RC-Monster Forums - View Single Post

BrianG · 11.05.2006, 12:53 AM

Providing your charger can charge at the proper rate, the charging process will take about 1.5 hours give or take.

Most lithium chargers have a power limit. This means that if the charge voltage X the charge current exceeds this limit, it will only charge up to that limit. Example: the Hyperion has a power limit of 120W. If you try to charge a 3s 12Ah pack at 12A, the charger will only charge at 9.5A instead of 12A. This is because 12A * 12.6v (4.2v/cell X 3 cells) is 151W. So, think about that before you buy a charger if you decide to go with a 3s pack at high capacity (over 8Ah).

You can either get two packs for 40 min each and change them out, or get one big pack. It depends what is most important to you. If you really want one long continuous runtime at the expense of a heavy single pack, then go with one big pack. If you don't mind replacing the pack halfway through, then two smaller packs is a better option. The less weight will actually increase total runtime over a large pack of equal total capacity because the truck won't have to haul that extra weight around. I would choose two smaller packs over one big one. Two 8Ah packs should be perfect IMO. Other people would suggest getting three 6Ah packs instead for less weight.

	(#16)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	11.05.2006, 12:53 AM Providing your charger can charge at the proper rate, the charging process will take about 1.5 hours give or take. Most lithium chargers have a power limit. This means that if the charge voltage X the charge current exceeds this limit, it will only charge up to that limit. Example: the Hyperion has a power limit of 120W. If you try to charge a 3s 12Ah pack at 12A, the charger will only charge at 9.5A instead of 12A. This is because 12A * 12.6v (4.2v/cell X 3 cells) is 151W. So, think about that before you buy a charger if you decide to go with a 3s pack at high capacity (over 8Ah). You can either get two packs for 40 min each and change them out, or get one big pack. It depends what is most important to you. If you really want one long continuous runtime at the expense of a heavy single pack, then go with one big pack. If you don't mind replacing the pack halfway through, then two smaller packs is a better option. The less weight will actually increase total runtime over a large pack of equal total capacity because the truck won't have to haul that extra weight around. I would choose two smaller packs over one big one. Two 8Ah packs should be perfect IMO. Other people would suggest getting three 6Ah packs instead for less weight.