<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr"></div><div dir="ltr">These are 100 amp hr eg4 48v batteries. </div><div dir="ltr">Tech support said their recommended charge rate per battery is 30-50 amps. </div><div dir="ltr"><br></div><div dir="ltr">I asked because Ive never heard this and it still doesn’t sound correct. </div><div dir="ltr"><br></div><div dir="ltr">All of the responses have been consistent and I will try to get someone higher up to review all this and report back</div><div dir="ltr"><br></div><div dir="ltr">Thx</div><div dir="ltr">Jay</div><div dir="ltr"><br></div><div dir="ltr"><br><blockquote type="cite">On Jun 27, 2023, at 10:07 AM, Starlight via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><meta http-equiv="Content-Type" content="text/html; charset=utf-8">Hi Steve,<div class=""><br class=""></div><div class="">My experience is different. First, I don’t know of any stationary battery systems that have C2 charge ability, many not even C1. A 20kWh bank C2 rate would be 40kW or over 770Amps @ 52V. I have 10 years experience with Li batteries, (hundreds of Li installations, mobile and off grid), and thousands of LiFeBlue Battery customers, low current charging works without issues. Most of these systems charge at the high end 0.35 C rate or less. Jay did not mention the bank size so we don’t know the C rate for the 30-50 Amp recommendation. But I guess it is far lower than 1C.</div><div class=""><br class=""></div><div class="">Long absorb (CV) times may cause a cell to saturate resulting in rapid voltage rise and the BMS protection inhibiting input current. This sudden loss of load (essentially a battery disconnect) can cause havoc with some inverter/chargers and PV solar controllers. In our experience, the best method to set Absorb times for any Li system is by trial. If the cell voltages are staying relatively close during discharge (6mv in the attached image), then balancing time (> 3.55V CV) is sufficient, whether it is 0.1 hours or much more. <br class=""><div class="">
<div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><br class=""></div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;">Larry Crutcher</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;">Starlight Solar Power Systems</div><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;">(GM, LiFeBlue Battery)</div><br class="Apple-interchange-newline">
</div>
<div><div><32ED5403-8A66-4ED5-AFFD-E308D5FC48C6_1_105_c.jpeg></div></div><div><br class=""></div><div><br class=""><div class="">On Jun 27, 2023, at 6:33 AM, Steve Higgins via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" class="">re-wrenches@lists.re-wrenches.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">For many LFP batteries, while some say you can charge at the C1 Rate, most want you to charge at the C2 or C3 rate. <div class=""><br class=""></div><div class="">While you don't have to get them full all the time like lead, as long as you are cycling regularly, it is still a good idea to get them to full regularly. Now if they are a backup system or not being cycled, they should not be held to full all the time. This can accelerate damage to the cells. </div><div class=""><br class=""></div><div class="">Where we see the major mistakes are the absorb timer settings. Too many people are setting the absorb timers too short, especially if they have parallel modules and are not running closed-loop communications, or the batteries can't communicate with each other or the chargers. </div><div class=""><br class=""></div><div class="">In these cases where you have 2,3,4... more batteries in parallel, the absorb timers can help balance them as the batteries that don't need balancing stop charging, while the cells that need the extra time get that time if you have longer absorb timers. </div><div class=""><br class=""></div><div class="">We advise for our LFP drop in's that you have the following. Assuming that you are charging at least the C2 Rate. </div><div class=""><br class=""></div><div class="">1 Parallel Connection = 30-45 mins absorb timers. </div><div class="">2 Parallel Connections = 45-60 mins. </div><div class="">3 Parallel Connections 60-90 mins. </div><div class="">4 Parallel Connections 90-120 mins </div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br clear="all" class=""><div class=""><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div style="float:left;padding:1px 10px 0 0" class=""><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""></a><a href="http://www.rollsbattery.com/" target="_blank" class=""><img src="https://i.imgur.com/YIluKhq.png" alt="" style="padding:3px 0px 0px 10px;float:left;margin-right:10px;width:98px;height:115px" class="" data-unique-identifier=""></a><div style="font-style:normal;font-variant:normal;font-weight:bold;font-stretch:normal;font-size:14px;line-height:20px;font-family:Arial,Helvetica,sans-serif;margin:0px" class=""><font color="#bb1a1d" class="">Steve Higgins ⋅
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<br class="">
I’m wondering if minimum charge amps for lithium is common or not?<br class="">
<br class="">
Or does it have to do with the cell shape: cylindrical vs prismatic vs pouch?<br class="">
<br class="">
A client purchased some EG4 batteries and they are getting a bit out of balanced. Tech support didn’t suggest higher volts or longer absorb but did mention they need 30-50 amps charge. It’s not in the manual. <br class="">
<br class="">
Wondering what you all think and know<br class="">
<br class="">
Thx<br class="">
Jay<br class="">
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