Parallel modules to reduce BMS expense

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prepared1

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Cheap 4-life: Thanks for that info. Very helpful. What Chargery unit are you using?
 

Cheap 4-life

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The
Cheap 4-life: Thanks for that info. Very helpful. What Chargery unit are you using?
one with the 100amp shunt. They can be purchased with up to a 600 or 500amp shunt. There’s a main-base unit and a screen and a shunt. Did I mention that they are cheap. FYI I did have to send mine back to China because it wasn’t reading the cells voltage accurately. Jason fixed it and sent it back. Has been very accurate and working well. It’s a cheap bms. Probably lacks some quality control.
 
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OffGridInTheCity

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The

one with the 100amp shunt. They can be purchased with up to a 600 or 500amp shunt. There’s a main-base unit and a screen and a shunt. Did I mention that they are cheap. FYI I did have to send mine back to China because it wasn’t reading the cells voltage accurately. Jason fixed it and sent it back. Has been very accurate and working well. It’s a cheap bms. Probably lacks some quality control.
Agree with @Cheap4Life - I have several Chargerys and they are 50/50 work or break. But I really like them because they require 12v coil external shunt and have their own external 'display screen' (no phone or bluetooth required) and because the power switch will turn them on 'for activation' - e.g. no complicated 'power up sequence'. :) Typically the shunt's never work for me as I've not been successful calibrating them- but I don't care about that.

This leads to the 100a vs 600a price difference - e.g. this is a software setting based on what the shunt says because you need an external relay regardless. Since my shunts don't work (report 0 amps), I just get the 100a... so I don't need to pay extra for 600a. Not sure how to explain it exactly - maybe others will have a comment - but this observation might work for you as well to save some $ if you go this route.
 
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prepared1

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Cheap 4-life, and OGITC:

Before I saw your post about the Chargery, I was contemplating the BMS that came with the BMZ batteries from Battery Hookup. Not BMW....BMZ. They are a fairly large German company that does a lot of work in the battery space, including ESS. The packs that Battery Hookup sold had a BMS installed that limited the charge and discharge parameters if you used them as is. Nice packs, with Samsung SDI cells. I have a bunch of them sitting on the shelf.

It appeared to me that they might have originally been used in one of their residential battery backup systems. Not sure. You can still read about the modules on the BH website. The point being that it appears to be a good example of pack level BMS versus a system level that drills down from ESS to cell level. I don't see any difference between that and what you guys are doing with the Chargery, except you have a nice screen display. It is really hard to say whether or not one approach or the other is more expensive, because it doesn't seem possible to predict failure rates of individual BMS's, especially those from China. (which means most of them)

Many people comment that one of the leading causes of failure is heat, so the idea of using a larger solid state relay to switch on/off is a pretty good idea. The Nuvation BMS I'm looking at includes that feature. Of course, those are all additional cost items.

It would be nice to hear feedback from people who have been using the BH BMS's. If they have held up. From what I've read about Chargery, the comments you two make seem preety much typical. People do like them overall.

Thanks!
 

Cheap 4-life

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I’m thinking the people saying heat is causing them issues with the chargery, are using cells that are badly out of balance. That would make the bms have to dissipate more heat. Or they discharge or charge with a lot of amps which could make the cells need to be balanced more often. Mine gets a little warm to the touch but my cells are very well balanced and I only use max of 3000w and charge with max of 4000w. While trying to use the bms to balance very unbalanced cells I’m sure it would get hotter.
 

Cheap 4-life

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Agree with @Cheap4Life - I have several Chargerys and they are 50/50 work or break. But I really like them because they require 12v coil external shunt and have their own external 'display screen' (no phone or bluetooth required) and because the power switch will turn them on 'for activation' - e.g. no complicated 'power up sequence'. :) Typically the shunt's never work for me as I've not been successful calibrating them- but I don't care about that.

This leads to the 100a vs 600a price difference - e.g. this is a software setting based on what the shunt says because you need an external relay regardless. Since my shunts don't work (report 0 amps), I just get the 100a... so I don't need to pay extra for 600a. Not sure how to explain it exactly - maybe others will have a comment - but this observation might work for you as well to save some $ if you go this route.
The newest update seemed to make the shunt-bms much more accurate, actually spot on. It now reads .10 of an amp. Did you try to recalibrate for the shunt? It’s supposed to come pre calibrated. Or instead of calibrating (if you already tried that) maybe reset to factory settings and get the newest update
 
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prepared1

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OGITC: Somehow I missed your post about the Lithium Solar review. I'll take a look right awy. Thanks!
 

prepared1

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LithiumSolar: Fabulous video! One of the best I have seen. Will this end up with Blockmons installed? Are they needed?
 
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