LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[mcarling]

Originally Posted by klaus53123

is 14.2 Volts too much???? My supplier tells me I can charge up to 3.65 V per cell (14,4 Volts) with no problem whatsoever. Even 3.8 V not too problematic!

Yes, 14.2 Volts is too high. It will significantly reduce the life of your batteries. Maximum charging voltage for LiFePO4 should be in the 13.8 to 14.0 Volt range.

[SV THIRD DAY]

Originally Posted by klaus53123

is 14.2 Volts too much???? My supplier tells me I can charge up to 3.65 V per cell (14,4 Volts) with no problem whatsoever. Even 3.8 V not too problematic!

A LiFePO4 battery supplier giving advice that is crazy....

So why do I see some LiFePO4 horror stories in the future coming from folks just following the advice of the experts?

You know they are coming to give the entire technology a Black Eye.

Kinda like how one Hunter sinks and then there is a 75 page thread about it trying to blame it on the boat!

[darylat8750]

One of the big takaways from this monster thread is the the LiFe battery sales people think in terms of electric vehicle use of their batteries. House bank use is completely different. If the difference doesn't make doesn't make sense to you, your move to LiFe at this time may be an expensive disappointment to you. If anything MainSail says doesn't ring true read some more. The reasoning is in the thread. Good luck.

[SV THIRD DAY]

Yep....and honestly if you don't have the time or patience to read through this thread....but would rather "cut to the chase" and just have someone on the thread hand hold you through, then frankly you shouldn't be messing with the technology at this point in the development curve.

[senormechanico]

Originally Posted by SV THIRD DAY

A LiFePO4 battery supplier giving advice that is crazy....

So why do I see some LiFePO4 horror stories in the future coming from folks just following the advice of the experts?

You know they are coming to give the entire technology a Black Eye.

Kinda like how one Hunter sinks and then there is a 75 page thread about it trying to blame it on the boat!

It's in the interest of LiFePo4 huckster salesmen to tell you that.
Call it "Job Security".
You'll be back (for more cells) because they're so much better even if they don't last as long due to the excess charging voltage advice

Stick to 13.8 absorb, then disconnect or go to 13.4 or less.

[klaus53123]

Originally Posted by SV THIRD DAY

Yep....and honestly if you don't have the time or patience to read through this thread....but would rather "cut to the chase" and just have someone on the thread hand hold you through, then frankly you shouldn't be messing with the technology at this point in the development curve.

I think that is a bit an unfair comment! I have read till page 235!!! and catching up with the rest. However things are not as obvious to me as they might be to you.

I am not expecting anybody to hand held me through the installation, however what exactly is wrong with asking questions?

Best regards
Klaus

[mrm]

Originally Posted by klaus53123

I think that is a bit an unfair comment! I have read till page 235!!! and catching up with the rest. However things are not as obvious to me as they might be to you.

I am not expecting anybody to hand held me through the installation, however what exactly is wrong with asking questions?

Best regards
Klaus

Klaus, first of all, congratulations for your perseverance in reading this thread. I honestly mean it. Now, as for asking questions, as you continue with the thread you will probably notice, that they had been asked and answered before. Some of them a couple of times. So, while nothing is wrong with asking, I think that it is more beneficial to the thread to ask after it had been read completely. This way some of the repeated questions may be avoided and the new questions will hopefully address areas which maybe are not explained well enough.

PS: If you need a short path, read and understand at least everything Maine Sail wrote.

Best regards,
Marius

[klaus53123]

Originally Posted by mrm

Klaus, first of all, congratulations for your perseverance in reading this thread. I honestly mean it. Now, as for asking questions, as you continue with the thread you will probably notice, that they had been asked and answered before. Some of them a couple of times. So, while nothing is wrong with asking, I think that it is more beneficial to the thread to ask after it had been read completely. This way some of the repeated questions may be avoided and the new questions will hopefully address areas which maybe are not explained well enough.

PS: If you need a short path, read and understand at least everything Maine Sail wrote.

Best regards,
Marius

Thanks Marius, will do so. Final 50 pages or so will be done tonight. Problem is that the object is sometimes very theoretical and difficult to understand for the non electronic nerd.

I have also already read the MaineSail article and will probably read it another three or five times.

I just dared to ask the question about the max Voltage because I am somewhat astonished about the difference what people say and do in this threat compared to what the vendor and producer say. The fact that I ask the question doesn't mean I doubt the statements made here. I just try to understand....

I do understand that my vendor has his background in the EV area with significantly different charge and discharge Amperes flowing. I was just astonished that this makes a difference in charge Voltage of nearly 1V.

Will be back after having read the remaining posts... :-)

Br
Klaus

[nimblemotors]

It is silly to expect someone to read 4,000 posts to install batteries.
This thread should be closed in fact.

[darylat8750]

But you don't need to read 4000 k posts just to install batteries. If you want to install new technology batteries and use them in a manner that the manufacturer has not tested for nor fully understand it would behoove you to do your homework.

Add to that first paragraph the reality that many business people are doing their best to cash in on this technology without fully understanding our type of use is really muddying the waters. Also at least some of the business folks in question are from a country where the concept of consumer protection is not even a small blip on their radar.

[klaus53123]

Originally Posted by nimblemotors

It is silly to expect someone to read 4,000 posts to install batteries.
This thread should be closed in fact.

Too late :-) I am at post 3850 now and I have to admit pages 235 and following are the most teaching ones. Learnt a lot and many questions about the proper installation are answered. However some other still open. Will ask them once I arrived at the end....

Best regards
Klaus

[boatpoker]

Can anyone tell me how to unsubscribe from this travesty.

[Maine Sail]

Originally Posted by boatpoker

Can anyone tell me how to unsubscribe from this travesty.

Scroll up to the first post on this page and look for THREAD TOOLS (in a greenish menu bar below POST REPLY)

Hit the drop down arrow next to TREAD TOOLS and then select UNSUBSCRIBE

[boatpoker]

Thanks Rod. It was hurting my head

[klaus53123]

Ok, here we are. I made it through all the posts and first of all I want to express my gratitude to all the valuable contribution made here. I learnt an awful lot and if I would have not read all this I probably would have destroyed my LFPs by listening to the advice I was given by the vendor.

What I am planning to now is the following:

Ensure that charging stops at 13.8V
Restart charging at 13,4 V
Wire a charge and a load bus
Have a HPBMS for LVC and HVC
not yet decided about the relays to fit

Alternator: I will go the Rotter route and change the point of Voltage measurement from downstream the separation diode to upstream the diode once the voltage hits the 13.8V. I will also do the alternation on the field cable, take it outside of the alternator and be then able to safely stop the it via a relay either automatically or manually if motoring long period. I have now decided to keep my two LA starter batteries to have flexibility with the alternator in case of an HVC event during motoring.

Victron mulitplus: I will change the programming so it matches the above mentioned values. My only question here is the following: The charge and supply cable for the inverter are the same. So I can only hook it up either to the load bus or the charge bus. I have seen recommendations in earlier post to hook it up to the load bus, but how can I than still cut it off in case of a HVC event? Coudnt't find anything in earlier post.

Solar Panels: There is no way to get my solar charger (Votronic) to stop charging at 13,8V. Minimum voltage I can adjust is 14.2. Thereafter it goes to float at 13,5. All not good. I see two options I have and would like to get your views on these options:

1. Use a programmable voltmeter and just switch it off once it reaches the 13.8 V threshold and switch it on at 13.4 V again.

2. Solder a Schottky diode into the cable downstream the regulator. That way the voltage will be reduced by 0.3V and than meeting the thresholds (more or less :-)). If I do so, I wold not need to worry about the float at 13.2 V which seems generally be considered ok for the LFPs (if I didn't misinterpreted the earlier posts).

What are your views on this?

Greetings from Portugal
Klaus