grazy+1949 wrote:So that leaves the 7 that go to the PL8v2 balance port.
I have an ex Silicon Engineer in the States currently calculating the power I will need from my new battery pack to do the 7 km climb to the next mountain village. I have a feeling that he will be advising: 48v 120-180 Ah pack, with a specific cell "C" rating for my particular duty cycle.
Burgerman wrote:ALL WRONG!!!
There are NO stock presets that will work properly.
Worse you are charging it to way too high voltage!!!
You have all the thing set wrong. Your lithium battery is LiFePO4 8S and its charge voltage should reach a MAXIMUM of 28.80V or rather 3.600V per cell, and fuel doesent work, its for lipo. Thats supposed to be turned off.
YOU are charging it with incorrect settings and as a lipo which it is not!!!
STOP doing anything. You are ruining your cells.
And use the PC to update firmware to the newest one, and then load THIS preset with the correct settings.
REMOVE .ZIP FROM THE FILE NAME. IT IS NOT A ZIP...
ex-Gooserider wrote:And simply looking for 'as big as I can fit' gets around needing to worry about a lot of those variables....
ex-Gooserider
ex-Gooserider wrote:You are sort of right about it being possible to come up with a 'spec' but it also is a bit of an exercise in futility as BM says... There are a huge number of variables, which he just mentions a few of...
As folks that don't have the somewhat easy option of hiking down the road to the gas station when the vehicle craps out, we basically have to plan either our trips or our vehicles to NEVER run out of 'gas' - aka charge...
So the basic requirement has to be set all variables to 'worst possible' and spec to handle it... Couple this with the fact that in order to get the best life out of your batteries (either lead or Lithium) you want to keep the C-rate and depth of discharge as low as possible, and you end up with our rule of thumb - namely stuff as many Ah of battery into the thing as you can make fit and keep the size reasonable... On a power chair, that is usually optimized as two group 24 lead bricks in volume - and if going to Lithium keep the same physical dimensions and stuff as many Ah worth of cells into it as possible to keep the C-rate on the pack down (and get the increased range as a bonus...)
And simply looking for 'as big as I can fit' gets around needing to worry about a lot of those variables....
ex-Gooserider
LROBBINS wrote:If you have your car along, you can also run the Pl8 off its 12V.
We have now uploaded the presets and got the display on the PC. It shows cell 4 as being approx 2.0v below the rest.
Before the BMS out op. the pack would charge to 26.5v using a 50€ charger. Today it charged to 28.61v.
Tomorrow I will road test it on flat roads with some short 20% inclines and see how it performs. It'll be interesting to watch the LOW on the voltmeter. As I've always said, this pack will go in my powerchair and the new pack will go in the single seater rover. Off-road and beach usage will become minimal.
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