| << . 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9 . |
| Author |
Message |
gcrank1
Member
|
# Posted: 17 Jan 2025 02:10pm
Reply
Around here 'they' were talking about building huge 'energy storage' for our solar and wind; sounded like a big battery to me.
What could go wrong, 'crank asks himself.....
|
|
paulz
Member
|
# Posted: 17 Jan 2025 02:46pm
Reply
Ha yeah. Moss Landing is a couple hours south of San Francisco near San Jose, is or was hi tech central. I’m the other way, north of SF. Can’t smell anything yet.
Pulled up this thread for another reason. I have a small charger, about beer can size, says lithium right on it. I think it ight have been for an e-bike or wheelchair. Measures about 29 volts, for two 12v bats I guess. But probably not lifepo4s, whatever lithiums those things use. I’d like to use it at the grid to charge 2 of my 100amp LFPs in series. No photo hear, it’s back at home. Hmm..
|
|
gcrank1
Member
|
# Posted: 18 Jan 2025 03:49pm - Edited by: gcrank1
Reply
If that lith-charger is a 'brick' then it may say something like
Input: 120vac
Output: xx milliamps amps Or x watts
Remember amps x volts equals watts so you can calc the amps.
|
|
paulz
Member
|
# Posted: 18 Jan 2025 04:18pm - Edited by: paulz
Reply
Ok back at the house. Here it is on a battery for sizing. I wrote the 24v on it a long time ago so I’d never put it on 12v. Just measured again, 30.01.
I brought the new 100ahs home too, and a Meanwell. I have one on it now, up to about 13.6. Do you let yours run up to 14.6 before unplugging?
|
|
gcrank1
Member
|
# Posted: 18 Jan 2025 05:09pm - Edited by: gcrank1
Reply
You have me confused with someone with a memory!
I wrote it all down here (maybe previously on this thread?) so it was all documented, lol.
IF irc I settled on 13.8 per Steve_S.
What voltage did the bat have when you started?
Take to 13.8 maybe just to when 13.9 hits and disconnect/shut down.
The bat will settle fairly quickly without load to 'about' 13.2 or a bit more. That is right at the top of the real usable volts in an lfp.
Mine are sitting in my cold basement (50ish degrees) to overwinter. If we go to cabin the little EcoFlow River is my take along power supply.
Come season I expect that 1.5-2 hrs on the Meanwell will put them right in the zone
Oh yeah....I see your brick is:
115vac (120)/3amps
230vac (240)/1.5 amps
Do you have a selector switch for the input voltage or does it auto-select?
|
|
paulz
Member
|
# Posted: 18 Jan 2025 05:42pm - Edited by: paulz
Reply
Thanks g. I brought all 4 of these new bats here. I had them in parallel with my old 4 bat Valence bank at the cabin all week, on minimal solar. Talk about power! They all measure 13.25 now, even the one I was test starting engines with (still don’t get how they sell Lfp for atvs and cycles with starters) so apparently it’s fine, whichever one it is. These were 99 bucks each on sale, plus about another 100 for tax and shipping. 500 bucks total, about what I paid for each of my old bats, used, a dozen years ago!
Anyway they don’t even need topping up I guess. I’m going to put each on the Meanwell though, it’s 40a as you know. The little 24 charger can wait for another time. It does have a 110/220 switch.
Next week I plan to run just the new bats and let the Vslence ones sit for a comparison.
|
|
gcrank1
Member
|
# Posted: 18 Jan 2025 07:30pm
Reply
Ive pretty much decided to just use mine for whatever/whenever and recharge when needed. After all, they are out of warrantee, paid for, been working well and are what they are; might as well use em as is.
Guess Ive become comfortable with them
|
|
paulz
Member
|
# Posted: 19 Jan 2025 07:22am - Edited by: paulz
Reply
And that’s the terrific part: run em down, recharge when convenient, no rush, no deterioration. Mine are usually run down by the time we leave the cabin. Just let the solar bring them back a little a day, ready on returning.
My new bats are sitting here at the house this morning after a couple hours each on the Meanwell last night. Sitting at 13.3-4 each so I guess a bit of charge did them well. I never went past 13.6.
Last week I used plumbers tape to hook them together in parallel! Worked fine but I need to come with something better.
|
|
|
ICC
Member
|
# Posted: 19 Jan 2025 01:34pm - Edited by: ICC
Reply
Quoting: paulz Ok back at the house. Here it is on a battery for sizing. I wrote the 24v on it a long time ago so I’d never put it on 12v. Just measured again, 30.01. I brought the new 100ahs home too, and a Meanwell. I have one on it now, up to about 13.6. Do you let yours run up to 14.6 before unplugging? IMG_4252.jpeg
You have me confused. The image posted is a Li-ion battery charger; not a charger for LFP. The label states Li-ion.
Are you using it to charge an LFP? The charge parameters are different. Is that why you are watching the voltages and disconnecting at 13.6 volts?
Why not just use a proper LFP charger and charge to the 14.6 volts? (3.65volts is the rated full charge voltage for all the LFP I have seen, x 4 cells = 14.6 volts)
|
|
paulz
Member
|
# Posted: 19 Jan 2025 02:06pm - Edited by: paulz
Reply
Quoting: paulz I think it ight have been for an e-bike or wheelchair. Measures about 29 volts, for two 12v bats I guess. But probably not lifepo4s, whatever lithiums those things use. I’d like to use it at the grid to charge 2 of my 100amp LFPs in series. No photo hear, it’s back at home. Hmm.
Sorry for the confusion. I have not used that charger, was waiting to hear back. Now that I have, I won’t, I guess the different lithiums charge differently. I had thought maybe just no equalization like LA chargers. Would have been nice with the lights to tell you charge was complete.
Anyway I’ve been using just the Meanwell set at 14.6. I have one on it now again after reading 100% charge is 13.6 at rest. Usually at the cabin on solar or generator they never get that high.
*The Meanwells is just a straight adjustable power supply, no extra features.
|
|
ICC
Member
|
# Posted: 19 Jan 2025 04:16pm - Edited by: ICC
Reply
Quoting: paulz The Meanwells is just a straight adjustable power supply, no extra features.
Ah yes. Useful for numerous things but needs watching. For LFP & Li-ion I prefer programmed turn-it-on-and-forget-it, as I tend to do that.
|
|
paulz
Member
|
# Posted: 19 Jan 2025 05:14pm
Reply
I have 3 Meanwells, 40 amps each. I have tried all 3 in parallel at the cabin but the genny has a hard enough time with 2. At that it takes hours to get the bank up and I don’t run the genny unobserved so no overcharging danger.
That said I just checked the one battery charging here at the grid. It’s up to 13.6 and the Meanwell is only giving it about 5 amps, so as the voltage goes up the amps go down.
|
|
gcrank1
Member
|
# Posted: 19 Jan 2025 05:45pm
Reply
I am very happy to use the lfp charging recommendations from Guru Steve_S.
He has established his 'cred' with me so Ive no reason to go to 'the max' with my lfp batteries.
Ymmv
|
|
ICC
Member
|
# Posted: 19 Jan 2025 06:52pm
Reply
Certainly, and it does.
For me, a full charge to maximum voltage doesn't last long once the sun goes down .... big but efficient fridge, heat pump heating (or cooling), heat recovery ventilation, humidifier in winter, internet, etc. So I go for a full fill-up as insurance for having all the power I might want, especially if I venture into the workshop.
|
|
paulz
Member
|
# Posted: 19 Jan 2025 07:28pm - Edited by: paulz
Reply
Brings up something else… when my bank drops to 13.0 and I fire up the genny (not much solar going on in January here), it shows about the max Meanwell charge, 80 amps. As the volts slowly climb, the amps drop to half or below. Meanwhile the genny keeps going, same rpm, same gas consumption, same wear.. Am I getting my moneys worth keeping it charging or better shutting it off at 13.3 or whatever and doing it again next day when it’s low again?
|
|
gcrank1
Member
|
# Posted: 19 Jan 2025 08:11pm - Edited by: gcrank1
Reply
IDK, lol
What I do know is that at the last charging to 14.4?ish it did take a fair long time on my Meanwell as the amps fell well off too. Then then the bats settled down to 13.2-13.3 anyway and pretty quick. When hooked up for use the 'top charge' burned off quick, quick enough that I figured it wasnt worth my extra time on the Meanwell. Iirc I got about 1/2 hr of 'extra' use, not enough for me to make a diff in everyday cabin living.
Pretty much the same thing happened (when I was checking time stuff) when I charged to 13.8 so why go past that?
Iirc, per Steve, it is the actual usable power that matters not the little bit 'up the high knee' that burns off quick. Not going there may be less stress on the battery too.
So why do the battery companies say 14.6? My impression is that is the high voltage cut-off in the BMS, it is a convenient 'top' for them to quote.
|
|
ICC
Member
|
# Posted: 19 Jan 2025 08:17pm - Edited by: ICC
Reply
With FLA batteries one of the rules of thumb was to terminate generator charging when the charger would switch from Bulk to Absorb charging. That is about the 80 to 90% level.
For LFP I believe it is about the same. So maybe charge until the voltage if up to 13.2 to 13.3 (12 volt system)? However, picking an amperage to quit charging maybe be more meaningful. That is how some solar charge controllers may be programmed to stop or change charging modes.
If the charger starts out charging at 80 amps, it is probably more efficient to stop charging at something like 20 amps and maybe having to run the generator again later, than to keep charging until the amps are down to 10 or so. Just thinking.....
This is one time an inverter generator is good to have. The genny will throttle down as the charger load decreases.
I seldom run a generator to charge and if I do it is usually first thing in the morning or late at night and only if the batteries are quite low or I intend to do some high current thing in the shop.
~~~~~~~~~~~~~
RE: never charging LFP to 100%.... I believe most BMS use top balancing for the cells. So, I think it is correct to think that if you never charge to 100% the cells will never top balance, which may lead to some imbalance between cells. If your BMS is Bluetooth, and if the app gives the voltage readings of individual cells it might be a good idea to keep an eye on that.
|
|
gcrank1
Member
|
# Posted: 19 Jan 2025 08:49pm
Reply
Ive read of various points of top balance beginning, but to go to 14.6/hvd on the BMS and triggering a shutdown (we hope the BMS works) is just premature tripping of the last line of defense for the bat. It is like tripping a circuit breaker, they can only take so many times before fail.
Iirc the top balance will take place over time anyway if you are regularly charging, even to 13.8.
I think Steve has said (maybe in a prev post on this thread?) that the cut-off for charging is when the amps falls off to 5amps for a 100ah bat? It will keep falling from there and take a long time to fully top.
|
|
paulz
Member
|
# Posted: 20 Jan 2025 06:54am - Edited by: paulz
Reply
Quoting: gcrank1 think Steve has said (maybe in a prev post on this thread?) that the cut-off for charging is when the amps falls off to 5amps for a 100ah bat? It will keep falling from there and take a long time to fully top.
Steve must be out slipping around in the snow.. your memory isn’t so bad if you remember that about the 5 amps. That was about my experience yesterday, the battery got up to about 13.7 on the charger at about 5 amps when I shut it down.
Back to the cabin today, plan is to parallel these 4 bats in place of my old bank for the week and see how it goes.
|
|
FishHog
Member
|
# Posted: 20 Jan 2025 07:31am
Reply
Been wondering where Steve has been. Hope he is ok.
As for charging lots of batteries only balance cells above 13.8v. So if you don’t charge up regularly you may want to at times to keep your cells balanced. Set your charger to 14.2-14.4 if you don’t want the bms to trip and let them charge to that. Perhaps when at home on the grid every once in a while. Drain them down after if storing
|
|
gcrank1
Member
|
# Posted: 20 Jan 2025 09:36am
Reply
That top sounds familiar FH and good to me
The drain down after storing Im not so good with. I certainly could be wrong but my use profile starts at the top and basically down to where my inverter trips off (Not the LVD on the BMS).
The drain down/recharge seems to me to be maybe more of a bottom balance and a wasted use cycle?
Shouldn't they be already balanced/stabilized at the storage voltage from months of off season lay-up? Start charging and it ups from that stable balance to your top 'setting'/cut-off.
That is to say, a battery that has been cycled and stored is more likely to be fairly close to balance than one that has been just assembled (poorly) with cells Not at the same voltage.
So what do we do with a bat that has a 'runner' that charges up faster than the others and makes the BMS trip the HVD, or a 'dog' that drops faster and trips the LVD. The usable amp hours are cut.
Well, if I understand correctly, unless we can get a warrantee replacement or pull that bat apart to manually bring that runner/dog into compliance it just is what it is, so use it just like you would a LA that doesn't have quite the beans it used to.
|
|
Nobadays
Member
|
# Posted: 20 Jan 2025 09:52am
Reply
Quoting: paulz Last week I used plumbers tape to hook them together in parallel! Worked fine but I need to come with something better.
I think "old school" busbars can be made by flattening copper tubing and drilling holes as needed. Surely you have some copper tubing around your shop. Way better than plumber's tape!
|
|
paulz
Member
|
# Posted: 20 Jan 2025 10:40am
Reply
Thanks, I’ll look around before I leave the house today,
All 4 bats settled to 14.20 ($10 voltmeter) this morning so at least I know I’ll be starting with an equal set.
These cheapo batteries don’t have Bluetooth (says BMS but who knows) so individual cell checking/balancing is out. Just plug, play and pray. Still, having a backup bank in case the other one takes a dump sounds pretty good.
|
|
FishHog
Member
|
# Posted: 20 Jan 2025 01:08pm
Reply
I was implying drain down for long term storage. Like 50-60% charge if you’re putting them away for winter.
As for balancing some internal balancers only work when being charged and then only at higher voltage levels. If balancing doesn’t start until after 13.8v and people stop charging there then they never get balanced and can get out of wack
If you have an unbalanced battery holding it in that high range at low amps for long periods can bring them back but it’s a slow process. I had one get too far out over winter storage. And while it may have eventually balanced I opened it and balanced cells individually. Now charge and hold it up at 14.4 every couple months then drain back down for storage and so far it’s staying balanced
|
|
gcrank1
Member
|
# Posted: 20 Jan 2025 01:49pm
Reply
|
|
| << . 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9 . |
