Hello all, long time no see - I'm almost certainly going to buy myself a ping battery, I'm a bit worried that I might blow up my bike though.
Bike is still a Sakura s200 running 36v 15ah SLAs, new battery will be a Lithium 36v 20ah weighing around half what the SLAs weigh.
Has anyone else changed chemistries on an electric bike / moped like this before, and what is the effect likely to be on my 200w motor and stock controller?
Overamping fun
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badnewswade
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Overamping fun
34 Watt Hours per mile, or > 700 MPG. What, me, smug?
I've been running a 36V, 10Ah Ping LiFePO4 battery on my recumbent for about 6 months. Previously I'd run it for a very short time, when testing, on a 36V sealed lead acid battery pack.
The LiFePO4 pack is astounding by comparison. Virtually no voltage drop under load at all and much more current available for acceleration. Range increased by about 30% for the same capacity battery.
You won't do any harm to your motor or controller, as the voltage is the same as a fully charged lead acid battery.
Based on my experience I think you will find that your bike will perform much better with the Ping LiFePO4. The only thing you need to watch is the battery wiring, as the Ping BMS has two negative leads, one for charging and a separate one for discharge, which may mean some wiring modifications.
Jeremy
The LiFePO4 pack is astounding by comparison. Virtually no voltage drop under load at all and much more current available for acceleration. Range increased by about 30% for the same capacity battery.
You won't do any harm to your motor or controller, as the voltage is the same as a fully charged lead acid battery.
Based on my experience I think you will find that your bike will perform much better with the Ping LiFePO4. The only thing you need to watch is the battery wiring, as the Ping BMS has two negative leads, one for charging and a separate one for discharge, which may mean some wiring modifications.
Jeremy
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badnewswade
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You're right, you can't just connect both negatives together, bad things may happen!
The Ping battery comes with a battery management system circuit board strapped to the side, which controls both charging, by making sure that no individual cell gets over-charged, and discharging, by making sure that the pack doesn't deliver a current that is greater than the cells are rated for. Both of these functions serve to increase the life of the pack.
When you get the pack you should get an instruction sheet letting you know how to connect it up. The pack will have two thick, discharge, wires and one thin negative charge wire.
The charging plug on the bike needs to be connected to the battery positive (thick red wire) and the thin negative wire (usually blue).
The bike electrical system needs to be connected to the battery positive (thick red wire) and the thick (usually black) discharging negative connection.
The LiFePO4 charger that comes with the Ping battery will need to be wired to a suitable connector to fit the bike charging plug.
In use, the battery always discharges through the BMS circuit. This provides over-current protection by turning the pack off if the current drawn exceeds about 35 to 40 amps (although your 20Ah pack may be set to 55 to 60 amps - I'm not sure if Ping has changed the limit on his bigger packs). This is far more than the small motor in your bike could ever draw, so it's really a fail safe, like a very fast fuse. If it ever trips, then the power needs to be turned off and on again to reset it.
Jeremy
The Ping battery comes with a battery management system circuit board strapped to the side, which controls both charging, by making sure that no individual cell gets over-charged, and discharging, by making sure that the pack doesn't deliver a current that is greater than the cells are rated for. Both of these functions serve to increase the life of the pack.
When you get the pack you should get an instruction sheet letting you know how to connect it up. The pack will have two thick, discharge, wires and one thin negative charge wire.
The charging plug on the bike needs to be connected to the battery positive (thick red wire) and the thin negative wire (usually blue).
The bike electrical system needs to be connected to the battery positive (thick red wire) and the thick (usually black) discharging negative connection.
The LiFePO4 charger that comes with the Ping battery will need to be wired to a suitable connector to fit the bike charging plug.
In use, the battery always discharges through the BMS circuit. This provides over-current protection by turning the pack off if the current drawn exceeds about 35 to 40 amps (although your 20Ah pack may be set to 55 to 60 amps - I'm not sure if Ping has changed the limit on his bigger packs). This is far more than the small motor in your bike could ever draw, so it's really a fail safe, like a very fast fuse. If it ever trips, then the power needs to be turned off and on again to reset it.
Jeremy
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badnewswade
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Hmmm.... 
maybe I could make the charger integral to the battery unit, so the thing's just got a standard plug coming out of it... hmmmm........
Anyway, I lost last nights' auction, so it should take a while before I actually see the battery. I have this feeling that they're going to come down in price, then again, I really freakin' WANT this one.
Think it will solve the whole hill-climbing problem?
maybe I could make the charger integral to the battery unit, so the thing's just got a standard plug coming out of it... hmmmm........
Anyway, I lost last nights' auction, so it should take a while before I actually see the battery. I have this feeling that they're going to come down in price, then again, I really freakin' WANT this one.
Think it will solve the whole hill-climbing problem?
34 Watt Hours per mile, or > 700 MPG. What, me, smug?
Shame about the auction, but if you email Ping directly on his eBay contact address he will give you a quote and supply direct - he'll send you a PayPal invoice directly.
Whether or not this battery will solve your hill climbing problem depends on whether or not the battery is the cause (I've just re-read that - sorry, it sounds a bit dumb!). If the bike used to climb hills OK, but now struggles because the lead acid battery performance has dropped, then the answer is a definite yes, the LiFePO4 battery will bring the bike back to what it used to be like, perhaps with a little more oomph and with much greater range.
On the other hand, if the bike struggled on hills even with new lead acid batteries then it's unlikely that changing to LiFePO4 will make much difference, as it's probably motor or controller limited, rather than battery limited.
It's perfectly possible to change the motor and controller for something more powerful, but probably doesn't make economic sense. You can buy a new or second hand ebike that is lighter than the Sakura and has greater power, complete with a decent battery, for around the same price as all of the parts needed. Alternatively, there are some decent kits around now that make converting an ordinary bike fairly cost effective.
If you were happy with the Sakura originally and it's just that the batteries are dying, then just go for the Ping pack.
Jeremy
Whether or not this battery will solve your hill climbing problem depends on whether or not the battery is the cause (I've just re-read that - sorry, it sounds a bit dumb!). If the bike used to climb hills OK, but now struggles because the lead acid battery performance has dropped, then the answer is a definite yes, the LiFePO4 battery will bring the bike back to what it used to be like, perhaps with a little more oomph and with much greater range.
On the other hand, if the bike struggled on hills even with new lead acid batteries then it's unlikely that changing to LiFePO4 will make much difference, as it's probably motor or controller limited, rather than battery limited.
It's perfectly possible to change the motor and controller for something more powerful, but probably doesn't make economic sense. You can buy a new or second hand ebike that is lighter than the Sakura and has greater power, complete with a decent battery, for around the same price as all of the parts needed. Alternatively, there are some decent kits around now that make converting an ordinary bike fairly cost effective.
If you were happy with the Sakura originally and it's just that the batteries are dying, then just go for the Ping pack.
Jeremy
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GregsGarage
- Posts: 870
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Ping auction
You can email Ping battery direct, depending on his stocks he will sell direct for a fixed price. You can pay using Paypal, I would recommend using a credit card instead of a debit card as you get more consumer protection with a credit card.
Greg Fordyce
Daewoo Matiz
http://www.evalbum.com/4191
Daewoo Matiz
http://www.evalbum.com/4191
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