Lithium battery upgrade on 17B

[dosby]

Originally Posted by Perry Butler

These are just another set of cheap battery monitors. They work fine as long as you don't have an issue. Read my previous posts again.

Pay me now, or pay me later,

Perry

Well, folks are saying in reviews that one of those 2 are non-brand versions of Renogy which is a good brand. The other one looks pretty similar.
I liked that their displays show more than 1 metric at once (Victron). Otherwise, I have nothing against Victron and I am all for quality if justified. The price difference is just $110 for Victron vs $70.
BT connections are always tricky, it's easier for me to bend down and look at the actual display

[dosby]

Originally Posted by Perry Butler

Shunts in that price range lack the one thing we need from a shunt. History.

One of the reviews for Victron BMV-712:

the device itself does not actually store any realtime data for download. It only tracks data when you are connected to the app and when you turn off the app or even switch apps it loses the data. For me this is the major reason for having a device such as this

https://www.amazon.com/gp/customer-r...at_pdctrvw_srp

[John in Santa Cruz]

The Victron Smart shunt definitely stores at least a week of data internally, you log on with the Bluetooth app and you can graph any 2 factors. . Usually battery voltage and battery current or charge state. When I first got mine, it did not do this, you had to leave the app running to collect data. But a firmware upgrade just a month or two after I got it added that ability.

[dosby]

Originally Posted by John in Santa Cruz

The Victron Smart shunt definitely stores at least a week of data internally, you log on with the Bluetooth app and you can graph any 2 factors. . Usually battery voltage and battery current or charge state. When I first got mine, it did not do this, you had to leave the app running to collect data. But a firmware upgrade just a month or two after I got it added that ability.

good to know they fixed it, thanks!

[Perry Butler]

Originally Posted by dosby

One of the reviews for Victron BMV-712:

https://www.amazon.com/gp/customer-r...at_pdctrvw_srp

That review was from January 2021. Plus, did you look at the positive reviews, or just pick out one negative. Amazon negative reviews are usually by someone who failed to do a proper setup. The Max Voltage history told me what was wrong in (guess what year) January 2021, same time as your linked review, when our AGMs were killed by the WFCO.

The problem with the SmartShunt is it's limited bluetooth range. With the BMV-712 you can store the head unit up high and see what's going on from your truck when on the road, rather than stop to go into the camper to read the info.

I gave up buying cheap, barely able to perform items decades ago when I finally realized cheap is just that, cheap.

Perry

[dosby]

Originally Posted by Perry Butler

That review was from January 2021. Plus, did you look at the positive reviews, or just pick out one negative. Amazon negative reviews are usually by someone who failed to do a proper setup. The Max Voltage history told me what was wrong in (guess what year) January 2021, same time as your linked review, when our AGMs were killed by the WFCO.

The problem with the SmartShunt is it's limited bluetooth range. With the BMV-712 you can store the head unit up high and see what's going on from your truck when on the road, rather than stop to go into the camper to read the info.

I gave up buying cheap, barely able to perform items decades ago when I finally realized cheap is just that, cheap.

Perry

Well, the other person said they fixed the history issue, and that's great.

Bluetooth is actually helpful on the road, to check on DC-DC and solar charging. I didn't think of that. Not sure how to differentiate between the two, though, except by driving at night (which we do quite often).

I could also check the Ah consumption while on the road, I guess.

I am just an amateur compared to you guys, and we camp on weekends, maybe 10 times a year. Just wanted to expand to non-electric campsites, since the E/W or full hookups are much harder to get.

[hugh]

Originally Posted by Perry Butler

These are just another set of cheap battery monitors. They work fine as long as you don't have an issue. Read my previous posts again.

Pay me now, or pay me later,

Perry

The quality of the battery monitor is irrelevant if you're using LifePO4 batteries. All LifePO4 batteries include a BMS (Battery Management System) that "monitors" the battery preventing over charging or discharging. It's basically impossible to over-charge a LifePO4 battery.


Hugh

[Perry Butler]

Originally Posted by hugh

The quality of the battery monitor is irrelevant if you're using LifePO4 batteries. All LifePO4 batteries include a BMS (Battery Management System) that "monitors" the battery preventing over charging or discharging. It's basically impossible to over-charge a LifePO4 battery.

Assuming the BMS is operating correctly. On the SOK, Victron, and Battleborn Facebook pages people have had failed BMS's. Electric circuit boards have been known to fail, just look at the current MaxxFan, Dometic furnace and water heater boards that fail. That's the major flaw of LiFePO4 batteries and the jury is out on how long these boards will actually last vibrating down the road.

Perry

[dstreight]

This might be unsettling to some...but I did not incorporate a BMS into my LFP battery on our 15A preferring to manually manage current in/out. I am using amperage-voltage balancers and its all worked out perfectly.

[Centex]

Originally Posted by hugh

The quality of the battery monitor is irrelevant if you're using LifePO4 batteries. All LifePO4 batteries include a BMS (Battery Management System) that "monitors" the battery preventing over charging or discharging. It's basically impossible to over-charge a LifePO4 battery.

While the typical built-in-the-battery BMS (should) prevent damaging extremes of max / min voltage, and in some cases damaging rates of charge / discharge, those typically don't provide for limiting those factors to value ranges which can beneficially optimize the useful service life of the battery.

I could be wrong yet again, but I think it's been demonstrated that LiFePO4 batteries can deliver a longer useful service life when the high / low voltage (and rates of charge / discharge) are limited to ranges somewhat narrower than the damage-protective limits provided by the typical internal BMS.

IMO that's where there's value to be had in quality configurable external monitoring devices and quality configurable charging and loading devices which can support useful longevity-optimizing management by the user.

[alanmalk]

Originally Posted by Centex

...

I could be wrong yet again, but I think it's been demonstrated that LiFePO4 batteries can deliver a longer useful service life when the high / low voltage (and rates of charge / discharge) are limited to ranges somewhat narrower than the damage-protective limits provided by the typical internal BMS.
...

There is also some consensus of thought that keeping a LiFePO4 at 100% full is not the best approach for long life. Some manufactures specifically state that 50-70% full is recommended for long term storage. My iphone has an option to not charge over 80% on a regular basis (100% about once every ten days.)

[John in Santa Cruz]

I use my trailer enough that there is no such thing as long-term storage. If it's not plugged in (most of the time), the battery will be down to 90% in the morning and 100% by noon if it's sunny, and so far so good. This SOK. Battery has held up quite well

[Perry Butler]

Originally Posted by Centex

While the typical built-in-the-battery BMS (should) prevent damaging extremes of max / min voltage, and in some cases damaging rates of charge / discharge, those typically don't provide for limiting those factors to value ranges which can beneficially optimize the useful service life of the battery.

I could be wrong yet again, but I think it's been demonstrated that LiFePO4 batteries can deliver a longer useful service life when the high / low voltage (and rates of charge / discharge) are limited to ranges somewhat narrower than the damage-protective limits provided by the typical internal BMS.

IMO that's where there's value to be had in quality configurable external monitoring devices and quality configurable charging and loading devices which can support useful longevity-optimizing management by the user.

Thanks, Centex for stating in better detail why I want more than a cheap battery monitor with a basic shunt. You've basically said what I wanted to say this morning, but we were leaving Sleeping Bear Campground, driving to Navajo Dam State Park and Terry said we had to leave Sleeping Bear where we stayed an extra night because of the 40-60 mph winds in the Monument Valley area. Here at Navajo Dam we have electricity for the 1st time in nearly a month. Tomorrow we leave for a BLM site near Taos.

We all make decisions we feel best for us. I was not happy when spending the money for the BMV-712, but it sure has been handy observing what has been going on over time with my electrical system, and, again, paid for itself diagnosing our AGM battery problem. I also found there is a peak voltage of 15.1v, but I've been told that's just a spike that can happen when starting any inverter and lasts perhaps a second in time. However, did that voltage ruin our MaxxFan board (installed a new MaxxFan board), and the board for our furnace (replaced by a Dinosaur board)?

Originally Posted by John in Santa Cruz

I use my trailer enough that there is no such thing as long-term storage. If it's not plugged in (most of the time), the battery will be down to 90% in the morning and 100% by noon if it's sunny, and so far so good. This SOK. Battery has held up quite well

We're also using the camper all the time, except from mid-Novenber to mid-January. We keep the solar running all year. I seriously doubt I'll have my SOK's for 10 years, so longevity is not an issue. If I had to do it over I would have bought another set of Soneil SiO2 batteries that aren't fussy and charge as quickly as my SOK's.

Food for thought,

Perry

[hugh]

Originally Posted by Centex

While the typical built-in-the-battery BMS (should) prevent damaging extremes of max / min voltage, and in some cases damaging rates of charge / discharge, those typically don't provide for limiting those factors to value ranges which can beneficially optimize the useful service life of the battery.

I could be wrong yet again, but I think it's been demonstrated that LiFePO4 batteries can deliver a longer useful service life when the high / low voltage (and rates of charge / discharge) are limited to ranges somewhat narrower than the damage-protective limits provided by the typical internal BMS.

IMO that's where there's value to be had in quality configurable external monitoring devices and quality configurable charging and loading devices which can support useful longevity-optimizing management by the user.

Yes, but what sort of service life are you looking for?

The cells in my batteries are rated for 80% capacity remaining after 3500 full charge/discharge cycles at voltage / current ranges that exceed what is allowed by my BMS.

Even if I fully charged / discharged my batteries to BMS limits every day (which I don't) that's still _10 years_ of life out of the batteries - and even then, I'd still have 80% of capacity remaining.

Could I stretch the life to 5,000, 10,000 or more cycles by further limiting SOC, temperatures, and voltages / currents? Yes, certainly.



But all of that is managed by the charger and/or BMS, not the shunt, so I'm still not seeing a huge benefit to having a high end shunt vs something very basic.

[dosby]

I made a lot of progress last night, after receiving my MOSEWORTH 300Ah battery (Amazon shows no longer in stock, BTW for 300Ah), paid $510 before tax, after their instant coupon.
I also received Victron BMV-712 (Grey).
Installed both last night. The battery went in the very back of the under bench space, basically sitting ~1.5ft from where the old battery used to be (outside).
Things to note - I had to pull the cables through the floor openings, and had to buy new 4 lugs at O'Reilly (they only had 2 packages in stock, 2 lugs each, for 2 AWG / 3/8" option). 2 new lugs just because of the shunt. And 2 smaller lugs for connecting 8AWG.
I also bough 2 corner brackets at HD. I did have a piece of spare 6AWG single wire for wiring grounding (the existing cable I pulled was just ~5" short). I did reuse the 2 AWG cables from ETI.

[dosby]

Here is where and how I installed the battery, with just small corner brackets and foam padding so it won't shake.

[dosby]

One interesting thought - the new battery is barely larger than the old one. Based on the size, it would fit the existing group 27 box just fine, very tight but would fit. So I could have kept it outside with no rewriting at all, except for the shunt wire.
I would have had to remove at least the half of side handles for lifting the battery, though - the only things that would not fit and made the battery 15" long. I would have had to lift the battery by the remaining small stumps.

[dosby]

I think I attached all the wires correctly.
The ground wire was running from the battery directly to the frame on the outside, I removed it and tried placing it inside, running it from the battery to the inverter grounding, but it was ~4-5" shorter than needed, so I made a new wire from 6 AWG cable I had.
I left the inverter grounding wire in place - it is still grounding inverter to the frame !

[dosby]

The Victron display installation was a piece of cake.
Bluetooth is working great, from 30-50 ft. The app is definitely night and day compared with ETI's.

[dosby]

Now I need to make sure the battery does not jump out of its place. I have some thoughts, will finish the installation later.