I built my Twins and six year old a playhouse in the garden and made it so that i could have two panels hidden on the back south facing side to capture the sun. In hindsight i wish i'd done the roof design different so i could have covered the whole roof and gotten 600 or 800 watts on it but everything is always easier on reflection
I've went with two panels of 100watt each and that way i can have them in parallel or series for a 12 or 24 system. I've got them in 12v currently using my existing lead acid setup charging up the cells of my new lithium 7s packs one by one so that when it goes into commission they are fully charged and hopefully fairly balanced.
I'm using a EPever Tracer A series 30A MPPT solar charge controller http://www.epsolarpv.com/en/index.php/Product/pro_content/id/654/am_id/136 which is total overkill in all honesty but i also have a smaller PWM model from EPEver the landstar LS1024B http://www.epsolarpv.com/en/index.php/Product/pro_content/id/478/am_id/136 which i'll probably place in their instead and use the 30A controller for putting panels on my garage roof.
I've went with these controllers as you can customise the battery configurations to fit better in with lithium setups and i'm hoping stop any kind of float charge.
For my packs i've went with 23p and 7 in series. I've used Paul Kennets excellent design and also his din rail mount design which i think looks great and gets them out of the way of the kids too I've kept the cells in pairs when removed from the laptop batteries so that there is less stress on the batteries when soldering and also less fusing to do. The logic is that they have lived in the laptop battery as a pair since being made so why not keep them as a pair still. The buss bar is nickel strip which is folder over a 4mm banana plug that is soldered together and i've used 0.2mm wire that i tested as blowing at a 5A so feel it's protected.
I'm looking at adding more and more of these packs in parallel with the current setup although if i add any more i'll have to make a cabinet for them and house them outside of the playhouse as i can't risk the kids tinkering with them. I have a bobby basic el cheapo BMS that i plan to link up to the first pack, not sure if i can get away with the same BMS if i start linking packs in parallel or if i need a BMS per 7s pack.
Can't wait to put it all in to action and hopefully won't burn the playhouse down
Some pics of the playhouse and the setup. should have one with it in full operation soon.
I've went with two panels of 100watt each and that way i can have them in parallel or series for a 12 or 24 system. I've got them in 12v currently using my existing lead acid setup charging up the cells of my new lithium 7s packs one by one so that when it goes into commission they are fully charged and hopefully fairly balanced.
I'm using a EPever Tracer A series 30A MPPT solar charge controller http://www.epsolarpv.com/en/index.php/Product/pro_content/id/654/am_id/136 which is total overkill in all honesty but i also have a smaller PWM model from EPEver the landstar LS1024B http://www.epsolarpv.com/en/index.php/Product/pro_content/id/478/am_id/136 which i'll probably place in their instead and use the 30A controller for putting panels on my garage roof.
I've went with these controllers as you can customise the battery configurations to fit better in with lithium setups and i'm hoping stop any kind of float charge.
For my packs i've went with 23p and 7 in series. I've used Paul Kennets excellent design and also his din rail mount design which i think looks great and gets them out of the way of the kids too I've kept the cells in pairs when removed from the laptop batteries so that there is less stress on the batteries when soldering and also less fusing to do. The logic is that they have lived in the laptop battery as a pair since being made so why not keep them as a pair still. The buss bar is nickel strip which is folder over a 4mm banana plug that is soldered together and i've used 0.2mm wire that i tested as blowing at a 5A so feel it's protected.
I'm looking at adding more and more of these packs in parallel with the current setup although if i add any more i'll have to make a cabinet for them and house them outside of the playhouse as i can't risk the kids tinkering with them. I have a bobby basic el cheapo BMS that i plan to link up to the first pack, not sure if i can get away with the same BMS if i start linking packs in parallel or if i need a BMS per 7s pack.
Can't wait to put it all in to action and hopefully won't burn the playhouse down
Some pics of the playhouse and the setup. should have one with it in full operation soon.