MEP Emergency Jump Starting

gatorbob

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Hello,

I realize there are many threads about jump starting a MEP but I haven't quite found what I am looking for and would appreciate some opinions. Although I have a battery charging solution via the NATO slave port, I am trying to solve for the problem where you're in a power out situation and the batteries are dead.

My understanding is there are a few solutions.

1 - You can buy an expensive 24V jump starter ($400+) but would need long enough cables to reach one terminal on both batteries. I guess you could cut the clamps off the jump starter and install a NATO slave connector.

2 - I happen to have a set of spare batteries. I was thinking it might be cheaper but just as effective to get some battery boxes, cable them in a series, and wire up a NATO connector. Some quick disconnect connectors at the battery boxes might make it easier to store/move and then connect near the generator.

3 - Use another 24V system although I don't have a 24V vehicle.

4 - I do not know if a pair of portable lithium ion 12V jump starters can be wired in a series and still work correctly. I don't understand the electronics in these things, if that's even applicable. I assume I'd still have to reach one terminal on each battery or wire in a NATO connector. This might be the lowest cost solution.

FWIW, and please correct me, I believe you can't connect a separate 12V jump starter to each battery independently while still having the interconnection cable connected between the MEP batteries.

Am I on track or off base here?

Thanks
 

zanther

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You might be complicating it too much. Knowing this is only for when you don't have shore power AND your MEP is dead, is a pretty low likely scenario.

I suggest you grab 2 sets of cheap jumper cables and keep your extra batteries on a maintenance charger. Then if you don't want to swap batteries out, you could connect the extra batteries in parallel to each of the MEP batteries without having to pull the dead ones out.

You can connect a 12v source to each battery while they're linked together; I do it with a dual bank charger for constant battery maintenance on my 803. I haven't tried the dual jump starter setup to see if it'd work mostly becuase the only time I needed to jump start my MEP, one of my batteries was so dead it wouldn't recover even using my NOCO genius charger. I ended up replacing that one battery.

for option #2, that's essentially all #1 is. I have a couple of jump packs that are fancy, ie small lithium high capacity batteries that I got specifically for size. NATO plugs get expensive so be warned !

Edit: If you aren't starting your MEP on a schedule to ensure it's always ready to go, get on one! Once a month is the general recommendation; I find that unrealistic for me to hit each month, we've got a 7 month old baby, I've often so sleep deprived I can't think well enough to cook let alone worry about maintenance on my MEP. I do have it on my list of monthly PM"s (I set a Outlook calendar reminder) but also know that if I skip a month, it's still likely to be okay as long as I hit the next month. If you don't have your MEP on a maintenance charger, I suggest investing in one. I happen to like the dual bank NOCO but it is spendy.
 
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gatorbob

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You're probably right on making it too complicated. It almost happened to me and it was concerning I didn't have a good solution. My batteries were dead right as a hurricane was possibly heading my way. The real issue is that my battery charger just took much longer than expected and it could have been a problem.

Thanks for correcting me on connecting 2x12V sources to each battery while linked. It's one of those things I thought I read but did not remember the context.

Thanks
 

Bmxenbrett

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Yes you can use two separate 12v jumper boxes. There just taking place of what your batteries should be doing.

Also no need to reach around the set with cables. The starter side has a power wire at the starter and ground a nut/bolt on the chassis.

Thinking outside the box a bit you could connect two batterys + to - with a pair or two of vise grips and only need one set of jumper cables. You can make a buss bar to connect the + to - between the batteries with almost anything metal and a set of vise grips to hold it tight. I wouldnt do this unless i had to.
 

Light in the Dark

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Did you just hook the ring terminals up to each bolt on the factory cable connectors on each battery, or are you running battery post adapters?
 

Light in the Dark

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For those that run these battery tenders/chargers, do you disconnect them before running? or because of their nature are they OK to leave in place as is?
 

zanther

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This particular model doesn't have the quick connects, the Rings are hardwired in. I put them between the nut and the connector shoulder on mine.
 

zanther

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I leave mine connected becuase it's not easy to disconnect, no disconnects as mentioned in my other post. I bet I could find the manual to confirm but haven't had a problem and the charger designed to be permanently mounted wherever you're installing.
 

rhurey

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The more percise question that seems important is:

Do you leave the charger plugged into 120V when starting and running?

(120 will be available for test starts, and may be available while running based on what's being backed up...)
Personally, I've left the charger plugged in, but try and remember to remove it....
 

Bmxenbrett

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Im going to give the Pro Mariner ProSport 8 43008 a try when i get to that point. There about $80-100 and 12/24v with dual bank charging

I have a older Pro Mariner sport charger that lived outside on a trailer for most of the first part of its life. Now its permidently plugged in and rotated between batterys in my basement. Its been down there about 3 yrs.
 

Light in the Dark

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I will share my install this weekend... been putting off doing something like this. Thanks, Santa.
 

csheath

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I'm thinking two cars should do it.

I run mine monthly but that doesn't mean it will always start when I need it.

I finally figured out my solar charge controller was actually creating a draw as was the original MIL controller that came on it. I just attached my solar panel directly to the batteries and it has remained charged since. Seems every solar maintainer I have the controller has failed on so I have all of them direct connected to the batteries now. The panel on the generator is only 20 watts so little likelihood of over charging.
 

Demoh

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FWIW I have had a few times where ive had to jump a mep where grid wasnt available and batteries were dead beyond repair. Ive done it a dozen times.

Since I dont own a gasoline vehicle all of my vehicles have 2 batteries. Ive gotten very efficient of disconnecting 1 battery and wiring it in series with the vehicle so the vehicle still has 12v from battery A and doesnt know battery B exists anymore, but I get 24V from the 2 in series to my slave jumper cable.

I was doing this often enough going out into the woods and needing to run the MEP that I was going to install a huge rotary switch which will isolate then reconnect the batteries of my truck which essentially changes the anderson connectors that I have on my truck from 12V to 24V.

I may actually still do that since I foresee me continuing to need 24v in the field for my non-mep work. I just need to find a switch with high enough rating in the proper configuration. On a normal day Ill run a diesel engine starter for that has no batteries for an air compressor through my cables, so full starting current is required through everything in that system, switch included. I wont be making or breaking connections under load so the switch doesnt need that kind of rating, only a high 1000A+ 'while connected' rating. (why maintain batteries or even spin an alternator if theres nothing electric except a starter, and the vehicle towing it already has a 12v system? btw its some backwoods hack of an air compressor, but it cost me a few thousand, not 10-15K like a proper unit. 4bd1t in the place of a 80hp electric motor of an old IR rotary)
 
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Light in the Dark

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I leave mine connected becuase it's not easy to disconnect, no disconnects as mentioned in my other post. I bet I could find the manual to confirm but haven't had a problem and the charger designed to be permanently mounted wherever you're installing.
Spoke with the manufacturer today. On this model it is fine to keep all hooked up and run, but its imperative to unplug the charging device or it may cause an overvoltage situation (where its trying to charge the battery, while the alternator is trying to as well...).
 

zanther

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That's good to know. I like to plan for forgetting things, I wonder if I can work up a simple relay to break the connection from house power when it detects the generator is running.
 

Bmxenbrett

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These chargers now are not just transformers. Leaving them connected while you run the generator durring load test or real run most likely wont do anything.

If the charger is still supplied power your batterys will be charging higher than the charger would turn on.

If the power is out it wont supply 120v back through the charger.

Its not something i would put any more effort into than plugging it in and connecting to the batteries.
 

Farmitall

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That's good to know. I like to plan for forgetting things, I wonder if I can work up a simple relay to break the connection from house power when it detects the generator is running.
Sure you can.

Probably easier and cheaper to break the low voltage/low current DC charger output connection than house power.
 
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