[RE-wrenches] RE-wrenches] replace part of rolls battery bank

Fri Apr 7 16:06:02 PDT 2023

Multiple battery banks of different topology work fine charging and 
discharging. Think about how you can do it and not how you can't.

Any takers?

-------------------------------------------------------------------------------------------------

John Blittersdorf via RE-wrenches [4] Thu, 06 Apr 2023 15:06:08 -0700 
[5]

Multiple battery banks work well as long as you are consuming.  When
charging the charge parameters change.  I'm running 8 Interstate L16's, 
1
Fortress e-flex, And 3 Simpliphi 3.8. With big switches between them.  I
was using all three but changing charge parameters on
My two controllers and inverter got to be too much trouble.  I ran all 
with
lithium settings but I'm retiring the L16s and putting in a second 
eFlex.
  2 eFlex or 3 Simpliphis do a great job replacing the 8.  The 3 
simpliphis
will be leaving for their summer home at a fishing club. Hi

John B

On 2023-04-06 8:43 am, Dave Angelini Offgrid Solar via RE-wrenches 
wrote:

> And the next step for hi reliability offgrid is to have both types of 
> battery in there own independent inverter power systems. Just switch 
> the DC bus from one power system or the other. I like the LFP just 
> turned off sitting as a spare power system. You can rotate or do a 
> monthly test like it is a genset.
> 
> This is also a good way to use up the old flooded and retire it when it 
> becomes useless and ready to recycle. Some LFP manufactures do provide 
> a spare BMS but probably better to just have an extra battery at the 
> offgrid home.
> 
> Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> http://members.sti.net/offgridsolar/
> e-mail  offgridsolar at sti.net
> text 209 813 0060
> 
> On 2023-04-05 6:30 pm, Scot Arey via RE-wrenches wrote:
> 
> Just attended the NABCEP conference last week and took in CEU classes 
> from Rolls and Midnite on battery charging and design. Just awesome 
> classes and I walked away thinking the FLA were kind of like my old 7.3 
> Powerstroke diesel…I could work on them and could see when issues were 
> developing. The lithium batteries are kind of like my 6.7 PSD. Great 
> power, fast but when something happens with a BMS…no idea except to go 
> to the manufacturer.
> 
> Just wanted to share this after reading your awesome post.
> 
> Scot
> 
> From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> On Behalf 
> Of Tump via RE-wrenches
> Sent: Wednesday, April 5, 2023 6:24 PM
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Cc: Tump <tump at swnl.net>
> Subject: Re: [RE-wrenches] RE-wrenches] replace part of rolls battery 
> bank
> 
> I would suggest that adding additional batteries to increase battery 
> voltages is fine 48 to 54V or what ever, I too have used this many 
> times on very remote sites. Please also increase your inverters hi 
> voltage cut out settings, as this can be a real bummer having the 
> system shut down in full sun.
> 
> Another thing; IF you have battery strings,  cables of equal length 
> from each string should be connected to a buss bar then buss bar to 
> inverter or inverters, this will reduce wiring headaches, voltage drop 
> as well as providing equal charging to all strings. (depending on 
> internal resistance).
> 
> I would also suggest fewer batteries of bigger cells. My preference is 
> 2 volt cells, less holes to water, less copper interconnects. Yeah 
> there heavy but for hi charging & discharging, a large battery is 
> always my choice.  OR the Surrette 6CS25P has been the MOST reliable 
> battery Surrette has put out. After almost 30 + years of installing 
> their batteries this one has been the best. They do have a EX series 2 
> Volt cell that has the same plate thickness as the 6 CS but I have had 
> issues w/ them. IF you are using the EX 2 volt check the polarity PRIOR 
> to installing them & mark the positive side. I have had the plastic 
> covers installed incorrectly and it plays havoc on your install.
> 
> Yep LEADITE I am, refractometer and a DVOM and I have a client that can 
> spot problems way before things become critical. AND that Surrette 
> warrantee Pit BULL Mr. Higgins & your client will be very happy when 
> Steve OKs a replacement because you have recorded your Spg readings.
> 
> My $.02 TUMP
> 
> On Apr 5, 2023, at 5:26 PM, greg egan via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Danny, My experience is if you are careful and use equal length 
> conductors for all 3 strings you can get good results.  The main 
> problem I have with 3 strings of 6 V cells @ 48 vdc is leaving the 
> customer with 72 cells to check and fill.  That's a lot of work if you 
> don't have a watering system.
> 
> I totally get why you'd want to give them 2 strings in case they lose a 
> battery or 2.  Most of my off grid customers live quite a ways from the 
> battery store and it's not uncommon for it to take a month to get 
> replacements - during the best of times.
> 
> Another option I've done is give them a string of 25 - 2V cells for a 
> 48V system.   You just set the charging parameters accordingly and go.  
> That way if they lose a cell or two, the remaining battery bank should 
> be able to keep them limping along until the replacement battery(s) 
> show up.  Need to check and make sure your charge controller and 
> inverter can charge at the slightly higher V but usually that's not a 
> problem.
> 
> Best,
> 
> Greg Egan
> Remote Power Inc.
> 
> greg at remotepowerinc.com
> 
> Message: 1
> 
> Date: Tue, 4 Apr 2023 20:45:44 +0000
> 
> From: Daniel Young <danny at sesre.com>
> 
> To: "offgridsolar at sti.net" <offgridsolar at sti.net>, RE-wrenches
> 
> <re-wrenches at lists.re-wrenches.org>
> 
> Subject: Re: [RE-wrenches] replace part of rolls battery bank
> 
> Message-ID:
> 
> <BL1PR12MB5921CDE5991F65FA842BC82CBB939 at BL1PR12MB5921.namprd12.prod.outlook.com>
> 
> Content-Type: text/plain; charset="utf-8"
> 
> Thanks all for the advice. I figured it was not worth trying on a 
> different battery brand. I honestly needed to be able to tell them I 
> researched it and asked my peers.
> 
> The client really uses the 3 x strings they have and did not really 
> want to go down to 3. They are currently choosing to get the two Rolls 
> under the prorated warranty, and hopes to get another 2 useful years 
> out of the bank before planning to replace.
> 
> Already prepared him on the cost of the equivalent Li+ at todays 
> prices. So he knows roughly where he is heading.
> 
> Side note: I am in the camp of trying for 2 x strings when possible 
> (agree that 3 x strings is the absolute limit, and not the best 
> option), simply because if a single cell goes bad, I don?t want a 
> client with essentially nothing available until we can get a 
> replacement and get on site. With 2 strings, they can make due at 
> least. That?ll go out the window with Lithium though. Looking at 
> Fortress Power for the next battery bank for this client. But we will 
> see what changes in the market by the time it?s needed.
> 
> With Regards,
> 
> --
> 
> Danny Young
> 
> NABCEP PV Installation Professional #031508-90
> 
> Engineering Team Lead
> 
> Solar Energy Solutions
> 
> Lexington | Louisville | Bloomington | Cincinnati | Evansville | 
> Indianapolis
> 
> 513-448-5176 (mobile)
> 
> 877-312-7456 (Main Office)
> 
> danny at sesre.com<mailto:danny at sesre.com>
> 
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