Jump to content

Featured Posts

Came back to the boat yesterday in the hope that we could get out for a short trip. 

 

We've never left the boat this long without running the engine before. Starter battery was new in March last year.

While we've been in the marina the domestic batteries have been kept on charge, unfortunately not the starter. Result: domestic 13.3V (will drop when I disconnect), starter 11.7V. 

 

Starter turns the engine over but doesn't have enough oomph to start it.

 

Is it a good idea to use a jump lead from the domestic bank to the starter? What are the possible problems with this approach? In particular is there a danger of causing damage to either alternator when the jump lead is disconnected?

Link to post
Share on other sites

I’ve done it a few times over the years without even thinking about it. Never caused a problem.

 

Alternatively, you could swap out the starter for one of the domestics and do it that way.

  • Greenie 1
Link to post
Share on other sites
4 minutes ago, George and Dragon said:

Came back to the boat yesterday in the hope that we could get out for a short trip. 

 

We've never left the boat this long without running the engine before. Starter battery was new in March last year.

While we've been in the marina the domestic batteries have been kept on charge, unfortunately not the starter. Result: domestic 13.3V (will drop when I disconnect), starter 11.7V. 

 

Starter turns the engine over but doesn't have enough oomph to start it.

 

Is it a good idea to use a jump lead from the domestic bank to the starter? What are the possible problems with this approach? In particular is there a danger of causing damage to either alternator when the jump lead is disconnected?

 

Did it once with no adverse effects. I don't think it's recommended  that you do it often or routinely but occasionally would normally be OK.

Link to post
Share on other sites

It will depend upon the domestic battery technology to a degree but as it seems most so-called leisure batteries are very similar construction wise to start batteries they should cope admirable, especially as you are sharing the load between more than one. I am not sure I would be so happy to try it with expensive, sealed deep cycle batteries though.

  • Greenie 1
Link to post
Share on other sites
32 minutes ago, Tony Brooks said:

It will depend upon the domestic battery technology to a degree but as it seems most so-called leisure batteries are very similar construction wise to start batteries they should cope admirable, especially as you are sharing the load between more than one. I am not sure I would be so happy to try it with expensive, sealed deep cycle batteries though.

People seem to be happy with their expensive sealed deep cycle batteries providing the 300 odd amps  needed to feed a 3 kVA  inverter at full output though. That, I think,  is a similar load to most modern automotive or plant derived engine starters. Not as much as a fully loaded BS5 or 6 though.

 

On that basis I can see no real risk in an infrequent  jump start from the domestics especially when, as in this case the OP says they are fully  charged.  The couple of Ah needed are going to come straight off the surface of the plates.

The OP will need a new start battery though as it is not likely to recover its full cold starting capacity after a spell at 11.7 V. 

 

N

 

  • Greenie 1
Link to post
Share on other sites

I hope I don't have to do that again! Various parts of my body complained about the things I was asking them to do. 

 

Thanks to everyone who replied. We'll leave the engine running for a good long time in the hope that the starter battery can recover some capacity. I asked Barras' advice about what to get on the basis that the boat might be left 3 months without the engine running, the fact it's been 6 months can't have helped though.

 

My only worries now are whether it was a mistake to start the engine with the domestic supply switched off and why was there no water in the coolant header tank.

Link to post
Share on other sites

Leave the jump lead connected when you go home.  That way your battery charger will keep the starter battery  topped up at the same time as the domestics.

 

If you are feeling flush, consider getting a two output battery charger.

N

Link to post
Share on other sites

Another option would be to get a small, 20W or so solar panel and connect it to the engine battery. No need for a charge controller with such a small panel. Will keep the starter batt trickle charged in the weak winter sunshine. A two output battery charger, or a second small mains trickle charger for the start batt would also do the trick, if you are on a shore lead much of the time.

Have had to do the jump leads from the house to engine battery thing once to get going after the engine battery died.

Is there anything connected to the engine battery all the time per chance, excluding the engine alternator? For example, a volt meter? Something that is drawing only a few milliamps can easily drain a starter battery if left connected for months. If there is, then move them down stream of the ignition key switch, so they only come on when the key is turned.

Is there an auto bilge pump connected to the start battery, rather than the house one? If this has run a few times over the winter, again it could have drained the battery, if there is nothing to recharge it.

Jen

Edited by Jen-in-Wellies
  • Greenie 1
Link to post
Share on other sites

I fitted a 10 watt solar panel without a charge controller,because that was the advice I received.

Went to the boat one day and the carbon monoxide alarm was going off.

Everything was switched off and after a bit of investigation found the battery gassing and registering 16.4 volts!

Even a small solar panel will keep charging regardless of the state of the battery.

Fitted a cheap (£7-50) controller and no further problems.Plus it's got two USB sockets on it,so I can charge my phone and electric cig at the same time.

 

  • Greenie 1
Link to post
Share on other sites

 

 

When leaving the boat for an extended time I link the starter batteries to the domestic bank via a Jump-Lead. This means that the solar can keep all of the batteries topped up.

  • Greenie 1
Link to post
Share on other sites
1 hour ago, Alan de Enfield said:

 

 

When leaving the boat for an extended time I link the starter batteries to the domestic bank via a Jump-Lead. This means that the solar can keep all of the batteries topped up.

Good advice . . .

Link to post
Share on other sites
7 minutes ago, NB Alnwick said:

Good advice . . .

 

1 hour ago, Alan de Enfield said:

 

 

When leaving the boat for an extended time I link the starter batteries to the domestic bank via a Jump-Lead. This means that the solar can keep all of the batteries topped up.

Now that would bother me. Leaving batteries connected by crocodile clips

Link to post
Share on other sites
2 minutes ago, ditchcrawler said:

 

Now that would bother me. Leaving batteries connected by crocodile clips

 

That's an advantage of single alternator boats. Do charge splitting with a VSR and solar will charge both banks. I think  would fit one to a twin alternator boat for the same effect and you would only need a single output charger.

Link to post
Share on other sites
20 minutes ago, ditchcrawler said:

 

Now that would bother me. Leaving batteries connected by crocodile clips

 

There is only a low current flowing (10 amps ?) so using big proper (strong springs) jump leads I happy they are not going to jump off.

Link to post
Share on other sites

I just have a VSR fitted, connects when on solar, when the charger is on and when the engine is running it parallels the alternators increasing the charge rate to the domestics.

https://www.durite.co.uk/itm/55875/Voltage-Sensitive-Relay/12V-Voltage-Sensitive-Relay-140A/072733

3 wires to fit it  cost about £40

Saves a lot of faffing about

 

Link to post
Share on other sites
37 minutes ago, Loddon said:

I just have a VSR fitted, connects when on solar, when the charger is on and when the engine is running it parallels the alternators increasing the charge rate to the domestics.

https://www.durite.co.uk/itm/55875/Voltage-Sensitive-Relay/12V-Voltage-Sensitive-Relay-140A/072733

3 wires to fit it  cost about £40

Saves a lot of faffing about

 

 

We just fitted one to replace a split charge relay that had gone faulty. We had several people whose advice we trust suggest it was the way to go. 

 

Our problem wasn't a flat starter battery but rather intermittent lack of charging on the domestic bank. 

Link to post
Share on other sites

A modern smart auto charger will have a program for restoring a battery, I think it takes a while, then I ran the same program after a few days, and this time it took about four hours.

Link to post
Share on other sites
8 hours ago, LadyG said:

A modern smart auto charger will have a program for restoring a battery, I think it takes a while, then I ran the same program after a few days, and this time it took about four hours.

 

I know that is what the blurb claims but the question is does it actually work and how does it work. A number of years ago this type of battery conditioning (pulses) was discussed on this forum. I looked for independent research and found two papers. One German and one Australian. One said it worked and one said it did not. Gibbo who was working intensively on  batteries said he had tested some units with mixed results. The results of using such devices  had result t hat seemed to be random were between apparently working as stated, apparently doing nothing and destroying the battery. I doubt use for such a short time would do much damage but keeping the batteries fully charged as often as possible is likely to give a better battery life.

 

If it works for you then that is good whether its  a real result or psychological one but i would not recommend a charger based on that claim.

  • Greenie 2
Link to post
Share on other sites

Very slightly off-topic - does anyone here use an Adverc battery management system? We have a fairly sophisticated charger installed for charging when connected to the mains and an Adverc for controlling the charge from our CAV AC5R alternator. Our boat has 24v electrics and when charging from the alternator the Adverc will cycle with higher voltage spikes for brief periods. The charge voltage is affected by battery temperature which is monitored by the Adverc and during very cold weather this higher voltage can be as much as 29 volts - 20% higher than the nominal battery voltage of 24v.

We recently had a problem with our starter batteries when they became completely dry. However, this was my fault because, having replaced the domestic bank with maintenance-free batteries, I failed to pay the required attention to the starter batteries. The starter batteries on 'Alnwick' take some punishment because they usually provide enough grunt to spin-up our Kelvin K3 on full compression and then get recharged fully. Normally, they would have been inspected and topped up with de-ionised water every week but during three years of an enforced lack of boating activity, I completely neglected this essential maintenance. Having said that I am wondering if the cyclic high voltage spikes from the Adverc may have exacerbated the failure of our starter batteries?

Link to post
Share on other sites

I had one in use until I fitted an alternator regulated at 14.6 volts and then I felt it not worth the effort modifying the new alternator. In theory the 15 to 20 minute higher voltage "pulse" is intended to last long enough to do some good but stop as the batteries would start to gas so on that score it should not have depleted the electrolyte - but. I tend towards the starter battery having partial internal shorts that do cause excess gassing at normal charging voltages but not bad enough to cause da to day noticeable problems. Then they got worse.

 

Not sure if this helps or goes any way to giving you answers.

Link to post
Share on other sites
15 hours ago, LadyG said:

A modern smart auto charger will have a program for restoring a battery, I think it takes a while, then I ran the same program after a few days, and this time it took about four hours.

But you need to have something to plug it into

Link to post
Share on other sites
5 minutes ago, ditchcrawler said:

But you need to have something to plug it into

 

 

Your Inverter ?

 

 

Smiley added :

 

 

 

 

happy-smiley-face.png

Edited by Alan de Enfield
Link to post
Share on other sites
3 minutes ago, Alan de Enfield said:

 

 

Your Inverter ?

 

Please, don't, or at least not without a smiley. I am convinced that some on here would take that as a  recommendation.

Link to post
Share on other sites

No internet at bridge 39 on the Leicester Line :( so I've no idea what other suggestions have been made.

 

Ran the engine for 5.7 hours according to the hour counter (there's a word for that other than clock, surely). Domestics at 12.6V but with load being drawn so it looks like I was worrying needlessly about the circuit being off when I started the engine, starter at 12.9V 100 minutes after switching off.

 

All looking good for now :) 

 

Update: 12.8V after 14 hours. Engine started first time.

 

 

Link to post
Share on other sites
On 09/05/2021 at 14:20, BEngo said:

Leave the jump lead connected when you go home.  That way your battery charger will keep the starter battery  topped up at the same time as the domestics.

 

I don't really like the jump lead very much. Sparks when connecting, difficult to see that you've got it securely connected and in the event it jumps off there's a 12V cable lying around waiting to connect to any other metalwork. I might put a 6mm cable between the positives of the two batteries with an automatic isolator so it can't connect when the ignition is switched on or a N/O contact that only closes when on shore power. Or some variation.

 

On 09/05/2021 at 14:33, Jen-in-Wellies said:

Is there anything connected to the engine battery all the time per chance, excluding the engine alternator? For example, a volt meter? Something that is drawing only a few milliamps can easily drain a starter battery if left connected for months. If there is, then move them down stream of the ignition key switch, so they only come on when the key is turned.

Is there an auto bilge pump connected to the start battery, rather than the house one? If this has run a few times over the winter, again it could have drained the battery, if there is nothing to recharge it.

 

Only the bilge pump, and judging by the amount of water I pumped out once the engine was running, I need to check that the float switch is working.

 

On 09/05/2021 at 14:33, Jen-in-Wellies said:

Another option would be to get a small, 20W or so solar panel and connect it to the engine battery. No need for a charge controller with such a small panel. Will keep the starter batt trickle charged in the weak winter sunshine.

 

On 09/05/2021 at 16:34, Mad Harold said:

I fitted a 10 watt solar panel without a charge controller,because that was the advice I received.

Went to the boat one day and the carbon monoxide alarm was going off.

Everything was switched off and after a bit of investigation found the battery gassing and registering 16.4 volts!

Even a small solar panel will keep charging regardless of the state of the battery.

Fitted a cheap (£7-50) controller and no further problems.Plus it's got two USB sockets on it,so I can charge my phone and electric cig at the same time.

 

Thank you both. I'll consider that too.

 

21 hours ago, Tony Brooks said:

 

That's an advantage of single alternator boats. Do charge splitting with a VSR and solar will charge both banks. I think  would fit one to a twin alternator boat for the same effect and you would only need a single output charger.

 

21 hours ago, Loddon said:

I just have a VSR fitted, connects when on solar, when the charger is on and when the engine is running it parallels the alternators increasing the charge rate to the domestics.

https://www.durite.co.uk/itm/55875/Voltage-Sensitive-Relay/12V-Voltage-Sensitive-Relay-140A/072733

3 wires to fit it  cost about £40

Saves a lot of faffing about

 

I don't know anything about VSRs. Will have to read up on them.

I did once have a split charge box that was supposed to allow you to charge both a leisure and starter battery from a single alternator. Never got as far as fitting it. 

 

I think I'd better check the electrolyte levels next week when we go back. 

Many thanks for everyone's input.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.