urgent battery question

[viago]

arrived at my boat and all was well, after a couple of days cabin lights started to dim.

the battery is charged with a tiny solar panel and never had a problem before.

checked leisure battery and reading 20.3v

engine wouldn't start, turning slowly. checked engine battery, reading 22.7v

lifting out monday morning and need to move boat.

do i try to discharge batteries to 12v?

should the batteries fall between the boat and pontoon when transferring them, would that be for the best?

 

[VicS]

arrived at my boat and all was well, after a couple of days cabin lights started to dim.

the battery is charged with a tiny solar panel and never had a problem before.

checked leisure battery and reading 20.3v

engine wouldn't start, turning slowly. checked engine battery, reading 22.7v

lifting out monday morning and need to move boat.

do i try to discharge batteries to 12v?

should the batteries fall between the boat and pontoon when transferring them, would that be for the best?

If you have a 12 volt system then the readings of 20-22 volts look more like the open circuit volts of the solar panel....... and I guess it has become disconnected and is no longer, as a result, charging your batteries


Find the reason for the disconnection and get it reconnected to the engine start battery at least and hope it recharges before Monday


OR do you actually have a 24 volt system ?

 

[Tim Good]

Exactly what VicS said above. The panels will create that sort of voltage on their own so if not connected to you batteries then they will out put around 20v. If you disconnect the Solar panel and put a volt meter directly to the battery and its still 20 odd volts then you have a 24 V system. If it is 24v then as you can see below, both you batteries are basically empty. However, I can't imagine you thought you had a 12v system if it is 24v... so i think the most likely issue is the open circuit voltage of you panels as VicS Said.

 

[viago]

If you have a 12 volt system then the readings of 20-22 volts look more like the open circuit volts of the solar panel....... and I guess it has become disconnected and is no longer, as a result, charging your batteries


Find the reason for the disconnection and get it reconnected to the engine start battery at least and hope it recharges before Monday


OR do you actually have a 24 volt system ?

no. i disconnected the charging panel immediately and prior to checking voltage. i also disconnected the terminals prior to testing.

the cabin bulbs are 12v. both batteries are 12v 110ah which does seem a bit strange. still usually starts first time, even without the water turned on.

i'll go check again. perhaps i'm using the meter wrong.

 

[viago]

ok, i checked it all out again and using the v straight line instead of the v wavy line i'm getting 10.76v on the leisure and 10.99v on the starter.

now we get into proper lizard territory.
when i attach the the (new) 12a charger to the leisure battery it shows about a quarter charge but when i connect to the starter battery the dial goes straight to fully charged banging against the right hand edge.

any thoughts?

 

[halcyon]

ok, i checked it all out again and using the v straight line instead of the v wavy line i'm getting 10.76v on the leisure and 10.99v on the starter.

now we get into proper lizard territory.
when i attach the the (new) 12a charger to the leisure battery it shows about a quarter charge but when i connect to the starter battery the dial goes straight to fully charged banging against the right hand edge.

any thoughts?

Little solar panel has not been upto job, result sulphation from under charge thus over use. If service battery taking 10/12 amp may charge up ( looking at 8 hours to 14.4 volt ) so you can use as engine battery, engine sounds dead.

Brian

 

[VicS]

no. i disconnected the charging panel immediately and prior to checking voltage. i also disconnected the terminals prior to testing.

the cabin bulbs are 12v. both batteries are 12v 110ah which does seem a bit strange. still usually starts first time, even without the water turned on.

i'll go check again. perhaps i'm using the meter wrong.

ok, i checked it all out again and using the v straight line instead of the v wavy line i'm getting 10.76v on the leisure and 10.99v on the starter.

now we get into proper lizard territory.
when i attach the the (new) 12a charger to the leisure battery it shows about a quarter charge but when i connect to the starter battery the dial goes straight to fully charged banging against the right hand edge.

any thoughts?

You were using the AC volts range! (V~) Cant explain the readings you got, but I get similar on the AC volts range

The DC volts readings you now get indicate both batteries are just about dead flat!

I guess you charger is going full scale on the starter battery because it it showing current, not state of charge.

Leave it connected to the starter battery but check periodically that the battery is not getting too warm.

Disconnect and check the battery volts after 12 hours and try the starter. Continue charging if looking promising, but it may be completely dead

If you can get the starter battery charged you are home and dry If not charge the leisure battery and use that to start the engine.

You need to learn to use the equipment you have properly

You also need to discover why the cabin lights ran the starter battery down. That should not happen!

Also find out why the solar panel is not charging the batteries. Maybe as Brian suggests just too small

 

[Tim Good]

You also need to discover why the cabin lights ran the starter battery down. That should not happen!

Why do you say that? If he isn't on LEDs yet they easily could have done after a couple of days on the hook if you throw in an anchor light here and there and little or no engine usage, assuming the alternator is working and any engine usage would have done some charging.

 

[PaulRainbow]

Why do you say that? If he isn't on LEDs yet they easily could have done after a couple of days on the hook if you throw in an anchor light here and there and little or no engine usage, assuming the alternator is working and any engine usage would have done some charging.

He should not be running cabin lights from the engine battery.

 

[VicS]

Why do you say that? If he isn't on LEDs yet they easily could have done after a couple of days on the hook if you throw in an anchor light here and there and little or no engine usage, assuming the alternator is working and any engine usage would have done some charging.

Because the engine starter batter should be used only for that purpose. The alternator should charge it when the engine is running but then it should retain its charge and still be capable of starting the engine weeks if not months later .

Cabin lights, anchor lights, be they incandescents, fluorescents or LEDs, navigation equipment, infotainment systems and other domestic equipment should not draw any current from the engine starter battery. They should all be powered by the domestic ( leisure ??) battery

 

[Tim Good]

He should not be running cabin lights from the engine battery.

Quite right..... unless he has a 1/2/both battery selector and left it on both while away from the boat so the solar would charge everything and forgot to turn it back. I've made that mistake before but fortunately I have 360w of solar and LEDs.

 

[viago]

thanks for all the advice and sorry for being stupid.

went a wandering around vrsa looking for a battery shop. forgot where i parked the car and spent an hour and a half looking for it.
popped into intermarche on the way back to pick up some ice for the fridge and found they sell batteries. i bought the biggest they had 92ah 720a which should turn over a 17hp lump a few times.

i didn't try to start the engine when i arrived so unable to say whether the lights drained the engine battery but i assume not.

decided to take the bull by the horns and run up £100 on the credit card.

got the leisure battery on fast charge to get get it going then will trickle charge it overnight.

my solar panel has no info on it but it's about 12'' x 4'' the red clip it pegged on the positive terminal of the leisure battery and the black one on the starter earth. both batteries share a common earth controlled by a standard 0, 1, 2 or both switch.

 

[macd]

my solar panel has no info on it but it's about 12'' x 4''

Glad you found a solution. A doubt a panel that size would put out even 1A...handy to keep the batteries topped up on a mooring, but next to useless for cruising.

 

[VicS]

thanks for all the advice and sorry for being stupid.



my solar panel has no info on it but it's about 12'' x 4''

Glad you found a solution. A doubt a panel that size would put out even 1A...handy to keep the batteries topped up on a mooring, but next to useless for cruising.

Probably no more than 1.5watts, if that.

Expect a max charging current of around 0.1 amps ......... useless for anything other than maintaining a fully charged small car battery while parked.

 

[Hoolie]

my solar panel has no info on it but it's about 12'' x 4''

Our solar phone chargers are about that size, and they take quite a while to charge up ...