Battery Fuses blowing frequently

[medusa569]

I am having my 30a battery fuses blow almost every time I ride my bike. No excess weight than normal to strain the bike. It didn't use to be like this...it will even blow when I've just finished replacing the fuse in the socket and it'll blow instantly without starting throttle. It seems like its a battery heat issue. The voltage seems to be alright when I take it home. What steps can I take to either cool off the battery and otherwise correct this frequent fuse blowing situation? I have an eZee battery with BMS. The BMS was checked out within the last 3 months by another local biker and he said it checked out alright.

medusa

 

[dnmun]

what are your peak amps on the cycle analyst? why not replace the fuse with a larger one? maybe you can just remove the fuse holder and solder the wire together to remove the fuse from the circuit.

 

[cassschr1]

If it blows instantly doesn't it have to be a short?
Or maybe this is when you turn controller on and you have a fast acting fuse in there ex AGC, try a time delay fuse.

 

[dogman dan]

Sounds like a short to me. If you replace it with a big enough fuse, the fire will show you where it's shorting.

Don't go and actually do that. Look for the short. got a wire that chafed somewhere?

 

[medusa569]

Sounds like a short to me. If you replace it with a big enough fuse, the fire will show you where it's shorting.

Don't go and actually do that. Look for the short. got a wire that chafed somewhere?

I as well don't think going to a larger fuse is the way. I don't think there is a chafed wire somewhere because this is what started many months ago when I thought the controller was the problem...i noticed today that when it happened again ( almost every time I ride for about 45 minutes....I thought the fut had blow as the power went fttttttttt...but I turned the battery off then on again and it started right up. So apparently its not necessarily the fuses will blow ( as they all didn't look blown) but it just seems to peter out and stop... what is a slow acting fuse?? How long do you other guys ride your bikes and do your batteries get hot???

 

[medusa569]

If it blows instantly doesn't it have to be a short?
Or maybe this is when you turn controller on and you have a fast acting fuse in there ex AGC, try a time delay fuse.

No its not when I turn the controller on....its after I've been riding....then after some time power will stop completely.. I thought the newly replaced fuse blew because of the heat of the battery case....its felt pretty dang hot.

 

[medusa569]

what are your peak amps on the cycle analyst? why not replace the fuse with a larger one? maybe you can just remove the fuse holder and solder the wire together to remove the fuse from the circuit.

I think keeping the fuse in the circuit is the wiser thing to do ro protect the battery and controller.

 

[dogman dan]

Well, now I'm just confused. Are actual fuses actually blowing? As in, they are cooked and never work again till replaced with a new one?

Or are you talking about a bms cutoff, or controller low voltage cutoff, and calling it a blown fuse. Or is it a "fuse" that's actually a circuit breaker that resets.

A really hot battery is being murdered by the rider, in general. Warm is fairly normal. Sounds to me like you got a lot of bike running on perhaps not enough battery.

 

[999zip999]

Do you know the amp draw of your controller ? What motor combo ? and a little more on the battery, voltage ah. Hot ? What. Help us help you. Info

 

[jateureka]

I am having my 30a battery fuses blow almost every time I ride my bike. ..... I have an eZee battery with BMS....
medusa

Most eZee controllers are limited to 20A and the 10Ahr batteries are rated at 2C. The battery output fuse is F30A 250V.

If your controller is allowing more than 20A current draw then you could be tripping the BMS in the battery.

If you are blowing the fuse (it should pass 30A all day at 25 degrees C) then you are exceeding the capabilities of the battery and you most likely have a short circuit somewhere.

 

[medusa569]

well in Some cases the fuse is actually blown as I can see the broken filament....but sometimes like yesterday when the power stopped I turn the on off switch again on the battery and thanks fully it started right up..no cooling off period, nothing. I remember that happened some times as well before. I have a regular glass cylindrical fuse..it does not reset itself to my knowledge ..I don't think the eZee batteries do that. As for a lot of riding...I don't know what's considered a lot. Generally its happened after traveling about 4-6 miles. Not much uphill grade in general and I pedal assist when it comes to hills as to help the battery out. I just hooked up the GT battery analyzer so I'll try and see if I can't get some numbers when this happens but frankly the display on that analyzer flashes so much outside of voltage I couldn't see an accurate picture of the other measurement. I wish I could change the display frequency and change it from 2-4 sec. to longer.

Well, now I'm just confused. Are actual fuses actually blowing? As in, they are cooked and never work again till replaced with a new one?

Or are you talking about a bms cutoff, or controller low voltage cutoff, and calling it a blown fuse. Or is it a "fuse" that's actually a circuit breaker that resets.

A really hot battery is being murdered by the rider, in general. Warm is fairly normal. Sounds to me like you got a lot of bike running on perhaps not enough battery.

 

[999zip999]

Still havn't heard about the controller from Medusa. The controller draws the amps. Yes ezee battery. And ? Most have. ? You have ?

 

[dnmun]

remove the fuse if it is blowing and solder the wire across the gap.

buy a cycle analyst or even just a wattmeter and use it.

if your battery case was that hot and it is limno4 then it is already overloaded.

if the fuse is not blowing frequently, then the title should reflect that. maybe something like 'i cooked my battery and even blew the fuse once'.

 

[dogman dan]

Sounding more and more like a medium battery running a big controller to me. Hot battery is being murdered. But maybe not really his fault. The heat may be a lone remaining good cell in a cell group toting all the load, and getting hot at 2-4c discharge rate. The early shut off of the bms symptomatic of a battery with a ruined cell or two reducing the capacity.

 

[docnjoj]

If the OP is willing he should get the battery out and test it. I know Justin keeps spare cells for these types of situations. We could walk him throug the test procedure, at least if the battery is not under warrantee.
otherDoc

 

[dogman dan]

Some kind of examination is in order, it's not just a problem with the fuse most likely. As bad as I see nowdays, I could put the wrong size in replacing it myself though. Is this fuse located in the metal battery box, or is it in a fues holder on the wires like Justins old nicad packs had? Mabye there is a chafed or pinched wire inside the metal box causing one of the problems? The other problem sounds like bms trips early.

But we still don't know what motor and controller this is. It could be just too much, causing the fuses to pop occasionally. I used to pop the 30a fuses on my nicad packs running a lawnmower with em. This weekend I finally got around to hooking the CA to the lawnmower while running it. The grass was very very thick this time, so I thought, lets see how bad it could be. Stopped the blade once in the thick stuff. Max amps 182. No wonder I popped a few 30 amp fuses. Normal cutting it still draws 1500-2000w. A mere 80 amps. No wonder the thing worked so bad on lead batteries.

 

[999zip999]

Maybe he has a 40amp controller.

 

[medusa569]

Some kind of examination is in order, it's not just a problem with the fuse most likely. As bad as I see nowdays, I could put the wrong size in replacing it myself though. Is this fuse located in the metal battery box, or is it in a fuse holder on the wires like Justins old nicad packs had? Maybe there is a chafed or pinched wire inside the metal box causing one of the problems? The other problem sounds like bms trips early.

But we still don't know what motor and controller this is. It could be just too much, causing the fuses to pop occasionally. I used to pop the 30a fuses on my nicad packs running a lawnmower with em. This weekend I finally got around to hooking the CA to the lawnmower while running it. The grass was very very thick this time, so I thought, lets see how bad it could be. Stopped the blade once in the thick stuff. Max amps 182. No wonder I popped a few 30 amp fuses. Normal cutting it still draws 1500-2000w. A mere 80 amps. No wonder the thing worked so bad on lead batteries.

I have a watt meter so I will be doing some test runs when I have nowhere important to go with my bike. I just got through mounting it so soon i i will try and see some numbers. I have a Nine Continent front hub motor 500W , sensored, ordered some cheapier chinese controllers supposedly for 36 volt. ..which is the battery size is Actually my shutdown problems started about 6 months ago..when I thought my controller that came with kit got rain damaged. With the great help of 2 local here they checked out my equipment and one guy even went into my Ezee battery and checked each cell and checked out the BMS and said everything checked out fine. But obviously something is wrong..and I think the BMS shutdown BUT I have had equally blown fuses...so now when the power peters out I went just lay back and turn the on off switch and see if it starts right up..which it did again today. But as usually this happens after I've been riding for a while...about an hour or so. If it doesn't start up and I'll check the fuse and replace that and I;'m good to go. The fuse on the eZee's is build on one side IN the plastic battery case. It is a 30 amp fuse. I made sure to replace it with the same Amp that was in it.
The battery I have is a Lithium Manganese...36 V.

 

[999zip999]

Almost enough info. How many amps is your controller set for ? This is The number one question to be answer. The controller demands power form the battery the battery gives it to it dies. So the new controller my be demanding to many amps for the fuses and shut down to save your battery. Amp draw of the controller ?

 

[dnmun]

take the fuse out of the circuit since you have a BMS on the pack. it is obviously too small and it is overheating because it has bad connections that are causing a big voltage drop across the connections. these experts who examined your battery were experienced in battery repairs? did they measure the voltages while the pack was on the charger and did they do a capacity test to verify that the pack was functioning normally? did they record the cell voltages so you can compare them now?

 

[dogman dan]

So it's just the fuse that heats up? Or is the whole battery getting hot?

It could be as simple as a poor contact at the fuse holder causing that point to heat up. Once hot, maybe enough amps to pop the fuse.

Doesn't sound so much like a permanent short anywhere now, so mabye just put a 40 amp in there?

We reaaaaaally need to know the amps of that replacement controller. It needs to be in the 20 amp range to work well with that battery. If you have a 40 amp controller, it could occasionaly draw all 40 amps, popping either the fuse or the bms easily.

I'm betting it's the controller causing some of the problem now.

 

[medusa569]

I just got the duplicate of the controller I am using. Its a KU123 High Speed Controller" The sticker on it gives the follows specs:
For 36 v battery , power 500w, over current 30a , LVC 27.5V Fits 3 speed switch kit For hall sensor and sensorless motors

Does this help any?

An interesting note..from my first run using watt meter during ride I noticed that the voltage reading occasionally dropped to allegedly 34 volts. I don't know if the GT watt meter is buggy or what but if the battery or controller is set for a safety cut off why didn't the system shut down?? I really hate this 2 second display switching..between trying to watch the road and watch the "dashboard" it's irksome.


medusa

 

[dnmun]

what was the max amps reading on your wattmeter after the ride where it dropped to 34V?

is this pack 10S or 11S of the LiMn2O4?

how hot was the fuse when you had the low voltage reading? it did not blow this time?

 

[dogman dan]

30 amps ought to be enough to seriously strain an Ezee battery. And if it doesn't shut itself off fast enough, pop a 30 amp fuse when you pull a 50 amp spike.

Yet another case of a controller/battery mismatch I think.

 

[amberwolf]

If you have a 40 amp controller, it could occasionaly draw all 40 amps, popping either the fuse or the bms easily.

It coudl draw a lot more htan that, potentially. My generic 12FET "40A" controller draws momentary peaks of over 60A during startup on CrazyBike2. An 18FET (probalby meant to be a 60A unit) draws momentary peaks of well over 100A.