Dual Battery Balancer circuit - experiences!

[m@Robertson]

I have been recommending against the use of these gadgets since they became AliExpress staples for months. It used to be a battery combiner/balancer/whatever was a very rare bird, very expensive ($500 or more for a 52v that takes decent amps for a 2wd bike that gulps power) and low production volume from only one or two reliable vendors. Now all manner of yokels are buying them from Ali for twenty bucks and singing their praises. Its idiotic for exactly the reasons @Ravi Kempaiah said... you have absolutely no assurance of efficacy or quality control from a vendor who is unaccountable legally, and who as a group are infamous for cutting corners. And its a device that can cause a serious, catastrophic fire if those corners get cut.

These are the same people who are saying their UPP pack hasn't burst into flames (yet) so the $129 they paid for it was a smart buy.

 

[Daffyh]

Mine have worked ok so far on 1 ebike an 1 trike.
2 48v/11.6 Ah same cells both batteries purchased with bike when new.
48v/14 ah an a 48v/15ah on the trike.
SOP feeling is the 2 matched capacity same cell 11.6Ah ones give a little more oomph when use on the bike.
The trike has 1 silverfish case and uses the second 48v/14Ah downtube battery i bought as an extra for the 2 wheeled bike before i did the dual setup on either.

 

[PCeBiker]

Mine have worked ok so far on 1 ebike an 1 trike.

The problem is when they don't work they don't fail safely by shutting down, and they can fail catastrophically and set your battery on fire too.

You may not even have enough time to get off the bike before it bursts into flames.

I'm simply going to carry a second battery and swap it out when it's drained.
It takes two minutes.

 

[6zfshdb]

When I first started using these isolators, it seemed like a good idea, especially for long rides. Eventually, I realized it made no sense to partially discharge two batteries on a ride where just one was needed. It's a hassle if you only have one charger and need to recharge both. It also adds an unnecessary charge cycle.

It was a no-brainer for me to ditch these things, especially after the overheating incident. To me anyway, swapping out batteries or using a switch makes much more sense.

 

[Nvreloader]

I wonder what all the Big name brands, Bikonit, Biktwix, BacCou etc are using as they are also dual batteries?
I remember seeing a couple of potted isolators on my Wart Hog MD 750 bike, I think I took a couple of photo's and asked what they were and no one replied.
Up date: Here is the photo of this battery balancer, I think?

20220418-083105 hosted at ImgBB

Image 20220418-083105 in Nvreloader's images album

ibb.co

20220418-083316 hosted at ImgBB

Image 20220418-083316 in Nvreloader's images album

ibb.co

 

[Daffyh]

The problem is when they don't work they don't fail safely by shutting down, and they can fail catastrophically and set your battery on fire too.

You may not even have enough time to get off the bike before it bursts into flames.

I'm simply going to carry a second battery and swap it out when it's drained.
It takes two minutes.

I'm a walking dead man already an 2 batteries gives a nice boost.

 

[PCeBiker]

I'm a walking dead man already an 2 batteries gives a nice boost.

Yeah, me too.
I'll be 60 next month, I've got severe emphysema, gout, IBS, I smoke a pack a day, and I smoke pot.
But I'm still not going to use a battery balancer.

I finally got a second battery reliability installed on my e-bike after snapping the rack off the back, but I'm installing a Big Ole Switch if I want to connect the batteries together,..

 

[PCeBiker]

.

Have you looked at this unit? Seems to be a bit more sophisticated?

DATEx2 Parallel Battery Adapter - Big Game Bikes

Upgrade your eBike journey with the DATEx2 Parallel Battery Adapter – the 'battery blender' for seamless rides. Connect up to three batteries, handle diverse types, chemistries, and charge states. Say goodbye to inconvenient swaps! Voltage range: 24V to 84V.

biggamebikes.com

The battery balancer in your link is no longer available.

I wonder if it's sold out or if it was pulled from the market?

 

[m@Robertson]

Big Game Bikes is just the reseller. The guy who makes them still sells them direct although his web site is very clunky. IIRC its a Google Drive page that is accessed thru his Facebook page. Also his prices are much less than the resellers, but still expensive (but if the things actually work...) These are the only battery balancers I would ever consider using given the fact they have been in the market for so long and I've heard of no negative experiences. You'll never be able to say that about the cheapo AliExpress mystery machines.

 

[PCeBiker]

Big Game Bikes is just the reseller. The guy who makes them still sells them direct although his web site is very clunky. IIRC its a Google Drive page that is accessed thru his Facebook page. Also his prices are much less than the resellers, but still expensive (but if the things actually work...) These are the only battery balancers I would ever consider using given the fact they have been in the market for so long and I've heard of no negative experiences. You'll never be able to say that about the cheapo AliExpress mystery machines.

Well, I still don't want a battery balancer.
I'd rather switch from one battery to the next when I want.

Right now I do that by swapping batteries, but I will do that with a switch if I decide that I'm too lazy to physically "switch" batteries.

I went for a ride today and didn't need to swap batteries, so I only had one battery to charge.

I don't have a lack of power/amps issue with my e-bike running a single battery at a time, I actually turned my controller down to 16 amps from 20.

I want to help extend the life of my ebike.
Turning down the power helps to extend the life of all the mechanical components as well, by not stressing them as hard.

 

[6zfshdb]

I used this balancer until it melted and nearly caught fire!

Amazon.com

Luckily, it was still within the return window, so I sent what was left of it back for a refund. I've heard others, including Ravi, complain about similar incidents, so I didn't order a replacement.

I question the practicality of the device anyway. Why partially discharge two batteries on rides where one would do? I began carrying two batteries and swapping if necessary.

Last winter, I installed a switch to make the process simpler. If you do this, be aware that a DC switch, capable of handling 30+ amps, is a big clunky piece of equipment, and difficult to mount on a bike. Instead, I used a 40 amp DPDT AC rated toggle switch with a center off position. This switch IS NOT capable of switching a DC load of 30 amps!! It works well under low or no load conditions though, so as a precaution, I installed it where it can't be reached while riding.

I'm sure a more elegant solution could be put together that would switch a 30+ amp load, but that's a future project. For now, I don't mind stopping to throw the switch, I stop frequently anyway, so it's no big deal.

 

[PCeBiker]

,.. a DC switch, capable of handling 30+ amps, is a big clunky piece of equipment, and difficult to mount on a bike.

I'm going old-school Frankenstyle like,..

I'm thinking of spring loading it and mounting it under my seat?

That way I have to get off my e-bike to flip the switch, and if I fall or crash, the power gets cut, cuz I like to lock my throttle.

Something like this,..