scalawag wrote:Clark could really help the durability of his boards by mounting an on board fuse like every other manufacturer seems to do.
After my string of blown boards I have built in glass blown fuses into my power line-in on the switch just in case.
Clark has always specify 7.2v, I think we are stretching it by saying that 2S operates on 7.4v which is close enough, but I can't fault him if I plug a battery in and it gives out 8.4v. That is 1.2v over the advertise limit. There is no documented support whatsoever for lipos such as low voltage warning or higher tolerance on 2S.
The funny thing is that I also found out the volt reg on the Clark will give out a warning before it blows. So if you turn it on and start hearing this clicking sound you have about 5 seconds to save your Clark board........
A quality Nimh in good/new condition will put out 8.4v when freshly charged. The quality ones are designed to drop to 7.2v quite quickly, and then maintain that voltage until it will drop to 6v quite quickly. The difference between cheap Nimh's and expensive ones is how long they maintain that consistent voltage. I use 3700mah - 4200mah Nimh batteries and even when attending weekend meets I haven't had one that needs recharging yet.
Lipo's kick out one hell of a current. They will melt Heng Long switchgear (they are only 0.5amp rated), so if using a Lipo the preferred mounting is to ditch the HL switch and install a heavy duty one, or do away with the switch altogether and have a direct plug, Deans connectors or any of the approved Lipo plugs are best.
Here's an example of what is going on
Current = power ÷ voltage
For example, what current flows through a 1.15 kW electric fire at a potential difference of 230 V? Remember that 1.15 kW is 1,150 W.
Current = 1150 ÷ 230 = 5 A
Fuses come in standard ratings of 3 A, 5 A or 13 A.
The best fuse to use in this example would be the 13A fuse. The 3A and 5A fuses would blow even when the fire was working normally.
So, when you hook up a board with no fuse, and use a battery with a high current, the current is channelled through the first component on the board with the least resistance, and if it is less than the current it's a bottleneck in the current flow, it will fry either when it is plugged in, or when the board starts pulling more current.
It's how electric fires work. Narrow gauge wire passing high current, the wire cannot pass all of the current through it, so it gets red hot when the heat builds up. Even a foam cutter attached to a 9v battery works the same way. Compare it to a river, when it rains and there is more water, the river bursts its banks. If the river is going down a pipe the water will build up backstream until it finds a weak point and flood there instead. A dam solves the problem, but even that will breach if there is enough water.
wibblywobbly wrote:
Lipo's kick out one hell of a current. They will melt Heng Long switchgear (they are only 0.5amp rated), so if using a Lipo the preferred mounting is to ditch the HL switch and install a heavy duty one, or do away with the switch altogether and have a direct plug, Deans connectors or any of the approved Lipo plugs are best.
So, when you hook up a board with no fuse, and use a battery with a high current, the current is channelled through the first component on the board with the least resistance, and if it is less than the current it's a bottleneck in the current flow, it will fry either when it is plugged in, or when the board starts pulling more current.
This isn't true, any battery will provide current in proportion to the work required of it (be it the esc, sound system etc), whilst a LIPOs are capable of sustaining a higher current than an nimh it will only provide what is asked of it. The exception is a short circuit, when the ability of a Lipo to provide more current can easily cause big problems.
If your not doing work then a big powerful battery of the correct voltage won't hurt your electronics. The problem is over voltage, or incorrect polarity, either of these will fry your electronics. Damage to components from current only happens when if your trying to do too much work such that the current damages the components:
