Complete Hobby King Lipo Protection Kit

[methods]

Here are those Battery Medic Test Results: Real vs Fake


-methods

[amberwolf]

So use some server PS's in series with one smart PS that can do CC? How does this limit what's coming out of the server PS's?

Because all current in a series circuit is the same. Lower current in one place and it drops in all of them.

[zukster]

So use some server PS's in series with one smart PS that can do CC? How does this limit what's coming out of the server PS's?

Because all current in a series circuit is the same. Lower current in one place and it drops in all of them.

Thanks, I'm more of a computer guy than electronics guy . I'm learning all the time though.

[methods]

I have made a correction to the picture of the Throttle Retard Assembly. It said TO HVC BREAKER when it should have said TO LVC/HVC/PARALLEL stack. Thanks to Jeff for the catching the error.... (somebody is paying attention )



-methods

[zukster]

Thanks to Jeff for the catching the error.... (somebody is paying attention )

I can't afford to pay attention. I spent all my spare cash on your boards

[ryan]

Hair dryer is perfect for Methods clear heat shrink. My torch was too hot and ended up splitting the shrink. Hair dryer was perfect.

[methods]

Yes... sadly that shrink is very thin. That is why I supply two layers. Just shrink it far enough to hug the connectors, don't go crazy and try to shrink it to 100%.

The original batch was a few mills thicker - and a prettier blueish color. This latest batch has a slight yellow tinge to it and is thin. Blame Matthew - he bought it

We are trying to find a new shrink supplier but it is harder than it sounds.

-methods

[zukster]

Here is how it works:
Normally - just plug in your charger and charge away!
If for some reason one of your cells gets overcharged this breaker will "lock up" and terminate charge. If this happens, please inspect your pack to determine the problem. After you have solved the problem - just press the green RESET button and you will be able to charge again.

The system is in the "ready" state - no need to press the RESET button unless something goes wrong. Thresholds are set at 4.29V so you should NOT need to press this button very often.... If you do, consider lowering your charge voltage or balancing your pack. -methods

So if we pretend that this is a relay, you mean its "Normally Closed?"

[methods]

Exactly

Like a latching relay really... if an HVC event occurs it blows the relay open and it stays open until you manually close it with the reset button.

-methods

[methods]

Somebody asked via Email if these are in stock.

Yes - 6S HVC/LVC/Parallel boards are in stock, HVC Breakers are in stock, LVC Retards are in stock, 5S and 6S extensions are in stock, and the super expensive 5S and 6S jumpers are technically available.

5S HVC/LVC/Parallel boards manufactured upon request

-methods

[ryan]

So I just received my 80A Maxi fuse and inline fuse holder and WOW is this thing HUGE! Is there anything a little more reasonably sized that you can recommend for an 18S setup? I have a cute little inline ceramic cylinder 20A 240v fuse for my charger. Do they make ones for more amps? Anything else smaller to recommend? I'm not sure I can fit this beast in my enclosure.

[zukster]

I think I used one of those on my car! You might need something that big for 80A though...

[acuteaero]

If you have a good high power iron and good flux you can solder wire directly to the terminals of the maxi fuse and save the space that the holder requires... You can also take a look at car-audio amplifier fuses, like an AGC or AGU fuse- they are glass cylindrical. Some people recommend paralleling small ATC blade fuses but I have had bad results doing that.

-H

[Kin]

So I just received my 80A Maxi fuse and inline fuse holder and WOW is this thing HUGE! Is there anything a little more reasonably sized that you can recommend for an 18S setup? I have a cute little inline ceramic cylinder 20A 240v fuse for my charger. Do they make ones for more amps? Anything else smaller to recommend? I'm not sure I can fit this beast in my enclosure.

I don't think AC fuses work for DC, so you can't just parallel a bunch of 240v 20a charger fuses.

I don't know what the answer is, but LFP asked a similar question for 125V viewtopic.php?f=7&t=32978

[ryan]

Thanks Kin. I bumped that thread to see if anyone has an answer yet.

[Alan B]

If you don't use a properly voltage rated DC fuse you run the risk that an arc will form and the current will continue for a much longer time, causing a lot of heat to be deposited into the fuse, wiring and short. DC fuses are designed to interrupt the arc up to some voltage, above that they may interrupt the current very late. Note that many maxifuses are not rated for high voltage, only certain models are.

[dougnutz]

I think most of us are just looking to stop catastrophic failures.
Since most of the fuses like the Maxi fuses are so large I've opted for fulible link wire on my high current leads. It's easy to fit into a lot of places and prevents the meltdowns associated with no Fuse.

[zukster]

Mr. Methods, what kind of epoxy were you using before for the boards? Anything special? Thermal conductive epoxies for potting at the local electronics store are expensive

Also, anyone out there know of a good 20 amp or better small waterproof power switch that works well?

Believe it or not, my best experience has been with regular wall light switches but they're not waterproof and they're kinda big. With a bit of glue gun glue, they hold up against most water, and they seem very resistant to carbonizing from the power-on sparks. 2 years + with 20 amp controller and 60V batteries with no problem. Ya - I know there are several ways to buffer the spark, but this works and is simple.

Still a smaller waterproof switch would be nice.

[ryan]

I think most of us are just looking to stop catastrophic failures.
Since most of the fuses like the Maxi fuses are so large I've opted for fulible link wire on my high current leads. It's easy to fit into a lot of places and prevents the meltdowns associated with no Fuse.

Please share more. I assume you mean "Fusible link wire". Can you link to an example?

[bigmoose]

This got me looking a little more:

Here is a page on fusible links: (I think 12 Gauge Fusible Link is for like 150 amps max, tried to find a good reference, but no luck yet. Going from memory....)
http://www.clipsandfasteners.com/12_Gauge_Fusible_Link_Wire_9_Length_p/a17465.htm

http://whiteproducts.com/fusible-faqs.shtml

Are there any general guidelines for choosing a suitable fusible link?
Typically, a given harness segment is protected by fusible link that is four gauge numbers smaller. A 14-gauge wire would be protected by an 18-gauge fusible link. A 6-gauge wire would be protected by a 10-gauge link, and so on. Odd number wire gauge sizes like 19, 15, 13 and 11 are counted when sizing a link. The length of a fusible link should not exceed 9"

Where can I find more technical information on automotive fusible links?
Specifications relating to conductors, insulation, wire size, length, location termination, identification and testing are spelled out in SAE Specification J156, The Society of Automotive Engineers.

There are some high current (up to 140 amps) slow blow rated fuse/fusible link like elements called Pacific Auto Links or PALs that are available through auto parts stores for about 5 bucks. When I pulled the data sheet on them, they are rated up to 58 Volts, which is a lot better than 24 volt rated fuses.

Here is a PAL with tabs:
http://www.clipsandfasteners.com/Pal_Fuse_100_Amp_Bent_Blue_p/a19296.htm

Here is the data sheet for these PALs: and a lot of automotive rated fuses. There is a nice EV fuse rated at 450V DC also:
http://www.pecj.co.jp/en/fuse/pdf/catalog.pdf

[methods]

I was just using standard epoxy. High end epoxy is WAY too expensive.

I use low voltage fuses in high voltage applications but the above posts are certainly correct... I have seen 100V DC sustain a 1" ark for several seconds. What is important to note is the load though... To rip a 1" spark like that you have to be pushing into an inductive load like a big oil heater. My experience has been a "short circuit" like you would see with a blown controller (shorted fets) or shorted wires (plugged in backwards) will quickly blow a MAXI fuse out. Really depends on whether you are trying to protect your sensitive electronics or if you are just trying to stop a major fire.

I dont really think the Maxi is that big... you really cant find a place to hide that? It is only 1cm thick....

I would not solder to the legs unless you have some way to bypass. I connectorize my fuses so that I can bypass them if needed. First time you blow a fuse 12 miles down a fire road in the middle of the national Forrest you will understand why.

-methods

[Kin]

I've heard of using metal dust/finest things you can find that aren't greasy, along with epoxy in some sort of suspension. I don't know how improved it is, though.

Was just looking for a few posts to verify my memory, most involve using thermal epoxy for adhesion of heatsinks, but it still seems relevant.

http://www.candlepowerforums.com/vb/sho ... rmal-Epoxy


I also know that certain high tempt epoxy putties advertise "includes titanium fillings!" whose point I guess is to reduce brittle fracture, but is still relevant to making things more thermally conductive.


If you use metal oxides it should still conduct heat and not be as conductive for shorting things.

[dougnutz]

I think most of us are just looking to stop catastrophic failures.
Since most of the fuses like the Maxi fuses are so large I've opted for fulible link wire on my high current leads. It's easy to fit into a lot of places and prevents the meltdowns associated with no Fuse.

Please share more. I assume you mean "Fusible link wire". Can you link to an example?

Yes, I ment fusible link Wire, I depend on spell check too much
Anyway it's common in the auto industry and most parts supply houses(ie Napa) will have it on the shelf. Most of the time it is rated at for amps, but if not it will list the wire size and the rule of thumb is to use a gauge size two sizes smaller than the circuit you are protecting. Again these things are designed to be "slow blow" but still stop catastrophic failures.

Another nice thing about fusible link wire is that if you do smoke the link while out on the road and need to make a road side repair you can twist the melted link back together and still have some level of circuit protection. That's pretty hard to do with a Maxi fuse, but you could carry a spare.

[zukster]

I connectorize my fuses so that I can bypass them if needed. -methods

Man - I'm thinking of connectorizing everything to make swapping failed components easier. I just went and got some standard 20A/30VDC M12 MODE SPST switches to replace a flaky one and I realized that connectorizing would be the way to go for everything. What kinds of connectors do you use for that?

I got some waterproof MODE boots with o-rings that thread onto the M12 part of the switch I bought to waterproof the switches. Epoxy the back, connectorize, done.

[atom1025]

Figured I would ask here in case any one else was unsure. So my throttle has red, black, and brown wires. The throttle retard cable is red, black, yellow.

My rc experience tells me the reds positive, blacks negative, brown is signal, yellow is signal.

Correct? Better safe then sorry.

Throttle is a thumb marked emaxi.

Adam


Edit to complete post.

So using the described method by methods two post down I determined my throttle wiring is as follows. Red +5v. Black ground. Yellow signal. Hooked it all up and everything moved like its supposed to.