My Schneider Conext SW4048 Inverter bit the dust so they sent me an XW5548. I've gone from max Inverter charging of 45a to 110a. My battery bank is eight Trojan L16RE-A batteries for a 48v 325ah bank. What is the max current I can safely bulk charge these batteries (C/10 is only 32.5 amps)? I'd love to minimize diesel genset run time but not at the expense of battery life. Thanks.
325ah Trojan bank max Inverter charger current
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Great battery choice. Keep in mind C/10 is generic safe recommendation for all batteries. Yours are an exception and C/6 is no problem. 60 amps requires a 5 Kw generator, That will give you minimum gen run time and best efficiency,. Assuming you not run then down below 80% you recharge in 4/5 hours. 2 would be normal.
Last edited by Sunking; 01-07-2017, 12:42 AM.MSEE, PE -
Great battery choice. Keep in mind C/10 is generic safe recommendation for all batteries. Yours are an exception and C/6 is no problem. 60 amps requires a 5 Kw generator, That will give you minimum gen run time and best efficiency,. Assuming you not run then down below 80% you recharge in 4/5 hours. 2 would be normal.
My generator use is mostly during winter cloudy days and I don't run it unless I'm around to monitor voltage. Battery temp sensor is installed on battery lug. I usually charge to 90% and let the solar take over.
I use an MEP-802a military diesel genset which is 5kw. It's 80% rated so it's actually roughly a 6kw genset at my 5,200' elevation
Do you think I am safe bulk charging at max charging rate as long as I shut it down at 57.6 volts? Then let the solar take over?Conext XW5548
Conext MPPT60-150Comment
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Gensets are rated at 100% power for 60 min or 80% indefinitely. Be sure you are not tricking yourself or doing the calculation bassakwards.
Battery charging is very demanding load on a genset
When I run mine, I charge at max rate (30A on my 3Kw rated Lister) At the end of bulk, the rate starts to taper off, and I usually shut down at about 20A going to the batteries,
Be sure you run 2-5 min cooling at no load before you shut off the genset, or the heavy continuous load, can allow residual heat to build up in the alternator windings and melt things if you just shut it off.
Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-ListerComment
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First time I've seen elevation increase a genset power. Maybe you are not using standard terms?
Gensets are rated at 100% power for 60 min or 80% indefinitely. Be sure you are not tricking yourself or doing the calculation bassakwards.
Battery charging is very demanding load on a genset
When I run mine, I charge at max rate (30A on my 3Kw rated Lister) At the end of bulk, the rate starts to taper off, and I usually shut down at about 20A going to the batteries,
Be sure you run 2-5 min cooling at no load before you shut off the genset, or the heavy continuous load, can allow residual heat to build up in the alternator windings and melt things if you just shut it off.
Thanks for the info on cool down. My 5kw genset has an Onan badged two cylinder diesel that is made by Lister Petter. I always do a good warm up and cool down before and after charging.
Conext XW5548
Conext MPPT60-150Comment
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So here is your homework assignment to answer your question. Look in your Trojans Owner Manual and look for the RECOMMENDED CHARGE RATE. I twill be the rate that gives you the best of both worlds. High enough to prevent Stratification, minimize charge time, minimum damage, and longest battery cycle life. It should be if memory serves me correctly 13% of the battery C/6 AH capacity. That way you will know for sure and never forget it.
MSEE, PEComment
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In theory yes sir, but in practice does not work that way. The faster you charge, the longer it takes to ABSORB. At generically at C/10 when you you hit 2.4 vpc or ABSORB you are roughly 80 to 90% SOC and spend the next 4 to 6 hours gassing (wasting water) and corroding the plates. Not real desirable. If you charge at say C/4 you hit ABSORD (2.4 Volts) more than twice as fast, but when you hit ABSORB are only 60% SOC which means you will be in ABSORD mode twice as long. You do not gain anything in time, you only loose by loosing more water and more corrosion which will significantly shorten battery life.
So here is your homework assignment to answer your question. Look in your Trojans Owner Manual and look for the RECOMMENDED CHARGE RATE. I twill be the rate that gives you the best of both worlds. High enough to prevent Stratification, minimize charge time, minimum damage, and longest battery cycle life. It should be if memory serves me correctly 13% of the battery C/6 AH capacity. That way you will know for sure and never forget it.
The RV solar geeks are bulk charging their batteries at crazy high amps. Like 60, 80 or even 100 amps into a 208 ah 12v bank. Sounds like they are killing their batteries.Conext XW5548
Conext MPPT60-150Comment
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Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-ListerComment
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Not sure I would call them GEEKS or NERDS as that implies they know what they are talking about. Just plain foolish wannabe jibber jabber. Like i said you hit a WALL in charge rates where faster charge rates buy you nothing in terms of Time. It is also very dangerous as the Battery Plates, Grids, and Term Post are not likely designed to handle that high of a Charge/Discharge rate leading to catastrophic damage and/or fire. Just Like a loose connection under normal heavy load can do this. Note if this happens is your fault and no waranty claim or Law Suit can be filled. You would be SOL. Ignore those wannabe's.
MSEE, PEComment
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When you say 13% of C/6 do you really mean 13% of C6 , the amp hour capacity at the 6 hour rate?
Otherwise some people will interpret what you wrote as 13% of 1/6 of C20.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Thx again.
MSEE, PEComment
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Great. I will make sure my genset charging doesn't exceed 45 amps. My solar charging tops out at 27 - 28 amps but I'll probably add three more panels to get it over 40a
Conext XW5548
Conext MPPT60-150Comment
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