Help me choose a battery
02-06-2015, 11:59 AM
#42
I haven't measured what my Miata's quiescent current is yet. Anyone?
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02-06-2015, 12:11 PM
#43
I dont even think you can use a special charger with that battery tender brand battery. I dont see a balance port on it. Its also a lot of money to spend on a battery with an amp hour less than the $75 hobby king battery. Sure you get a form factor that looks like a car battery, but at twice the cost for something the performs less and weighs more. If the battery tender one used a123 cells it could be a different story because those are theoretically better than prismatic cells.
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02-06-2015, 12:16 PM
#44
With a 4S charger, you're just making sure you don't over-capacity charge like a lead-acid trickle charger would do. There's no way to know if the pack has top-down balancers built-in. A balance port would inherently top-balance a pack, sure, but I think the important take-away is a lead-acid trickle charger is not compatible with a LiFePO4 pack.
To expand your point further, my Chimera did not have a balance port or top-down balancers, and the cells also had poorly matched internal impedance. The result is 6 of the 8 cells were over-taxed over many cycles and got bottomed out. Game over. I rebuilt it and added top-down balancers on each row, which is better than nothing.
At the Battery Tender's price-point, I doubt it has any balancers. As a result you're relying on good impedance matching. It won't last as long as a balance-port battery that's heavily balanced [like every week], or even as long as my top-down row balanced setup. But it's inexpensive and you can buy 2 or more for every 1 premium setup.
To expand your point further, my Chimera did not have a balance port or top-down balancers, and the cells also had poorly matched internal impedance. The result is 6 of the 8 cells were over-taxed over many cycles and got bottomed out. Game over. I rebuilt it and added top-down balancers on each row, which is better than nothing.
At the Battery Tender's price-point, I doubt it has any balancers. As a result you're relying on good impedance matching. It won't last as long as a balance-port battery that's heavily balanced [like every week], or even as long as my top-down row balanced setup. But it's inexpensive and you can buy 2 or more for every 1 premium setup.
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02-06-2015, 12:30 PM
#45
I guess it depends on the charger. A normal 5amp lead acid charger is fine to use on one of these batteries as long as you baby sit it with the volt meter and disconnect it as soon as its fully charged.
But you dont need to pay a premium to get a balance port. $75 bucks buys you a 8.4Ah 4S2P prismatic pack that weighs under 2 lbs, has a balance port, and uses 5.5mm bullet connectors rather than 10mm screw terminals.
But you dont need to pay a premium to get a balance port. $75 bucks buys you a 8.4Ah 4S2P prismatic pack that weighs under 2 lbs, has a balance port, and uses 5.5mm bullet connectors rather than 10mm screw terminals.
Last edited by Leafy; 02-06-2015 at 12:45 PM.
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02-06-2015, 02:59 PM
#52
Yes. It'll start and run a street car miata too. I'd suggest one of the blinkly balancer type devices though to help keep the packs more balanced as its being charged by the alternator, those are fairly cheap. It doesnt need one but it will increase the time between when you should pull it off the car and put it on a balance charger. Once the cell to cell variation in voltage gets beyond a certain point its normally recommended to balance charge these types of batteries (all lipo type batteries) for maximum life.
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02-20-2015, 06:10 PM
#53
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Finally pulled the trigger on a legit yuasa on Amazon, had a gift card to burn. $85 shipped and another $14 in terminals. Can't wait for it to show so I can build a bracket for it
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02-20-2015, 07:21 PM
#54
Haha, you did the same thing I did when I bought my Yuasa.
Research, then compare, almost decide Yuasa, research some more, "Oh wow, Lithium batteries are tempting", research, compare, then finally decide on the Yuasa after a solid month of debating with yourself. Fun stuff!
Research, then compare, almost decide Yuasa, research some more, "Oh wow, Lithium batteries are tempting", research, compare, then finally decide on the Yuasa after a solid month of debating with yourself. Fun stuff!
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02-28-2015, 02:19 PM
#55
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Lol yeah. It was a little nerve wracking.
So far this has been my worst amazon experience ever. I ordered it on the 20th with two day prime shipping, it came from Indiana, I'm in Atlanta. First it was weather delayed, and when it finally got to the Roswell, GA shipping center, it was damaged. Now they (UPS) are sending it back to amazon, and instead of sending me one out right away they want to credit my account back 2-3 days after they recieve it, at which point I'll have to re-order. Its probably going ground or whatever slow boat shipping on the way back, so in the meantime I'm out a battery and the money. Its a good thing I don't need it right now.
So far this has been my worst amazon experience ever. I ordered it on the 20th with two day prime shipping, it came from Indiana, I'm in Atlanta. First it was weather delayed, and when it finally got to the Roswell, GA shipping center, it was damaged. Now they (UPS) are sending it back to amazon, and instead of sending me one out right away they want to credit my account back 2-3 days after they recieve it, at which point I'll have to re-order. Its probably going ground or whatever slow boat shipping on the way back, so in the meantime I'm out a battery and the money. Its a good thing I don't need it right now.
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02-28-2015, 03:13 PM
#56
Wow, that's super weird. If Amazon is the seller, they always rapidly send me a replacement or issue a refund before I even ship back the return. They usually upgrade it to one-day shipping as well, for free. When I buy from a prime eligible 3rd party reseller, the process happens in the way you describe.
Maybe the process is different because it's a battery? Maybe it's because UPS damaged it. Although, they should be even more courteous to the customer when that happens.
UPS must have done something really stupid to the package to damage it. Mine came packaged extremely well.
Maybe the process is different because it's a battery? Maybe it's because UPS damaged it. Although, they should be even more courteous to the customer when that happens.
UPS must have done something really stupid to the package to damage it. Mine came packaged extremely well.
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03-28-2015, 12:14 PM
#58
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So this is frustrating. I fill the battery up with acid, it hits 12v immediately and about 5 minutes later it starts leaking out into my garage floor. 
Its a slow leak, so I look under it and there is a tiny pinhole in the bottom with the acid bubbling out. I called up Amazon, and they are taking my word for it and sending out a new one. I'd probably have my car started tomorrow if it weren't for this. Now I have to figure out how to dispose of a tray of battery acid.
Its a slow leak, so I look under it and there is a tiny pinhole in the bottom with the acid bubbling out. I called up Amazon, and they are taking my word for it and sending out a new one. I'd probably have my car started tomorrow if it weren't for this. Now I have to figure out how to dispose of a tray of battery acid.
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