Great video. Thanks for this as I was wondering.

Great video. I've been asking about this and everybody kept on saying it was impossible to mix them. Please release the next video with final results.

@garethevans3074

Жыл бұрын

Not recommended though

@kayjay4060

Жыл бұрын

@@garethevans3074 Only because of the pitfalls. Once you figure them all out, you can have a safe connection between them.

@7071SydcHome

4 ай бұрын

@@garethevans3074 Not recommended by who? The salesperson?

I really appreciate that you were honest about not knowing! The general answer you get in the industry is just "no" because it's easier than a "yes but...". I personally think it's not a problem for low current applications, but should be avoided for high current applications as the Peukert exponent is very different between the two.

@ev-power

9 ай бұрын

Peukerts Exponent only relates to the (dis)charging efficiency and therefore State of Charge estimation. So as long as you don't require super accurate SOC then low or high current makes no difference. My system is still connected and still going fine. IMO there could be some advantages in cranking applications using a small high power SLA battery in combination with a light weight high energy LFP battery. I've not seen it done yet, might try it on my van one day.

I'm wanting to connect my nissan leaf powerwall with my lifepo4 powerwall. I know I'll have to reconfigure my packs but if you have any idea which way would be best please let me know. It's It's 24 volt system

have you got an Ah rating for the parallel configuration?

Sound so low. Volume on max. Hard to figure out what is said. :S

@timetobeast7261

Жыл бұрын

You have a crappy device then my friend i hear it fine

@Mikeywatches

Жыл бұрын

Your correct volume low

Hi! Your videos are great! Are you interested in reviewing LifePo4 battery charger?

Both during the discharge and charge one might connect the negative lead of one battery and the positive of the other so both are drawn from and charged in more of a balanced state.

@ev-power

Жыл бұрын

I understand you are trying to say that the leads should be symmetrical. This is true when connecting Lithium batteries in parallel. Not to misunderstand - NEVER connect the positive terminal of one battery to the negative of the other and vice versa or you will immediately have a direct short circuit. For Parallel connection always connect positive to positive and negative to negative.

only when the lithium disconnects by the bms will the lead acid get fully charged

recently installed a lifepo4 battery 100ah in my campervan.it’s smart Bluetooth bms so can see power being consumed by my stereo x3 power amps ‘homemade sub fosgate driver plus kenwood speakers about 15amps on the bms app when wick turned up.I thought why don’t I use my spare agm battery.only new last year one one weak.as had a pair of 115ah arm’s.I know u not supposed to mix lead with lithium but thought could use the agm when stereo on by using a switch to kick in the agm battery.I’m using a separate circuit for agm charged by my old dc charger 12amp and some solar 100watt with epever 10amp mppt.The lifepo4 has victron dc charger 18amp Orion and a Renogy rover 20amp mppt from another 100watt panel..so if I link batteries with fused link and a switch by drivers seat what you reckon ?

@ev-power

Жыл бұрын

I reckon... (my opinion only, you do your own testing), switching any batteries in parallel that are potentially at very different states of charge is fraught with danger. If there is even a small difference in the terminal voltage, very large currents can flow between the batteries. You need to check for this, especially potential edge cases. Batteries permanently connected together do not have this problem as they are both always at the same voltage.

@stevemcgowan3017

Жыл бұрын

@evxpower thanks.had a few opinions.the boat guy says can work if use vsr relay and his own design bms battery management thing about 300£ plus ship to uk🤣.my lifepo4 works well doesn’t lose volts just capacity obviously as my compressor fridge on and want use stereo usually when driving.only thing is the victron 18amp charger says 12 to 15 amps on lifepo4 Bluetooth amp could probably do with 30amp model but if I do longer drive it charges up to 100%but with price fuel don’t want drive around Willy Nilly.I’ve got cheap eBay smart lifepo4 charger 10amp does it over daytime I keep watch weekends.Probably safest bet is another lifepo4 battery but they 400£ .can’t afford at moment.you keep safe anyway😀

@stevemcgowan3017

Жыл бұрын

@evxpower I did parallel my old 12 amp dc charger with the victron 18amp dc charger but according to the lifepo4 Bluetooth app it didn’t show the 30amp charge rate 18+12 .so use them separately now for each different chemistry battery separate circuits seems safer.Will probably use agm for my led lights ,usb charging .

My experience with lipo4 and c- 10 lead acid tubular in parallel for my solar back up system is much exciting. When 7.2kwh lipo4 was connected without the tubular la battery, the lipo4 suddenly gets shutoff due to bms gets into protection mood at fully charged during day time and at low battery during discharge at night. In that situation the system was found not functioning smoothly. But after connection of 3.6kwh tubular la in parallel to lipo4, the problem of sudden shutting off of lipo4 due to bms, gets resolved and the functioning of system become flawless and smoother. Tubular la battery sits at full charged all along in most of the time and only lipo4 takes all the burdens of charging and discharging without shutting down the system . Two separate individual charg / discharge monitor have also been connected for both the lipo4 and tubular for monitoring the inter battery flow of current if occurred, but in last 60 days there are not such inter battery flow occurred. Back up also improved up to 8 kWh from battery backup for round the trip system backup.

@spanishtreasure9551

8 ай бұрын

exactly lithium likes to have lead as a electricity sharing buffer /partner and it makes Both lithium and lead last longer

What I have been told is that you can parallel AGM and LifePO4 together as long as they are the same AmpHour rating and Rate of Discharge is similar. You must have all batteries fully charged or else you can get a surge from one to the other. The other suggestions have been to use fuses or circuit breakers between the battery banks in case the AGM/Lead Acid has a catastrophic cell failure and it will disconnect it from the circuit.

@kayjay4060

Жыл бұрын

@Russell Hank What is the cheapest way to safely hook up a 400 ah Overkill 100a BMS lifepo4 to my minivan? Looking to get away with spending little to no money to do this. My cells are all balanced, and my pack is good. I have all of the wiring, connections, and a solar panel and charge controller. Just need a way to safely hook up the bank to my lead acid starter battery.

@spanishtreasure9551

8 ай бұрын

the chinese , others etc dont want people to know you can combine lead with lithium together, when you do this as many people with home boats have already done, lithium will do the work when not charging at night, and keep the lead up in voltage . Rule is always keep lead charged up and have same amphr and have more lead battery volume than lithium (example 2 or 3 lead batteries to every 1 lithium) . if in a structure , i would also make sure batteries are in outside inside of brick enclosure area for fire prevention.

@7071SydcHome

4 ай бұрын

Best to use WATT/Hr when comparing different battery chemistries. The nominal voltage of LiFEPO4 is higher than older battery chemistries, so while the amp hours may be the same, the watts/hrs of the LiFEPO4 will be higher - hence the reason why people rave about the greater capacity of LiFEPO4 batteries. Frankly, I'd be more worried about catastrophic failure in Lithium, than lead acid - however, a fuse between the two types, an excellent idea. The number of lithium battery fires is quite worrying.

@vevenaneathna

3 ай бұрын

@@7071SydcHome amp hours are what people who know little about batteries use. atleast this guy is honest about his knowlege gaps.

I have installed my older 115AMP AGM BATTERY ON A SEPARATE CIRCUIT CONNECTED TO 100WATTS SOLAR AND EPEVER MPPT CONTROLLER.I HAVE ALSO RENOGY MPPT CONTROLLER FED FROM ANOTHER 100WATT SOLAR IT FEEDS THE LIFEPO4 BATTERY AND HAS LIFEPO4 SETTING LIKE THE VICTRON DOES .

I run a 48v offgrid system with 28Ah of lithium split between two packs on one sled connector along with 10Ah of lead acid, allows me to hot swap my lithium packs without needing to power off my inverter loads

I have 2 lipo4 12v 280 ah tied to 10 of those 6 volt lead acid battery.. my charger is a 2 cyl kubota diesel engine with a gm 254 amp 12 volt alternator.. if I only have lipo4, my alternator would get destroyed from overvolting when lipo4 bms shut off at full charge and maybe cause damage to the inverter. When it's too cold, the lipo4 shuts off, and the lead keeps everything going. Also, the engine starter draws amps hard, so the lead helps level that out. It's working out very well so far.

@ev-power

7 ай бұрын

That is a very good point and my experience also. Lithium BMS can shut off when the batteries near full charge. This can be very hard on charging sources. Lead acid in parallel will absorb any voltage spikes.

I really hope this can work because the lithium never makes it to the low voltage shut off of the inverter or the charge controller. They disconnect the battery while the inverter and charger are on. if I had a big load of sun coming in or drawing a big load on the inverter when the battery gets suddenly disconnected because one cell gets too low, POOF. MAGIC SMOKE ALL OVER. I've been trying it a few times and things seem ok but, I can't seem to find an expect opinion on the subject. Same thing with using a power source into a charge controller, instead or with solar panels. I do it but, some say do not. I can't understand why using a highly erratic volt watt,amp, output of solar panels ,is OK but a steady clean source is not?

@ev-power

Жыл бұрын

This is a very good point. What happens when the lithium BMS disconnects the battery? This can actually happen often with MosFET based switching BMS's. If there is a lead acid battery in parallel then it can absorb any disconnections and prevent potential voltage spikes that might occur with a sudden disconnection. Unexpected bonus.

I’ve just installed new 100 lifepo4 battery it runs my compressor fridge 24\7 and my 3 power amps for campervan stereo .it’s subwoofer system .I have victron dc to dc charger use stereo mostly when driving.I bought a cheap lifepo4 smart charger off eBay to get lifepo4 to 100%charge on weekends charges up to 10amps.was 25£ charger works ok.the victron is 18 amp charger

The resting voltage of the lead acid batteries about 12.9 volts resting voltage of the lithium iron phosphate is about 13 3 or 4 which is the a good float charge level which will keep the lead acid battery fully charged not overcharged what happens if you if you connect the those batteries to allowed is that the the list of our phosphate will pull down first because it has less internal resistance and then the lead acid will kick in what's the lithium iron phosphate gets down to about 8 or 10 volts but you want them closely matched voltage wise when you connect them together to keep any current from Exchange overload

The efficiency of a lead acid battery is only about 80%, so in fact it is not at all optimized for energy storage compared to lifepo4

trying to connect a 12v 90Ah Lead acid with a 12v 200Ah to use in my solar inverter. lets see how it goes

@ev-power

Жыл бұрын

Let us all know !

@Zenmartian

Жыл бұрын

How did it go? I’m having a 200amp lithium with two 100amp lead acid

@anandapriyadarshan

Жыл бұрын

@@Zenmartian did not get a chance to connect. Found a way to make a 24v with the lifepo4 . the change from lead acid to lipo was day and night! use the lipo only. lead acid will just weaken the link IMO

@ev-power

Жыл бұрын

@@Zenmartian It's still going...

@alias8785

Жыл бұрын

Same capacity for me, please let me know what you did :)

Guys, can I just say - how much I enjoyed using your 120Ah EV Power battery in my boat last weekend. I ended up changing out my traditional AGM/high CCA (heavy!) boat engine starter battery to an ultra-light NOCO NLP9 lithium (under 1Kg!) designed for motorcycles, mowers etc. I also added a CTEK D250SE in between the starter and your EV Power battery. The EV Power battery is for my boat accessories, trolling motor etc. When running the Yamaha engine, its alternator charges the lithium starter battery and also the EV Power (up 20amps max) via the D250SE on “lithium” settings. The cool part was using your phone app to monitor (over BT) the battery output amps, input amps and SOC. It’s great how the readings “cycle” back and forth. A powerful feature I didn’t think I would need, and let’s me know the other systems (alternator, D250SE etc) are also running A-OK. Great product and well done guys.

@ev-power

2 жыл бұрын

Aw shucks, it ain't nothin really... But thanks, always nice to hear positive feedback. We do try.

@doireallywantmynameonthein3834

Жыл бұрын

@@ev-power Very hard to hear.

@ev-power

Жыл бұрын

@@doireallywantmynameonthein3834 Yes, being an introvert I am a quietly spoken mumbler. Will try to be more extroverted next video ;)

@doireallywantmynameonthein3834

Жыл бұрын

@@ev-power Just use one of those bluetooth earbuds. They link right into your laptop, phones etc.

the chinese , others etc dont want people to know you can combine lead with lithium together, when you do this as many people with home boats have already done, lithium will do the work when not charging at night, and keep the lead up in voltage . Rule is always keep lead charged up and have more lead battery volume than lithium. i would also make sure batteries are in outside inside of brick enclosure area for fire prevention.

@ev-power

8 ай бұрын

Makes sense.

You should NOT leave a LIthium battery connected to a powered Lead "smart" charger for a longer period of time, as that could either damage the lithium or make the BMS disconnect. A lithium charger charging a lithium and a lead in paralell is less of a problem I think. And he does say he's using a lithium charger. .... If the lead is old/faulty it could overheat and vent (or explode). I think some chargers has external temperature sensor to guard against that.

@ev-power

Ай бұрын

What tests have you done to back up your claims?

@finnerutavdet

Ай бұрын

No tests, but I'm in the process of doing this on my boat with two consumer banks (like you show, but 2 off) and one starter Lead. I've probably been watching 20 hours of youtube videos on this specific subject, and I'm an electronics engineer. And at the moment it looks like I will basically end up doing the same you're testing out here. ...... Lead chargers has intermittent a bit too high voltages in their later charging cycles, which, depending on the Lithium BMS could cause problems. I have exploded one old lead battery by the way, that's thoroughly tested, but the charger didn't have an external temperature sensor in that case (as most don't have).

@ev-power

Ай бұрын

@@finnerutavdet When you have done the actual testing and found the actual problems perhaps you can report back. This is scientific and engineering method. To date I have not found any real issues but that is certainly not to say that there aren't any, esp. given the variety of chargers out there.

Sorry but when chargin the together the lithium will take nearly all the amps for itself

@ev-power

6 ай бұрын

That is not true from my testing.

A lot of people have been messing around with connecting lead and LiFePO4 together for several years now, but to be frank it just isn't a good idea. In an emergency? Sure. For regular use? No. Sure, the LiFePO4 battery can tolerate just about anything in its voltage range, probably for years. But remember... that LiFepO4 battery is expensive, and is supposed to last 15+ years. Considering the investment, you really want to keep that LiFePO4 battery in optimum condition. And that means NOT paralleling it with lead. In anycase, it really is the easiest thing in the world to put the lead on a separate charge controller. This is doubly true if the lead is only being used as a starter battery or something like that. If you don't have anything pulling a high number of amps all the time, then a cheap low-amperage DC-to-DC charge controller will keep the lead in tip-top condition and do it with relatively high efficiency. A 12V-to-12V charge controller runs roughly 90% efficiency. It gets even better if you decide to use a higher voltage lithium "home" bank. Then you can charge your lead from the home bank with a cheap buck-only charge controller (97% efficiency). Something like a Victron 75/15 (24V home bank to 12V lead), or Victron 100/20 (24V/48V home bank to 12V/24V lead), for example. Perfect if you don't need to charge the lead at more than around 15A. There are many, many advantages to using a higher-voltage lithium-based home bank. In anycase, there are lots of options and lots of topologies. There is no need whatsoever to parallel the lead with the lithium and maintain neither of them optimally. -Matt

@ev-power

8 ай бұрын

With due respect, it sounds like you have not ever tested it.

@junkerzn7312

8 ай бұрын

@@ev-power With all due respect, connecting the batteries together for a few hours, days, or even weeks and then calling it a day is completely meaningless when it comes to determining whether you are putting excessive wear on a LiFePO4 battery or not. What did you think would happen? A big red light turns on and admonishes you? The LiFePO4 battery has protection built into it. It will not let you mess it up so badly that it stops working entirely. But that protection does NOT protect against excessive wear due to bad setups. These batteries are expensive and they should last at least 15 years and only have lost roughly 20% of their capacity at that time. You don't want to plop down that kind of money only to find 5 years down the line that your battery has lost 30% of its capacity due to cycling and sloshing, because you couldn't be bothered to spend $100 on a DC-to-DC charge controller to separate the lead out. -Matt

@ev-power

8 ай бұрын

I've tested it and am testing it for months already. When you have done the same you can come back to me and we'll compare notes. Please, empirical evidence, not hypotheses. @@junkerzn7312

@junkerzn7312

8 ай бұрын

​@@ev-power You don't get it. You AREN'T TESTING IT. What exactly do you think is going to happen in the failure case? Tell me that. What exactly do you think is supposed to happen? What are you testing FOR? Going by your video, you aren't testing for anything other than the LiFePO4 battery not outright failing on you. Have you done any capacity tests? Have you characterized the wear rate? Have you done any accelerated cycling so, YOU KNOW, you don't have to wait 5 years to find out that it didn't work as well as you would have liked? No, you aren't. You are just throwing the batteries into a system and messing around with it a little then calling it a day. Are you even adhering to the LiFePO4 battery's safety specs? What is the paralleling limit for that particular battery? Look it up. It's approximately N x Ah in amps (so a paralleling limit of 4 for a 100Ah battery is basically that the BMS can protect against a 400A dump and still disconnect before something catches on fire). Now, how many amps will that lead-acid battery dump if it gets shorted? That's just one of several issues. How about the charge target? Are you charging the LiFePO4 battery to its full vendor-specified target? Because if you AREN'T doing that due to the voltage being too high for the lead-acid battery, there is a good chance that the LiFePO4 battery's internal balancing circuits aren't even activating and you are slowly letting the battery go out of balance over time. Is the lead acid battery going to stay healthy without equalization? Because, you know, you can't put an equalization voltage on those paralleled batteries without overcharging the LiFePO4. Come on. Learn something about the batteries you are throwing together before you make a video like this.

@7071SydcHome

4 ай бұрын

You may find this interesting - this comment is from another YT channel, on the same subject. Quote (boatelectricaldiy) I'm a marine professional and I won't install lifepo4 without it being directly in parallel with a lead acid battery. I have left a 300ah LiFePO4 hooked to a lead acid battery for months and the lead acid was full and the LiFePO4 was at 98%

One will always drag the other one down because they have different discharge rates. That's why an isolation switch is recommended. They'll charge together, but don't run them down at the same time because you won't get the full potential out of either.

@ev-power

Жыл бұрын

I don't quite follow what you mean by different charge rates. In my experience the LFP will keep the LA almost fully charged until the LFP is nearly flat and then the LA will keep the LFP from going suddenly to low voltage. As far as I can see the system is complementary.

@cristianpopescu78

Жыл бұрын

What a happiness that there are people like you guys.Have already a Li Fe Phosphate battery but a bit too small,no other Li fe phosphate avable,so I was thinking to help it,for a while with a cheap lead battery in parallel conection. I knew,otherwise, that alkaline battery never,ever ,should work along side a lead acid battery, chemistry stuff..So I was wondering if there would be such a issue for a Li Fe - lead acid working Tandem . Thanks!

@kayjay4060

Жыл бұрын

@@ev-power I think he got confused by lead acid discharge is higher. This only means the LFP bank is going to be drained slightly from the LA. You can work out how many amps it will draw on the LFP bank. It's not much though, but can be high if the LA is bad. LFP essentially becomes a battery charger for the LA, and also handles the loads.

@ev-power

Жыл бұрын

@@kayjay4060 Yes, agree from what I have seen so far.

@kingdommusic5456

8 ай бұрын

@@ev-power exactly

Can’t hear