Another Question about Batteries!!

[lewisericeric]

Sorry if this is really simple but as I'm a complete total newbie, I just don't know if I've been a bit naive about what electrical appliances I thought I could use....

 

We have three leisure batteries and the other day, we did three hours cruising. In the evening we did a little bit of vaccumming (with a cheap 1400w argos vaccuum) and then had the radio on on the stereo/hi-fi. (its a new one with i pod dock etc)

 

Basically, the radio went off after an hour and the inverter closed down.

 

Today, I had the engine running for around hour and a half. I did some vaccuuming again whilst the engine was running, and I've had a small 10" laptop on charge and on since 6pm and at now 9pm, the inverter has bleeped to tell me its closing down again.

 

Lights, 12v stuff are and always have been ok (12v fridge included)

 

Is this normal? Is that the amount of electric im supposed to get????? Or should my batteries be able to supply me with more?

[NB Willawaw]

Not enough information.

 

Probably you are not charging the batteries up enough before discharging them.

[matty40s]

With 3 batteries in your bank, invest in a brush, or if you have a carpet,one of those manual (shake and vac) picker up thingies.

 

And stick your vac on e-bay.

 

Microwaves, Irons,vacs.hair straighteners and dryers etc should not be used with a set up your size, whatever inverter you may have, charge your lappy whilst cruising, or at the local costa/macdonalds!!

 

I have 6 batteries, and will be disconnecting fridge soon, as the solar panel starts to lose the battle as the sun drops down the autumn sky. Unless you have landline, your electrical regime needs to be assessed quickly, before you kill your batteries. 1 and a half hours charging isprobably only just getting your batteries to the correct voltage, not putting a decent charge into them.

[blodger]

It's normal that you get less than you thought you would. You have to put back up to 50% more than you take out. If you do not regularly recharge batts to nigh on 100% state of charge then you get less out of the batts each time you use them and they age, get knackered, quicker.

[lewisericeric]

what sort of charging time are batteries supposed to have then?

[NB Willawaw]

What size of leisure batteries do you have in AH ?

 

What is the rating of your alternator in Amps ?

[DustyDave]

I'm no expert on power consumption but I wouldn't be running a vacuum and stereo in the evening having only done 3 hours cruising. I really look at doing 4-6 hours bare minimum. I'm only a leisure user though so I can easily put that restriction on the family. Even so I'm in the process of putting led bulbs in the lights, batteries in the radio and books on the shelves.

 

Dave

[lewisericeric]

thanks guys - btw I'm not questioning it, I'm just trying to find out what I should be doing/not doing.

 

Ill check the Amps/AH tomorrow guys and get back to you on this one, hopefully you'll be able to give me some good advice (as always!)

 

one other thing....i notice when the inverter goes off, when i use water the pump comes on and takes AGES to switch off again..... we bought a new pump the other day so I know its not that- could it be related ? Perhaps it's struggling to run at the normal rate to pump water when the batteries are low so its doing it more slowly and thats why its taking longer to turn off?

[matty40s]

thanks guys - btw I'm not questioning it, I'm just trying to find out what I should be doing/not doing.

 

Ill check the Amps/AH tomorrow guys and get back to you on this one, hopefully you'll be able to give me some good advice (as always!)

 

one other thing....i notice when the inverter goes off, when i use water the pump comes on and takes AGES to switch off again..... we bought a new pump the other day so I know its not that- could it be related ? Perhaps it's struggling to run at the normal rate to pump water when the batteries are low so its doing it more slowly and thats why its taking longer to turn off?

yes, your water pump will be running very slowly, and if you have a shower with a gulper pump, this will also run slowly and slower. 12v appliances tend to carry on running until your batteries are completely (fookedflat, whereas 240v appliances tend to just stop working.

[blodger]

thanks guys - btw I'm not questioning it, I'm just trying to find out what I should be doing/not doing.

 

Ill check the Amps/AH tomorrow guys and get back to you on this one, hopefully you'll be able to give me some good advice (as always!)

 

one other thing....i notice when the inverter goes off, when i use water the pump comes on and takes AGES to switch off again..... we bought a new pump the other day so I know its not that- could it be related ? Perhaps it's struggling to run at the normal rate to pump water when the batteries are low so its doing it more slowly and thats why its taking longer to turn off?

The water pump draws a fair few amps, up to 10. The inverter goes off because the volts have dropped to below a set figure probably below 12.2v which represents 50% State of Charge. Below 12.2 the amps do not flow so freely and fridges & pumps will struggle. Your water pump appears to be struggling because it is having a job drawing the power to do its job IMHO

[lewisericeric]

thanks matty. it kinda sounds like the pump is going still just a little lower in tone.....and then its on for bloody ages. when the tap's still open though it just sounds normal.... its when you switch the tap off that the tone changes and then its just on forever!

[steelaway]

thanks guys - btw I'm not questioning it, I'm just trying to find out what I should be doing/not doing.

 

Ill check the Amps/AH tomorrow guys and get back to you on this one, hopefully you'll be able to give me some good advice (as always!)

 

one other thing....i notice when the inverter goes off, when i use water the pump comes on and takes AGES to switch off again..... we bought a new pump the other day so I know its not that- could it be related ? Perhaps it's struggling to run at the normal rate to pump water when the batteries are low so its doing it more slowly and thats why its taking longer to turn off?

 

Let us know what engine/alternators you have. also do you know how old are the battery's?

Do not use that vac -1400W is a very large load. It could be drawing 100A while ever it is switched on!

 

Alex

Edited October 6, 2011 by steelaway

[ditchcrawler]

Sorry if this is really simple but as I'm a complete total newbie, I just don't know if I've been a bit naive about what electrical appliances I thought I could use....

 

We have three leisure batteries and the other day, we did three hours cruising. In the evening we did a little bit of vaccumming (with a cheap 1400w argos vaccuum) and then had the radio on on the stereo/hi-fi. (its a new one with i pod dock etc)

 

Basically, the radio went off after an hour and the inverter closed down.

 

Today, I had the engine running for around hour and a half. I did some vaccuuming again whilst the engine was running, and I've had a small 10" laptop on charge and on since 6pm and at now 9pm, the inverter has bleeped to tell me its closing down again.

 

Lights, 12v stuff are and always have been ok (12v fridge included)

I see you have only had the boat for a couple of months, do you now how old the batteries are and what condition they are in?

 

 

Is this normal? Is that the amount of electric im supposed to get????? Or should my batteries be able to supply me with more?

Edited because my reply disappeared

I don't think you have had the boat long, do you know how old the batteries are or what condition they are in?

Edited October 6, 2011 by ditchcrawler

[Chalky]

I would suggest that you google the following terms - load balance and power audit. Basically you need to work out how much power you're using and how much your putting back. Have a look on the smartgauge web site. I think you're using more than your generating and are heading towards damaging your batteries.

[Chris Pink]

Sorry if this is really simple but as I'm a complete total newbie, I just don't know if I've been a bit naive about what electrical appliances I thought I could use....

 

We have three leisure batteries and the other day, we did three hours cruising. In the evening we did a little bit of vaccumming (with a cheap 1400w argos vaccuum) and then had the radio on on the stereo/hi-fi. (its a new one with i pod dock etc)

 

Basically, the radio went off after an hour and the inverter closed down.

 

Today, I had the engine running for around hour and a half. I did some vaccuuming again whilst the engine was running, and I've had a small 10" laptop on charge and on since 6pm and at now 9pm, the inverter has bleeped to tell me its closing down again.

 

Lights, 12v stuff are and always have been ok (12v fridge included)

 

Is this normal? Is that the amount of electric im supposed to get????? Or should my batteries be able to supply me with more?

 

Basically you should be looking at your inverter as a occasional rather than normal way of powering things. You need to get your power requirements down to the absolute minimum or you will become a slave to electricity generation. Unfortunately what is possible and what is feasible in electrical terms on a boat are miles apart.

 

If you wish the kind of consumption you are talking about you will have to invest a minimum of £1-2,000 in power generation. So the first step is to analyse your needs (needs not wants) and then allocate any surplus to your wants or develop a strategy to meet the shortfall.

Edited October 6, 2011 by Chris Pink

[MtB]

Yep, the fridge is a MAJOR drain on your battery power. You'll prolly need to run the engine for three or four hours a day just to replenish the fridge drain. The vaccuum cleaner is a total disater too in terms of power drain. Ten hours of engine running to replace an hour of vaccuuming, roughly.

 

All this depends though on your alterator output and your battery bank capacity, and if tyou have any sort of klever alternator management device.

 

Mike

[Dominic M]

Your fridge may be a high consumer of your battery bank. If you are "off the grid" for extended periods it may be worth looking at energy efficient models such as WAECO's Coolmatic.

 

I think 3 batteries is enough - if you add more you will only need to run your engine longer to replace what you use so it is a vicious circle. The output of your alternator is important, but bear in mind that too high an output can damage the batteries. I have always been told (bring on Gibbo to correct me if I am horribly wrong) that the output of the alternator ideally should not exceed 20% of the total battery capacity. So, if you have 3 x 110Ah batteries (the most common size in boats) then the alternator output should be be no more than around 70A. What you really need to address is your power consumption. Charging a lap top or using the radio is a tiny current draw. Anything with a motor is a high current draw, and anything with a heater element (hair dryer for example) is frightening.

 

In the real world, replenishing batteries to 100% doesn't happen often, and you should treat them as consumable items to be replaced perhaps every third year. I'm not a believer in expensive gel or AGM batteries, because I don't believe they have a longer life that justifies the substantial cost. Overcharge them and you will knacker them irreparably. Wet lead acid batteries are relatively cheap, and easy to top up if needed.

[homer2911]

Yep, the fridge is a MAJOR drain on your battery power. You'll prolly need to run the engine for three or four hours a day just to replenish the fridge drain. The vaccuum cleaner is a total disater too in terms of power drain. Ten hours of engine running to replace an hour of vaccuuming, roughly.

 

All this depends though on your alterator output and your battery bank capacity, and if tyou have any sort of klever alternator management device.

 

Mike

 

 

Put more simply, it's all about amp-hours. A single 20 watt light bulb run off a 12 volt battery bank will draw 1.7 amps per hour, so left on for four hours of an evening will represent almost 7 amp hours. Add three more of them and that's about 28 amp hours. Even a decent 12 volt fridge will represent say 25 amp hours a day, so a 70 amp alternator will need to run for getting on for an hour to put back what has just been consumed. That is an extremely simplistic view, but you get the gist.

 

Battery condition - at the very least, get a battery hydrometer - a fiver in Halfords - and check every cell of every battery. If one cell is below par (and the hydrometer will have a green and red zone to indicate this), the battery is knackered, and more importantly may have knackered the other batteries. Best advice seems to be replace all batteries at the same time.

 

 

I've never looked back since fitting a Sterlling Power Management Panel, which tells me what each of my alternators is doing in terms of volts and amps output, but - and this is important - also counts the amp-hours as I use them from the domestic battery bank, adding amp hours used and deducting amp/hours put back by the alternator.

Edited October 6, 2011 by homer2911

[homer2911]

Yep, the fridge is a MAJOR drain on your battery power. You'll prolly need to run the engine for three or four hours a day just to replenish the fridge drain. The vaccuum cleaner is a total disater too in terms of power drain. Ten hours of engine running to replace an hour of vaccuuming, roughly.

 

All this depends though on your alterator output and your battery bank capacity, and if tyou have any sort of klever alternator management device.

 

Mike

 

 

I may be wrong but:

 

 

A new Shoreline is reputed to consume 1.4 amps per hour, so a total of 34 amps in 24 hours. Why would it take three or four hours running of even a 70 amp alternator to replace that consumption?

 

Similarly, a 2000 watt vaccuum cleaner running off 240 volts would consume just over 8 amps per hour (and who vaccuums for an hour?). Even allowing for inverter losses, a 70 amp alternator run for half an hour would more than replace the power consumed in an hour by a vaccuum cleaner

 

Unless the battery bank is knackered of course.

[blodger]

I may be wrong but:

 

 

A new Shoreline is reputed to consume 1.4 amps per hour, so a total of 34 amps in 24 hours. Why would it take three or four hours running of even a 70 amp alternator to replace that consumption?

 

Similarly, a 2000 watt vaccuum cleaner running off 240 volts would consume just over 8 amps per hour (and who vaccuums for an hour?). Even allowing for inverter losses, a 70 amp alternator run for half an hour would more than replace the power consumed in an hour by a vaccuum cleaner

 

Unless the battery bank is knackered of course.

Most do not have a new Shoreline and the older models consume at least double and, a 70amp alt does not give 70 amp if there is residual charge in the batts and unless pulleyed and driven at the optimum speed plus you have to put back roughly 50% more than taken out due to inherent inefficiencies plus you are still consuming and, as batt volt climbs the alt clamps down the amps even more so three hours is pretty conservative.

 

Your 2000w hoover is using 12v amps from the inverter, 12 into 2000 is roughly 160 amps so 1/2 an hour is 80 ah to put back in; My guess would be about 4 hrs to get back up to say 95% SOC but leaving the batts worse

Edited October 7, 2011 by blodger

[Alan de Enfield]

 

...........Similarly, a 2000 watt vaccuum cleaner running off 240 volts would consume just over 8 amps per hour

 

Correct - if it was running off a mains supply - however if it is running off an inverter the inverter will be drawing 200 AMPS (approx) from the batteries to supply the 8 amps at 220 volts.

Thats going to take 3 hours to replace (if it is a 70 amp alternator, if its - say - a 45 amp alternator its going to be 4 hours +)

 

Blodger beat me to it & got his fingers going whilst I was slowly typing !!!!!

Edited October 7, 2011 by Alan de Enfield

[WotEver]

A new Shoreline is reputed to consume 1.4 amps per hour, so a total of 34 amps in 24 hours. Why would it take three or four hours running of even a 70 amp alternator to replace that consumption?

Because the charge curve isn't flat. The last 10% of battery capacity takes hours and hours to replenish.

 

Similarly, a 2000 watt vaccuum cleaner running off 240 volts would consume just over 8 amps per hour (and who vaccuums for an hour?).

A 2kW 240V appliance will take approximately 200Ah from a 12V battery bank in an hour.

 

Even allowing for inverter losses, a 70 amp alternator run for half an hour would more than replace the power consumed in an hour by a vaccuum cleaner

Not even close.

 

Tony

 

oh well, better late than never

Edited October 7, 2011 by WotEver

[AJLintern]

I guess it's better to get batteries which aren't the sealed type so you can maintain them properly, topping up electrolyte etc?

[WotEver]

I guess it's better to get batteries which aren't the sealed type so you can maintain them properly, topping up electrolyte etc?

Not necessarily. If you monitor and charge them correctly then the electrolyte is unlikely to ever need topping up.

 

If you're unsure how to (or simply can't be arsed to) determine your bank's state of charge from voltages and current flow then the simplest solution is to fit a SmartGauge. A quick glance will inform you whether you're anywhere near the 100% charge state that you thought you were at.

 

Tony

[homer2911]

Because the charge curve isn't flat. The last 10% of battery capacity takes hours and hours to replenish.

 

 

A 2kW 240V appliance will take approximately 200Ah from a 12V battery bank in an hour.

 

 

Not even close.

 

Tony

 

oh well, better late than never

 

 

I said I might be wrong! Thank you. for the clarification