POWERMASTER, has anyone heard of these?

[WotEver]

OP might as well get a Chinese one that records Ampere-hours (Ah) other wise it is only useful when he's sat watching it.

 

Here's one on eBay but it will take a while for delivery and customs.

 

http://www.ebay.co.uk/itm/Battery-Monitor-State-of-Charge-120V-300A-Voltage-Current-Capacity-Power-Meter-/172212544299?hash=item2818aae32b:g:PWcAAOSwB9xXPIcq

Looks great for the price

[WotEver]

 

Ordered

Just be aware that the Ah counting in and out plus the instantaneous current flow and voltage readings will all be useful whereas the State of Charge readings will not. As long as you don't rely on it for SoC indication you'll do very well with it.

 

The reasons are numerous but put simply any Ah counter cannot know the true capacity of the batteries that it's measuring simply because that figure constantly changes.

 

All the rest of the information will be very useful though.

 

Tony

[christophert]

Great. Now check the rating of the bulb and connect it to each battery in turn whilst measuring the voltage. When the voltage drops to 12.2v disconnect the bulb and let us know how long that took and what the bulb wattage is. We can then tell you the approximate capacity of your batteries. You might find that a few minutes after disconnecting the bulb the voltage rises a bit. If so, reconnect for a short while and repeat the excercise, adding the time.

 

Tony

Hi, Tony

 

10am, 24 hours after disconnecting batteries.

Using Halogen 12v 50w spot purchased from Wicks store.

Battery 1 – 13.1 amps Using spot – amps drop to 12.2 in four minutes.

Battery 2 Experiment interrupted by someone ‘mooring’ their boat in marina, hitting mine and sending equipment all over floor.

Restarted with battery 2 at 12.9 amps Using spot – amps at 12.4 and have been for past 20 minutes

[christophert]

Battery 2 seems to be taking forever

[mross]

There's no pleasing some people!

[WotEver]

Sounds like Batt1 is totally shot. Batt 2 will hopefully give you a few hours.

 

Note that you are measuring voltage not current so your readings are 12.2V not 12.2A.

 

The spot is drawing less than 4A so the battery should last many hours. When you finally get to 12.2V multiply the time taken to get there by 2 (because 12.2V is 'half full') then multiply by 4 (the amps drawn by the spot). The answer is your current battery capacity in Ah (Amp hours).

 

Tony

 

Battery 2 seems to be taking forever

Good!

Edited October 12, 2016 by WotEver

[christophert]

Sounds like Batt1 is totally shot. Batt 2 will hopefully give you a few hours.

 

Note that you are measuring voltage not current so your readings are 12.2V not 12.2A.

 

The spot is drawing less than 4A so the battery should last many hours. When you finally get to 12.2V multiply the time taken to get there by 2 (because 12.2V is 'half full') then multiply by 4 (the amps drawn by the spot). The answer is your current battery capacity in Ah (Amp hours).

 

Tony

 

 

Good!

Thank you Tony, so if one is shot, I'm guessing it'll drag two down with it when they are connected together?

[WotEver]

Thank you Tony, so if one is shot, I'm guessing it'll drag two down with it when they are connected together?

Yup.

[christophert]

Final score

 

10am this morning, 24 hours after disconnecting batteries.

UsedHalogen 12v 50w spot purchased from Wicks store.

Battery 1 – 13.1 amps Using spot – amps drop to 12.2 in four minutes.

Battery 2 Experiment interrupted by someone ‘mooring’ their boat in marina, hitting mine and sending equipment all over floor.

Restarted with battery 2 at 12.9 amps Using spot – reached 12.2 after 1 hour sixteen minutes

Re test on battery one – amps back up to 13.1 Using spot - dropped to 12.2 after 2 hours five minutes

Need to do the maths bit now which I'm rubbish at

Strange how battery 1 dropped so fast on first test

Edited October 12, 2016 by christophert

[WotEver]

Doesn't much matter - both batteries have had it.

 

They should have lasted for hours and hours.

 

 

If we say they lasted 2 hours, then x2 = 4. X4 = 16

 

So the batteries now have a capacity of around 16Ah each. Down from 110Ah. That's why they only last a short while: very little capacity.

[christophert]

Doesn't much matter - both batteries have had it.

 

They should have lasted for hours and hours.

 

 

If we say they lasted 2 hours, then x2 = 4. X4 = 16

 

So the batteries now have a capacity of around 16Ah each. Down from 110Ah. That's why they only last a short while: very little capacity.

New batteries it is then. But not before I get the basic monitor fitted which I ordered today. Again, a big thank you

[WotEver]

New batteries it is then. But not before I get the basic monitor fitted which I ordered today. Again, a big thank you

No probs. Once you have the monitor we'll help you set it up if required. And then tell you how to interpret the results.

[mross]

Here's the manual for the Chinese battery monitor. It seems very complicated!

BM-MTX105P_1.2.pdf

[christophert]

Here's the manual for the Chinese battery monitor. It seems very complicated!

Complicated!! Oh my!! Is there a Janet and John version for me?

[christophert]

Yep, had a quick look at manual. This shouldn't be a problem. I have a hammer and chisel, and a screwdriver somewhere. I have a MA degree in Creative Writing so maybe I can re-write it so it makes sense to me :-)

 

And why have I chosen a peanut shaped like a duck as my avatar ??

Edited October 12, 2016 by christophert

[WotEver]

Complicated!! Oh my!! Is there a Janet and John version for me?

From the first diagram...

 

Battery +ve to P+ and C

 

Remove any connections that are currently on the battery -ve and connect them to one side of the shunt. Run a wire from the small terminal on this end of the shunt to A+

 

Connect the battery -ve to the other end of the shunt. Run a wire from the small terminal on this end of the shunt to A- and P-

 

Yep, had a quick look at manual. This shouldn't be a problem. I have a hammer and chisel, and a screwdriver somewhere.

You've got the idea...

[mross]

Chris, I'm sorry, I did not mean to frighten you. The manual contains a lot of technical info that you won't need. The gadget has a wealth of extra settings that are not needed for your purposes. Fitting it will be straightforward and everyone here will advise if necessary.

[christophert]

One more question please, so I can get my head around this. It's been three days with the batteries disconnected and no charge going in. Yesterday they were drained down to 12.2 using halogen bulb. today they are sitting at 12.7. If the batteries are shot, should they not be reading a lower volt?

[mross]

Are the batteries connected to each other still? If yes, the good one is holding up the voltage of the bad one. Can you post a photo of the batteries showing how they are connected?

Edited October 14, 2016 by mross

[cuthound]

Batteries will always recover some voltage when the load is removed.

 

This suggests to me that your batteries are knackered and in urgent need of replacement.

 

Leaving them in a discharged state will ensure that they get sulphated, even if they are not (unlikely)

[christophert]

Are the batteries connected to each other still? If yes, the good one is holding up the voltage of the bad one. Can you post a photo of the batteries showing how they are connected?

No, still disconnected and separate from each other.

Batteries will always recover some voltage when the load is removed.

 

This suggests to me that your batteries are knackered and in urgent need of replacement.

 

Leaving them in a discharged state will ensure that they get sulphated, even if they are not (unlikely)

Yep, I'm sure they are knackered and will be replacing them. Thought it strange they went back up to 12.7 and settled at that. I've learned so much from this thread about batteries and their workings, but for me there's still a lot to learn

[cuthound]

No, still disconnected and separate from each other.

Yep, I'm sure they are knackered and will be replacing them. Thought it strange they went back up to 12.7 and settled at that. I've learned so much from this thread about batteries and their workings, but for me there's still a lot to learn

Make sure you study this forum on how to look after batteries before buying new ones, especially if you choose expensive ones.

 

It is depressingly easy to ruin any battery (cheap or expensive) in a few weeks if you over-discharge it and/or under-charge it.

[christophert]

I now need to find out if my existing battery charger is powerful enough to do the job.

[cuthound]

I now need to find out if my existing battery charger is powerful enough to do the job.

This should help.

 

http://www.smartgauge.co.uk/chargesize.html

 

However if time is not of the essence, then any charger which has an output current greater than the batteries internal self dischsrge current will eventually charge it.

 

Edited for spillung.

Edited October 14, 2016 by cuthound