Tiny BMS s516 - 150A/750A

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rexgoodwin

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Mar 12, 2021
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As I am building a 48v, 400A and 40Ah battery pack (13S) to power a 360A controller, has anyone used this particular BMS (Tiny BMS s516 - 150A/750A) to operate on the 750A peak/600A continuous side instead of the 150A peak/60A continuous? If so, can you explain the connections highlighted in the image below please?


1615808006206.png
 

rexgoodwin

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Mar 12, 2021
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The red square on the left is your current CT sensor the red box on the right is a relay to enable current to go to your load.
Later floyd
The current sensor is a lem 150/750 https://www.ebay.com/itm/LEM-Curren...682051?hash=item2ce736b083:g:WPgAAOSwjfhcir8H
Are both the current CT sensor and relays mandatory? Would it function if I bypass these two components and connect the left red square directly to the main battery negative and the right directly to the load running from the main battery positive?
 

floydR

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without the CT sensor and relay the bms is limited to 30A charge/ 150A discharge I believe

later floyd
 

rexgoodwin

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without the CT sensor and relay the bms is limited to 30A charge/ 150A discharge I believe

later floyd
Just curious, do you happen to know any other bms rated at 360A/+ continuous discharge current? Or the tiny bms the only bms capable of running such continuous current?
 

floydR

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(tiny bms)The ct sensor isnot included with the bms. and the relay(s) are not part of most bms's I have seen
The chargery bms has a 600A unit but how good it is I can't say. A several levels up you run into more capable bms's you have the batrium, the REC bms , you have midlevel bms's such as the tiny bms, emusbms, diybms, a few bms's with relay support come after the midlevel bms's Chargery bms is one that comes to mind.
later floyd
 

OffGridInTheCity

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I've purchased nearly 10 Chargerys so far... because I like that they have an external 'display' but....

The 100a, 200a, ... options are only how much you can change the setting in the software! You still must have an external relay with a 12v coil. Gigivac makes hi-amp relays - https://www.gigavac.com/sites/default/files/catalog/spec_sheet/mxnc14.pdf I use a 200a Gigivac relay with a Chargery 16T on my APC 3000. And a Chargery 16T can do 13s.

The Chargerys are a bit fragile - I wouldn't strongly recommend them as I burned 3 up already on stilly stuff....
- The temp sensor touched the negative side of a battery and shorted (somehow) - should not have been electrically active in my opinion
- One unit just blew something inside - no reason
- I shorted a an 18650 7s7p battery + -> - accidentally, the fuse wires blew (just fine) but now the Chargery won't balance.

You also might want to consider Daly for really large amps. Not sure if they do 13s. 500a Example: https://www.amazon.com/DALY-Protect...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
@DIY Solar Power with Will Prowse has done several 'tests' of these -
 
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floydR

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Daly bms's have had a few problems too https://www.facebook.com/photo?fbid=4297027043659736&set=gm.1376576496022241, Since this is for an EV? use the best BMS you can afford. With the Ct sensor the tiny bms is around 300 usd add a relay/contactor The Gigavac ones mentioned in OGITC post would work. i just bought 10 GX14BBB-1 on ebay for about 17 Usd each. The ones I have have 12v coils which would have to be steped down from 48v for use with many relay capable bms's.
Later floyd
 

OffGridInTheCity

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Gigavac makes all kinds of (high quality) relays. In addition to the 12vdc coil I got a 48vdc coil from Evolve Electrics - here's an example of 350a @ 48vdc coil ($123) - https://evolveelectrics.com/products/gigavac-gv200?variant=29041999806562 The folks there helped me get the exact one I needed. $123 for a relay is not bad and will let you buy a 'regular' BMS and just use this relay instead of a high-current / high priced BMS.

Here's a youtube on using you're own relay on a cheaper BMS to help with the visuals. Sometimes a 'visual' inspires me - maybe it will for you as well. :)

@floydR - thanks for the tip on Daly. I've yet to find the perfect BMS for my needs. I just ordered some BatteryHookup ones for my 7s7p APC batteries and plan to give them a try.
 
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floydR

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Thanks OGITC for the link to evolveelectrics I have been looking for 48v contactors wasn't finding many. probably wasn't looking in the right places.
later floyd
 

rexgoodwin

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Mar 12, 2021
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@floydR @OffGridInTheCity Thanks guys this definitely helps with my case :)

So essentially I just hook up the battery main positive to the input of the relay and wire the output of the relay to the load positive. I will look into it more just so I am aware of the DOs and DON'Ts, also thanks again!
 
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