Recent content by jas67

I was concerned about the swing arm contacting the battery and bracket. I took it for a ride with just the box in the bracket, and purposely hit some dips that I think fully compress the suspension. There was no signs of contact. Also concerning was the change of lateral balance, hanging...

The second battery is now installed! It is a very tight fit. Test fitting the "battery analog": I lack welding skills and equipment, so, this is a bit crude, but, functional.

Wow, beautiful work. Sadly (for me) it is a bit above my pay grade.

If you use a BMS with balance leads, the charger does not need balance leads.

I have a Kweld, and couldn't get a good weld with .16mm copper + either a .1mm .2mm nickel strip on top. It would weld, but, pulled off too easily IMHO. .1mm nickel on top of .08mm copper works great for me though. I use 80J to weld that sandwich. The .08mm copper has the same conductivity...

OP: As others have said, you're not going to get any efficiency gain trying to make your scooter a hybrid. Maybe you should consider two removable batteries. My EV-converted Vespa weighs about 90kg as I bought it from the ES member JimVonBaden. He equipped it with a 2.7kwh battery that weighs...

I received the 15A charger. It works, the high/low switch works (15A/7.5A), but, the LED display, and the green/red LED status LED do not work. I'm trying to decide if it worth dealing with the return, or if I'll just keep it. EDIT: I'm returning it, just in case something else in it wants...

Regarding charging to 80%, I just program the BMSs to turn off charging at 82V instead of 84V.

It varies a lot, but, if I ride to my job about 40 miles (64km). I often go out to lunch when in the office, so, that could add another 10 miles. My range on the 38ah battery is about 35 miles given the speeds I typically ride (not an urban environment, but, one requiring 45-50 MPH). So...

I just ordered the 15A one. It alone will satisfy my needs most of the time. If I need a quicker charge, I'll hook up all three. Even the 4A one is good enough for an overnight charge from 20% back to 80%. Part of why I am adding battery capacity is to be able to aways keep my SOC...

I've already thought of this (I'm an electrical engineer), not a problem. The outlets in my garage are two duplex outlets per location with two different 20A circuits. I'll plug the 15A one into one of them, and the other two into the other.

As my EV-converted Vespa will have 70AH (72V/20S) of battery capacity, I'd like to get a higher-current charger (currently have a 4A and an 8A, which I've used in parallel for 12A). I'm looking at this 15A model: https://www.ebay.com/itm/234812216422 and this 25A model...

Each pack has its own BMS, which will handle balancing within each pack. As other stated, the packs must be at the same overall voltage when connected together. Once connected together, the overall voltage will remain the same, as current is drawn from them, the higher amp-hour pack will...

The second battery pack is now finished. I had chosen Samsung 40T cells for their high-current capability. The the first pack it is a 20s8p pack. In retrospect, I should've chosen a higher-capacity cell such as a 4800mAh or 5000mAh cell instead of these that are only 4000mHa. As this...

In this application, loads are 100-140A for up to a minute or two when climbing some hills at speed (400# total scooter and rider at 45-50 MPH). Flat(ish) ground cruising loads at 50 MPH are about 50-80A. I like overkill. The SB175 are definitely going to be overkill once the second battery...