Fiido Dual Hub Motor Setup

The decent China guy's that have good custom/hot battery experience - Cohnis/Risun have a very decent combiner/blender tech. I have their original 40A which has worked reliably for me over 2yrs now. Thes guys also claim to have 80A and 120A versions that I have not had occasion to buy/evaluate yet - these guys have at least 2 hats - connhis motor - and risunmotor - a friend of mine has bought (2) Molicel 72V batteries from them to complete his CYC Ripper Build stiff - my friend is still Pissed with me - with every upgrade he does - every time he still gets dusted by my Rion Scooter - and that gives me that one more ride on my Rion that I come back alive from.
I will say that I have bought motors from both Conhis and Risun and things went well with both. Very well with Conhis who DHL'd me a motor in a week from China. When it arrived with a broken casing (wrapped fully in padding so whoever packed it on the line did so knowing they had dropped it and broken it), they DHL'd me a replacement casing.
Oh, so they ARE, or HAVE BEEN, offered by vendors in the civilized world, it's just that two of them are out of business and the one remaining is not actively selling them, and none of these have sold any large quantities. OK.

SO, these two batteries, with different max voltages, different AH capacities, different ages, cell types, and construction techniques, once they reach the same voltage, are they expected to STAY that way? They won't, because they will have different rates of voltage sag. So, either the unit is frequently switching back and forth from using only the strongest battery, while each cycles between sag and rebound, or, is there some sort of difference threshold, wherein they are paralleled but with a slight voltage difference?

Tell me how accurate the BMS readings will be when there is an incoming current.
Jeezus enough with the whining already. If you are afraid of DIY, or not up to the task, don't do it. Its not for everyone (i.e. adults only).

SO, these two batteries, with different max voltages, different AH capacities, different ages, cell types, and construction techniques <snip>
You made all that up. Nobody said 'hey lets do everything wrong and say its ok'.

Here's a good counterpoint from a vendor I trust. I don't fully agree with what he's saying, but he's echoing some things I've already said here about them being black boxes whose reliability is not uniform or necessarily trustworthy.

This is a Voltage Sensing electronic one-direction Gateway. - all current from either battery goes "Out" - it is IMPOSSIBLE for current from the connected battery(s) to go back thru the Blender to another connected battery.

This is a Voltage Sensing electronic one-way Gateway to PREVENT the dangers of direct parralel cbattery connection- you get this part - right ?
Some owners want to consider going to Double-Battery system - if they want Added Range and they are wiiling to take on added weight.

From my side - I would ONLY add a 2nd battery if it was same voltage and same chemistry - from the onset I have said NOT responsible for any goofball products or goofball applications.


The "BRAND NAME" component on ALL my eBike's are the Samsung or LG battery cells - Bafang motors (if they have them) as Bafang is publically traded on the SHA exchange.

Man - if 2X Batteris is not your direction - that's OK - but for Forum members looking to go 2X - YES a Combiner/Blender/Discharge-Converter is ONE GOOD WAY TO GO.
So, Mr Fabb, you would only use one of these with two batteries of the same max charged voltage, and I'm sure Mr. Spock agrees, which would mean you disagree with nearly single ad posted for these boxes, almost all of which tout mixed-voltage capability? You will, of course, remove that section from ads which you post in the future, won't you?

This is not "DIY", it is "sure you can trust half-assed chinese engineering". I'd sooner just make a Y-cable and monitor voltages myself, though THAT sure won't get popular because nobody is making a buck on that deal.

I, also believe that they are "black boxes whose reliability is not uniform or necessarily trustworthy".

I also will note this statement "Nobody said 'hey lets do everything wrong and say its ok'." Estimate for me the percentage of the userbase seeing these ads on this site who could tell you ANY ONE SINGLE THING to do "wrong" in this situation. Less than 10%, IMO.

You don't hand out 5-gallon cans of gasoline, along with a pack of matches, to six-year-olds. Putting such devices in the hands of users here or on most such sites is an equivalent action.
High Voltage - with respectable 8K+channel subscribers - my summary of what he says - " I haven't seen the product - I haven't used the product - if you need more capacity buy a bigger single battery" .... gee's he is almost too technical for me to understand !

JohnnyNerdOut - 55K+ subscribers - my summmary - "I have customers asking me about combiners - and I tell them if you are looking to increase your range by adding a 2nd battery - a Combiner/Blender will maximize your range with two batteris - heck it's $60 and here are the two versions you can buy from my web store".

My eBike Zen Quote for today : "My life would be Perfect if I just stopped thinking about it"