Over-volting YesComUSA kit

[smorse1]

I have the 48v 1000watt motor/controller kit from YesComUsa--the ebay special.
I am running 4 10ah SLA batteries that get me the 5 miles to work easily, just a little heavy. (6 lb each) Before anyone suggests another battery technology, let me say that I am happy with this, at the distance I am travelling.
I am interested, however in just a little more speed, which I am assuming would be more voltage. The SLA batteries are at ~54v total coming off of the charger or 13.5v.
My main question, if I add a 5th one to make 67.5 volts, will I fry anything, ie my controller or motor? Will it make any kind of difference in the performance of the bike over the 5 mile run?
Thanks in advance!

 

[dogman dan]

You'd need a different controller. Almost all 36-48v controllers have 63v capacitors inside which might blow with 5 sla's. So look for a controller with 36-72v operating range.

Of course, you'd go a bit faster on 48v without the sag, but it's true for 5 miles sla can work fine. Just don't replace em with more lead.

 

[smorse1]

Thanks Dogman, either the good or the bad, I have a virtually unlimited supply of the SLA batteries, for free. I hate the weight, the mongoose bike I have them on now has lasted about 350 miles, to and from work, and is showing signs of wearing out.
I have a Trek that I got at an auction that has better components and I built a battery box that fits 4 of these SLA's in the frame triangle nicely, but I have yet to switch the motor over.
any recommendations on a controller that would work without breaking the bank?

 

[wesnewell]

I've got the same kit. The controller that comes with it was an infinion EB215 15 fet controller with 75v fets but only 63v caps, so you're limited to 63 v technically. You could add a 6v sla in series and still be within specs, but another 12v would likely blow the caps. 6v more will get you a little more speed and range, but not much, but if you have a 6v sla, adding it will work fine. LVC will still be 42v, so it leaves the potential for over discharging the 54v pack, so you'd need to watch that. If you want to invest about $35 for another controller like I did, you could go up to an 84v pack of 7 12v batteries, if you could fit them on the bike.
Also, the EB 215 controller that comes in the kit supports regen braking, cruise control, and other features that aren't enabled when shipped. You can enable these if you want to.