Generator keeps blowing battery charger

[WotEver]

Because Tony's page linked to by Ditchrawler is a bit long and the audit part can be hard to find, here's a copy/paste.

 

The formatting is probably all over the place but you should get the idea.

 

Take each piece of equipment in turn and multiply its current draw by the time it is on during the period in hours. Then total your answers. My power audit is shown below.

 

Device. Amps drawn. Hours used. Amp hours required

 

Fridge. 2.3 12. 28

 

Internal lights

6x 1.5 = 9. 3. 27

 

Water pump. 4. 2. 8

 

TV. 3. 3. 9

 

TOTAL 72

 

The 12 hours for the fridge assumes the thermostat will only let it run for about 50% of the time.

 

This shows that I need 72 Amphour capacity from my batteries; unfortunately the problems now start because of limitations within the batteries and the charging system.

Edited to make the copy/paste more obvious and to correct the error in the last paragraph.

Edited December 6, 2015 by WotEver

[tommyleyland]

Do I calculate this from the input or output of the appliance?

[Graham.m]

Thanks for your help everyone. I guess the next step is the batteries. How often do you think I'd be recharging if I got two Trojan T105?

 

Also remember you only have a 40amp charger. So if you use say 100Ahs a day that has to be put back into the battery fully. So say it takes 3 hours to get to 80% (80Ahs) The remaining 20Ahs will take about 4 to 6 hrs to put back into the battery.

 

So that power audit is important so you can design your system to best advantage. If you have old fashioned lighting, maybe a good idea to convert to LEDs, they should use about a third of the power.

[tommyleyland]

We're using LEDs at the moment. The only thing that will take power is the laptops which I would use for maybe 4 hours a day for both of them.

[Graham.m]

Do I calculate this from the input or output of the appliance?

 

You calculate it from the power the item uses from the batteries x the number of hours a day you think it will be on

[MtB]

Device. Amps drawn. Hours used. Amp hours required

 

Fridge. 2.3 12. 28

 

Internal lights

6x 1.5 = 9. 3. 27

 

Water pump. 4. 2. 8

 

TV. 3. 3. 9

 

TOTAL 72

 

The 12 hours for the fridge assumes the thermostat will only let it run for about 50% of the time.

 

This shows that I need 72 Amp capacity from my batteries; unfortunately the problems now start because of limitations within the batteries and the charging system.

 

 

No it doesn't. This just serves to confuse anyone reading your advice and struggling to understand the different units you use.

 

It shows you need 72 Amp Hours of capacity.

Edited December 6, 2015 by Mike the Boilerman

[Graham.m]

We're using LEDs at the moment. The only thing that will take power is the laptops which I would use for maybe 4 hours a day for both of them.

 

So how many lights have you go that will be on and their power?

 

The laptop does that run from an AC adapter or how is it powered?

[nicknorman]

No it doesn't. This just serves to confuse anyone reading your advice.

 

I t shows you need 72 AmpHours of capacity.

Not only that but 2 hours solid of water pump running! He must be very dirty, and have a huge water tank!

[WotEver]

Suggest you both go back to the original thread and read it again. But I am not going to engage here. The OP has a problem that needs solving without being walked over by you two and your worship of a box

OP has a SmartGauge. He knows, as do we, that it is accurately showing him the SoC. We are assisting him in getting his batteries up to a decent SoC.

 

He has previously abused his batteries. Thanks to SmartGauge and advice on here he is learning about his abuse and how best to avoid it.

 

In due course he needs to purchase new batteries but not until he has sorted out a good charging regime which will be very easy to do by reference to his SmartGauge.

 

You would have him purchase new equipment and take pointless readings purely because of your irrational bias against a proven piece of technology.

 

We already know what is wrong. OP already knows what's wrong. OP knows how to correct what's wrong. He doesn't need to buy any more equipment other than a hydrometer.

 

Are you on commission for sales of BVMs or something?

 

Tony

Edited December 6, 2015 by WotEver

[MtB]

Not only that but 2 hours solid of water pump running! He must be very dirty, and have a huge water tank!

 

 

Yes I noticed that too. I doubt my whole water tank holds enough for two hours of pump running!

[WotEver]

 

 

No it doesn't. This just serves to confuse anyone reading your advice and struggling to understand the different units you use.

 

It shows you need 72 Amp Hours of capacity.

Not my advice, Mike - that is a copy/paste from TB's training notes. Edited December 6, 2015 by WotEver

[ditchcrawler]

Because Tony's page linked to by Ditchrawler is a bit long and the audit part can be hard to find, here's a copy/paste.

 

The formatting is probably all over the place but you should get the idea.

 

Take each piece of equipment in turn and multiply its current draw by the time it is on during the period in hours. Then total your answers. My power audit is shown below.

 

Device. Amps drawn. Hours used. Amp hours required

 

Fridge. 2.3 12. 28

 

Internal lights

6x 1.5 = 9. 3. 27

 

Water pump. 4. 2. 8

 

TV. 3. 3. 9

 

TOTAL 72

 

The 12 hours for the fridge assumes the thermostat will only let it run for about 50% of the time.

 

This shows that I need 72 Amp capacity from my batteries; unfortunately the problems now start because of limitations within the batteries and the charging system.

How strange because I copied the url for the page but for some reason it doesn't go there

[Graham.m]

Not my advice, Mike - that is a copy/paste from TB's training notes.

 

Surely you have made it your advice by posting it

[WotEver]

How strange because I copied the url for the page but for some reason it doesn't go there

Yeah, that's happened to me in the past with TB's notes. As Mike pointed out though, there's a schoolboy error at the end as well - A instead of Ah. I didn't notice when I pasted it.

 

Surely you have made it your advice by posting it

Try putting on your glasses and reading my post again. Specifically the bit that says "here's a copy/paste"

[tommyleyland]

OP has a SmartGauge. He knows, as do we, that it is accurately showing him the SoC. We are assisting him in getting his batteries up to a decent SoC.

 

He has previously abused his batteries. Thanks to SmartGauge and advice on here he is learning about his abuse and how best to avoid it.

 

In due course he needs to purchase new batteries but not until he has sorted out a good charging regime which will be very easy to do by reference to his SmartGauge.

 

You would have him purchase new equipment and take pointless readings purely because of your irrational bias against a proven piece of technology.

 

We already know what is wrong. OP already knows what's wrong. OP knows how to correct what's wrong. He doesn't need to buy any more equipment other than a hydrometer.

 

Are you on commission for sales of BVMs or something?

 

Tony

Thanks Tony haha

 

I've tried to calculate how much power the chargers use. One says:

Input: 11.5v - 16v DC 5.6amps max

 

Do I count this as 5.6 amps per hour or do I need to calculate the watts (which is around 90w)

 

Also, my fridge (which is currently running on gas :/) says its 100w which by calculating at 12 hours a day is around 100w!

 

Is there a simple way of calculating things? I only use the 2 laptop chargers at the moment and the LED lighting which uses next to nothing even if used all day.

Sorry, I meant 1200 watts!

[WotEver]

Thanks Tony haha

 

I've tried to calculate how much power the chargers use. One says:

Input: 11.5v - 16v DC 5.6amps max

 

Do I count this as 5.6 amps per hour or do I need to calculate the watts (which is around 90w)

 

Also, my fridge (which is currently running on gas :/) says its 100w which by calculating at 12 hours a day is around 100w!

 

Is there a simple way of calculating things? I only use the 2 laptop chargers at the moment and the LED lighting which uses next to nothing even if used all day.

Sorry, I meant 1200 watts!

Hi Tommy, yep you have the basic idea.

 

All we are interested in is Ah, and as you say a 5A draw for one hour is 5Ah.

 

You have an absorption fridge - NEVER run it from 12V for the reason you worked out above ?

Now, the rating of your lappy charger is a MAX of 5.6A so it'll probably only draw that when the lappy battery is flat and you're playing a DVD, but for safety's sake let's use 5A. If you have it on for say 4 hours then that's 20Ah you've used.

 

As you can see, it can quickly add up.

 

Hope that helps,

Tony

[nicknorman]

Thanks Tony haha

I've tried to calculate how much power the chargers use. One says:

Input: 11.5v - 16v DC 5.6amps max

Do I count this as 5.6 amps per hour or do I need to calculate the watts (which is around 90w)

Also, my fridge (which is currently running on gas :/) says its 100w which by calculating at 12 hours a day is around 100w!

Is there a simple way of calculating things? I only use the 2 laptop chargers at the moment and the LED lighting which uses next to nothing even if used all day.Sorry, I meant 1200 watts!

Just to pick up in the fridge calculation, 100 watts at 12v is 100/12= 8.3A. Run that for 24 hrs and you get 8.3 X 24 = 200AH (which is A LOT!)

 

Since your battery capacity is measured in AH rather than watt hours, you need to divide any wattage figure by the voltage to get the current, and then multiply by the hours of use to get the AH, which you can then relate to the capacity of the battery (also in AH)

[WotEver]

Oh, and of course TWO lappy chargers each drawing the same and each on for 4 hours could be using 40Ah

[Graham.m]

So it is looking like a total of 30/40Ahs/24hrs

[WotEver]

So it is looking like a total of 30/40Ahs/24hrs

Yup, ish. I reckon his batts are probably down to less than 50% capacity. Be nice if we could reverse some of that Sulphation once he has a hydrometer.

[tommyleyland]

How do people usually run the fridge? Isn't is against the safety standards to use gas?

And 40amps is easy enough to put back in every day

[ditchcrawler]

I have an Acer laptop and if its being charged and used at the same time I am drawing about 3 Amps from a 24 volt supply

How do people usually run the fridge? Isn't is against the safety standards to use gas?

No its not, that type of fridge should be run on gas. its really a caravan fridge and the 12 volt option is for while the car is towing it.

[Graham.m]

Yup, ish. I reckon his batts are probably down to less than 50% capacity. Be nice if we could reverse some of that Sulphation once he has a hydrometer.

 

I think they could be lower than that.. If we use 40Ahs a day he was going to dim lights. Now most LEDs are OK on 9.5V

How do people usually run the fridge? Isn't is against the safety standards to use gas?

And 40amps is easy enough to put back in every day

 

Your Fridge is OK to be run on gas.

 

Might help if you can remember to charge the lappys when you charge the batteries, then they will use less when you use them in the evening, batterywise

Edited December 6, 2015 by Graham.m

[nicknorman]

How do people usually run the fridge? Isn't is against the safety standards to use gas?

There are different types of fridge. Modern ones tend to have an electric motor / compressor and run efficiently on 12v, or on 230v via an inverter (the latter usually being a cheaper fridge to buy). Caravan type fridges use a different method of cooling and run off heat, produced either by gas, by 12v or by 230v. They are very inefficient when using electricity and best used only with gas. It is not against the safety rules to use gas in a pre-existing and correctly installed fridge. I think there is an issue with installing a new gas fridge in a boat, not sure but I think it's simply due to the fact that the fridge manufacturer won't say the fridge is suitable for a boat.

[WotEver]

Modern fridges have compressors and use power a magnitude less than old absorption fridges. The type you have was designed for caravans where they could be run on 12V whilst on tow just to keep the contents cool and then switched over to gas once pitched up.

 

As I understand the BSS rules you can continue to run yours on gas until you replace it.

 

If you replace it you then have a choice of a 12V compressor or (as many do) a 240V compressor run off a small inverter. The arguments usually fall 50:50 between these choices. 12V fridges cost 4 or 5 times as much as 240V fridges which sometimes makes the decision easier.

 

Tony

I have an Acer laptop and if its being charged and used at the same time I am drawing about 3 Amps from a 24 volt supply.

So 6A @ 12V. Maybe my 5A is a little conservative.

Fridge post cross-posted with previous replies.

And 40amps is easy enough to put back in every day

Tommy - what does SmartGauge show your SoC is in the evening and the morning?

 

Tony