Water in GM battery pack when raining...

[Cornelius]

I had my concerns for a while, and today they was realized; enough water had seeped into my battery pack (on the bms side) during a short period of rain that the bms cut the power.

Normally, my bike are parked under a roof, but I was down in the harbour this afternoon to help a friend with his boat motor (that had been under water...  ). During my go at being a mechanic, there was a half'n hour of rain. When I was ready to go home, the bike was totally dead. Fortunately, my friend had his car with a trailer with him, so I was saved from an unmotorized bikeride home.

Well at home, I measured the outlet of the battery, and there was 0 Volts. I opened the bms end of the battery, and there was several droplets of water on the circuit board, and it was damp inside the plastic end. (BTW: the charger plug was also in the process of getting loose...)
As soon as I dried the water off and blew a bit to get the rest of the water off between some of the component legs, there was 39 Volts at the outlet...

I've been thinking of sealing the battery ends, and drill some draining holes at the bottom ends, but a thought struck me; a simple water resistant cover over the top of the battery would be better than sealing the battery. But i'm going to drill the draining holes anyway, so that any condens water has a way out...

And yes, I did get my friend's motor to run...

[GM Brazil]

a simple water resistant cover over the top of the battery would be better than sealing the battery.  But i'm going to drill the draining holes anyway, so that any condens water has a way out.

Both excelent I'm planning to crate come type of cover as an accesory to sell with the batteris. As my batteries will be shipped with velcro stripes for silent running, will be useful to hold the cover too

[Leslie]

Lucky duck.

Sealing the case ends Putting holes in it  is an interesting subject.

Depending where you have the pack and if there is water spinning off the wheel at the bottom may get wet as well.  The hole/holes should only need to be small.

The rain travels at an angle when you ride so putting holes at the front maybe a bad idea.

On the bottom is the best place.  Maybe put a rubber flap over the hole so it works like a valve it allows water and air out but nothing big like water and dirt in. 

A small hole/s, a rubber flap to go over the hole and some tiny steel screws to keep the rubber over the hole.  Not to seal the hole but to resist foreign matter from getting in.

Please show us what you come up with.

BTW how old is your battery and how many cycles and KM'S has it done so far?

Thank you for sharing.

[Cornelius]

Water from the wheel could be a problem for those without a mudguard; though, the battery works nicely as a mudguard for the rider...

That rubber flap should just shield the holes, not cover it completely. A little moisture on its way out of the holes wouldn't manage to push open the flap...

I bought the battery in May this year, and it have given me 355km so far, which should amount to 10 full recharges... I think I have drained the battery completely 2-3 times, but mostly discharged it to around 50% before charging it. So I have 'put the charger on' maybe 20-25 times... (In other words; barely used... )

[Leslie]

Water from the wheel could be a problem for those without a mudguard; though, the battery works nicely as a mudguard for the rider...

One way expensive mudguard you have .

Whats the range at 100% dod of the 48v 12ah pack or 36v 16ah pack you have there?

[Cornelius]

36V, 16Ah; around 35-38km with varied hills and flat ground...

I've just drilled three 2.5mm holes from the inside in the lower edge of the rear plastic cap of the battery. The holes are at an angle pointing down-backwards. With a little luck, the wind would even create a suction effect...

[Leslie]

Water from the wheel could be a problem for those without a mudguard; though, the battery works nicely as a mudguard for the rider...

One way expensive mudguard you have .

Whats the range at 100% dod of the 48v 12ah pack or 36v 16ah pack you have there?

Yea watch where that bit drills into.  You wont have water leak out of it, it will be smelly chemical ooze.

Thats pretty good range.  Nice, I would be lucky to get that with my 24ah SLA's.  Maybe new and freshly broke in they could do 50kms but it doesn't take long for them to loose that.

See I ride sometimes 50kms 60 kms a day and have to recharge between runs.  So I was doing up to 1.5 full discharges per day and almost every day,  The 12ah SLA would lucky to do 2 weeks before Id get the ships with them.  LOL  The 24ah batts were ok but as heavy as Ned Kelly on the day he died.

I bet you look into the batt box in 6mths time and it will be as dry as a bone.  Did you seal the caps?  Maybe with silicon sealant?

LOL at the suction.  You'd be the first to say "The faster my battery pushes my bike the more it sucks". JKe!

Oh well, I hope your mod works the trick.  I guess it sounds a little weird where you did the holes but I think you have an idea of how to put holes in something so it leaks the right way..

[Cornelius]

Here's a pic from the inside of the plastic end of the battery. The holes can be seen at the bottom; one in each corner, and one in the center...


I haven't sealed the end-caps; I think i'll go for the cover idea... A kind of a bathing cap...

Last year I used three 12V, 18Ah sla's, and I got only 15km between each recharge...

[Cornelius]

Once again, my battery was left out in the rain, and once again, the bms had small droplets of water on it, making it cut the output...
Due to the construction of the end-cap, the water seeps through the joint, and drips directly down on the bms...

I really have to try to make that cover soon...

[karen]

Some bags to put on the bike might fit... My battery had cardboard/carton around inside... saw no water... but been inside for a couple of days...

[Cornelius]

Just finished my cover for the battery...



I'm no wizard on a sewing machine, but it turned out fine I think... I threaded a rubber-band (for clothes) around the folded edges...

Karen:
no water now after some days inside doesn't mean it wasn't moist inside a couple a days ago... I'm guessing that your battery works ok now?

There is a cardboard inside my battery too, but only on the front of the bms. I think I try to reposition it so it covers the upper edge, like a shield from the top joint..

[karen]

Cardboard all around on mine. Battery works but the 48V battery is "unstabile". Both 24 and 36v works fine... sounds like there is something loose inside the 48v battery. When it starts, works fine... but sometimes have to turn on and off... and once gave up and took the 36v. Not sure what might be the problem... Might be water...

[MonkeyMagic]

nice shower cap corni



thats tops

[Cornelius]

Karen:
Something loose could be the charge plug; mine had a loose nut that rattled around. That nut also secure the minus lead from the charge plug, so it might be worth a check? it also could be a drop of hot-glue...

The cover seems to work rather nice. Though the material I chose does not breathe at all, so after much damp weather there's little bit of moisture underneath the cover.

[atcspaul]

nice job on the battery cover. I am going to try something like that