Which JK 24v BMS?

[740GLE]

Looking to convert my 2P4S 230ah bank to a 24v 8s and would like to jump from JBD to JK. I’d like to stick with 200a range.

Is there any reason to go with the more expensive JK-B2A24S20P, vs JK-B2A8S20P?

This is for a modest 2.5 season camp with plans for a 3k inverter, maybe a 9k mini split for load. I can’t envision ever needing to jump up to 48v.

Anyone aware of and major design changes between the two BMS that would warrant paying for the more 8s-16s version?

Thanks!

 

[BentleyJ]

Unless you plan on later upgrading to a 48V battery with 16 cells, the lower priced BMS will function the same as the higher cell count model.

 

[DIYrich]

Some complaints about the heater connection on the 24s on older models. That would be a reason to stick with the 8s.

 

[E. Cho]

I use the JK_B2A24S20P in my 24V 8S DIY battery and it has been working very well for the 30 days of use. The app works well is simple and the Bluetooth connection is good at 25-30 feet distance, walls and 2 floors.

 

[740GLE]

Some complaints about the heater connection on the 24s on older models. That would be a reason to stick with the 8s.

Yeah I have no plan on using the heater, just low temp protection is fine but I put the camp to bed before deer freeze and the battery stays warm in the garage all winter.

Thanks for the info

 

[Rednecktek]

Some complaints about the heater connection on the 24s on older models. That would be a reason to stick with the 8s.

I've got one of those that has the heater cable, but I've never figured out how it's supposed to connect to what. 1 tiny red, 1 tiny black, and 5 tiny green wires all bound up in a tiny ring terminal.

Also, the 24s version is a LOT of extra wires that have to go in weird places. I'd stick with the straight 8s.

 

[740GLE]

I've got one of those that has the heater cable, but I've never figured out how it's supposed to connect to what. 1 tiny red, 1 tiny black, and 5 tiny green wires all bound up in a tiny ring terminal.

Also, the 24s version is a LOT of extra wires that have to go in weird places. I'd stick with the straight 8s.

thanks I’m thinking of leaning toward the 8s, just suits my needs and saves a couple bucks.

 

[SolaroSsaurius]

IIRC last years's 8s was more prone to problems that the 24s, but I don't know how is the current crop doing...
Maybe ping @upnorthandpersonal ?

 

[upnorthandpersonal]

In the current version that is shipped out, the issues are resolved. There was a batch that had the wrong voltage converter installed and it would break after some time and would have to be replaced with the correct version. But as I said, those sold right now should have that all fixed.

 

[740GLE]

Thanks for the insight

 

[740GLE]

B2A8S20P Ordered via aliexpress and slow shipping, we’ll see if the price was too good to be true when something arrives in mid September.

 

[googdot]

B2A8S20P Ordered via aliexpress and slow shipping, we’ll see if the price was too good to be true when something arrives in mid September.

I ordered mine from Hankzor on aliexpress a couple of months ago. Shipping was estimated to be 6 weeks to New Zealand when I placed the order, but it arrived in about 10 days.

 

[740GLE]

I ordered via the JKbms store (whoever that is these days) in ali, already said it’s in the forwarders hands, time will tell what arrives.

Hopefully I don’t regret trying to save a few bucks vs a US supplier or Hankzor.

 

[upnorthandpersonal]

I ordered via the JKbms store (whoever that is these days) in ali, already said it’s in the forwarders hands, time will tell what arrives.

Hopefully I don’t regret trying to save a few bucks vs a US supplier or Hankzor.

As far as I know, it's also Hankzor, or at least @Nami.

 

[Nami]

I've got one of those that has the heater cable, but I've never figured out how it's supposed to connect to what. 1 tiny red, 1 tiny black, and 5 tiny green wires all bound up in a tiny ring terminal.

Also, the 24s version is a LOT of extra wires that have to go in weird places. I'd stick with the straight 8s.

NOTE: For instructions on heating cables,
the green 5PIN cable of the heating cable needs to be linked to the heating pad,
and the rest of the black and red cables are linked to the smart charger
(after the smart charger links the BMS,
it detects the temperature of the battery through the BMS,
which automatically monitors the charging status of the battery)
Heat Function interface
Description of heating function:
Battery temperature is below low temperature charge protection, turn off charging, turn on heating.

Cryogenic charge protection is a parameter that can be set within APP

The heating power depends on the battery voltage and the resistance value of the heating film.

Battery voltage U.

Heating resistance R.

Power equals U*U/R

Heating current I=U/R;

The maximum I (current) of the board design is 3A.

MAX heating power 200W(100W OF B2A8S20P).

 

[Nami]

As far as I know, it's also Hankzor, or at least @Nami.

YEAH

 

[Rednecktek]

@Nami you're my hero, although I'm still a little confused. So green wires to heating POS+, red to batt Pos+, and black to battery Neg-? Heating pad to batt Neg- as well?

 

[740GLE]

So my 8S arrived last week, package was just in a bubble wrap and cardboard box. Slight dent to the cardboard box only damage appears to be the connector for the on/off switch.

I never wired up the same switch on my JBD, always used a manual switch plus the app to turn on turn off so I’m not that concerned.

Including lugs is a nice touch even though I’ll prob upgrade to a larger awg, I have 4awg on hand I intend to double up on and be good.

 

[omaigadlol]

So my 8S arrived last week, package was just in a bubble wrap and cardboard box. Slight dent to the cardboard box only damage appears to be the connector for the on/off switch.

I never wired up the same switch on my JBD, always used a manual switch plus the app to turn on turn off so I’m not that concerned.

Including lugs is a nice touch even though I’ll prob upgrade to a larger awg, I have 4awg on hand I intend to double up on and be good.

Sorry what's this mean, that you don't need a JK switch? or that you can use a generic one?

 

[Rednecktek]

Sorry what's this mean, that you don't need a JK switch? or that you can use a generic one?

More importantly, is there a way to NOT need the switch??