I am on the verge of ‘pulling the trigger’ and placing an order for one of Overkill Solar’s 4S 120a LiFePo4 BMS’s.
The BMS comes standard with a Bluetooth communication module so I should be able to use the associated android app to communicate with it to both monitor the status of the battery I plan on building up and configure various parameters to my tastes. (If I’m correct, I would have to pay a few bucks extra to upgrade to a Professional version of this software because, though I understand it, the free version only comes with the Monitoring functions enabled, but that’s not a problem).
I also plan on including the ‘optional USB module’ in my order because, as I understand things currently, this option and nothing over and above this option is required if I want to use ‘the’ Windows PC Software available to interface with the BMS. (Please inform me if I’m wrong).
But I have a few questions I would appreciate if someone could answer for me before I finalize and submit my order so that I don’t make some decisions I might regret later. (It’s always nice to listen to people who already been there before you and done things THEY regretted).
Briefly, here are the two general areas I would welcome some advice and suggestions on:
With regards to the ‘hole Diameter’ of the lugs I should select:
Should I go with ¼ inch or 5/16 inch or 3/8 inch?
If I recall correctly, the terminals on the cells use a 6 mm screw or post whatever and so even ¼-inch lugs should be sufficient to fit over the post. (6 mm = .236”). BUT:
On the other hand, I was just thinking that there might be ‘trade-offs’/some implications. I can think of at least two POSSIBLE factors: depending upon the overall size – length and width – of the ‘flat part’ listen to me of the lug which makes contact with the cell terminal ‘underneath’ – if that does not also simultaneously increase as the hole size enlarges, then you would be giving up some surface area underneath where the lug ‘meets whatever’ the battery it is connected to – i.e. – listen to me which would result in a little bit of increased resistance. (Not sure if this would happen and/or how significant it might be and do not feel like trying to try to dig up the data and estimated) but anyway, it is a thought that I had.
And second, on the subject, depending upon how much space there might be between the ‘tapered end’ of the ‘socket’ of the lug into which the wires are inserted and crimped, if that might – because of the smaller lug used – e.g. say ¼ inch – MIGHT that pose some ‘interference problems’ adding additional wires with terminals to the post in question? (I plan to use M6 threaded posts (‘setscrews’ I think they’re called) so that might not be a problem because I could just use some washers to create some extra horizontal space for additional lugs but just thought I’d throw it out there is a thought).
So, bottom line:
Thanks, and ‘Cheers’.
The BMS comes standard with a Bluetooth communication module so I should be able to use the associated android app to communicate with it to both monitor the status of the battery I plan on building up and configure various parameters to my tastes. (If I’m correct, I would have to pay a few bucks extra to upgrade to a Professional version of this software because, though I understand it, the free version only comes with the Monitoring functions enabled, but that’s not a problem).
I also plan on including the ‘optional USB module’ in my order because, as I understand things currently, this option and nothing over and above this option is required if I want to use ‘the’ Windows PC Software available to interface with the BMS. (Please inform me if I’m wrong).
But I have a few questions I would appreciate if someone could answer for me before I finalize and submit my order so that I don’t make some decisions I might regret later. (It’s always nice to listen to people who already been there before you and done things THEY regretted).
Briefly, here are the two general areas I would welcome some advice and suggestions on:
- Should I go with ‘only’ the 12 inch cable length option or should I ‘pop for’ the 22 inch option? (“Does size matter? Currently I am leaning towards going with the 12 inch soldered on cable option. If I didn’t plan on ALSO going with an option to have Crimped Copper Lugs included as well, I probably would pay the extra cost for the 22 inch cables and just cut them to length BUT I really don’t want to have to install my own Copper lugs because I don’t have any decent crimper tool, let alone have to worry about figuring out what lugs to buy and use. To me, it is worth the extra money to have Overkill install them.
- Regarding the ‘Crimped Copper Lugs’: Suggestion as to whether I should go with ¼ inch or 5/16 inch or 3/8 inch lugs? I am inclined to go with the 5/16 inch lugs as a decent compromise but would be interested in suggestions from people who have already built their own batteries.
With regards to the ‘hole Diameter’ of the lugs I should select:
Should I go with ¼ inch or 5/16 inch or 3/8 inch?
If I recall correctly, the terminals on the cells use a 6 mm screw or post whatever and so even ¼-inch lugs should be sufficient to fit over the post. (6 mm = .236”). BUT:
On the other hand, I was just thinking that there might be ‘trade-offs’/some implications. I can think of at least two POSSIBLE factors: depending upon the overall size – length and width – of the ‘flat part’ listen to me of the lug which makes contact with the cell terminal ‘underneath’ – if that does not also simultaneously increase as the hole size enlarges, then you would be giving up some surface area underneath where the lug ‘meets whatever’ the battery it is connected to – i.e. – listen to me which would result in a little bit of increased resistance. (Not sure if this would happen and/or how significant it might be and do not feel like trying to try to dig up the data and estimated) but anyway, it is a thought that I had.
And second, on the subject, depending upon how much space there might be between the ‘tapered end’ of the ‘socket’ of the lug into which the wires are inserted and crimped, if that might – because of the smaller lug used – e.g. say ¼ inch – MIGHT that pose some ‘interference problems’ adding additional wires with terminals to the post in question? (I plan to use M6 threaded posts (‘setscrews’ I think they’re called) so that might not be a problem because I could just use some washers to create some extra horizontal space for additional lugs but just thought I’d throw it out there is a thought).
So, bottom line:
- 12 inch (“I’m leaning”) or 22 inch wires ‘soldered on’?
- 5/16 inch (“I’m leaning”) or a different hole diameter?
Thanks, and ‘Cheers’.