Recent content by Indubitably

I recently had one of the cells on my lifepo4 motorcycle battery go poof, and when I opened the thing up I noticed that the shunt resistors on the BMS seemed somewhat less than impressive. I know these things are only built to take 3 or 4 amps, but we're talking gnat's ass surface mount...

Yeah, that's what I'm thinking. I mean, why NOT balance the cells every time you drive if you can? The problem I have at this point is finding a 4 channel bms that is rated for that short 150 to 200amp discharge peak. Charging should be good, since bms modules with a 30amp charge rate are...

No BMS, eh? So you're saying I should just manually top balance the cells and have something to disconnect the pack at low voltage? Still seems like I should have some over-charge protection for each of the cells since they're basically charging every time I get on the bike.

Anyone know of a BMS that would be suitable for use in a vehicle starter battery? They want about $170 for a 4ah motorcycle battery and I just can't bring myself to shell out that kind of cash for a battery with so little capacity. I was thinking maybe 4 15ah headway cells in series would do...

I have about a dozen 40ah lifep04 batteries (split into 3 packs, of 4 parallel cells each) that I want to charge, and I was hoping somebody might be able to give me some advice on which power supply I should go with. The two that best seem to fit my needs are the meanwell rsp-500-3.3 (or...

Mega: Not all that much really, the transformer is obviously your major stumbling block when it comes to weight. I suppose you could make it work with a coreless or aluminum wire transformer if you could find a way to cool it fast enough and were willing to trade volume for weight. Kepler: My...

I don't know about the 900w units, but the "2kw" units are pretty heavy. I dare say that you wouldn't want one tagging along for the ride on anything built for performance, even something in the motorcycle or scooter weight class. I suppose it might be worth the sacrifice for the right combo of...

So I bought one of these bad boys about a year ago (EMC 2000) and at the time I was using a 68.5v pack, but recently decided to down size to a 24v pack (3.6v * 7 thundersky 40a) to run a geared RC motor system. I've never had any trouble with the charger at the original 68.5v setting, but the...

So, apparently an ebike controller wouldn't really make sense as the inverter drive for a welding machine, but what about an induction heater? It seems to me that if you could target the ideal frequency for heating the filler metal instead of the base metal you could braze something like...

Hah! Excellent, so I'm not entirely crazy after all. I was afraid I might have to couple a pair of them to get true torque reduction though, and this does seem to confirm that such is the case. Perhaps it could be done in such a way that the differential housing would serve as the sun gear for...

Yeah, looks like my main problem was that I was simply failing to scale my mental model correctly. I was thinking we were talking coffee cup hot, when its looking a lot more like we're talking espresso machine hot, or hotter. If you visualize it in this range the whole thing goes to shit in no...

I appreciate that you're taking the time to explain where I'm going wrong, because that's how my ideas improve, but there is obviously some sort of disconnect, because all I'm seeing here is a reiteration of the basic reasoning behind my argument, only with a contradicting conclusion. What I'm...

I get that conventional wisdom says that compressed gas is inefficient, which is all well and good because most people don't stop to think about the fact that the majority of the kinetic energy being pumped into your system is going into thermal excitation of the gas molecules, but it is not the...

I've been farting around with the idea of using a high speed rc motor for my next build, simply because the little buggers are cheap as frak, crazy efficient, and weigh a fraction of what a comprably rated hub would weigh. The only problem is that no matter how I slice it, I keep coming back to...

I don't know, it seems to me like people have glued aluminum to great effect in the past with bikes, and it is certainly common practice among the DIY aircraft folks (not to mention the aircraft industry for that mater). Either way, it won't cost me much to try, so I'll let you know if it turns...