Help a Newbie With Some Battery Problems (+LiFePO)

[senormechanico]

"There is no necessity to charge lithium at maximum rates, but it is an advantage".

No kidding.

I found that if I put a big load on my LiFePo4 200aH bank (for example, making a smoothie with the VitaMix) bringing batteries down to about 95% and then started the engine, the alternator belt would let me know IMMEDIATELY if it needed tightening (again).
I'm glad my solar setup normally takes care of all charging or I'd be broke from buying alternator belts.

[Toubab]

Thanks everyone!

I appreciate the advice but let's not make this a thread about the pros and cons of LiFePO batteries... There are already a few loooooong threads about that and I've read through them and pretty much made my decision. I'm still sifting through that info so I might change my mind but if I get a good charger that can handle lithiums, it should handle gels or whatever if I decide to go with something else... right?

As far as having duplicate charging sources, I don't quite get the drawbacks... I mean of course it's added cost and weight and all but if one fails you do run the RISK of the whole system failing but then if you only have one charger and it fails then the whole system will DEFINITELY fail... Or am I missing something? If it's just completely unnecessary then great, I'll save myself the money but I just wanna make sure I understand.

As far as inverter/chargers go, are there any that work like the smart chargers that can handle multiple banks with different chemistries? If so, wouldn't that be the way to go?

Thanks!

[ebaugh]

I don't know of an inverter charger that would handle multiple chemistries. But there may be one.

A low current charger (low cost), should handle the engine start bank OK if needed. For the moment, I just charge that bank off the engine.

[senormechanico]

Originally Posted by Toubab

Thanks everyone!

I appreciate the advice but let's not make this a thread about the pros and cons of LiFePO batteries... There are already a few loooooong threads about that and I've read through them and pretty much made my decision.

Aren't you the one who put LiFePo4 in your title to the thread?
I was just giving you some info to use when you graduate from your "learner's permit". Geez.

[chef2sail]

One thing most people forget in charging their batteries is the role the engine alternator plays in the equation. Some people buy gynormous house banks , large expensive 3 stage chargers, and keep their original small amp alternators. The difficulty here using that it runs forever to put the charge in the bank and burns out. Don't piece meal it, good batteries deserve good chargers, shore and alternators to maintain them, good monitor.

Keep your system simple. We have 6-6volt lifeline AGM for house bank Of 640 ah ( 320 usable) + blue topped odyssey start battery. 80 amp
Mastervolt three stage charger. Xantex echo to the starter, and 80 amp electromaxx alternator with temp sensor and smart regulator.

Dave

[s/v Holiday]

Originally Posted by chef2sail

One thing most people forget in charging their batteries is the role the engine alternator plays in the equation. Some people buy gynormous house banks , large expensive 3 stage chargers, and keep their original small amp alternators. The difficulty here using that it runs forever to put the charge in the bank and burns out. Don't piece meal it, good batteries deserve good chargers, shore and alternators to maintain them, good monitor.

Keep your system simple. We have 6-6volt lifeline AGM for house bank Of 640 ah ( 320 usable) + blue topped odyssey start battery. 80 amp
Mastervolt three stage charger. Xantex echo to the starter, and 80 amp electromaxx alternator with temp sensor and smart regulator.

Dave

Hi Dave,

How do you like your electromaax system? Did you get their serpentine belt system as well?

I am expecting delivery of my 160amp alternator system next week. So far I have only herd good things about Electromaax .

Thanks,

CJ

[MarkSF]

Originally Posted by Toubab

Hello everyone!

I have a somewhat selfish request to make... I'm basically a complete newbie to all things electrical and mechanical but I moved on to a sailboat a few months ago so I'm trying my best to learn as quick as possible. My problem right now is I was counting on the dated equipment on board to last me long enough for me to learn what I needed in order to replace and upgrade things but that's not working out. Several systems are having major problems and my 12.5 hour night shifts make doing the research tough and right now my head is spinning trying to figure out what to do with my batteries. I was hoping to throw myself on the mercy of the forums and see if someone could maybe just spell a few things out for me.

First thing... my house battery is shot... done. It's so dead that even plugged in to shore power it couldn't even run a few lights. I jerry-rigged my engine start battery to do double duty and that worked for a little while but now that battery is starting to do the same thing. Plugged in to shore power, I tried to turn on my water pump and everything on board went dark. No tripped circuits or anything, just as if someone pulled the plug. I just bought 2 Group 31 AGMs that I planned on using in parallel as a starting bank with a big reserve capacity. My thought was this would give me a good back up if my house bank dies while out on the water (as it did last week) and I need to do a quick ghetto rig to run lights and radio (as I did last week). Would there be any problem, theoretically, with using these to pull double duty as house and starting batteries until I get my actual house bank figured out?

I'm worried that there could be something wrong with my battery charger since the battery I've been using is now also starting to die, but that battery is also really old so I think it's pretty likely that that's the real issue. However, my boat did flood a good bit a few weeks ago (a story for another time) so it's possible that the charger got damaged then. I have a Sentry G120-3NL. I tried googleing to find a user's manual or something for it but was unsuccessful (I am stuck using my phone though...) Is there some way to check the charger and make sure it's working properly?

Next issue... I'm planning on replacing my house batteries with LiFePO and I've been reading all the info I can find on here about those and I think I'm just starting to get a handle on the fundamentals there. I'm trying now to figure out how much capacity I can fit and where I can fit it so I can start to price that out. I didn't get a chance to do a survey of my average power usage since I hadn't even gotten everything working before my house battery died. My goal is to eventually be able to live off-grid, so does anyone know of a good way to get at least a rough estimate of the capacity I'll need?

Then I obviously have some more research and work to do on how I'm gunna set up my LiFePO bank but I think there are a few fundamental things I need to figure out ASAP.

I don't think my current charger will be suitable for the LiFePOs so I've been thinking about how to replace it. My current best idea is to have 2 separate chargers, one for the LiFePO house bank and one for the AGM engine bank, and have shore power and the generator run both of them. That way, I can easily set up the charging regimes for the different chemistries, have some redundancy in case of emergency, and run the generator off the AGMs without worrying about running them down. (The generator was wired to run off the house batt before, which seemed silly to me...) Then I'd have the engine alternator also hooked up to the AGMs. Is there anything wrong/stupid with this idea? Would it cause a problem when I want to add solar/wind/whatever?

And then just something that's in my mind is that I'll also need to add an inverter at some point but I'm not sure if this is really an important consideration right now or not.

Sorry for the long post and especially for requesting the bit of spoon-feeding but it's been so hard to find info for complete beginners. The info I've found has been great but it really makes my head spin and for every question it answers I have 2-3 new ones!

Thanks so much!

Something can be jury-rigged, or jerry-built, but not jerry-rigged.

[chef2sail]

CJ ,

Did not go with the serpentine belt. Had I done the 100 amp or large one, that would have been necessary, but my tiny 3GMF while quite a workhorse couldn't fit a larger alternator. I love the electromax. Bought it on MaineSail's recommendation and comparisons with the Balmar series. I have been very happy with it. Especially see an output of 55 amps at idle and 74 at our crushing rpms of 2700. That coupled with the dual fans is why I went with the electromax.

Dave

[deckofficer]

I just bought (8) 100 a/hr LiFePO cells today with a 3 week lead time. I'll keep you posted on how I like them. $110 for each 3.2 volt single cell from Balqon - Advanced Transportation Solution

[Toubab]

Originally Posted by senormechanico

Aren't you the one who put LiFePo4 in your title to the thread?
I was just giving you some info to use when you graduate from your "learner's permit". Geez.

I didn't mean anything by it... sorry if I offended you. I just was trying to keep the thread on topic. I mentioned LiFePO in the title because I'm trying to keep that in mind as a future goal that any new purchases should be compatible with. I appreciate all the help and I'm gunna keep in mind that lithiums are not really "beginner" batteries, but beyond that there are other threads to discuss their pros and cons.

As far as I can tell my alternator is not hooked up to my house batteries at all. It looked like the alternator charged the engine batteries and the generator charged the house batt.

Is there a reason to have the alternator hooked up to house batteries too? Besides just having another back up charging source?

I want to make sure the engine batteries are being topped off by shore power and by the generator so I can start the generator with them and not the house batt. Is there a reason to have the generator start from the house bank? It seems silly since if I accidentally run the house batt all the way down then how am I supposed to start the generator to charge them?

Originally Posted by MarkSF

Something can be jury-rigged, or jerry-built, but not jerry-rigged.

Did you need to quote my whole post? lol I was gunna say ghetto-rigged but thought I'd try to be a bit more PC... haha

[ebaugh]

You probably want the main engine alternator to charge the house batteries. If the physical space allows it, and the generator has an alternator (usually a really small one), I would combine the engine start and house banks to one large bank. Have a really good isolated start battery for the generator.

With this scenario, you maximize the house bank capacity. If you run it all the way down accidentally, you can start the generator and charge. Should you run it down and the generator won't start for a fuel or mechanical reason, have a way to move the engine start cable to the generator start battery. This means you need a good battery on the generator, I suggest a SLA/AGM that tends to hold a charge better then wet lead acid.

You can do this manually or with a 1/2/Both battery switch. Position 1 is engine to house, Position 2 is engine to generator start, the Both position combines the generator and house batteries. The Both position should only be used to get the generator going if the dedicated battery gets weak and won't start the generator.

Should the generator not have an alternator, some don't, I'd either have a trickle charge to the generator start from an aux charge connection found on some inverter chargers, or use a single engine start battery for both the main engine and generator. Add a battery combiner to link the start bank to house bank underway.

[chef2sail]

We have the engine alternator battery charging the large house bank with an echo charger from the house bank to the starting battery. Very likely the small amount of charge you take out of the tarting battery will require that your engine solely recharges that, while when you ate under way chances re that youll be drawing off your house bank for refrigeration instruments etc. this is also the reason I mentioned previously you will want to increase the alternators size to Martha larger house battery bank. Failure to do this when you increase the ah of our up use bank at lead to the alternator running all the time as well as overheating it thus reducing its life. As I mentioned before many people only look at improving their electrical capabilities by increasing the ah of the house bank and shore power charger and do not give enough thought to the engine charging system, thus piecemealing it. AGM like to be recharged fully. Your goal is to maximize their life and cycling as they are so expensive. Also remember that the total ah in your house bank should be cut in half for whats available to be used. You should do an ah diet (what your daily use in ah is for all your needs) ore yu redesign your whole system so it makes sense. Having a generator can be a big plus, but many also have passive ways of recharging such as wind or solar. With a generator it may not be necessary to have such a large ah house bank.

We have a 720 ah house bank (6- 6 volt lifeline AGM ) . Approximently 360 ah of usable. Our diet is 75 ah per day. Refrig takes up more than half of that, even after major insulation and improvement. We also have a small Odessey blue top starting battery. We can go at least 4days without any recharging of any means.

Take the time to think out your entire electrical system and then have at it is all I am saying.

Dave

[Pete7]

Originally Posted by Toubab

Is there a reason to have the alternator hooked up to house batteries too? Besides just having another back up charging source?

I want to make sure the engine batteries are being topped off by shore power and by the generator so I can start the generator with them and not the house batt. Is there a reason to have the generator start from the house bank? It seems silly since if I accidentally run the house batt all the way down then how am I supposed to start the generator to charge them?

I simply don't understand why you are trying to make it so complicated and I suspect this over complication is why it's all gone pear shaped.

One of the new 31s batteries for the engine that's it, no more no less, you simply don't need two, take the other one back and get a refund.

House bank, you already have a genny so spec and purchase a couple of new batteries totalling 250 - 300 AH and that's it. No more no less. Ditch the old ones they are knackered from the flood.

Once you have got a grip of your electrical system and worked out how much you use and therefore need as a house bank, then think about expanding.

You shouldn't charge the house bank with the engine on a regular basis because it doesn't do the engine any good and takes for ever. That said a VSR between them wouldn't hurt if you are doing a lot of motoring but it's extra wiring and an added complication so it can wait.

Pete

[chef2sail]

Pete,

How many boats have the ,alternators charging the house banks from the engines. I'll be it's a huge majority. That doesn't mean it's the only way, but it's stupid not to use that, especially if you motor at all. That being said with the correct alternator setup, it doesn't take forever as you put it.

You are right about overthinking this until he figures out his usage and needs. use every advantage you can to charge.

Dave

[Pete7]

Dave, I think the majority, either by a 1/2/off switch or a VSR. However, this boat has had a flood. Batteries knackered and the mains charger suspect. Wiring runs not documented.

What is needed is back to basics approach to make the boat liveable, so that's one engine battery and a couple of house batteries. A new mains charger and the genny wired to the house bank, though if he is sat in a marina then the mains charger is going to do the work.

Once on board and the daily loads calculated then there is the opportunity to build a tailor made system, but at the moment adding two engine start batteries whilst ignoring the dead house batteries, then wondering if the engine batteries can be used as house batteries is just going to end in tears and another trip to the battery shop with a fist full of dollars.

Pete