₦airaland Forum

Enrythesis:
zero eight zero 27038104

ok bro

Enrythesis:
yes Available

check your email or drop your contacts let's connect.

Enrythesis:
magnum inverter for sale

hello bro, is your magnum inverter still available?

saint2ace:
Good afternoon all, please who has dealt with solar depot before, are they really a biz or individuals with an "I don't care attitude to customers"?

How can I make an order and not get a notification from the seller, not even an email; I called over the weekend and no one took calls nor bothered to return calls on resumption of duty, I still continued to call only to be told item is out of stock and they will issue a refund.
3days later their chat to ask for location that's already in the order form and when asked for update, a supposed "customer service representative" replies that am I asking questions cos she buzzed to ask for location? All these cos I brought biz to an entity?

Please is this their modus operandi or this is just a freak occurrence from the blues.

I await responses........

i see solardepot has already responded above. i've been doing business with that outfit for several years now.
my second magnum e-panel was bought from them along with my first set of solar roof mounts, tristar mppt-60
charge controller, etc. they're quite friendly and business minded folks overall. i'm sure yours is a one-off
case or maybe the lady at the reception was just having a bad day...

samir101ng:
I hail fellow house members in the Solar Ministry

As a new convert to the LifeP04 battery geng, i have been doing a lot of research on the different brands and capacities available. Of course, using LifeP04 also means you have to learn about the BMS (Battery Management System) and how it is included in your entire inverter system. Now one of the initial drawbacks of the move to LifeP04 was its high cost and availability. Buying from big name brands will seriously dent your wallet and a lot of people preferred the DIY approach by busing cells directly from China and attaching a BMS to the installation. This greatly reduced costs but now added complexity of installation and needed some technical knowledge. While most users will have preferred the first option many were driven to the latter due to costs and therefore led to a surge in demand for battery cells and installers. There are some new products out now that appears to have a middle ground option.

Server Rack LifeP04 batteries

SOK Battery | 100Ah 48v | Server Rack Battery
https://www.currentconnected.com/product/sk48v100/

EG4 48V 100AH LiFePower4 Battery
https://shop.signaturesolar.us/products/48v-100ah-lifepower4-battery-by-eg4

Now, most LifeP04 cells bought from China from Manufacturers like EVE, CATL, LISHEN are 3.2V. So, if you need to build a 12V, 24V or 48V battery bank, you will need to buy multiples of these cells to build a bank. You will also need to buy a BMS and other necessary accessories to build the battery bank. This entails a lot of research and technical expertise for which many may not have the time nor energy for. With these pre-built LifeP04 Server Racks, its just plug and play. Though right now they are limited to 48V 100ah capacities, i think for the ease of mind and integration they offer at their price points its a good deal. What do you all think ?

we live in quite interesting times indeed. this is what some of us predicted some time ago with lithium technology.
finally it's beginning to go mainstream. soon, we will have more oems coming out with these sort of plug and play
models that require nothing but rudimentary knowledge of positive and negative battery connections and by
then lithium would be a household name.
i think it's the way to go provided price point is reasonable and quality of cells can be guaranteed.

bigrovar:
[Quote author=olopan post=110434089] As a contribution to the ongoing solar panel energy production debate, which many with monitoring system can attest to is.

For us a rule of thumb,

1. Tier 2 panels are calculated with 0.55% of nameplate or total PV capacity for period of 4 Hours.

2. Tier 1 panels are calculated with 0.65% of nameplate pr total PV capacity for period of 4 Hours


If the system is loaded I.e. energy storage and loads then it is expected to see energy production in line with above.

This proven true by remote monitoring.

Conditions based on a normal sunny day



I have been taking logs of my solar installation since 2017 over 80% of those logs collects real time to information every 10sec of panel generation including peak power and total generated energy for the day.

What I have come to understand is, a lot goes into your solar panel harvest than just being tier 1 or tier 2.

The most important thing is how the panels were installed. What is the angle of inclination and the direction the panel is facing.

What is th installation design. Does it flush with the roof or is it installed on a roof rack. Lastly Location location. A solar panel installed in jos would have a different average yield compared to one installed in calaba.

A well optimized panel installation beats a tier 1 panel installed "wrongly"

Here are key pointers.

Ensure your panels are installed as flat as possible. Nigeria is just above the equator so your panels so the flater your get your panel the better.

7°horizontal tilt facing through true south. Send down the rain type of roof you see in many "mansion" in Nigeria are not ideal for solar.

As much as possible avoid your panel facing the north of you have no choice then make it as flat as possible using the roof rack to offset the non ideal roof angle.

Best to avoid mounting your panel directly on the roof. The roof is the hottest part of the house and heat is the enemy of solar generation. In fact panels derate the hotter it gets and you can lose close to 10 to 20% of your generation due to heat. Mounting on a rack that elevates the panel above the roof allows for it to be air cooled and reduces heat transfer from the roof.

If you have a large compound consider ground mount but ensure they are no partial shading. Ground mounts are best. Your panels can be tilted optimally, can be easily cleaned during the dusty period and easy to earth them.

Wiring is also very important. Lots of losses can happen between the panel and charge controller. As much as possible strive for higher voltage configuration to avoid pushing too much amps down the wire. This is one of the beauty of MPPT. It allows your to string your panel into higher voltage strings thus reducing the need for large wiring and associated cost between panel and controller.

Note that the thiner the wiring conductor surface area the higher the resistance and losses. There are lots of site that that help calculate how to size your wiring relative to amps/voltage and distance.

If your panels are far from your cc, you need thicker longer cables or you might want to consider a controller that can table high voltage panel Strings like 250v and use that to reduce loses and wiring cost.

In all, it is very reasonable to get 70% or even higher from your panel if the condition is right. My 3kw panel does 2500w standard as need demand and as weather permits.

It is however good practice to size your system in the design stage with conservative figures just ensure you thrive to beat those figures in the actual implementation.

very spot on. i couldn't agree more. tier 1, tier 2 or tier 3 means nothing if the basics are swept under the rug.

mrmachine:
Please I need advice or review on this brand. @Niyi, GeorgeD, Ojesky, and others; your input would be appreciated. Thanks

the 'xtrapower' brand doesn't seem to be among the regular brands we are familiar with.
it might be a new kid on the block trying to gain market share or might just be a white label.
either way, i'd be careful if i were you because given its obviously unknown history it would
be acting in blind faith to throw hard earned money at such product range.

samnaija:
Controllers cant guaranty constant voltage, cloud effects , bad wheather and so on. You can carry out a little experiment charge with nepa only and discharge, also charge with controller and discharge. You will notice a difference in run time. The rule is once a while charge with nepa

bro, you might want to check the veracity of your statement again. what the cc can't guarantee you is max
current output for a given voltage range all through the day. it can certainly guarantee you steady/constant
voltage for the greater part of the day while the sun is up except for an exceptionally cloudy/rainy day.
also, its not a rule of thumb to charge your battery bank with public power or nepa/phcn. some of us here
have been off-grid for years now, only using the sun to charge our banks and our systems are doing
extremely well. it depends on the size of your solar array and cc quality among other factors.

SuleimanKano:
Good morning House, am forced to bring to the members of these thread.

In brief,

I bought 10 units of 60W Yohako All In One Solar Street Lights around February from Justcallmenuel fast forward October 7 out of the 10 units no longer works, the client called again that an additional unit no longer works making a total of 8 units not working again.

I reach out to Justcallmenuel and usually that we would be needing additional units of the street light, he said they're available and comes with one year warranty. I told him unfortunately, the previous ones I bought no longer works, he said he'll inform the company about it, after couple of days, I reached out to him again regarding my complaint as the client is on my neck, Justcallmenuel reply was "The company said there is no warranty on it".

This is concerning as the client plans to install more of these products for his factory in Zaria, Kaduna.

sorry for your loss bro. unfortunately not everyone who comes to post here is really a solar enthusiast.
most are here just to make profit and that's it. they are not necessarily grounded in the products they're selling.
going forward, any seller who just comes to dump adverts on the thread and vanishes into thin air should be
avoided at all cost. they don't weigh in on discussions. they don't offer any suggestions on problem solving.
they are just business focused. chances are that they don't know much about what they are selling and will be
very unlikely to help you sort out your issues if you call them up on any product purchased from them.
a word is enough for the wise...

mustaphagreens:
My roof is very steep o, not easy to access. I had called the guys that did the installation to rectify the issue today but they couldn't make it. I don't have the devices to run these measurements right away but I should get the clamp multimeter by tomorrow, with the device I should be able to measure the current and voltage at the panels and cc.

I am looking to boost the current supplied by the panels, will a series connection not cause the current to drop instead?

the bolded may be part of your issues among other factors. if your roof is too steep and your panels were installed directly
on it without using adjustable brackets it means you won't be getting optimum charging current abinitio regardless how
efficient your cc is. to get maximum juice from your panels, aim at a maximum of between 15 to 25 degrees orientation.

mustaphagreens:
I never get a full charge. Is my charge controller fake?

while your charge controller may not really be the best for the job, i think you have to also look
at other factors like panel orientation, cable size and distance. all this can contribute to your issues.
besides, you didn't mention whether inverter is being used during the day simultaneously while
battery is being charged.

mustaphagreens:
Chai! I got two 350W panels some weeks ago. Both connected in parallel and are still unable to charge my 12v 200ah mopower battery full in a day.

your 12v 200ah will have a total of 1,920 watthours if you deplete your battery to 80% dod.
your solar panels have a combined output of 700w at 24v.
on a good sunny day with a well installed system, you should have a full battery under 4 hrs.

babaegun:
Very, very true.

I have been underutilizing my setup before but with node red, my ACs work even at night and only go off when the threshold is breached and keeps the battery healthy. Before, I will be checking and turning appliances off through the internet but now, its done automatically. Solar is sweet

well done bro. using solar energy should really be a pleasurable experience. that was the number one goal most of us
had years back when we embarked on this journey. after suffering endlessly from generator wahala, it makes no sense
to find oneself caught up in the hassles of solar. that would be double jeopardy.

Daboomb:
Good one from you there.
So, without the 'deception' of semantics, these "Second Life" Lithium batteries are USED, Second-Hand Batteries. Full Stop.

Now, if that is the case, my questions are: How do you guarantee or confirm the amount of Cycles left inside it, bearing in mind that the only reason we go for LiPo4 Cell batteries are because of its reputed 5000+ Cycles?

How do you TEST, that a Buyer is not being given a Used, second-life Cells, for the price of a New Ones, if a buyer requires New, grade A battery Cells.

It could well be that such Cells in a battery are closer to their "End of Life", than a "Second Life", without the new owner being aware, yet having paid top money for them!

I know you are a seller and l should not be asking you a question like that but l have the feeling you are a honest person and will always speak the truth.


Other Experienced/Expert/DIY RE proponents should please weigh-in on my question.
George_D
Ojeysky
Niyi
Trippledot
Valto
Earthrealm
Olopan
Ceaser
Dam5reey
McTrinity
And others whose name l cant remember now.
G

in addition to what others have said so far, you have to know that charge/discharge cycles is not an exact science.
a battery may be rated for 5000 cycles based on lab tests under standard conditions but in real world terms such
cells could actually put out 6000 or more cycles all depending on amount of current drawn per cycle/ length
of time. regardless of battery chemistry, this is a proven fact although lithium generally handles large draw down
currents better than other common battery technologies, e.g lead acid.
to answer your question, when it comes to second hand cells or batteries, you cannot totally eliminate the risk
of being saddled with almost depleted cells being traded as top grade. that is why the reputation of the seller
becomes key since a seller with a reputation to protect will not want to soil his name by selling junk just to make a
few bucks.

gadgetplanetng:
How fast is their delivery

Before covid-19 it used to be like a week from when shipment is initiated to delivery in Lagos.
But now it takes a little longer (for obvious reasons).

Spy360:
Someone told me that 5e is hard to get with 180cm. He also said that the c band is from 240cm and above. I am now confused. I stay in Owerri. I have also attempted 60e c band but no way. Yesterday, my wife was even begging me to leave it and manage the small dishes.

Since i don't have 180cm I may not be able to confirm that but I think you should still give it a try
using the directions above, By the way it is 7e i meant to write. I have corrected it in my original post.
Move from 7e as if you're going west.

Spy360:
Report Card

I have been trying to track Ses 5 c band since weekend. So far it has been elusive.

In order to achieve this I had to take a patient step by step approach from known to unknown. So I connected a Ku lnb and tracked 28.5e which I got easily. Then I tracked 51.5e which I also got easily.

Now sure that the dish, lnb and cables are ok, I proceeded to track 5e but didn't get signals. Instead I got 7e. Despite all efforts through tiny adjustments, 5e remained elusive.

Why is this so?

My next step was to use the 7e direction and connect my c band lnb. Yet it didn't work. What am I doing wrong?

Cc GeorgeD1, Bencote, adubam, Odilibe, Blexxonmak, Olenyi, ManirBK, Digitman

I am calling on all my fta gurus.

Bros, honestly this 5e don really suffer you oooh.
But if you can get 7e, then you can get 5e easily because both satellites are just 2 degrees apart!
Move your dish to 7e, be mindful of your east and west direction and slowly move the dish as if you're going west.
Make sure you change the TP to 12054v 3000sr (BET Naija). When you hit green, change your Ku lnb back to C band
and blindscan. You're good to go.

ojeysky:
The smile was mutual as I read through your post, especially when you term sharing lithium experience as glorification above other chemistries when people were very specific about LA. How a good LA will have any advantage over a good littium remains what I am yet to hear. Today my peak discharge was over 120A and charge over 100A on a 510AH battery bank, can you even do that with LA of same capacity without the voltage sagging below lvd.

However everyone to his own poison/food.

bro, as long as everyone is smiling, i guess that's all that matters. and, niyi already nailed it with his reply as usual.
i started this journey into energy freedom over 10yrs ago because i was tired of all the hassles associated with running
fuel guzzling generators. the oil changes, servicing, maintenance...the works. switching over to renewables shouldn't
take me back to that old forgotten era where i have to worry about whether my battery bank is top balanced or
bottom balanced. whether i have the right bms or whether my bank will suffer an unexplained voltage run-away...
i just want a system that just plain works and if i can get it with my lead-acid bank, what is there not to like?
lithium will eventually mature, i wager probably in another couple of years and by then most of these teething issues
would have been taken care of. who knows? instead of lifepo4 we all would be stocking up on lithium titanate or some
other higher version of lithium battery technology. like they always say, the best is yet to come.

mcTrinity:
Good evening Mr. Obimind....

I think we can actually always try to share experiences with certain type(s) of RE item technology without completely painting one type black, especially a type that has proven and is still proving reliable.

This forum deals with facts and details. And as far as this your story goes, it's completely devoid of details.

A lot of newbies and guests come in to this forum to get enlightened and its bad if they always tend to meet misleading stories

I'll go straight to my observation in your story. I strongly believe that the problems you had with your LA batteries (as far back as 2013, 2014 etc) weren't because they were LA technology. I believe they were as a result of misuse; in fact, consistent misuse.
Details that you didn't tell us here are the size of your battery bank and the load that you use. You also didn't tell us how you cycle it and how appropriately you were charging them.

We all know that LA has a big fault when it comes to maximum current you can pull from it at any time, and recommended DoD.

Imagine drawing 30ADC from a 20hr 200AH LA battery bank. Even the likes of Varta or US Trojan or Quanta would die within months.
Draw same 30A from a 200AH Li battery bank, and the battery would be smiling, and the voltage won't even dip. Drawing 30A from a 200Ah Li battery bank is even a "misuse"

I deal on both LA and Li and I always explain the Pros and Cons of each to new clients and allow them make their choice.

Folks are still using same LA, going to more than 5years and yet to change their batteries.

LA technology does not forgive abuse and misuse of any kind. Folks that understands it and are willing to abide by its "regulations" are still venturing into it happily. So, if you had consistently misused yours, don't come and dump unfounded conclusions here without facts and details of what actually happened, especially detail of your load, charging, and usage.

Just 2 months into Li technology and you're already concluding. I'll strongly advise you to study that guy very well and use it properly, otherwise you'll come back tomorrow to blame Lithium and now testify about NiCad technology...
Remember that those years, LA battery was amazing to you too until something started going wrong.

This is not for debate, as plenty have already been done, but to prevent new guys that are still trying to find their way around RE world from being mislead by your post.

Cheers

lolz. i couldn't have said it better. after our last extensive debate here on this lead-acid vs lithium thingy,
i just smile, read and waka pass whenever i stumble upon any post glorifying lithium above other battery chemistries.
the question i ask myself is, "how long will it take these peeps to realize that you don't change a winning team?"
we all watch the epl, and we see how winning teams are celebrated. there's no season i've seen where a ucl or premier
league winning coach was sacked for winning or where the highest goal scorer for the previous year was asked to go
just because the club owner found a new, sharp looking, sleek untested player!
so, what's the point here? for those of us who have used lead acid over the years and seen the benefits its a hard sell
telling us to dump our tested and trusted banks for a new bride still going through puberty.
my last zenith batteries served me for over 8yrs and when i eventually changed them out my friend who bought them
called to thank me for their good second hand value. if they had been scrap i doubt he would be thanking me for
selling junk to him.
lithium has its advantages and so does lead acid. we should all just learn to accept that fact while we continue our
collective journey to energy freedom.

Spy360:
Is there possibility of obstruction from trees or fence since it is facing the sky? My dish is located near the fence. I will give it another shot tomorrow.

Since your dish will be facing the sky directly, its unlikely that any obstruction will prevent you
from receiving signal unless of course if you decide to install the dish directly under a tree or canopy

Spy360:
GeorgeD1 please assist me on steps to track Ses5 on 5e on 1.8m with c band lnb. I am mostly after the local channels there. Thanks.

I think Penuelseun has answered you. Remember that with 5e, your dish is facing the sky directly.
Install your C band LNB and use TVC frequency and symbol rate (3701H, 5000SR). Skew ur LNB initially
at the 2 o'clock position, if it doesn't work, use 10 o' clock position. Move slowly from west to east while
gently rocking your dish up and down. Be patient and you will hit signal.

alstacs:
I empathize with those who lost parts of their systems as a result of lightning. I have been a victim as well. My lightning surge protector on the roof is superb with its earthing but it didn't stop my CCTV and inverter from getting roasted.
Nice enlightenment in your post sir but I want to ask about a different type of surge protector I saw and installed.
Does this also work line the Midnite one? Seems to be on the high side in cost compared to others.

Please see this below

i'm not familiar with this brand but i guess if it's working for others, it might as well work for you.
however, midnite solar has been a very reliable brand in the industry and when it comes to quality,
you can't go wrong with them.

hiidee:
Pls is it a must to install thunder arrestor for bungalow with solar panel?? If it is what is price range to install arrestor and if not is there any alternative to stop thunder??

the answer to your question is yes. a lightning or surge protection device is very much necessary for your bungalow
to protect your solar installation. however, you did not state if yours is a new building without earthing or already existing
building with a good earthing system. if your building already has a good earth, all you need do is to incorporate an
spd (surge protective device) like the midnite solar mnspd 115 and mnspd 300 and you're fine. budget for this would
be under 250k to 300k i think.
note that installing a 'thunder arrestor' as we normally call all those copper spikes on top of your roof will not necessarily
save your solar investment from lightning strikes. i learnt that lesson the hard way in my former abode.

https://www.solar-electric.com/suprdemn.html
https://www.solar-electric.com/midnite-solar-mnspd-300-ac-surge-protector.html

kd10:
Pls for those us shopping on foreign � online stores under one platform and get it delivered in Nigeria .for me i use Mallforafrica online but since today i can't log in to my account with them , i have called there customer care line and nobody is picking the call even WhatsApp no reply so i don't know if they have stopped operations.
Pls if anybody here knows any other similar online services provider that is useful pls � help me with there link Thanks house members.

Bro, why don't you try heroshe? I been using them for over 2yrs now and so far I've been impressed with
their services.
https://myheroshe.com/auth/signin

Spy360:
GeorgeD1 viewing silently.

The BOSS.

Lolz. My guy. I hail oh

swordswifter:
That's true.
Life takes us on different journey's but home will always where the wifi connects fastest so i'm back to learn from the new kings on the block and share when i can.
It feels good to be back

Hello bro, welcome back.
You can use an AV to RF adapter for your TV and use an RF headphone to listen to clean, clear audio from your TV set.
No need to go the firmware upgrade route if really its the external noise that's your main challenge.

ajabani4allah,
there's absolutely nothing wrong with an inverter charging a battery bank 24/7 without load.
provided the charging parameters are set correctly, it can theoretically charge at infinum.
depending on the battery type and state of charge/depletion, it would most certainly start with
bulk charging before tapering off into float/maintenance charge when battery is full. it will
remain in this state until when duty calls and inverter kicks in to draw power for critical loads.

lexi28:
Guys, good day.
I need some info.
I read online that running an inverter aircon 24/7 at 25°c is more efficient and consumes less energy in the long term than running it on turbo mode for a few hours and switching to gen mode. I do not have the battery capacity to run this test 24/7, can you guys help out and run a 1hp inverter AC for 24/48hrs to compare kWh consumed @25°c vs gen/turbo modes? Anyone with substation capacity PV/battery bank should kindly assist with this small test.
@NiyiOmoIyunade
@ojeysky
@Adrusa
@olopan
@GeorgeD1
@babaegun
@dapsyra
@oshomo12
@McTrinity
@Valto
@dam5reey
@Saipro

Muchos gracias!!

brother,
this test you're suggesting is totally unnecessary. i have a couple genpals or what lg calls 'inverter' ac and i can tell you it does
consume less power and is more efficient over time compared to traditional acs.
your energy savings should not be limited to a narrow 24/48hrs range else you will miss the whole essence. rather think more
of a wider band like perhaps 3, 6 or 12 months. and for this you will really need an energy meter plugged in permanently to
that equipment.

kiekie1:
Okay thanks for the clarification, pls which of the product price Sir

the growatt advert. it has lithium-ion and underneath its also saying lifepo4. the two
battery chemistries are slightly different. both cannot be in the same battery.

Passion8:
Greetings to everyone.
This is my first Post on this thread. Please kindly pardon me if I ask a question that has already been attended to.
Is it possible for me to install this solar system by myself since I am a professional electrical installer?
And how much is the cost of the the complete set with maximum output of 1.8Kva?.

passion8,
welcome on board and glad you finally made the decision to take the plunge into renewables.
i assure you, its a life changing step you're about to take for which you will be forever grateful.
yes, absolutely. you can install your solar system by yourself and this is what the thread is all
about. almost everyone here is a do-it-yourself solar enthusiast apart from a few marketers just
here to make a few bucks who don't contribute anything to trending topics.
as for the cost of a complete setup, that would depend on what load you want to power. you
can forget about the estimated 1.8kva output and just list what loads you want to run based on
their wattage and other good members in the house will weigh in and offer suggestions how
you can go about it.

kiekie1:
Discounted product prices! Seek no further!!!

Growatt :

Growatt 3kva 48v inverter ... 295,000
Growatt SPF 5000es 48v "can be paralleled" .. 470,000
Growatt 6kva 48v .... 635,000
Growatt 8kva 48v .... 870,000
Growatt 10kva 48v ... 1,090,000
Growatt 12kva 48v ... 1,140,000

Phocos 5000w 48v pure sinewave inverter "can function without batteries" ... 550,000

Vmax 1500w 12v pure sinewave inverter "with 30a inbuilt pwm solar controller" ... 100,000

Growatt hope 3.3kwh 48v lithium battery .. 685,000
Pylontech Us 3000c lithium battery ... 880,000
Pylontech Us 2000c .... 635,000
Shoto 4.8kwh lithium battery "48v 100a" ... 860,000



Contact,
Smartcell global services
CALL ONLY:: 081-350-31951
WHATSAPP ONLY::: http://.us/w/?c=a46ea5

bros,
you may want to revisit your advert (especially the flyers). i see lithium-ion and lifepo4 lumped together
referring to same product.

isangjohnson:
NB: Batteries are tubular.

Pv Array 1 will face south while Pv Array 2 will face west in diagram one and two.

The second diagram are to be installed separately.

In the first diagram, I intend to connect the output of the two CCs in parallel to the battery bank to work in sync.

QUESTION: 1. In the first diagram, can Pv Array1 and 2 charge the battery bank simultaneously?
2. At what point will I allow one array to sleep?
3. Is installation of HA02 really necessary since monthly equalisation of these tubular batteries are mandatory?

Your advice is highly appreciated all

i see a lot has been said already on this.
1) the two arrays will charge your battery bank simultaneously. there's absolutely nothing wrong in installing your panels
facing west as long as they're not the only set of panels you have.
personally, i have west facing panels and to my surprise they seem to outperform my south facing panels which is still a
phenomenon i'm trying to understand till date.
2) you don't have to worry about one array going to sleep or whatever. your cc takes care of that
3) i'm not a fan of balancers (never installed one) and i rather think they're overrated. if you do your basic wiring properly
you won't need one as your batteries will always be in sync.