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Forum Index : Electronics : battery ?
| Author | Message | ||||
| Eddie Newbie  Joined: 16/10/2011 Location: United StatesPosts: 25 |
Anyone know if a battery is only marked cranking amps, if there is a way to convert that to amp hours? |
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TexAcoon Newbie Joined: 14/11/2011 Location: United StatesPosts: 8 |
This was copied from Battery Capacity/Power Hopefully you can get something out of it .. Doug Units such as CA (cranking amps), CCA (cold cranking amps), and MCA (marine cranking amps) are the number of amps a battery can supply for 30 seconds at a specific temperature. CA - 0° C CCA - 0° F MCA - 32° F So you would take amperes multiply by the time in hours, which is (30 / 60 / 60) = 1/120 hours. 490 amperes * 1/120 hours = 4.08 ampere hours at 0° F You cant directly convert between CA, CCA, and MCA, because its at a different temperature. Same with converting to the european standard. So to avoid confusion always included the temperature it was measured at. |
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| Eddie Newbie Joined: 16/10/2011 Location: United StatesPosts: 25 |
Thanks for the info.I was hopeing it might be more. |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Eddie, if its a cranking battery its not much good for a storage battery. Cranking batteries are designed to supply lots of power for a few seconds (until the engine starts) and then be recharged immediately from the alternator. For power storage you need to look for 'deep cycle' batteries, which is a very different type. Klaus |
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| Eddie Newbie Joined: 16/10/2011 Location: United StatesPosts: 25 |
Yeah,I was aware that deep cycle batterys were better for storage. Right now I'm useing a lawn mower battery with my system.I only use it to monitor a 2 meter radio and an LED light.Some times I will watch my tv with it for short periods of time. I've had it hooked up for over a year and no signs of the battery getting weak. My system is a 60 Watt solar panel and a 125 watt wind turbine.I installed it for emergencys Like when we were out of power for a couple weeks a while back and I couldn't get hold of my children and had no lights etc. I do plan on upgrading the system as time and money permits.I want to get up to close to 100 amp hours eventualy. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I wouldn't give up that easily eddie, it is still handy to know what an automotive battery is capable of. If you have a look on the internet most battery manufacturers publish spec sheets for their products. you should see a listing for Reserve Capacity (RC) this is a 25 Amp load applied until the voltage reaches 1.75 volts per cell and written in minutes.Once you know a bit about battery chemistry you can use this number to estimate how many amps can be drawn off and at what rate. there has been some major innovations in the last 10 years that mean car batteries have greater reserve capacity.Temperature control with vented cooling enclosures and modified chemistry means that charging to higher voltages and 95% capacity is possible. Car electronics are now switching alternators off in certain conditions so cars are running entirely from the battery, so the focus is slowly shifting to a more dual purpose style unit. the 450 cca in my car has a RC of 125 minutes, that's 52 Amps, I would be comfortable with using 20 to 25 amps overnight. I'm confused, no wait... maybe I'm not... |
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| Eddie Newbie Joined: 16/10/2011 Location: United StatesPosts: 25 |
That sounds a lot more comforting.I might be able to get away with 2 car batterys and a system big enough to keep them topped off daily. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
the car batteries will do it but may only last for 150 to 400 cycles depending how hard you push them. A good deep cycle battery will do the same job for 1500 to 4000 cycles or even double that if they are treated well. mobility scooters, golf carts, fork lifts, UPS's, telephone exchanges, hospitals all have traction batteries or backup batteries, not as good as deep cycles but still OK. They can sometimes be had cheap if you know where to look, and some companies replace them early, so second hand you may only pay a lead scrap price if you pick them up yourself. yahoo I'm confused, no wait... maybe I'm not... |
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| Eddie Newbie Joined: 16/10/2011 Location: United StatesPosts: 25 |
I really only plan on pulling my batterys down to about 80% charge to help extend their life a little.The only thing I have that will do any real damage is a Koolatron cooler,draws about 3 amps. |
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MrDelanco Senior Member  Joined: 12/11/2011 Location: United StatesPosts: 101 |
An ultracapacitor is different than a battery, and depending on the application, may be a better solution. Often, a combination of the two is the best approach, combining the excellent power performance of the ultracapacitor with the greater energy storage of a battery. The ultracapacitor is able to deliver frequent pulses of energy without any detrimental effects. Many batteries experience reduced life if exposed to frequent high power pulses. An ultracapacitor can be charged extremely quickly. Many batteries are damaged by fast charging. An ultracapacitor can be cycled hundreds of thousands of times. Batteries are capable of only a few hundred cycles. By combing ultra caps with the battery a stable current output is built to handle multiple start-up loads and places less of a strain on the battery cells. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Eddie Newbie Joined: 16/10/2011 Location: United StatesPosts: 25 |
Has this combination been tried?Has anyone tried it and how does it work?I'd like to hear more on this idea. |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Ultra-Caps in circuit MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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