SMC 28C 4000/5000 Hardcase Lipo part 2
#1456
If you show up to tech above the limit you're sitting the run out. There's not "do overs" in tech.
Here's an idea for big races that use a spec item: How about handout batteries- pre-charged! It'd be a bit of a load keeping batteries charged but you wouldn't need one battery for each racer, they could be on rotation. This would probably only be good for the lower amp-draw classes.
Here's an idea for big races that use a spec item: How about handout batteries- pre-charged! It'd be a bit of a load keeping batteries charged but you wouldn't need one battery for each racer, they could be on rotation. This would probably only be good for the lower amp-draw classes.
#1457
Tech Elite
iTrader: (8)
If you show up to tech above the limit you're sitting the run out. There's not "do overs" in tech.
Here's an idea for big races that use a spec item: How about handout batteries- pre-charged! It'd be a bit of a load keeping batteries charged but you wouldn't need one battery for each racer, they could be on rotation. This would probably only be good for the lower amp-draw classes.
Here's an idea for big races that use a spec item: How about handout batteries- pre-charged! It'd be a bit of a load keeping batteries charged but you wouldn't need one battery for each racer, they could be on rotation. This would probably only be good for the lower amp-draw classes.
#1458
I didn't know they were doing that. I think a "one shot" policyis necessary to prevent people from overcharging. They won't do it if they know they'll miss their run. Allowing them to come back around doesn't really address the safety, not performance, issue that the rule is designed to prevent.
#1459
Tech Champion
iTrader: (73)
I didn't know they were doing that. I think a "one shot" policyis necessary to prevent people from overcharging. They won't do it if they know they'll miss their run. Allowing them to come back around doesn't really address the safety, not performance, issue that the rule is designed to prevent.
#1460
That's a variance but your charger still doesn't appear to be overcharging. If somebody's fluke resulted in a 8.48 voltage, then the charger is not made to the safety standard it should've been and it should no longer be used. Teching for voltage is a way to weed out those things. It doesn't even matter if the overcharging was intentional or not, it's the responsibility of the racer to abide by the rules and to be sure that their gear does too.
#1461
well put!
#1462
I didn't know they were doing that. I think a "one shot" policyis necessary to prevent people from overcharging. They won't do it if they know they'll miss their run. Allowing them to come back around doesn't really address the safety, not performance, issue that the rule is designed to prevent.
#1463
I didn't know they were doing that. I think a "one shot" policyis necessary to prevent people from overcharging. They won't do it if they know they'll miss their run. Allowing them to come back around doesn't really address the safety, not performance, issue that the rule is designed to prevent.
#1464
#1465
I think it was exactly the opposite (the reason for teching voltage). But either way, it's an important thing to police. Mkint one shot will guarantee that racers will check their gear at home and be sure that their chargers are calibrated right. Things like the LRP charger coming out with a voltage adjustable voltage threshold are dangerous. LiPo battery chemistry isn't flexible (correct me if that's wrong), 8.4v is the cieling for safety, isn't it?
#1466
Tech Master
iTrader: (13)
its going to come down to you are going to have to go up during practice and compare your charger to the voltmeter being used at tech and see where it falls, just like you don't depend on your scale at home for car weight, i'd hope you would weigh your car on the tech scale when you practice, get there and just do the same with the tech voltmeter, now thinking about it CE should make the peak adjustable to allow for this "self teching", not a massive range but 8.30 to 8.50 volt maybe
#1467
I don't want to encourage overcharging but if you think that it's a saftey issue that a charger overcharges a pack by .08 which equals to .04 per cell then your way to freaked out about Lipos. The standard is to charge at 4.2 per cell but there is a margin of error with these packs. The cell will not catch on fire if it goes to 4.24 or even a bit higher. ROAR does overcharging tests and apporved packs will withstand some oevrcharging.
#1468
Man! If you volt meter is that far off .. get a new one or replace the battery!
#1469
I just wanted to know if I could send my GFX back? I didn't mean to start a riot about the rules ROAR has already laid down.
John St.Amant my parents used to tell me....."if you don't have anything nice to say don't say it at all". Please show Danny/SMC and this thread some respect as they are here for customer support and to help guys out that use or are planning to use their product. The man knows a lot more about battery technology then you, as proven by your recent posts. So if you have something productive to add feel free...................
Casey
John St.Amant my parents used to tell me....."if you don't have anything nice to say don't say it at all". Please show Danny/SMC and this thread some respect as they are here for customer support and to help guys out that use or are planning to use their product. The man knows a lot more about battery technology then you, as proven by your recent posts. So if you have something productive to add feel free...................
Casey
#1470
I don't want to encourage overcharging but if you think that it's a saftey issue that a charger overcharges a pack by .08 which equals to .04 per cell then your way to freaked out about Lipos. The standard is to charge at 4.2 per cell but there is a margin of error with these packs. The cell will not catch on fire if it goes to 4.24 or even a bit higher. ROAR does overcharging tests and apporved packs will withstand some oevrcharging.
2. OVERCHARGE – LiPos are extremely non tolerant to an overcharge condition. A standard charge profile is CC/CV to 4.200V. Drastically overcharging a cell just once is a sure way to send a cell into thermal runaway. Overcharging a cell slightly but repeatedly is also extremely bad for a cell. For example, it you charge a cell to 4.300V, the lithium ions start plating on the electrodes forming lithium metal. Lithium ions are not flammable, but lithium metal is. Every slight overcharge cycle will plate more and more lithium metal resulting in a battery that is very prone to igniting.
http://www.rctech.net/forum/electric...res-101-a.html