52V = PITA

So, Ive built a 52V battery for my 48V 1000W DD hub kit.

I havn't plugged anything in yet but Im worries the SW900 LCD won't read out the 52V as its made for 48V.
Im also unable to find a simple 52V LCD voltmeter anywhere in UK so I can see the V left if the SW900 fails to work.

Any ideas or experience with 52V woes.
Thanks

Pretty sure the SW900 will have some trouble displaying/processing the 52v. The internal battery gauge isn't gonna work right. The display will be off. The matching controller's LVC isn't gonna work either.

Other than that everything else should still function.

BTW: You will probably lose 10 hours looking for a "52v LCD voltmeter". Try searching for a 0-99v LCD voltmeter. Less than $5 shipped from China.

Once you have one of those just remember

Full battery = 14s x 4.2v = 58.8v
Half = 14s x 3.6v = 50.4v
Dead = 14s x 3.0 = 42v

I have to agree with the title of your post. My new 52 volt battery seems to be semi incompatable with my S12S controllers and their LCD 5 displays. It seems that the system was designed to recognize specific common battery configurations and the 14S pack falls between what it would see as a 48V pack and a 60V pack. The result is that for the first 10 miles on a full charge it periodically cuts power. I'm running throttle only so when the power cuts off all I have to do is release the throttle momentarily and it turns back on. As soon as the pack discharges to below 56V the problem goes away and everything works fine till the next full charge. I am going to start charging to only 56 volts to minimize this annoyance and possibly extend the life of the battery.
Back to your question. I don't know if your controller and LCD meter will like the 52 volt pack or not. You have to just try it and find out. As for volt meters, just search Ebay, the selection is astounding. Try to find one that has only two wires and takes it's operating power from the voltage being measured. That way you don't have to make a seperate circuit to power the meter.

Cheers folks, really good to get some solid info on this matter!

I'll have to look out for potential issues when fully charged. Maybe the Sw900 will be different to yours.
Im still not sure how you actually turn the bike 'on'. I've everything built but im just waiting for my BMS to finish the project. I see YT videos that show holding the middle button on the accompanying button set thats attached to the SW900. If the sw900 doesnt like 52V wonder will it turn on!?

Also...

I can only find 3 wire 0-99V LCD screens on UK eBay. Where does the 3rd wire go presuming the other 2 are + - .


In fact... ?

https://www.ebay.co.uk/itm/10V-100V-Universal-Digital-Battery-Capacity-Voltage-Voltmeter-Indicator-Ammeter/192592908520?hash=item2cd76e90e8:g:dj8AAOSwjodZ6Ir6

Oh... just been looking online more and it would appear that the sw900 has a 36V 48V + a 72V option. That would make me think that'll be ok however I think I'll still need a voltmeter as the % is bound to be out running a 52V on the 72V setting. I guess I'll only know what happens when I finally get the batter on there!

The SW 900 display looks suspiciously like the LCD3. The LCD3 is the big brother to the more compact LCD5 which I have. They use the same programing manual for both models the only difference being that the smaller LCD3 lacks a couple of features. If yours turns out to be a clone of the LCD 3 you may end up with the same problem I have.
Yes it will turn on with a long push of the center button. If yours came as a kit it hopefully will not need to programed but It is a good idea to review the programing and be familiar with it. Programing is done through the three buttons no other equipment is needed.
Yes It will turn on and will probably operate OK but don't be surprised to find that it has an annoying glitch or two.

Thanks man. I'll keep this forum informed... fingers crossed!

Don't these "smart controller w/ displays" read the initial Voltage when the pack/battery is connected? Has anyone tried this w/ a dis-charged batt. to a value approximating a 48 V batt. and see what happens?

I haven't tried a lower voltage aka 48 volt but I did put together a 15S "fooler" pack charged to 63 volts and used it to try and trick the controllers into thinking my 52 volt pack was a 60 volt pack. It didn't make any difference though.

0. 44 .8. 0 amps
10 % 46.2. 2
20% 47.6. 4
30. 49. 6
40. 50.4. 8
50. 51.8. 10
60. 53.2. 12
70. 54.6. 14
80. 56. 16
90. 57.4. 18
100. 58.8 or 59.1. 100.
the way to figure out how long to charge besides use volt meter while it's charging. if the battery is at 20 percent and you want to go to 80 percent. use the amp conversion the subtract. 16 amps minus 4 is 12 amp so if you habe a 3 amp charger charge it for 4 hrs. my 52 volt battery 20amp works fine with the sw900. I have a ebikeling 1500 watt motor

OK, I am now officially senile or maybe just retarded. I went back and looked at the listings for the S12S comtrollers I bought from BMSB. These are 36 or 48 volt controllers. There is another model that is 72 volts. The reason my controllers don't like 56 volts and above is because they weren't ment for that high of voltage and are trying to protect themselves.
Disregard everything I have said up to this point. I should replace my bike helmet with a dunce cap.

Hwy89, I'm pretty sure the SW900 is not a clone of the LCD3. My SW900 has the same connector as my LCD3's, but doesn't communicate with my KT controllers.

Ha, it barely communicates with the controller that came with it. Can't read external speed sensor, so won't work on a geared motor, and any PAS input takes motor to max speed, with nothing in between. I think there is an alternate version that supports variable PAS and speed, but mine is not that one.

As for 52V on my LCD3, I've run that with several 36/48 KT controllers, both the PSWpower sine wave and square wave 20A models, and the one Luna sells too. I'm not sure they all sets the correct LVC for 52V, but I now make a point of shutting down when the indicated voltage drops to 46V. The one time I let it go til the display blinked off, I couldn't get my 52V Luna charger to start the 52V battery. Might have been below Luna's LVC. (Of course, my Luna chargers have always been balky. I've had two others fail.) I had to start it with a 48V charger and later switched chargers.

motomech said:

Don't these "smart controller w/ displays" read the initial Voltage when the pack/battery is connected? Has anyone tried this w/ a dis-charged batt. to a value approximating a 48 V batt. and see what happens?

Click to expand...

I posted early about LVC may not be set on these controllers for 52V.

I run several of my bikes on either 36V and 48V batteries. I don't keep the batteries on my bikes overnight, so the controller will be discharged and recognize what battery is installed. If I switch batteries quickly, the batt indicator will often read one-two bars, usually when going to 48V from 36V, but as soon as the motor runs, it switches to full. I'm not sure what that implies. Probably related to the P5 setting on the LCD3.

Once, I played evil scientist and I put a almost depleted 48V battery on a bike, and the KT-controller saw it as a 36V unit. I suppose I could have run it down til the battery BMS fired, but that is not good for the battery.

Bestboy, my SW900 has a P03 capability to select 24.36,48.60, and 72. I powered it up on my 52V battery (56V) when I checked this.

It does make the batt gauge react in real time. On 72V, it showed discharge, etc.

docw009 said:

Bestboy, my SW900 has a P03 capability to select 24.36,48.60, and 72. I powered it up on my 52V battery (56V) when I checked this.

It does make the batt gauge react in real time. On 72V, it showed discharge, etc.

Click to expand...

This sounds promising... So, why not choose 60V instead of 72? Is 60V aimed at lead acid batts?