Charging Proble

[dumbass]

I know it’s an old problem but I just can’t find the answer. I have a 48v 11.6ah dolphin pack that’s not taking a charge. I’ve had it about 5 years but it’s been very generally used. Never been below 40% and charged to 90% to 100%.

Last week I tried to charge it and nothing. I tried with 3 different chargers just to be sure it wasn’t a charger problem. I opened the pack and checked (with great hope) that it was just a broken wire but no such luck. I’m thinking it’s the charge side of the BMS so I was looking on Amazon for a replacement. I’ve noticed most or all replacement BMSs sold there require free wiring. Whereas, my current BMS is plug and play.

Does anyone know where to get a plug and play 48v 30a BMS? I have also been trying to find a place to just send it for repair but the costs I found online are crazy.

 

[markz]

Why risk it on ANOTHER random back alley BMS?
Just unplug the BMS and measure the voltages and see where its at.
Then simply charge the P sections up to equal and bulk charge and plug the random back alley batteries BMS back into the random back alley battery and see what happens.
Might save you some money

 

[john61ct]

Yes to test the cells just bypass the BMS.

Likely past EoL

 

[Chalo]

All the BMSes I've ever used to replace failed ones came with plugs for the sense wires. These almost never match the size, pin count, or wiring order of the BMS that's being replaced. The vast majority of the time, I have to solder the leads of the new plug onto the leads cut from the old plug, one by one. It's tedious but pretty easy because the wires are small.

Every single BMS I've ever replaced must have at least the cell negative and pack negative leads soldered or butt-spliced on. So in my observation, there is no "plug and play" solution. If you have an exception to this, please post a photo of it.

A five year old lithium ion pack is tired, even if you never used it at all. You probably won't get enough life or performance out of it to justify paying to have it repaired. Before you try to repair it yourself, at least use a multimeter to check the cell groups for balance. If you find significant imbalances, that's another point of favor of "do not resuscitate".

 

[dumbass]

I have not checked the individual cell groups but the current pack voltage is 47.2v but it has over 25 miles on the last charge so I would expect this low overall voltage.

Honestly I really don’t want to fool with it a lot. I currently have 3 ebikes (plus 1 for my wife). Two of them use this pack while the third is a behind the seat type pack. Because I don’t use this pack very much I didn’t want to drop $500+ into a new pack. But there are those times I want a second bike for a friend.

What’s the opinion of the cheap $300 pack from say Amazon?

I’ll have to go and read up on how to post pics it’s been a long time.

 

[markz]

Maybe wait for a sale on batteries from reputable sellers then going for some mystery bag off the usual back alley rando's on ebay/amazon/ali's

Probably some sales on before or after xmas.

But thats if you plan on riding more often then you were.
Otherwise might as well sell the ebike and ride a non-ebike whats coined an "Analog bike"

More to my point, your problem is a common one and is going to be more and more common as more and more people buy ebikes.

Chalo probably has a hundred thousand stories being as he has worked in and is working as a bike mechanic. Good thing for him, hopefully he doesnt have to deal with the public, just rock in, hide in the back, spin wrenches and let a smiling face at the repair desk do all talking. Be a rare setup but yeah dealing with the public theres always lots of stories man, I worked once as a teenager in a grocery store, many moons ago and dealing with the public is dreadful so full respects for anyone thats gotta deal with the public.
But I got a story for ya....
Slow day at the desk today


But let the story begin.

-----------> Bike owner will be enthusiastic and ride a lot, at first.
Then what normally happens?
Over time they become less and less enthusiastic about riding bikes (whether analog or ebike store bought/ready to ride) or maybe they get their license back and are driving again.
And the bikes get stored in the garage.
Batteries have a shelf life whether used or not.... as Chalo stated. Might be less of an issue then 10 yrs ago with the advancement of battery tech, chemistry mixtures and such.
On with the story - Time passes and the bikes in the garage are getting in the way
So the bikes are moved to the back yard shed or to storage unit called "The Cabin"
Rust sets in, chains, cables and gears discolor and cable housings deform.
Temperature fluctuations over the years of seasons destroy the battery
Then one year, enthusiasm kicks in, health kick, new years resolution

Then a few scenerio's happen.

1) Take the store bought ebike out of the shed, it wont work
Take ebike to your local neighborhood bicycle store
Bike mechanic shrugs but is nice and tries to help the best they can, yet they laugh internally because now the salesman walks over and is trying to sell you a new bike, as you walk away with salesman the bike mechanic says "They dont make a battery for your proprietary ebike anymore, sorry." and you have your credit card in hand as the salesman smiles selling you a new bike.
And guess what? The story repeats itself. ----------->

2) If its an Analog bike the bike mechanic gets a big wide smile says yes we can fix it, it will cost you $100+, but you say the Walmart bike aint worth that much, so you walk out of store and put the bike in the garage and the story repeats itself. ----------->

3) Now a third scenerio is you built your own ebike, which means you just buy a new battery and guess what happens. Ah ya you know it....

The story repeats itself.

 

[dumbass]

Yeah, back in the good old days I built my first 5 ebikes. The last 3 using Bafang 750w mod- drives. I still have 2 of them which I use this pack on. But I too have succumb to off the shelf ebikes. So my newest bikes for my wife and I have the behind the seat type packs. I really don’t want to have to buy another new odd pack which this old pack is. Hence the reason I was looking for a BMS replacement. But I’m 75 now and just not into the electronic side of things anymore. Hell I can’t even remember how to post a few pics. on here. On the flip side it’s hard to sell an ebike let alone one without a working Battery.

 

[markz]

Well the good news is you built your own ebikes from kits or piece by piece, twisting 8-10 wires together and spinning some wrenches aint that hard. People with proprietary ebikes are screwed.

Buying BMS'es is a crap shoot unless you know the BMS is good, like Besttechpower
http://bestechpower.com/ or you've confirmed a good BMS through someone else on ES who purchased one from a certain vendor.

 

[dumbass]

markz

Ok, I followed your link. I gotta tell ya that place is not for the amateur wire puller. And your right swishing wires and hanging off the shelf kits is easy. But that’s not all I did. But I wasn’t 75 years old then ether.

I think I picked out the right BMS (HCX-D270) all be it overkill with built in communications. But I can’t find the pricing on anything. Would you recommend I just call them and let them make a recommendation of what I need? Or am I getting in over my bald head on this? I’m willing to buy a new pack but I’m convinced these cells are still good cause I just ran them 25+ miles and they aren’t that low on charge. So I hate to just kick them to the curb. Beside, it’s a PITA to find a recycler that takes your old cells.