Dual battery

[tomjasz]

@Thomas Jaszewski can you give me more details on the switch and voltmeter, like the name/model and where it was purchased?

Last product on the spec sheet.

 

[Ayl]

Perfect! Thank you @Thomas Jaszewski.

 

[Jermaine468]

Hey
I was wondering what is the height from the ground to the top of the second battery with the bike standing straight?
Seems like a nice setup but looks like it would be in the way when you come to a full stop.

 

[pushkar]

What size bike ? With second battery on top, the stand over height of Medium is around 33 , large would be 34/35.

 

[Jermaine468]

I am 6' 1" so it would be large bike.

Thanks

 

[TomD]

Pushkar, can you translate this post? I think it has to do with dual battery setup but not sure if you use diodes.

My Bafang Ultra Mountain Bike! Frey AM1000

That is crazy heavy. My guess was that weight with both batteries and an extra large. Bummer. Tom If that was "with" batteries it would still be heavy but, alas, that's without them!!

endless-sphere.com

 

[pushkar]

That is slightly confusing to me as well. I’ll do more research but based on my limited understanding, I believe this is what this person wants to say-

1. Frey dual battery converter design has a limitation that they don’t have the “cap” (capacitor) to limit voltage overages.

2. If all they are using are diodes (and no capacitors) then there is a situation that the total voltage to the controller is 48+48 or 52+52 (not sure how but I think that’s what he is saying)

3. Newer stock Bafang controller is specked for up to 90v input voltage. However the corresponding displays don’t have that protection so they get fried if the input voltage is beyond the display design spec.

So what he is recommending is to let innotrace know if someone is using the Frey dual battery system, since the input voltage is not constant.

If this is the issue OP is referring to, then does this affect watt Wagons dual battery system?
No it does not. https://wattwagons.com/collections/accessories/products/dual-battery-converter. You will see capacitors (small components sticking out over the heat sink) on inputs and outputs. Cutoff is 60V. You can safely use it with any 48/52v system (even non Bafang).

But this is not just a Frey problem IMO. I am aware of atleast 2 other manufacturers (that I won’t name here) that are using the non voltage limiting “dual battery system”.

 

[Nashville615]

Pushkar, just digging up this old thread for a question or two. So with the battery module. It only discharges one battery at a time right? Assuming it round robins the using the two based on which one has the most voltage at the time? I'm assuming this is how your keeping both batteries in isolation but still using the capacity of both (regardless if one is 14ah or 19ah).

Thinking about ordering one of these but wanted to make sure that the system keeps both batteries in isolation and protects one from the other.

 

[pushkar]

Pushkar, just digging up this old thread for a question or two. So with the battery module. It only discharges one battery at a time right? Assuming it round robins the using the two based on which one has the most voltage at the time? I'm assuming this is how your keeping both batteries in isolation but still using the capacity of both (regardless if one is 14ah or 19ah).

Correct.

Thinking about ordering one of these but wanted to make sure that the system keeps both batteries in isolation and protects one from the other.

yes it does protect each battery.

 

[Nashville615]

Thanks. Will get one ordered.