needing a little advice please

[tom]

hi everybody i am looking for a little help as i am new to solar so can any of you give me some advice on this please?
thanks in advance
i have
8 x lithium-ion battery cells all connected in parallel
model ca100
nominal voltage 3.2v
rated capacity 100ah
rated energy 320wh
multi meter shows on main positive and negative of batterys 13.18v with my battery charger disconnected
but when my victron blue smart charger 12v 20a is connected on li-ion mode it shows on the victron connect app that the voltage is 14.11 and current 20 amps this is on bulk charge . i thought that the batterys would be fully charged at 14.2 volts or am i missing something ? i really cant afford to damage the batterys so hence the reason i need some advice thanks

 

[wildebus]

hi everybody i am looking for a little help as i am new to solar so can any of you give me some advice on this please?
thanks in advance
i have
8 x lithium-ion battery cells all connected in parallel
model ca100
nominal voltage 3.2v
rated capacity 100ah
rated energy 320wh
multi meter shows on main positive and negative of batterys 13.18v with my battery charger disconnected
but when my victron blue smart charger 12v 20a is connected on li-ion mode it shows on the victron connect app that the voltage is 14.11 and current 20 amps this is on bulk charge . i thought that the batterys would be fully charged at 14.2 volts or am i missing something ? i really cant afford to damage the batterys so hence the reason i need some advice thanks

If you have the batteries connected as you describe, they will not give the voltages you state.
cells are 3.2V - when you connect all in parallel, you are not increasing the voltage. so 8 3.2V 100Ah cells in parallel will give you a battery bank of 800Ah at 3.2V.
If your multimeter is correct, then you have the cells in a Parallel/Series configuration giving you a nominal 12.8V 200Ah Battery Bank (this sounds quite likely, but you you should confirm by reply if this is the case or not).

Lithium at 13.18V is probably not 100% fully charged so I could imagine the battery bank could take more charge. 14.11V on a 12V battery bank seems ok. What are the charge parameters for the cells in terms of main charge and float voltages?
Have you got a BMS installed on the battery bank?
What are you doing about low temp charge protection? getting to the time of year that you need to consider this.

 

[tom]

If you have the batteries connected as you describe, they will not give the voltages you state.
cells are 3.2V - when you connect all in parallel, you are not increasing the voltage. so 8 3.2V 100Ah cells in parallel will give you a battery bank of 800Ah at 3.2V.
If your multimeter is correct, then you have the cells in a Parallel/Series configuration giving you a nominal 12.8V 200Ah Battery Bank (this sounds quite likely, but you you should confirm by reply if this is the case or not).

Lithium at 13.18V is probably not 100% fully charged so I could imagine the battery bank could take more charge. 14.11V on a 12V battery bank seems ok. What are the charge parameters for the cells in terms of main charge and float voltages?
Have you got a BMS installed on the battery bank?
What are you doing about low temp charge protection? getting to the time of year that you need to consider this.

Hi thanks for your reply i really appreciate it this is all new to me but i like to learn ,to make things a bit easier i have attached some photos of the setup for you to see , i also connected the batterys from wills youtube like

hope you can point me in the right direction as i do not want to damage my batterys thank you .tom

 

[wildebus]

Ok, so you have taken pairs of cells and paralleled them - so giving you 4 "mini banks" of 3.2V 200Ah batteries.
Then put those 4 mini banks in series, which gives you a battery of 12.8V 200Ah capacity.

It is important to know how they are combined in order to know how to setup the BMS connections. You have a BMS connection on each of the 4 "mini banks" (I don't know if there is a better or proper name for the pair of 3.2V cells connected in parallel, so I will just call them that )

It all looks right to me and if you are following Will Prowses guide strictly then I am sure it will be correct. The Victron IP22 is a good reliable charger so that is fine.

The only thing that is missing (at least in the info and pictures shared above) is the mechanism to disconnect the charger at low temps, as I had mentioned before. That really is important, and not something to be ignored! I don't know where you are in the Country (or even which Country for that matter), but where I am, the temp today is below 5C, which is the start point to get critical for cutting charge to Lithium (in fact I had my laptop outside today and the Laptop gave me a battery performance warning due to low temp and told me to move it to a warmer place!).
That Daly BMS you have fitted will not cut the charge circuit at low temp and you need an external solution. There are a few ways to do this - I think Will Prowses usual recommendation is with a Victron SmartSolar Controller and the SBS unit? is that something you have/are looking to use?

 

[tom]

hi, thanks for your quick reply i do have a victron smart solar mppt controller with a battery temp cutout which i will use when i install the batterys in my motorhome ,they are in the house just now 20c in the room so that should keep them safe so should i just connect my blue smart charger and leave it till the lights change from bulk to float or storage? i take that would mean they would be fully charged? thanks again for all your valuble advice ,ps i live in sunny scotland but at the moment it aint sunny just bloody cold lol
regards tom

 

[wildebus]

hi, thanks for your quick reply i do have a victron smart solar mppt controller with a battery temp cutout which i will use when i install the batterys in my motorhome ,they are in the house just now 20c in the room so that should keep them safe so should i just connect my blue smart charger and leave it till the lights change from bulk to float or storage? i take that would mean they would be fully charged? thanks again for all your valuble advice ,ps i live in sunny scotland but at the moment it aint sunny just bloody cold lol
regards tom

I'm in Scotland as well. Was really bright this morning and looked lovely - but when I went outside, it was blooming freezing!! quick retreat back inside!

The Victron Charger can be, if you want, left on 24/7 and it will drop to float and then storage automatically (that is how it works with the non-Lithium profiles and I am pretty sure also with the Li-Ion setting as well). With Lithiums, I'd probably turn the charger off once it went to Storage and disconnect from the bank just to check for self-discharge levels over time being a new bank (should be virtually zero).
As an aside, Victron are working on a firmware update to the IP22 chargers which will let you see the voltage parameters up with the same level of flexibility that say the Smart Solar has. Don't have a date for that but will be great when available If they add on Smart Networking to allow the IP22 Charger to use the SBS as well, that would be really good.

If you don't have the SBS (Smart Battery Sense) to go with the MPPT, I would strongly recommend it - the internal temp sensor in the MPPT is only read once a day - on initial startup. So if you start the day with the temp low and so charger off, it will not change throughout the entire day even after the interior of the motorhome and the batteries have warmed up. The SBS adds dynamic real-time temperature monitoring to the MPPT.

 

[tom]

thanks for all your help its very much appreciated i am sure i bought some leads from you last year for my t5 lights ,david from down the east coast area? will have a look at your website see if i need anything more i will put my business your way .thanks again
regards

 

[wildebus]

thanks for all your help its very much appreciated i am sure i bought some leads from you last year for my t5 lights ,david from down the east coast area? will have a look at your website see if i need anything more i will put my business your way .thanks again
regards

Sounds like probably me Glad to have been of help. Keep us posted on this thread about your progress and experience with this battery pack. I know there is at least one other person who is looking to build their own lithium battery so I am sure your postings will be of interest

 

[tom]

will do cheers

 

[xsilvergs]

hi everybody i am looking for a little help as i am new to solar so can any of you give me some advice on this please?
thanks in advance
i have
8 x lithium-ion battery cells all connected in parallel
model ca100
nominal voltage 3.2v
rated capacity 100ah
rated energy 320wh
multi meter shows on main positive and negative of batterys 13.18v with my battery charger disconnected
but when my victron blue smart charger 12v 20a is connected on li-ion mode it shows on the victron connect app that the voltage is 14.11 and current 20 amps this is on bulk charge . i thought that the batterys would be fully charged at 14.2 volts or am i missing something ? i really cant afford to damage the batterys so hence the reason i need some advice thanks

Hi Tom,

Where did you purchase your Calb cells from? I follow Will P' on YouTube and have seen these cells but have never known anyone in the UK buy some.

 

[Silver sprinter]

I know I have said this before Dave your a gem at going way beyond helping people, and I thank you for that, gerry

 

[tom]

Hi Tom,

Where did you purchase your Calb cells from? I follow Will P' on YouTube and have seen these cells but have never known anyone in the UK buy some.

Hi sorry for the late reply but been away working . i bought them from ali express let me know if you want the stores name and i will send it to you

 

[Admin]

Hi sorry for the late reply but been away working . i bought them from ali express let me know if you want the stores name and i will send it to you

Hi Tom,
I am guessing you won't be using an inverter with such a small (60A) BMS?

 

[tom]

Hi Tom,
I am guessing you won't be using an inverter with such a small (60A) BMS?

Hi ive not got to that stage yet batterys not installed yet ,i will be using an inverter 2000w what size bms would you advise?

 

[wildebus]

Hi Tom,
I am guessing you won't be using an inverter with such a small (60A) BMS?

IIRC, they way Will Prowse deals with that limited BMS capability on the DIY setup Tom is looking at is bypassing the BMS (or using it to control a high-power relay?) on the load side? I can't recall the details but there is a workround. But a BMS designed to deliver the demand would be better of course

Hi ive not got to that stage yet batterys not installed yet ,i will be using an inverter 2000w what size bms would you advise?

So for a 2000W inverter, it would be around 200A load

I was looking at different BMS kits a while back and while didn't like some aspects of the following one (like having to drill to enlarge the mount holes), I think the 123 Smart BMS looks very good - and the manual talks about 2000 Amp setups. One of the Forum members has this setup with Winston Cells (he has a 2 part Youtube video on the setup and install which is interesting to watch)

This is a link to the 123 Smart BMS PDF - http://123smartbms.se/uploads/file/123SmartBMS_manual_1v2.pdf

 

[tom]

interesting but all getting above my level to understand everything . starting to hurt the wallet as well lol

 

[wildebus]

You can get an approximate idea by looking at the picture of you posted of the Daly BMS unit and the size of the blue cable that goes from the banks main -ve connection to the BMS and then the black cable from the BMS to I guess a -ve Busbar....
That cable looks like either a 10mm2 or 16mm2 cable.
To support a 2000W inverter you would likely be looking at a 35mm2 cable at a minimum and likely more (I upgraded my 50mm2 cable to 70mm2 for my 2400W inverter as it was getting quite warm (and heat equals wasted power). So just on a physical side you can tell it could not support that Inverter. A 60A load maximum would use probably 10mm2 or preferably 16mm2, so in that respect it looks right for the BMS spec.

 

[Nabsim]

Presumably not that hard to change that cable and the bms for heavier duty items though if you wanted to run a bigger inverter?

 

[wildebus]

Presumably not that hard to change that cable and the bms for heavier duty items though if you wanted to run a bigger inverter?

Yup. Can fit any BMS you like - but price becomes a factor.... The 123Smsrt BMS I mentioned is a lot more expensive than the Daly BMS Tom has.

Not seen it in the flesh, but the BMS in the new Poweroad Infinity battery from Alpha looks very good... 150A current capability per battery and the Bluetooth monitoring also. Would support any inverter likely to want to use