Overclocked
Member
A month ago I built a small solar panel, and it outputs 5V @346mA, for a while Ive been wanting to use the power it gives..But Id have to be outside in order to use that power. I now want to be able to store it. So which battery do I use? To chose from I have:
Now My Question is not of capacity, but Of longevity and temp range and shelf life. I have read that LiPols and LiOns only have a 2 year shelf life..that seems rather off putting. I can get LiPols for 0.99 cents if I order more than 10 (I planned on ordering 21). The Li-Pols are from a surplus store and are rated at 3.7v at 670mAh and have over and under voltage protection along with over current protection. Is this True that Li-Pols only last 2 years even if you use them or not?
Ive also read that Sealed Lead Acid batteries last 2 to 5 years as well. I have not been able to find Data on the longevity of NiMh Cells.
Now, since this is going to be outside, Ive taken in the temp range of Each of these batteries. Right now in the North east of the US, its spring time, so temp hits around 70F (some days 80) and a low of 50 to 60F. LiPols/Lions have a temp range of 0 to 50C (32F to 122F). Now it never gets that Hot here..but it does get that cold. So Id have to build a box and keep them shaded. Lead Acids on the other hand have a temp range of -60C to 60C (they seem to last a good 5 years in cars with the crazy temps). NiMh Cells can be charged at 0 to +45C (32F to 113F)
Cost Analysis:
4V 10Ah Sealed Lead Acid Battery $15.95+8.58 Shipping = $24.43
21 3.7v 670mAh = $20.79 +$8.00 shipping (estimated) = $28.79.
The SLA will give 40W of power
The Li-Pols will give 52W of Power (all hooked up in parallel) however, Ive been thinking of charging in parallel, using them in series/parallel.
SLA price per watt = $0.61
LiPol price per watt = $0.55
Link to LiPol battery
**broken link removed**
Link to SLA
**broken link removed**
Now Im not lookin to power my house...I really just want a storage element with occasional use. There a slight problem with the LiPols, since their surplus, I dont know how long theyve been in storage, or when they were made, and if theve been there for 2 years they could be dead already. Same with the SLA, I dont know if they top off their battery's and trickle charge them
So to sum up my question, which battery type will be best for storage? Which has the best temp range to stand up to the elements? Which will last the longest? Both SLA and LiPol seem to be around the same price. I do Not plan on leaving the system outside in the rain or snow. It also seems NiMh cells are rather expensive, and for roughly the same price LiPol and SLA batteries seem to be competing against each other. I *did* plan on building a small box to put the batteries in, to keep them sealed from the weather or bugs. I am Really edging towards Li-Pol but I am afraid of them melting because of the hot sun or because of the summer (Summer peaks at around 100F)
I also do have a charger IC in mind for the Li-Poly Batteries, so that is no concern to me. Yes i do realise it will take a while to charge a huge battery, but time is what I have.
add: The LiPoL Cells will also give me more flexibility and allow me the hook them up in series for a higher Voltage, instead of having to use a boost converter to boost up the voltage for use.
- NiMH
- Li-Pol (or Lion)
- Sealed Lead Acid
Now My Question is not of capacity, but Of longevity and temp range and shelf life. I have read that LiPols and LiOns only have a 2 year shelf life..that seems rather off putting. I can get LiPols for 0.99 cents if I order more than 10 (I planned on ordering 21). The Li-Pols are from a surplus store and are rated at 3.7v at 670mAh and have over and under voltage protection along with over current protection. Is this True that Li-Pols only last 2 years even if you use them or not?
Ive also read that Sealed Lead Acid batteries last 2 to 5 years as well. I have not been able to find Data on the longevity of NiMh Cells.
Now, since this is going to be outside, Ive taken in the temp range of Each of these batteries. Right now in the North east of the US, its spring time, so temp hits around 70F (some days 80) and a low of 50 to 60F. LiPols/Lions have a temp range of 0 to 50C (32F to 122F). Now it never gets that Hot here..but it does get that cold. So Id have to build a box and keep them shaded. Lead Acids on the other hand have a temp range of -60C to 60C (they seem to last a good 5 years in cars with the crazy temps). NiMh Cells can be charged at 0 to +45C (32F to 113F)
Cost Analysis:
4V 10Ah Sealed Lead Acid Battery $15.95+8.58 Shipping = $24.43
21 3.7v 670mAh = $20.79 +$8.00 shipping (estimated) = $28.79.
The SLA will give 40W of power
The Li-Pols will give 52W of Power (all hooked up in parallel) however, Ive been thinking of charging in parallel, using them in series/parallel.
SLA price per watt = $0.61
LiPol price per watt = $0.55
Link to LiPol battery
**broken link removed**
Link to SLA
**broken link removed**
Now Im not lookin to power my house...I really just want a storage element with occasional use. There a slight problem with the LiPols, since their surplus, I dont know how long theyve been in storage, or when they were made, and if theve been there for 2 years they could be dead already. Same with the SLA, I dont know if they top off their battery's and trickle charge them
So to sum up my question, which battery type will be best for storage? Which has the best temp range to stand up to the elements? Which will last the longest? Both SLA and LiPol seem to be around the same price. I do Not plan on leaving the system outside in the rain or snow. It also seems NiMh cells are rather expensive, and for roughly the same price LiPol and SLA batteries seem to be competing against each other. I *did* plan on building a small box to put the batteries in, to keep them sealed from the weather or bugs. I am Really edging towards Li-Pol but I am afraid of them melting because of the hot sun or because of the summer (Summer peaks at around 100F)
I also do have a charger IC in mind for the Li-Poly Batteries, so that is no concern to me. Yes i do realise it will take a while to charge a huge battery, but time is what I have.
add: The LiPoL Cells will also give me more flexibility and allow me the hook them up in series for a higher Voltage, instead of having to use a boost converter to boost up the voltage for use.
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