Mixed fortunes sort of day outt

[ColinR]

I always leave my battery disconnected when the boat is stored. Also rather than that expensive start kit just have a smaller spare battery that you keep charged at home and take with you when you go out

Dennis

That is certainly a good approach. Out battery is isolated every time we leave it but the battery is shot so that's the first step. Keeping a spare is a good solution, with some decent jump leads as well. Would be cheaper than a booster pack.

I might look into setting up a dual battery system with shore power so that I can fit a trickle charger to keep things topped up but that's a longer term project.

[betty boop]

Talking of battery jump packs.

Have you seen these?

https://www.toolstoday.co.uk/sealey-lit ... Gwod6lgKuQ

I saw one being used multiple times to start a bike at a show. Small enough to fit in a glove box and will also charge a phone etc.

interesting kit and worth a look at, esp as my £150 booster died after 1 year - not sure what the USB charge will be of use- if you're in the car/boat a lighter socket charger will do the same. may have a use in a camping/camper van sito though

[_Ed_]

Thing is with these starter packs is that whilst they can provide quite high currents, they often cannot do it for that long. The batteries in them don't actually store that much energy say 10-15Ah which would run a typical single headlight bulb for say 2-3 hours. A typical car battery 65-80ah would be more like 10-15~ hours, or a 110ah boat leisure battery around 20 hours. Also what is not mentioned is they are deeply affected by being cold. It could be that whilst a good car battery has enough to start cold one of these little things if left in the glove box may not.

Just FYI

[Matt13]

I've been relying on a solar panel this year as I do not have shore power. Worked ok last year but I think the battery is shot. It is 6 years old after all.

A second battery should do the trick but I may invest in a better booster as well. What make and model did you buy?

This one http://www.portablepowerpacks.co.uk/product/mr26-12hsp

Can't remember how much I paid wasn't as much as this but still expensive.

[annageek]

Talking of battery jump packs.

Have you seen these?

https://www.toolstoday.co.uk/sealey-lit ... Gwod6lgKuQ

I saw one being used multiple times to start a bike at a show. Small enough to fit in a glove box and will also charge a phone etc.

Up until very recently, I was working as the engineer for a battery design company, and had one of these things in to evaluate (as the company I worked for make high end battery jump packs) to see how they stack up. Based on my testing I wouldn't waste my money on these little things. Its basically a 3 series lithium polymer battery pack with no protection on the high current output. Build quality was actually really good, but from a safety/reliability point of view, the design is shocking! Jumping any engine with a battery that's gone high impedance would result in the alternator pumping loads of current back into this lithium battery at 60A or so. In theory it could take it, but there's no balancing (when charged from the high current output - especially at high rate) and you therefore run a very real risk of blowing the thing up due to one cell becoming rapidly over charged and going into thermal runaway. 50% of the time, you'll have a jump start pack that blows up (figuratively speaking) after a few uses and the other 50% of the time you'll have a jump start pack that blows up (literally!!) after a few uses.

In fairness though, the one I tried had really low internal impedance, and on our test rig I got a peak of about 450A with the voltage only dropping to about 8.0V... which is equivalent to a reasonably sized lead-acid equivalent.

[Gazjen]

Cheers for that. That does all make sense, they are supposed to have diodes in place to stop current going back to the battery but I've not personally tested one. I'd just put on my Christmas list

[annageek]

I have seen some with a 'chunk' in the little jump cable that comes supplied with them. I assume this is a load of chunky schottky diodes., but with them in, at typical engine start currents, I expect you'd get too much forward volt drop to make the pack effective.