Hy Protocol217,
Unlike audioguru, I can find nothing wrong or contradictionary about the battery pack protection board that you have ordered, and while some eBay products are unreliable and badly specified, in my experience most are OK, and excellent value for money.
audioguru is quite right about needing a separate battery charger as the circuit you have ordered does not do that.
Before you go any further though you need to do a few basic calculations.
(1) What maximum current will your skateboard take? LiIon batteries have a maximum continuous current rating, typically, C/10 or C/1, where C is the Amp/hour capacity of the battery, in your case 2A/H.
There are two consequences of taking too much current from a battery.
(1.1) You will damage the battery and possibly cause an explosion.
(1.2) You will radically reduce the battery duration so that a 2A/H battery may only provide 0.2/AH
There are high current LiIon batteries that are designed to provide a high current, typically 20A and 30A safely and without reducing capacity too much.
(2) You need to decide what your priorities are:
(2.1) Long battery life
(2.2) High battery duration.
For (2.1) if you charge at a current of no more than C/10 and charge to no more than 4V and discharge to no less than 3V you will have a good battery life.
With this approach you can use a simple constant voltage charger with a current limited of your chosen charge current, 300mA.
For (2.2) you can charge to 4.2V and discharge to 2.6V to get maximum capacity but reduced battery life. In practice, unless you have a constant voltage inverter between the battery pack and skateboard motor, there would be little point in discharging to 2.6V.
If you are going to charge your batteries for maximum duration, you need a smart charger with -dv/dt detection to complete the topping charge without wrecking the batteries.
This will be anathema to tcmtech
, but my strong recommendation would be to build your battery packs so that the individual batteries can be removed for charging. To charge seven batteries you would probably need two four-way chargers, but I think you can get eight-way chargers. This will give you maximum flexibility and give you the best battery life and endurance.
Just the routine word of caution, only buy main-line manufacturer's batteries: Sanyo, Panasonic, Sony, Varta, LG, Samsung, from a reliable supplier, because batteries are the biggest rip-off items on the net and generally. Don't be tempted by fantastic paper specifications and low prices.
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