Please can I ask where I can buy in South Africa 250 amp M8 battery terminals, also looking for 250 amp fuse and fuse holder. Also how have you guys connected from the BMS (Seplos v2 10E) to the fuse and terminals. Sorry for all the questions, I am also looking for the EVA foam that goes between the prismatic cells. I found a place in Cape Town but you have to order 10 sheets and I might need only 1 sheet. Also looking for a crimper that can crimp 50mm cable, will only be for this project so not expensive, or best way to do this, I may need to do +- 10 crimps.

1 hour ago, Greglsh said:

Please can I ask where I can buy in South Africa 250 amp M8 battery terminals, also looking for 250 amp fuse and fuse holder. Also how have you guys connected from the BMS (Seplos v2 10E) to the fuse and terminals. Sorry for all the questions, I am also looking for the EVA foam that goes between the prismatic cells. I found a place in Cape Town but you have to order 10 sheets and I might need only 1 sheet. Also looking for a crimper that can crimp 50mm cable, will only be for this project so not expensive, or best way to do this, I may need to do +- 10 crimps.

https://www.takealot.com/2-pcs-m6-m8-power-junction-post-connector-terminal-kit/PLID94065420

Phone a few battery dealers. They normally have a crimper. Take your cable and lugs to one. 

Edited December 18, 20232 yr by Scorp007

@Greglsh

I do all my own cables so you are welcome to message me and let me know your location in CPT, if you are not too far away will gladly visit and help you do the crimps

Thanks for the offer @WannabeSolarSparky but I am in Durban.

2 hours ago, Greglsh said:

I am also looking for the EVA foam that goes between the prismatic cells.

In Pretoria when I need foam I buy from Sondor at their outlet not far from me, here are their contact details for the Durban branch I usually contact them via email and ask if they have stock and if they don't I ask them to order:

35 Lanner Road Falcon Park New Germany, Durban, 3610
Hours: Closed ⋅ Opens 7:30 am Tue
Phone: 031 705 4220
[email protected]

Measure the size and work out how much foam you will need and buy accordingly.

2 hours ago, Greglsh said:

Also looking for a crimper that can crimp 50mm cable, will only be for this project so not expensive, or best way to do this, I may need to do +- 10 crimps.

To crimp the lugs I would suggest a welding shop which does repairs, auto electrician or a battery shop, to finish the crimp off use a piece of heat shrink over the crimped part of the lug and over the cable end so that the crimp looks like these two crimps.

It is better to strip the insulation off just before the lug is crimped on to avoid that the cable end fray and you struggle to put the lug over the stripped cable end which is frayed, so I suggest that you cut the cables beforehand or take all the components with and measure, cut , strip and put the heat shrink on the cables at the crimping facility before the crimp is made.

1 hour ago, Greglsh said:

Thanks for the offer @WannabeSolarSparky but I am in Durban.

Lol no worries ...
 

3 hours ago, Greglsh said:

I found a place in Cape Town

.I thought you meant you found a place in Cpt meaning you lived in Cpt 🤣 🙃
I am sure someone will assist you, or as @Scorp007 mentioned go to battery place they usually kind enough to assist, I used to do that before I bought my crimper.

3 hours ago, Greglsh said:

Please can I ask where I can buy in South Africa 250 amp M8 battery terminals.

I saw these charger studs on Maverick Sales https://www.mavericksales.co.za/products/1-pair-car-battery-charger-studs-battery-terminal-connectors?_pos=1&_sid=b45772526&_ss=r the seller does not specify the tread size so contact the seller and ask, these will also work https://www.mavericksales.co.za/products/1-pair-car-20mm-stud-battery-charger-binding-post?pr_prod_strat=e5_desc&pr_rec_id=0612efc31&pr_rec_pid=8122315178290&pr_ref_pid=8122296729906&pr_seq=uniform

I recently picked up a pair of these recently for about £12 GBP (R50?)...

..and was pleasantly surprised that they actually worked OK.  They can leave a bit of an 'ear', but if you make sure it's facing the back and cover with heatshrink, who's gonna know, right?

I even cut a crimp open with an angle grinder after doing it, to see what it was like inside - pretty solid!

Edited December 18, 20232 yr by HedgeSlammer

24 minutes ago, HedgeSlammer said:

I recently picked up a pair of these recently for about £12 GBP (R50?)...

 

 

No not R50 but R282 today. 

😖 Oops, cheers Scorp007...  I'd wondered why kit in ZAR looked so expensive to me. 😅

15 minutes ago, HedgeSlammer said:

😖 Oops, cheers Scorp007...  I'd wondered why kit in ZAR looked so expensive to me. 😅

Way back in the late 1970's it was R2 a £. The good old days. 😀

1 hour ago, HedgeSlammer said:

I recently picked up a pair of these recently for about £12 GBP (R50?)...

..and was pleasantly surprised that they actually worked OK.  They can leave a bit of an 'ear', but if you make sure it's facing the back and cover with heatshrink, who's gonna know, right?

I even cut a crimp open with an angle grinder after doing it, to see what it was like inside - pretty solid!

One of the crimpers that I use also leaves an ear and I just file the ear down so that it does not damage the heat shrink when the heat shrink is shrunk.

Adendorff for the crimper

https://www.adendorff.co.za/mac-afric-hhy-70a-8-ton-hydraulic-crimper-ecrimp001?gad_source=1&gclid=CjwKCAiA-P-rBhBEEiwAQEXhH7yX1FU2dSw9euEWfArKQiU1mIY8kI-p0kPgQZWa8OD8B7jhTd6WdhoC4IkQAvD_BwE

https://parmegastore.com/

For foam

What fuse and rating do you guys use between the BMS and the battery, I have seen the Victron Mega fuse holder and the 58v 250amp fuse, but have heard these take a long time and quite a bit more current than there rating suggest? Any suggestions and where to buy please. 

Thanks for all the other suggestions so far.

10 hours ago, Greglsh said:

What fuse and rating do you guys use between the BMS and the battery, I have seen the Victron Mega fuse holder and the 58v 250amp fuse, but have heard these take a long time and quite a bit more current than there rating suggest? Any suggestions and where to buy please. 

Thanks for all the other suggestions so far.

I used the victron fuse holder with this fuse. 

https://za.rs-online.com/web/p/car-fuses/2260901?cm_mmc=ZA-PLA-DS3A-_-google-_-PLA_ZA_EN_PMAX_Catch+All-_--_-2260901&matchtype=&&gad_source=1&gclid=CjwKCAiAvoqsBhB9EiwA9XTWGf0ZjLxfxOe2u8KowS_sz3cZR6fJSHxzhmBum-WpBSUc2c0tSSBERhoCjL4QAvD_BwE&gclsrc=aw.ds

11 hours ago, Greglsh said:

What fuse and rating do you guys use between the BMS and the battery, I have seen the Victron Mega fuse holder and the 58v 250amp fuse, but have heard these take a long time and quite a bit more current than there rating suggest? Any suggestions and where to buy please. 

Thanks for all the other suggestions so far.

Why would you want to provide the voltage drop of a fuse? 

A BMS does already switch off in case of high current and can act many times faster than a fuse. 

 

Edited December 21, 20232 yr by Scorp007

5 hours ago, Scorp007 said:

Why would you want to provide the voltage drop of a fuse? 

A BMS does already switch off in case of high current and can act many times faster than a fuse. 

 

What if bms mosfets go short? It will make a fire quickly. Atleast have a breaker or a fuse. I use both. 

2 hours ago, Chris_S said:

What if bms mosfets go short? It will make a fire quickly. Atleast have a breaker or a fuse. I use both. 

Good 😀or the BMS will make a permanent connection to the neg side of the battery? 

Just look at mega fuses on takealot. 

Get your theoreticall max power draw, if you have a 5000w max draw, then 5000/52= ~95, get a step high around 125 then. 

250 would just be overkill, if you will never reach its max

I went pretty safe on my fuse choice. My inverter has a max battery charge/discharge of 135A. My BMS is 150A so I went with a 160A fuse on the positive and negative cables

 

Oh hang on you talking about between the BMS and battery. Again I would go with a fuse rated slightly higher than your BMS 

Edited December 21, 20232 yr by cp69

Your bms is there for overcurrent protection. Don't match your fuse to your inverter max. Fuse should be higher value than the bms max current. 

Fuse is there to protect against any short circuit. I direct +- short could easily be 500+ amps

I used this specific connecter. Great quality. Strong and waterproof 

https://x.alibaba.com/AvKkfp?ck=pdp

11 hours ago, Chris_S said:

Your bms is there for overcurrent protection. Don't match your fuse to your inverter max. Fuse should be higher value than the bms max current. 

Fuse is there to protect against any short circuit. I direct +- short could easily be 500+ amps

This might be a stupid question, but wouldn't accounting for short circuits defeat the purpose of a fuse? 

 

Edit: I might have misunderstood the second phrase completely. Think you meant that is the reason why the fuse should be there.

Edited December 22, 20232 yr by Pho3niX90

On 2023/12/21 at 1:46 PM, Chris_S said:

What if bms mosfets go short? It will make a fire quickly. Atleast have a breaker or a fuse. I use both. 

I would agree with a dc mcb between the bms output and the negative battery output terminal. Why would you need a fuse and a curcuit breaker between the cells and the input of the bms?? As @Scorp007mentioned mosfets would act much faster during short cutcuit across the terminals that any fuse or dc mcb. The bms does checks on individual cells for malfunction and would act on any abnormalities. Should you have a short curcuit across the output terminals the dc mcb would shut the battery down.

Edited December 22, 20232 yr by TaliaB

On 2023/12/22 at 9:49 PM, TaliaB said:

I would agree with a dc mcb between the bms output and the negative battery output terminal. Why would you need a fuse and a curcuit breaker between the cells and the input of the bms?? As @Scorp007mentioned mosfets would act much faster during short cutcuit across the terminals that any fuse or dc mcb. The bms does checks on individual cells for malfunction and would act on any abnormalities. Should you have a short curcuit across the output terminals the dc mcb would shut the battery down.

I have a fast blow fuse as close to the cell + as I can before the bms. Bms is electronic and if electronics fail then the fuse protects against that. I then have a breaker for each battery bank to the busbar. I can disconnect any bank from the busbar if it needs maintenance. 

Breakers easily go over their max but a fuse is fast. 

Fuse is only there to protect against any bms failure.