Sunthing battery 48V 15Ah

[dogman dan]

I say bullshit that you will ever see 35 miles range at 24 mph out of that size battery.

At 24 kph, you would go that far, so maybe that's just a typo. My personal best was 39 miles, and I got 30-35 miles from 48v 15 ah many many times, by riding about 15 mph.

At 24 mph, I would get a very consistent 22 miles from a full 700wh. The question remains though, does the cheaper sunthing pack deliver 700wh?

I think it will, or come very close to that. It's the V power packs that have had the history of under delivering capacity under a 1-2c load. Those packs were using a much cheaper round cell. Your sunthing pack has a 5 ah pouch cell that should deliver very close to 5 ah in use.

Once you get your CA dialed in, you will get very accurate miles. The best way is to measure the distance the wheel rolls in one revolution, in mm. That's the number you enter into the CA. It will differ for different tires, but I tend to just use 2025 for my 26" street tires as a close enough number.

You will still have a good record of total ah discharged, and cycle count by looking at another screen. So reset your CA every time you charge your battery.

 

[dnmun]

How many watt hours of the 720 should I expect to get before the bms shuts it off? One last question. I've read that opportunity charging is not wise as it heats the battery up. Is this true for the LiFePo chemestry? I had a chance to do some opportunity charging today, but wasn't sure if I should.

how much energy you can get from the battery depends on the balance and if one cell is low it will hit the LVC before the others and shut off the BMS. you don't really wanna discharge the pack that deep unless it is an emergency.

you should charge the pack at every opportunity. it supplies power more easily when it is fully charged than when discharged. not sure who told you that stuff but there are a lotta half brained ideas that get posted here as though they are true.

 

[overtonmath]

Today I went on a long ride. I put a trailer on the bike and put some gear in the trailer. I wanted to ride until the battery turned off. I got 24 miles, the last 5 miles were wide open throttle. The battery turned off at 14.69 Ah and 690 Whrs. So I guess I didn' quite get that 700 Whrs out of it, but very close as was Mr. Dogman's prediction.

Thank you dnum for the advice on the opportunity charging. I'm going to start bringing my charger with me everywhere I go now. Thank you everyone for your words of advice and encouragement. I don't think I would have gotten this far without them. I'm going to order a second battery and begin to prepare for a trip over winter break. So. California is in a drought, so I'm going to take advantage of the wet free winter. It looks like my Sunthing battery has (so far) turned out pretty good.

I really think alot has to do with those early charges when I first got the battery. Putting on the charger overnight and then only going on a very short ride like 100 yards and then recharging to get the battery balanced. Thank you all again for making this point, as I would have taken off on a long ride right away and maybe would have had some of the problems that I've read others having.

 

[dnmun]

when you run the battery down to low voltage it is harder for the lithium ions to go from the cathodic matrix over to the anode because there are not many ions left to go over there from the chathodic matrix. so try to avoid discharging the battery so far down as this, as much as you can.

but the other side of maintaining the battery is to not overcharge it which is why the BMS is critical, and there is an aging phenomena associated with charging that causes the lithium to 'plate' out of the electrolyte when you keep charging above 3.60V.

so once the cells charge up then you can use it right away. if you don't use it much, then leave it partially discharged and then when you need to use it then charge it up. once the pack is balanced it should stay that way for a long time, and the BMS will compensate as the individual cells age and their resistance to charging changes by allowing them to balance at the end of the charging cycle when the charger reduces the output current down to the 47mA level of the shunts.

 

[NeezyDeezy]

Hi Overtonmath - would you mind giving us an update on your battery? Are you continuing to get about 700wh out of it?

 

[imorton]

I'm also curious