Spoon
Contributor
guys was wondering how i could make my own 9am nimh batteries for my hid lights? can someone point me in the right direction? thanks
DIY Hid light batteries
- Thread starter Spoon
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OP
Spoon
Contributor
hilk:
THANKS thats the link i was looking for!
OP
Spoon
Contributor
426Scuba:
im quite ignorant but lets say i got a 21w hid running on 9amp 14.4volt batts, what batteries would i need? dont exactly understand how these work. will any 10amp battery just plug and play?
Airspeed press - Divelight Companion has a decent section on batteries - also see http://www.batteryuniversity.com/ for some really good info.
Im no expert, but I will give it a shot.
NIMH cells are rated at 1.2 volts when fully charged they can go up to 1.4v when depleted they are at 1.0v.
1000 mAh = to provide one amp for 1 hour (the more amps the longer it will run)
to make a battery pack you can do it one of 2 ways when you wire in series (alternate + to - terminals) you add the voltage up, in parallel (all + wired together and all- wired together) you add up the current.
so for this battery http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=325 you would buy 10 and wire them in series to get 12v 10000 mAh battery pack (10 amp battery pack). if you wanted a 20 amp battery pack make 2 12volt packs and wire them in parallel to get it.
your 21w hid should only draw 1.75 amps and on paper burn for over 5 hours.
check out this caculator its kind of cool
http://www.angelfire.com/pa/baconbacon/page2.html
This site also has some great info on batteries.
http://www.powerstream.com/BPD.htm
NIMH cells are rated at 1.2 volts when fully charged they can go up to 1.4v when depleted they are at 1.0v.
1000 mAh = to provide one amp for 1 hour (the more amps the longer it will run)
to make a battery pack you can do it one of 2 ways when you wire in series (alternate + to - terminals) you add the voltage up, in parallel (all + wired together and all- wired together) you add up the current.
so for this battery http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=325 you would buy 10 and wire them in series to get 12v 10000 mAh battery pack (10 amp battery pack). if you wanted a 20 amp battery pack make 2 12volt packs and wire them in parallel to get it.
your 21w hid should only draw 1.75 amps and on paper burn for over 5 hours.
check out this caculator its kind of cool
http://www.angelfire.com/pa/baconbacon/page2.html
This site also has some great info on batteries.
http://www.powerstream.com/BPD.htm
FatRob
Contributor
Power(watts) = Voltage(Volts) * current (Amps)
1 amp hour is 1 amp for 1 hour
so 21watts @ 12v = 21/12 = 1.75A of current
in order to run for one hour under IDEAL conditions you would therefore need 1.75Ah of battery capacity.
In reality there are issues such as losses and de-rating of capacity with temperature, current draw... (i.e. the more current you draw, the lower the rated capacity)
best way to make batts is to get one or two of the old style Bag Cellphone batteries and put them in a pot! They are 12v already and come in nice big Ah sizes... also try motorcycle batteries! But for high current you probably want lead acids...
Nimhs are ok... so are NiCd's the F size are rated at 7 Ah for example.. You'll need 10 for 12V of power...
1 amp hour is 1 amp for 1 hour
so 21watts @ 12v = 21/12 = 1.75A of current
in order to run for one hour under IDEAL conditions you would therefore need 1.75Ah of battery capacity.
In reality there are issues such as losses and de-rating of capacity with temperature, current draw... (i.e. the more current you draw, the lower the rated capacity)
best way to make batts is to get one or two of the old style Bag Cellphone batteries and put them in a pot! They are 12v already and come in nice big Ah sizes... also try motorcycle batteries! But for high current you probably want lead acids...
Nimhs are ok... so are NiCd's the F size are rated at 7 Ah for example.. You'll need 10 for 12V of power...
Are you looking to replace a battery from an existing light? If so, you want to copy its design. If you're building a new light, I'd recommend this:
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=988
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=988
Great info guys. I had the chance to build a replacement pack for my Dive Rite 10W HID last year. Flooded it the second dive and hated to spend the dough on a brand new battery pack so I reverse enginered it for a little over $40 vs $125 for a new one. The project is fairly simple; the hardest part was getting the batteries soldered together; I couldn't find an exact cell replacement with the tabs pre-soldered. If you can get those batteries, the project is much simpler.
I do have a question since I need another project and may build a 21W for fun. Has anyone worked with Lithium Batteries; and if not what are the reasons. Feedback is welcome.
I do have a question since I need another project and may build a 21W for fun. Has anyone worked with Lithium Batteries; and if not what are the reasons. Feedback is welcome.
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