Hank the Tanks Dodgy battery and solar system

[Pudsey Bear]

David, not having your breadth of knowledge "If say it takes 3 hours to go down to 12V, that will mean the battery has dropped from 100Ah to 30Ah." is that god or bad?

And how would you actually do this "put a set load on it of around 5A per 100Ah of nominal capacity"

Asking for a friend as I know my LB is goosed but it has been for 3 years but still does what we need.

 

[barryd]

My question is why are you using an inverter to charge a phone ? Converting 12 volts upto 240 volts then back down to 5 volts one of the first jobs would be fit a cigarette lighter socket or usb socket to charge your phones straight from the battery!
That will save you a good few amps to start with, an iPhone only charges at 1 amp the inverter will possibly use 5-12 amps depending on model

It's just a 300w Bestek portable inverter. We have 12v sockets. I only use it to charge my phone really as it's a fast charger. It will go from flat to full in less than an hour. The logic (normally) being that if I charge it early it's more than enough time for the solar to catch up. I have a dedicated 12v charger for the tv, Freesat box and loads of other stuff. Michelle uses the inverter for her laptop as I've never found a 12v charger for it. It only adds about a 10w overhead. I agree with you though.

 

[barryd]

One of the problems with knackered batteries is a multimeter will tell you it is good after you have charged it as it will at a full charge voltage.
Plus ... you think you have a super charging system as it gets the battery from low to full so quickly

But it is all smoke and mirrors! The only way to know how good your battery still is is to do a load discharge test. Simple enough to do ... just charge the battery until it takes no more current, then put a set load on it of around 5A per 100Ah of nominal capacity (the C20 rate that is usually quoted) and see how long it takes the voltage to drop to 12.0V - that will have discharged to 50% at that point. If say it takes 3 hours to go down to 12V, that will mean the battery has dropped from 100Ah to 30Ah.

It is showing fully charged very quickly. I guess we will find out tonight anyway if it dies in an hour or so regardless. Of course it could also be a faulty controller but I suspect not.

I don't now though see much point in messing with it and testing it. It's more a question of getting it all upgraded and quickly! So a case of who, where, what and how much?

 

[wildebus]

David, not having your breadth of knowledge "If say it takes 3 hours to go down to 12V, that will mean the battery has dropped from 100Ah to 30Ah." is that god or bad?

I should have said the CAPACITY has dropped from 100Ah to 30Ah - so battery is goosed in that situation!
And this is why the charging appears to be working so well as you *think* you are recharging a 100Ah battery but you are really recharging a piddly little 30Ah battery in effect.

And how would you actually do this "put a set load on it of around 5A per 100Ah of nominal capacity"

Find something that draws that load and switch it on. it is that simple. A good way if you have an inverter is plug in a simple old-fashioned lightbulb. a 5A load at a nominal 12V is 60W - so say you are testing a 100Ah battery and use an inverter for the test, a 40W bulb or a 60W bulb will give you a set power load - one a bit less and one a bit more than 5A DC (with inverter overhead), but just a matter of doing the maths....
Load of x Amps multiplied by y hours before voltage drops to 12.0V = z AmpHours drawn. multiply that Amphours value by two gives you the current total capacity of the battery. It is generally considered that when the current max total capacity of a battery has dropped by 18% (I think that is the accepted value?) of the design capacity, the battery is gone and should be replaced.
the 12.0V could vary depending on the type of battery but it is a close enough value to get a good feeling. basic lead acid is 12.04V at 50% and under a load there is a sag so 12.0V is a nice rememorable number to use.

Asking for a friend as I know my LB is goosed but it has been for 3 years but still does what we need.

My own motorhome was similar to barrys .... came with two good brand batteries and the voltage was decent but the pair of 120Ah batteries lasted one evening on the first trip away. I was planning on upgrading anyway (like barry), but I thought I would have had a bit more time to plan it (as did barry ).
If someone tends to use EHU when camping (like the owner of my Motorhome did), then a knackered battery can still be enough to use betwen site A and site B.

 

[Pudsey Bear]

Thanks David, I have to say I have since starting my self struggled and am still struggling with the sparky stuff (230v I'm okay) but 12v is so very complicated what with the length of run and wire sizes, (I understand now that basically you need a bigger wire as there is not enough force to get the power where you need it) not to mention the correct fuse is to protect the cable (not the appliance), I am wiser but not by very much so it pleases me greatly that when I ask a (possibly) dumb question, you never give the short answer, you go into some detail about so that later if I need to know again it's there for me to read.

You should write a MoHo electricals for dummies book, it'd sell well I think.

 

[maingate]

It is showing fully charged very quickly. I guess we will find out tonight anyway if it dies in an hour or so regardless. Of course it could also be a faulty controller but I suspect not.

I don't now though see much point in messing with it and testing it. It's more a question of getting it all upgraded and quickly! So a case of who, where, what and how much?

Quick discharge followed by quick charge usually means goosed battery.

There are plenty of small 12 volt devices on the market that will charge your phone quickly. A 12 volt socket is usually rated up to 10 amps or 150 watts. The one I had was rated at about 90 watts.

 

[wildebus]

Thanks David, I have to say I have since starting my self struggled and am still struggling with the sparky stuff (230v I'm okay) but 12v is so very complicated what with the length of run and wire sizes, (I understand now that basically you need a bigger wire as there is not enough force to get the power where you need it) not to mention the correct fuse is to protect the cable (not the appliance), I am wiser but not by very much so it pleases me greatly that when I ask a (possibly) dumb question, you never give the short answer, you go into some detail about so that later if I need to know again it's there for me to read.

You should write a MoHo electricals for dummies book, it'd sell well I think.

Thay say there is no such thing as a dumb question. Well, to be honest there certainly are but yours certainly was not
Sadly, I am rarely accused of giving a short answer for anything ("what you fancy for dinner?". "well ..... ") . I used to have the same problem when I was on a technical helpdesk around 30 odd years ago - my colleagues would do about 20 calls an hour, I would do about 5 as I would not tell the customer just the 'What' but also the 'Why' so they wouldn't have to call back the next time with the exact same question next time the same thing happened to them.

 

[Glandwr]

What are you reading that says the Barry is charged Barry? A voltmeter readout on your control panel? That will tell you the volts output from your Solar, not the state of your battery.

As yo say try it when it's dark.

 

[trevskoda]

I've never found a 12v charger for it. It only adds about a 10w overhead. I agree with you though.

Dont look to far did you.

 

[rugbyken]

i must say as well as the sheer power from my fogstar battery i do love the App not just showing the reserve in the battery but the input and also the discharge ie my kettle drawing 150A only for 3 minutes but it also told me the fridge freezer was also running lol, can’t have too much information but it can turn you obsessive,

 

[barryd]

Quick discharge followed by quick charge usually means goosed battery.

There are plenty of small 12 volt devices on the market that will charge your phone quickly. A 12 volt socket is usually rated up to 10 amps or 150 watts. The one I had was rated at about 90 watts.

Yep I agree with that. Those were my thoughts also. As David said it's probably charging a much diminished battery. I can charge stuff in the morning on good sunlight though when it's probably putting in enough power to charge the battery and our phones etc. if it don't work out I'll just move and find a CL with hookup. All depends how quickly I can locate an expert. That process begins tomorrow.

Will be switching on the TV or laptop later for a few hours. Will see how long it lasts.

I'm sure I saw a receipt for this battery from last year but I could be mistaken. The battery bay looks like it was originally designed for two 85s or maybe two 105s. Now long gone.

All fun and games!

 

[Robmac]

I use a charger similar to this one for 'phones etc Barry;

https://www.amazon.co.uk/gp/product/B0CQ2MMKS8/ref=pe_2443651_1055380381_em_1p_0_lm

 

[barryd]

I use a charger similar to this one for 'phones etc Barry;

https://www.amazon.co.uk/gp/product/B0CQ2MMKS8/ref=pe_2443651_1055380381_em_1p_0_lm

Presumably you still have to charge the charger though Rob at some point. What about some kind of treadmill charger? I could site it outside the van and ride the Honda Biff Chariot on it at full chat. Got to be better than solar or a windmill. Could have hit on something there. You heard it first here!

 

[Robmac]

Presumably you still have to charge the charger though Rob at some point. What about some kind of treadmill charger? I could site it outside the van and ride the Honda Biff Chariot on it at full chat. Got to be better than solar or a windmill. Could have hit on something there. You heard it first here!

On the bike Barry I charge it from the USB while I'm on the move. I've had it years and it's still going strong (not as powerful as the one in the link though).

 

[maingate]

Hundreds of chargers to choose from here Barry. It's all you need.

Amazon.co.uk : 12 volt phone charger

 

[barryd]

Hundreds of chargers to choose from here Barry. It's all you need.

Amazon.co.uk : 12 volt phone charger

Got various ones of those. The main issue with Michelle's laptop is it's a very nice 14" Honor and when I got it I quizzed them about it and there simply wasn't one for it. It's usb c the charging point and I did find one or two that might have been up to the job but I had concerns about the warranty and as it only drew about 20w through the inverter it seemed a bit pointless really bothering. If we get a nuclear lithium liposuction life battery system I won't care.

So we watched the tour de France for an hour and now the TV. So far so good. Ive opened the bar we well. Should we have bets as to when it all goes off?

 

[1 Cup]

I Got fast charger = 3amp like this for truck and these for usb light and phone charge at the head of bed over night for van.

300 w invertor pulls about 20 amp @ 12v

 

[barryd]

Bollocks! It's worked all night tonight from 7pm till after 11pm. It's gonna be a harder sell now!

 

[Nabsim]

Presumably you still have to charge the charger though Rob at some point. What about some kind of treadmill charger? I could site it outside the van and ride the Honda Biff Chariot on it at full chat. Got to be better than solar or a windmill. Could have hit on something there. You heard it first here!

Hmmmm, easier with a genny lol

 

[1 Cup]

It rained all day as well. Lol