April 24, 201510 yr Would anyone be able to tell if this battery, I have three, could in any way be converted for use on an ebike? Thanks.
April 28, 201510 yr You might get away with connecting those in series, but AFAIK SLA's don't cycle through charging anything like Li-ion. I presume that they're all fairly new and in good condition, if only one of them has a dodgy cell then series connection will not give much current. Also, for recharging, you'd have to split them and trickle-charge them individually. And then you have the problem of putting them somewhere on the bike (I presume that all 3 gives a heavy weight).
April 29, 201510 yr Author Thanks Fred, I just wanted to know if it was possible, now I know it is I won't be doing it!! Seriously though they came out of those 5 in 1 car booster things, the 17AH was the bit that got me thinking, that is a hell of a lot, isn't it.
April 29, 201510 yr I read somewhere on this forum that Ah of SLA is not as useful as Ah of Li-ion, something like equivalent to 2/3, so they're equivalent to a 36V 11Ah Li-ion, but a lot heavier, I googled "SLA 12V 17Ah" and founf that they weigh 6.7 kg, so 3 would weigh 20 kg, which is a big weight to "permanently" put onto a bike LOL
April 29, 201510 yr That type of battery is designed to give very high peak discharges very short term. That one is probably capable of giving over 100 Amps of initial boost starting current, some of these jump starter batteries go much higher than that. As others have said, too heavy for e-bike use and realistically more like 10Ah if used for that purpose due to the Peukert effect which rates capacity by discharge rate. .
April 29, 201510 yr Author Errrm ok, Lost me at very high peak lol Fred I suppose I could go on a very very strict diet! It is heavy but I didn't think it was that heavy, to pick it up it feels about 3.0kg tops.
April 29, 201510 yr ....or maybe use them on a 24V electric trike to give more speed, with a lot of luck it could be like the granny on the stairlift in Gremlins LOL
April 29, 201510 yr It's all about how you measure capacity. This particular battery states it on the front: 20hr. That means that it was measured while discharging over 20 hours, so it was delivering 0.85 amps (almost nothing in ebike terms) As Flecc said, the Peukert effect means that discharging at a greater rate would have a significant impact on this result. I'd guess at the 1hr rate it would deliver about 8 or 9 ah. Maybe less.
April 29, 201510 yr Author So all in all pretty useless then? If it was fully charged could it be used for testing things? Just thinking out loud with no idea what i'm thinking about, excuse my lack of basic understanding regarding electronics or electrics even, I can change a bulb or a plug!
April 29, 201510 yr So all in all pretty useless then? If it was fully charged could it be used for testing things? Just thinking out loud with no idea what i'm thinking about, excuse my lack of basic understanding regarding electronics or electrics even, I can change a bulb or a plug! Knowing that there's a difference between electronics and electrics puts you way ahead of the general public! Yes, those batteries will be fine for testing . They are also good for running gadgets. I use one with a cheap (less than a tenner) compressor to inflate tyres/rugby balls. I use another to power a portable soldering iron. I keep a few handy in the workshop for use as a general power supply. I have long since given up lugging them around on the back of a bike though.
April 29, 201510 yr Author Thanks for that Mike, Lots of possibilities then, better than disposing of them. All I need now then is to find out what I can test! All good fun, or will be when I know what i'm doing lol Anyway I have learned a lot tonight, thanks all.
May 5, 201510 yr If you work out watt hours by kilo or volume then lead acid is a terrible choice for a bike battery. The cost is too good to ignore though if you live in a flat area.
May 5, 201510 yr Hi, Why do you mention lead acid. Is the one I have pictured lead? what do you think SLA stands for (see #2, #4) ?
May 5, 201510 yr Ooooops! Thought it was a brand name, I got a very, very long way to go! LOL yep ...."Sealed Lead Acid" batteries are totally sealed, the only way to get at the acid in a true SLA is with a drill. True SLA's are used in ebikes, mobility scooters, caravans, small ones in some toys, etc, etc. Note that some car batteries say "sealed" but they are not truly sealed because there are vent caps on each cell (sometimes hidden by a cover). "Sealed" car batteries are better known as "maintenance free" which means that the battery is not expected to be topped up with distilled water during its working lifetime, but you can get to the acid without needing a drill (should you ever want to).
May 5, 201510 yr Author Well, you won't believe this..... I had been looking at utube videos of guys making their own batteries from lithium batteries soldered together. Bright spark that I am (no pun intended) I thought I could break the casing on this and the two others I have and use the batteries inside to do the same. As I keep on saying I have one hell of a lot to learn, unless I kill myself first with my "experiments"
May 5, 201510 yr Well if you get an electric chainsaw and cut the long side off one you'll find six individual cells, each with lead and acid inside (and possibly some kind of gel or foam to stop the acid sloshing about). Obviously ....do not do that :o
May 5, 201510 yr There's nothing wrong with experimrnting, but make sure that you understand the basics of cell voltages and their management beforeyou start.
May 6, 201510 yr Author Good advice. To Fred there will be no chainsaw activity anytime soon. The reason I started this thread is because I was thinking of using my normal bike to convert to ebike. I have just bought a new 36v wheel 9.5 amp 250 watt new off ebay and am now searching for a 36v battery. The wheel was cheap so might not be much good we shall see. Thing is my mind has had another complete blockage. The wheel just arrived today this is what the seller say's 60cm OF WIRING FOR 5 PLUG THROTTLE & 3 MOTOR POWER WIRES WITH BULLET ENDS It looks like the cable should connect to the controller? If so how do I connect it to the battery, or vice versa? Hope all this makes sense!
May 6, 201510 yr 3 thick wires are power, the five thin ones are hall sensors (x3) and power for sensors (x2, normally black/red). All this needs to be connected to a controller, as does battery and whatever controls you need.
May 6, 201510 yr Author Thanks, I get all that but when I get a battery they don't come with a cable, do they? so how do I connect the battery to the controller, don't worry I will have you confused before long lol
May 6, 201510 yr The controller will have a set of cables to match, plus the connections for the battery terminals, throttle, pedelec sensor and any other facilities that it has like brake cut-outs, Here's an example controller illustrated on ebay, and you can see all the connectors etc coming from it. . .
May 6, 201510 yr Author I am missing the point somewhere. When I connect all the power leads and hall sensor from the bike cable supplied with the wheel to the controller where does the cable from the battery to connect the power to the motor come from..... Sorry for being an idiot
May 6, 201510 yr Asking for information is never idiotic, it's sensible. The power from the battery doesn't go directly to the motor. The battery connects to the controller and the controller feeds the necessary power pulses to the motor. If your controller doesn't have the two cables to go to the battery, you'll have to connect some. .
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