period , its not just a pizza we eat in 10 min and shlte out after an hour

billi




 hysteria  hysteria What about using the Inverter to switch on AC loads as charge control ? Not as sophisticated but could be an option ?
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http://lifeattheendoftheroad.wordpress.com/

'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
biff
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« Reply #47 on: September 18, 2015, 11:59:39 AM »

I have run experiments (still at it)
                        On solar PV charging straight into forklift packs without controllers. I have also tried it with sealed lead acid batts, (NOT ADVISABLE,!!) with the sealed plated removed but the rubber tops still on. So a 100ah x 48pack taking a charge from a 165watt x 72v panel will pop the rubber tops off the cells in quick succession after a period of about 10 minutes. So obviously the voltage is a bit too high, however,i can reroute through the controller and keep a steady 56v going non stop,
   I can boost the forklifts the same way, letting them climb steady but they can resist the charge better,still if left unattended they will gently simmer and the battery fluid will evapourate in summer in less than 3 weeks if no load is applied, The array is only two 165watt panels vmp36 with Y connectors for the 24 volt forklift pack and plugged in series for the 48v pack.
  I know that If I ran the systems with a more suitable panel voltage, say 30volts,the battery fluid would not evapourate as quickly. So I have come to the conclusion that for peace of mind, the controller such as a xantrex c40 would be well worth the extra 100euros.
                                                           Biff
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An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
rogeriko
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« Reply #48 on: September 18, 2015, 09:23:03 PM »

Of course you should use a pwm controller, plenty of 48v 60A controllers around for 40 pounds thats 1/10th the price of a mppt. My original comments were that you dont need really heavy duty cable. As long as the cable is rated for the current a few volts lost along the way will be taken up by the panels.
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billi
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« Reply #49 on: September 19, 2015, 11:52:13 AM »

hi roger

time flies   ..... i get a 60 a  mppt controller capable 150 volt input  for close nothing  today


 just as a present with an 4000 watt  pure sinewave off grid inverter .....




« Last Edit: September 19, 2015, 06:09:17 PM by billi » Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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