diy solar

diy solar

Which BMS to buy?

R

RyanNicholas

New Member
Joined
Dec 18, 2020
Messages
89
Hey, so I have a 4s lifepo4 280ah (EVE) setup that currently doesn't have a working BMS. I originally got a Daly 200a Smart BMS with the whole package (from Alibaba), but a few months ago it was screwing up so I retired it and got a refund. I've been running my system without a BMS, but with my charge controller set to max out at 13.6v, just to be safe. But I want to put a better BMS in the system, so I actually have one like I should (and so I can safely hook up the battery isolator from my van to the battery so there's another way to charge it when it's cloudy and raining).

I've been thinking of getting the Overkill Solar 4s unit (there's a backorder wait still), but I've gathered that there are different pros and cons for different BMS's depending on what kind of use your battery gets. I'd like to get one that doesn't cost several hundred dollars oh, and that has features like Bluetooth connectivity and low temperature disconnect, in case I am in sub-freezing temperatures again with the van. High temperature disconnect would be nice as well, since I often seem to find myself in rather hot climates. I'd really like to have a fully functional system that is safe to take into hot summertime places as well as cold wintertime places. Do you think the overkill model is my best bet?

Not sure how much this matters, but my biggest load is a 60 liter 12v fridge. Other than that it's pretty much lights and phones, occasional laptop charge, Etc. Plus the maxxair fan in the ceiling, and an additional fan in the summer or small diesel heater unit in the winter. Even though the faulty BMS I had was a 200-AMP model, I'm sure I probably don't need something that high and it would be fine with the overkill unit, which I think is 120 amp.

I'm thinking the overkill might be best but I'm not sure if it has a high temperature disconnect. Any advice is welcome. Thank you!
 
Try Hightech lab:
diysolarforum.com

JBD BMS USA Inventory - Is there Community Interest?

All of that is something for the entrepreneur to figure out, not for us the end consumers. The current market for the exact same hardware is out of stock from Overkill at $120+ or from China in stock with long shipping times at under $60. To me doesn't matter much. I'm happy buying the same...
diysolarforum.com diysolarforum.com
I would suggest no less than 150A for good margin & surge handling
 
It's also like a "religious" question which to buy :) Usually dictated by how much you are willing to spend, time available, and acceptable risk. Those who want higher percent chance of not having to deal with BMS issues, get support directly from the company spend more money and get something like a REC, Batrium, Orion, etc. There is also case where your other equipment may make it more advantageous to get a certain BMS such as if you have Victron equipment and the BMS can directly talk to it. Others are perfectly happy with Chargery, JBD, Daly, etc. But I have seen people go through multiple "cheap" BMSs to save money. Smaller battery banks also mean the BMS represents a larger percent of total battery cost which makes it harder to justify more expensive BMS. Going with someone in the USA like Hightech lab that Steve_S mentioned alleviates some of the risk going with that brand of BMS at least.
 
MisterSandals said:
Possibly because this question gets asked and answered nearly every day. This
and the “do i need a BMS” question.

diysolarforum.com

Search results for query: Which bms

diysolarforum.com diysolarforum.com
Click to expand...
I've seen some other forum threads on the matter, but the ones I've come across have been rather specific for other setups different from mine (8s, 16s, 24v, etc) - and, since there are different BMS models for each different type of setup, it seemed prudent to ask about mine.
 
rhino said:
It's also like a "religious" question which to buy :) Usually dictated by how much you are willing to spend, time available, and acceptable risk. Those who want higher percent chance of not having to deal with BMS issues, get support directly from the company spend more money and get something like a REC, Batrium, Orion, etc. There is also case where your other equipment may make it more advantageous to get a certain BMS such as if you have Victron equipment and the BMS can directly talk to it. Others are perfectly happy with Chargery, JBD, Daly, etc. But I have seen people go through multiple "cheap" BMSs to save money. Smaller battery banks also mean the BMS represents a larger percent of total battery cost which makes it harder to justify more expensive BMS. Going with someone in the USA like Hightech lab that Steve_S mentioned alleviates some of the risk going with that brand of BMS at least.
Click to expand...
Thank you for this reply. I was looking at the other linked Forum thread from the Hightech Labs recommendation. It looks like most of the stuff on that thread is about jbd products, and I couldn't tell from the pictures posted by the high-tech person whether they were selling stuff they produce or if they are Distributing jbd or other stuff. So far I'm only familiar with Daly, so I'm not able to recognize by looking at them. I don't have any religious preferences when it comes to Dear, as long as it's reliable and it works. I want Bluetooth connectivity and programmable features like high and low temperature disconnect.
 
Last edited:
rhino said:
It's also like a "religious" question which to buy :) Usually dictated by how much you are willing to spend, time available, and acceptable risk. Those who want higher percent chance of not having to deal with BMS issues, get support directly from the company spend more money and get something like a REC, Batrium, Orion, etc. There is also case where your other equipment may make it more advantageous to get a certain BMS such as if you have Victron equipment and the BMS can directly talk to it. Others are perfectly happy with Chargery, JBD, Daly, etc. But I have seen people go through multiple "cheap" BMSs to save money. Smaller battery banks also mean the BMS represents a larger percent of total battery cost which makes it harder to justify more expensive BMS. Going with someone in the USA like Hightech lab that Steve_S mentioned alleviates some of the risk going with that brand of BMS at least.
Click to expand...

I always tell them to buy the same one I bought (as I've never tested any of the ones I didn't buy), because I only know of course I surely must've bought the best one in existence...
 
Last edited:
I tend to stay away from answering BMS posts since I'm a little biased - either go for something like a Batrium and be done, or (and this is where the bias comes in), go with the JK/Heltec BMS which I've been using for over a year now without issues (or other low cost ones you find on the forum). I think it's a great BMS, others might not - and for your case it doesn't matter since they don't have a 4 cell version in this line.
 
RyanNicholas said:
and I couldn't tell from the pictures posted by the high-tech person whether they were selling stuff they produce or if they are Distributing jbd or other stuff.
Click to expand...
He purchased large number of them directly from JBD but you get the added benefit of having someone in the USA for support, he is testing each one himself so you don't get something DOA, and if I recall was making some modification to make them easier to wire up.. whereas if you purchased JBD from someone on ali-express you would likely have to wait a lot longer for any issue to be resolved, especially if you needed a replacement.
 
rhino said:
He purchased large number of them directly from JBD but you get the added benefit of having someone in the USA for support, he is testing each one himself so you don't get something DOA, and if I recall was making some modification to make them easier to wire up.. whereas if you purchased JBD from someone on ali-express you would likely have to wait a lot longer for any issue to be resolved, especially if you needed a replacement.
Click to expand...
That sounds good. Are the JBD ones good? As good as Overkill? And do they have the features I'm looking for?
 
I only have experience with Batrium and Qucc. The qucc is a newer one with a built in brand name contactor. I only used it to speed up top balancing. The high cell voltage cutout worked. Can't speak to any other function. IMO, you really need only look at the solder job on those cheap chinese bms to figure out exactly what you are getting. The ones with multiple leads crimped into one lug make me cringe.
 
RyanNicholas said:
That sounds good. Are the JBD ones good? As good as Overkill? And do they have the features I'm looking for?
Click to expand...
Overkill solar was doing same thing and selling same BMS.. for whatever reason Overkill was having trouble keeping stock in so people were looking for alternatives where to get that BMS brand from the USA. In case you weren't aware if you order enough X on aliexpress/alibaba most manufacturers then allow you to put your own label on it.. that is why there is an "Overkill" BMS.
 
  • Like
Reactions: HHH
rhino said:
Overkill solar was doing same thing and selling same BMS.. for whatever reason Overkill was having trouble keeping stock in so people were looking for alternatives where to get that BMS brand from the USA. In case you weren't aware if you order enough X on aliexpress/alibaba most manufacturers then allow you to put your own label on it.. that is why there is an "Overkill" BMS.
Click to expand...
Whaaaat? Wow, I had no idea, lol... are there any other differences? The overkill ones are sold with 8 gauge cables on them, but I thought I saw another post saying the jbd ones don't come with cables...
 
RyanNicholas said:
Whaaaat? Wow, I had no idea, lol... are there any other differences? The overkill ones are sold with 8 gauge cables on them, but I thought I saw another post saying the jbd ones don't come with cables...
Click to expand...
If you are buying enough you can ask them to make some changes... I'm not sure if that is what Overkill did or if he was adding them cables on himself after receiving them.. Hightech was also making modifications after receiving them. Not sure of other differences.
 
rhino said:
If you are buying enough you can ask them to make some changes... I'm not sure if that is what Overkill did or if he was adding them cables on himself after receiving them.. Hightech was also making modifications after receiving them. Not sure of other differences.
Click to expand...
Awesome, thank you for these clarifications. I sent a message to the high tech guy's profile, so hopefully he'll respond soon!
 
RyanNicholas said:
Aaaand, which one might that be?
Click to expand...

If it's for 12v (4s), then OverKill 120a BMS of course.

In fact I just bought 2 extra ones for spares to put in my faraday / spare parts bin, like a couple weeks ago, and they just came the other day, so now I have 2 mains, and 2 spares in case an EMP takes out my current setup. :geek:

1627504520440.jpeg
 
You must log in or register to reply here.

Similar threads

D
Where to buy a BMS from a reputable retailer?
Replies
3
Views
286
Dinobot248
D
H
Daly BMS problems.
Replies
5
Views
240
sunshine_eggo
sunshine_eggo
D
BMS quality, Which battery to buy.
Replies
5
Views
217
Ampster
Ampster
D
I really dunno which one to buy and based off their websites .....who can tell?
Replies
7
Views
293
OffGridForGood
OffGridForGood
kipper
JBD AP21S002 BMS failed? Intermittent relay operation and limited communication over Bluetooth and RS485
Replies
5
Views
287
kipper
kipper
Back
Top