Battery Drain

SquirrellCook

Full Member
Just 200Wh for our last day. During the trip home a Sterling Inverter connected to the engine batteries charged the leisure batteries via a Victron charger. After a four and half hour drive in the dark everything was in the high 90's for state of charge.
I think being stationary for a few days is going to require some topping up with the generator.

And still no batteries from Battery Megastore!
 

SquirrellCook

Full Member
Today hooray! Two batteries arrived for Battery Megastore. One @12.74 volts and the other @12.75 volts.
Too be honest I don't think a battery guarantee is worth while.
For just the time spent dealing with them we could have earnt enough to buy four of them.
They will be going on charge this afternoon. I feel I should run a capacity test. But then life is for living and I've waisted enough time on this.
I'll fit them in a few days during the clean and stocking for the southern meet. It's much easier to do this at work as it has better resources.
 

wildebus

Full Member
Today hooray! Two batteries arrived for Battery Megastore. One @12.74 volts and the other @12.75 volts.
Too be honest I don't think a battery guarantee is worth while.
For just the time spent dealing with them we could have earnt enough to buy four of them.
They will be going on charge this afternoon. I feel I should run a capacity test. But then life is for living and I've waisted enough time on this.
I'll fit them in a few days during the clean and stocking for the southern meet. It's much easier to do this at work as it has better resources.
Well, you will have a full log of the batteries from the BMV so that will be a good indication of how they perform.
Would be worth resetting the BMV History to start the log with a clean sheet?
 

SquirrellCook

Full Member
Read or dreamt something about putting new batteries through a charge discharge cycle to improve their capacity. So each new battery got a charge and then 21 watt discharge for 15 hours. When charged again and after a day’s rest the voltage went from 12.9v to 13.1v. Anyways fitted now. Still showing an imbalance when charging, I’m thinking I need a new link cable. Also thinking my alternators regulator is set a bit high.
 

wildebus

Full Member
I can't see how a link cable can cause an imbalance? losses yes, but not an imbalance on a single series connection.
 

SquirrellCook

Full Member
I can't see how a link cable can cause an imbalance? losses yes, but not an imbalance on a single series connection.
Just fishing Dave, it's the only thing the two batteries have in common. I guess I can prove the idea by adding a temporary link wire in before removing the fitted link.
 

wildebus

Full Member
I think it will be just battery production variances - lead impurities and plate thickness variances and what have you. A battery balancer is the only way to really keep the batteries in charge sync.

I would be inclined to try one of these "HA01" balancers, from around £11.50 from HK/China to around £20 sourced from UK Stock.
 

SquirrellCook

Full Member
I replaced the alternator regulator last night. Volts dropped to 28 on a fast idle. Charged the batteries again with the Victron charger and then tried running the engine again. Seemed to be holding around 28 volts. Interestingly the lower the idle speed was set the higher the voltage. Managed to see 28.6 volts. So the next test was to turn on every thing I could find. Even using the sterling inverter to charge the habitation batteries. I never managed to load the alternator enough to take current from the engine start batteries. It will be interesting to see the engine batteries after the trip to Hereford.
 

wildebus

Full Member
Just fishing Dave, it's the only thing the two batteries have in common. I guess I can prove the idea by adding a temporary link wire in before removing the fitted link.
Just had a thought on your battery imbalance and the battery link which I had not considered before ....
When you are measuring your battery voltages to compare the two, are you measuring at the battery terminals of each battery? or are you measuring from the same mid-point location (like the BMV mid-point connection would do)?
If you did have a poor battery link and you used a common mid-point for measuring at one of the terminals, then you would get an apparent inbalance between the two even though they may be actually exactly the same. If you have the common point, it would be interesting to move the midpoint connection to the other side of the link and see if the battery voltage difference is reversed?
A poor link would not affect how the two batteries work together but could affect the reported measurements - and a battery balancer could actually by attempting to balance an already balanced battery take them out of balance! (I guess ideally you need the midpoint connection to be the midpoint in the link cable. maybe cut a slit in the insulation and solder a fly-wire to tap onto?)
 

SquirrellCook

Full Member
(I guess ideally you need the midpoint connection to be the midpoint in the link cable. maybe cut a slit in the insulation and solder a fly-wire to tap onto?)
Makes a lot of sense Dave. My link cable is not the prettiest, so it would be a good idea to replace and alter it. The imbalance only shows up towards the end of charge btw.
 

SquirrellCook

Full Member
Think the cable was around 3 inches long end to end?
Yes that would be the perfect answer. When I got Murky the link cable was seriously horrible. So I made a horrible cable with one end cut from a scrap car. For many years I have intended to replace it. Soon as the lid is shut, the memory of it goes away.
IMG_0845.JPG
 

SquirrellCook

Full Member
After one day and a little solar help all is good in the world. The generator is ran for 3 hours and the batteries are topped up. Next was to run for 2 days on batteries Solar was not as good and 3 hours charging was not enough. Three and a half hours drive home was not enough to get everything back to 100%. I guess the trick is not to drain them to much with limited charging resources.
 
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wildebus

Full Member
so an improvement though :)

Ref the generator use ... while the batteries are below around 70% charge (exact SOC will depend on batteries), the charger should work at 100%, but above that, the charge rate drops and drops so getting the final 10-15% of charge into a battery from a Generator becomes pretty inefficient (unless it is in use for other reasons of course :) )
 

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