Ooops! Water in battery case, won't charge.

[jimriley]

Just found water in the battery case, HL 36v 17ah. I'd left the bike out in the rain last week. The battery is now showing only a glimmer of red on the scale when I push the button on the case, reading 36.04v with the meter, the charger light is staying green when I connect the charger so it isn't accepting charge.
I've opened it up and am drying it out. It had about 75% charge when I left it off the bike a couple of days ago so it has drained itself. My initial thoughts are that the BMS may be knackered. I think, from the meter reading, the cells haven't dropped below the minimum voltage, though I'm not sure what that is exactly.

Any thoughts on resurrecting it? I'll try again when it's dried out.

 

[saneagle]

It depends where the water got to. In principle, the damage should be minor and repairable if you open the battery quickly, disconnect the cell leads (multipin connector), then get the water out.

First thing to check is each cell voltage. You can do that where the multipin connector is soldered to the pcb, or disconnect it and check the voltages on the side slits.

If any cells are down, they need to be charged individually with a single-cell lithium charger of any 5v charger.

When you get all the cells up to the same as eeach other, you can reconnect the BMS and leave it overnight to make sure that none of the bleed transistors are staying open and draining the cells back down. You can get a good idea about that straight away by putting a finger on the bleed resistors. if any are bleeding, they'll be warm.

 

[Nealh]

Are you related to Cwah .
He's famous on here for drowning a 48v battery by leaving it out in the rain.
Depends how much H2o got in, invariably H2o will kill cells so as d8veh has said one will need to check individual cells.

 

[jimriley]

Update. Tony woosh has advised me to talk to Andy woosh, will do. However, having read the replies and using stuff sucked up by osmosis reading the forum I've done some checks with meter and nose. Nose tells me there's a fried vole odour around the BMS. Meter tells me, taking the cumulative readings from the multicore plug, that the 10 groups are all 4.1v . So looks like a new BMS will fix it.

 

[saneagle]

BMSs always smell burnt.

 

[sjpt]

BMSs always smell burnt.

Shame we don't see many reviews of BMSs. It would be good to know if they had a hint of blackberry aroma, or just a touch of burnt rosemary to the nose.

 

[guerney]

Just found water in the battery case, HL 36v 17ah. I'd left the bike out in the rain last week.

Why did you do that @jimriley? My bike has been left to stand in rain for hours while I'm gardening, after cycling in the rain 12 miles there, then again for 12 miles back - after your battery is repaired, put two waterproof rucksack covers over your battery! Because one cover is never waterproof enough when exposed to hours of rain - secured with velcro straps, they don't look at all tidy, but they do the job of keeping my battery dry.

 

[jimriley]

It wasn't actually the bike that got left out in the rain, I left the battery out, I'd put it down upside down so water gathered in it*. After last nights meter testing is full - 41v, I'm wondering if its the led voltage level gubbins that has suffered. The initial symptom I noticed, when I pressed the voltage level button, was just a glimmer on the red bottom light but voltage indicator led. The light on the charger was showing green. I'll check it later today when I've got time. It may well be working now it's dried out.

* I'm advertising for competent staff!!!

 

[saneagle]

Why did you do that @jimriley? My bike has been left to stand in rain for hours while I'm gardening, after cycling in the rain 12 miles there, then again for 12 miles back - after your battery is repaired, put two waterproof rucksack covers over your battery! Because one cover is never waterproof enough when exposed to hours of rain - secured with velcro straps, they don't look at all tidy, but they do the job of keeping my battery dry.

What you have to be mindful of is the expansion of the air in the LCD and battery. When they're operating, they both get quite warm, so the air expands. When you park the bike, they cool down and the air shrinks, which sucks in more air from outside. If water is sitting at the location where the air comes in, it gets dragged in with the air.

In an LCD, the water goes up where the cable comes out.

Batteries are not such a problem because the air comes in the connector, which is normally fairly well protected and should give an easy path for air flow, so no pressure to suck water in; however, manufacturers sometimes try to seal the battery completely. In that case, the pressure would be large and it'll suck the air in wherever it can, like the case joint. Many of the batteries I had to repair or diagnose were completely sealed and had water in them.

Likewise all the drowned controllers I've seen were after the owner tried to seal them.

It's counter-intuitive, but sometimes it's better to give the water an easy way in and out rather than try to seal. The trick is to let it in where it doesn't matter

 

[Saracen]

Leave a bike in the rain NO problem common sense cover battery with bag, mine is a cut down black bag and Bungee tied round easily removed and fitted. Surely common sense !!!

 

[Saracen]

Also winter riding guards CORREX cut to size and Cable ties

 

[Saracen]

Why did you do that @jimriley? My bike has been left to stand in rain for hours while I'm gardening, after cycling in the rain 12 miles there, then again for 12 miles back - after your battery is repaired, put two waterproof rucksack covers over your battery! Because one cover is never waterproof enough when exposed to hours of rain - secured with velcro straps, they don't look at all tidy, but they do the job of keeping my battery dry.

No but 5p black bin liners are waterproof

 

[jimriley]

Update on the update, now all dried out reassembled and working fine. Phew! At least I kno how to check battery cell state with meter. Also don't leave battery upside down in rain, it really isn't waterproof that way up!

 

[guerney]

No but 5p black bin liners are waterproof

My battery is bolted to the rear rack, so for me at least, a black waterproof rucksack cover plus this hi-viz version over it has proven effective as a battery rain hat. I've used them for years, but your seepage may vary.

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(old long exposure phone camera photo illuminated by nothing but moonlight, on top of a hill overlooking the city while I'm enjoying a kebab and coke one hot summer night, before cable tidying and installation of extra headlights, plus other lights and other things)

 

[guerney]

In an LCD, the water goes up where the cable comes out.

You've seen this before but @Saracen might not have: Because I don't trust waterproofing claims made about anything, a couple of years ago I made a rain hat for my LCD. It shields the cable exit, doesn't completely enclose the LCD - rectangle cut from the very thick and very strong clear plastic bag my Aeroshell 22 arrived in; placed over the LCD, folded it over, so that the hood extends a couple of inches down, gaffa taped around the edge of the display, then a bit of self-amalgamating rubber tape was stretched around to make it look neater and add a little light impact resistance. Works a treat.





@Saracen - perhaps you could cut a bin liner into sheets, cover your battery with a sheet and stick it in place using sellotape temporarily, glue on 10 more sheets, then transfer the lot to make an interior lining for a rucksack cover? Glue it in. Velcro it on using velcro straps? My straps stay on my rack, kept there by zipties. Might make it easier to take off and put back on than 5 bin liners? Also bin liners are pretty flimsy, you'll forever be replacing them. Better still, you could use thicker plastic sheets, for a longer lived waterproof battery rain hood.