SW900 LCD and 52V battery

[zag0]

Hi guys,

I just ordered parts for my first e-bike:
- Voilamart 1000W 48V 26" kit with SW900 LCD from Amazon (voilamartcomau)
- 52V 14Ah 14S4P battery with Samsung 3.7V 3500mAh 10A 3C cells from Aliexpress (UNITPACKPOWER)

I'm looking at some SW900 reviews online and I can't find an option to set the correct battery voltage for my 52V pack. I see that option 3 in the LCD's settings menu is for voltage control but it doesn't have 52V option at all. It goes from 48V straight to 60V. Any idea how to work with SW900 and 52V battery?

Hope I didn't make a mistake ordering 52V pack instead of 48V...

Thanks!

 

[eee291]

52V is still within the 48V range.

 

[zag0]

Thanks eee291. And SW900 will correctly show level indicator according to the actual juice left in the battery, despite the 48V/52V difference?

 

[zag0]

Also, an additional question.

I was advised by the kit reseller (Voilamart) that it would best to use the kit with a 48V battery. I understand that since they sell it as a 48V kit. But just to double check here: Is there any chance their motor is not as voltage-tolerant as others on the market and 52V battery could actually do damage to it? I haven't ordered the battery yet and I'm indecisive whether to go with 48V or 52V.

Looking at the Youtube e-bike kit reviews I see 52V is usually used with 1200W or 1500W kits. I ordered a 1000W.

What's your opinion?

 

[eee291]

You don't have to worry about the motor voltage, there is no such thing as a voltage intolerant Motor.

Also the battery capacity display is already inaccurate since it just measures battery voltage. If you want a really accurate Battery indicator, you will need a Ammeter or a Cycle Analyst.

 

[docw009]

SW900 doesn't show voltage, just graphics. After a week, you'll be able to correlate the graphics with your range. Try not to run the battery flat when riding. It kills the life.

Technically, you never run the battery flat when riding. The bike electronics is usually set to shut it off with 20% left. The problem you will have is that your SW900, if set for 48V, will take your 52V battery down to 40V which is about 3V lower than it should go. Not the best for long battery life. You battery lasts longer if you don't run it as low as the electronics allows. I rarely run one down to where the bike stops, even when I carry a spare..

You might look at a inexpensive $15 Tenergy wattmater. It will show current and voltage, plus peak amps, min voltage, watt-hrs (inaccurate in my opinion), and AH used. A couple of rides with it, and you kind of know how far you can go before you should recharge.

 

[zag0]

Thanks guys. So basically I can treat 1/5 bars as zero and recharge the bike then instead of waiting for it to drop to 0/5, right? Can I replace the SW900 some time in future to LCD3 which has a 52V setting or does the controller knows how to speak only to SW900?

 

[wturber]

Thanks guys. So basically I can treat 1/5 bars as zero and recharge the bike then instead of waiting for it to drop to 0/5, right? Can I replace the SW900 some time in future to LCD3 which has a 52V setting or does the controller knows how to speak only to SW900?

Probably only speaks SW900. The LCD3 needs to have a Kunteng (KT) motor controller and I'm guessing your controller is not made by Kunteng. But you could buy a new controller and LCD3 or LCD5 and replace your current controller and display - keeping them as backup. It wouldn't cost that much to do so. That said, I'd suggest seeing how you like the current setup first. The $15 inline Tenergy ammeter mentioned previously might be all you need in order to "calibrate" your segment display to practical range and capacity estimates. That's what I used for about eight months until mine got a bit flaky. (Though it never seemed to tally watt-hours right and I don't trust its amp-hour tally much either - thought it was at least plausible.

I've since upgraded to a two part ammeter where the shunt/meter module sends volt, amp, watt, amp-hr and watt-hr numbers to a (radio) remote display mounted on the handlebar ($35-50 to do something similar). I find that generally more useful than just tracking volts or using something like a five segment display. But it also adds more stuff to the configuration that you may not need or want. Fact is that I don't really "need" mine. But I think there's a benefit to seeing directly what's happening with power use and charging. I can directly observe voltage sag and quickly notice if things aren't behaving normally. Hopefully it will help me to catch small problems before they become big ones. I think of it as having gauges in the car rather than just "idiot" lights.

 

[thewiseguy8411]

SW900 doesn't show voltage, just graphics. After a week, you'll be able to correlate the graphics with your range. Try not to run the battery flat when riding. It kills the life.

Technically, you never run the battery flat when riding. The bike electronics is usually set to shut it off with 20% left. The problem you will have is that your SW900, if set for 48V, will take your 52V battery down to 40V which is about 3V lower than it should go. Not the best for long battery life. You battery lasts longer if you don't run it as low as the electronics allows. I rarely run one down to where the bike stops, even when I carry a spare..

You might look at a inexpensive $15 Tenergy wattmater. It will show current and voltage, plus peak amps, min voltage, watt-hrs (inaccurate in my opinion), and AH used. A couple of rides with it, and you kind of know how far you can go before you should recharge.

Hold down M and up for 5 seconds or so 3x voltage is shown