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Post by Deleted on Nov 22, 2018 11:49:11 GMT
Ok I know enough to know that is like asking how long is a piece of string, however just trying to get a feeling of whether my batteries are performing ok or not - I was expecting better...
Voltages taken from MPPT controller readout.
After cruising or running engine each day for a minimum of 4hrs, after an hour or so the battery is showing 12.6/12.7 volts (seems ok), by morning this has dropped to somewhere between 11.7 to 12.0 volts (not as good as I had expected).
Electric usage is 12v fridge, a couple of lights, 3 to 4 hrs laptop charging (although one night no charging to see what difference it made to the batteries - none), Bubble stove diesel pump and water circulation pump, water pump, inverter (turned off overnight).
Battery bank 4 x 110 amps.
Initially just looking for info as whether this seems ok or is something wrong.
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Post by Deleted on Nov 22, 2018 12:13:35 GMT
Ok I know enough to know that is like asking how long is a piece of string, however just trying to get a feeling of whether my batteries are performing ok or not - I was expecting better...
Voltages taken from MPPT controller readout.
After cruising or running engine each day for a minimum of 4hrs, after an hour or so the battery is showing 12.6/12.7 volts (seems ok), by morning this has dropped to somewhere between 11.7 to 12.0 volts (not as good as I had expected).
Electric usage is 12v fridge, a couple of lights, 3 to 4 hrs laptop charging (although one night no charging to see what difference it made to the batteries - none), Bubble stove diesel pump and water circulation pump, water pump, inverter (turned off overnight).
Battery bank 4 x 110 amps.
Initially just looking for info as whether this seems ok or is something wrong.
My experience is that unless lead acid based batteries can get a regular overnight trickle charge (for a lot more than 4 hours) , they will only last 1.5 to 2 years. Effectively you lose a little bit of the battery each time you can’t trickle charge it to near 100%. If you are regularly connected to a shore line you can do this. Solar panels will extend the life a bit. I suspect the 12v fridge is the main killer, we run ours on gas. That’s why if you are off line most of the time it’s probably best to go for the cheapest solution (unless you can afford lithium!). The best thing you can do is reduce your demand.
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Post by Deleted on Nov 22, 2018 12:22:55 GMT
Ok I know enough to know that is like asking how long is a piece of string, however just trying to get a feeling of whether my batteries are performing ok or not - I was expecting better...
Voltages taken from MPPT controller readout.
After cruising or running engine each day for a minimum of 4hrs, after an hour or so the battery is showing 12.6/12.7 volts (seems ok), by morning this has dropped to somewhere between 11.7 to 12.0 volts (not as good as I had expected).
Electric usage is 12v fridge, a couple of lights, 3 to 4 hrs laptop charging (although one night no charging to see what difference it made to the batteries - none), Bubble stove diesel pump and water circulation pump, water pump, inverter (turned off overnight).
Battery bank 4 x 110 amps.
Initially just looking for info as whether this seems ok or is something wrong.
My experience is that unless lead acid based batteries can get a regular overnight trickle charge (for a lot more than 4 hours) , they will only last 1.5 to 2 years. Effectively you lose a little bit of the battery each time you can’t trickle charge it to near 100%. If you are regularly connected to a shore line you can do this. Solar panels will extend the life a bit. I suspect the 12v fridge is the main killer, we run ours on gas. That’s why if you are off line most of the time it’s probably best to go for the cheapest solution (unless you can afford lithium!). The best thing you can do is reduce your demand. I thought a 12v fridge took about 50 amps per 24hrs was hoping to get a couple of days between charges then 3 or 4 hrs engine running for a top up, then a longer run to properly charge the batteries.
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Post by kris on Nov 22, 2018 12:27:05 GMT
Just turn the fridge off. Are the readings you gave with the batteries at rest or under load? If they are at rest then you batteries are on their last legs. Cutting the load will prolong their life.
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Post by Deleted on Nov 22, 2018 12:29:12 GMT
Just turn the fridge off. Are the readings you gave with the batteries at rest or under load? If they are at trest then you batteries are on their last legs. Cutting the last ad will prolong their life. Sorry numpty here, can you explain what at rest and under load means. Thanks
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Post by kris on Nov 22, 2018 12:30:51 GMT
At rest is with nothing switched on and under load is with things switched on
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Post by Jim on Nov 22, 2018 12:32:03 GMT
Is it a 12 vole compressor fridge? I presume so. I have a small waeco/now dometic, compressor fridge, uses 2ah ish. However what do you have in the fridge, if not using freezer, why not find and use a cold place on the boat for milk, butter and beer? I have a cupboard lined with insutlation - 5mm foam and reflective foil, air can circulate from the bilge, keeps milk etc fine in winter, maybe just buy smaller bottles, keep powdered milk for spare.
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Post by Deleted on Nov 22, 2018 12:34:20 GMT
Thanks Kris. Readings were taken under load. I'll check today/overnight with everything switched off.
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Post by kris on Nov 22, 2018 12:36:40 GMT
It's very difficult to get an accurate reading of a batteries state if there is a load or its being charged. As I say turning the fridge off will help them.
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Post by Deleted on Nov 22, 2018 12:39:44 GMT
Is it a 12 vole compressor fridge? I presume so. I have a small waeco/now dometic, compressor fridge, uses 2ah ish. However what do you have in the fridge, if not using freezer, why not find and use a cold place on the boat for milk, butter and beer? I have a cupboard lined with insutlation - 5mm foam and reflective foil, air can circulate from the bilge, keeps milk etc fine in winter, maybe just buy smaller bottles, keep powdered milk for spare. I can cope without a fridge but thought I wouldn't have to. This is as much about exploring what is reasonable/are the batteries knackered etc. No fridge in the winter is fine, but if I can run a fridge then I'd like to, if the only reason I can't is because the batteries are on their last legs then I can afford some news ones. Just trying to work out what I should expect.
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Post by Deleted on Nov 22, 2018 12:44:56 GMT
Is it a 12 vole compressor fridge? ? Good question. If it isn't and its a 3 way caravan type fridge its going to cane the batteries much more than a Dan Foss compressor type.
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Post by Deleted on Nov 22, 2018 12:49:03 GMT
Just 12 volts - I assume compressor - sounds like a normal fridge.
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Post by Deleted on Nov 22, 2018 13:14:11 GMT
I have two 110 batteries just for the fridge (actually they're for the bow thruster too, but we never use it).
I believe the fridge is the bug bear due to it's constant drain. Everything else (pumps etc) is fairly short bursts of use.
With separate fridge batteries I can pretty much forget about the usage of the other three service batteries.
Rog
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Post by Jim on Nov 22, 2018 13:20:18 GMT
I installed 135w solar with mppt controller, the old batteries didn't go above 12.8 resting state, I now get 13+ resting with a new set of batteries. When I fitted the new batteries I also replaced the cables, so all are the same length, running from + & - busbars. All the batteries then react equally to charge and drain. No doubt Telemachus our resident electrickery wizard and vole tamer will be along with the right answer in a bit.
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Post by Deleted on Nov 22, 2018 13:23:30 GMT
My experience is that unless lead acid based batteries can get a regular overnight trickle charge (for a lot more than 4 hours) , they will only last 1.5 to 2 years. Effectively you lose a little bit of the battery each time you can’t trickle charge it to near 100%. If you are regularly connected to a shore line you can do this. Solar panels will extend the life a bit. I suspect the 12v fridge is the main killer, we run ours on gas. That’s why if you are off line most of the time it’s probably best to go for the cheapest solution (unless you can afford lithium!). The best thing you can do is reduce your demand. I thought a 12v fridge took about 50 amps per 24hrs was hoping to get a couple of days between charges then 3 or 4 hrs engine running for a top up, then a longer run to properly charge the batteries. Yes, but you have to put a lot more into batteries than you take out. Although trickle charging for another 10 hours only puts a few extra amps back in, if you don’t do it, you lose that few percent for good. Your battery effectively gets smaller and smaller in capacity. How old are your batteries? How were they charged up by the previous owner? Depending on where you measure voltage you will see a voltage drop when you are using current from the battery (i.e the battery is under load)
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