More battery questions, R-27

W

wincrasher

Well-known member
Joined
Apr 3, 2013
Messages
110
Fluid Motion Model
C-28
Vessel Name
Tugtanic
MMSI Number
338209998
Does anyone know the cranking amps required for the D3-200 engine that is in the R-27?

I've seen posts indicating the AGM batteries supplied (if you got the upgrade) are 1000 A. This sounds more like a starting battery than a true deep cycle battery. Can anyone confirm the type of battery we have, and the crank amps?

I have 3 choices on my lithium project for the engine battery - 1) leave it as is. 2) use a spare lithium battery I have rated at 1000 A for 5 second. 3) use one of the new batteries that is only rated 400 A for 2 sec - could possibly use the parallel switch to get more amps if 400 is not enough (the battery's BMS electronically limts this).

The spare battery I have is a cylindrical type that I use with my trolling motor - it's a 100 AH. It just has a high CCA for some reason, but it's still a deep cycle battery. Charging requirements are the same as my new batteries.

Keeping the AGM for the engine battery would require some changes in the charging setup. Our ProMariner uses one profile for all banks.

I'm leery about depending on using the parallel switch for normal starting. defeats the purpose of having it. but I don't know for sure the engine won't crank on 400 A until I test it.
 
My R27 came with 4 ea UB 121100 AGM, 110 amp ea, group 31
 
I've found that the standard UB 121100's struggle to start the D4-260 in very cold weather. so I would er on the side of more cranking amps even for the slighlty more agile D3-200.. I dare say the factory will have the best advice though.
 
The safety record of lithium batteries has not improved enough to be used in an expensive boat simply as a hobby.
They burn up. They burn up spectacularly. They burn up without warning.
This is not me being alarmist. This is me having had lithium batteries (LiPo to be precise) go up in flames
(and you cannot put them out)
You might want to see how your insurance adjuster feels about your experiments.
 
Levitation":19hni62d said:
The safety record of lithium batteries has not improved enough to be used in an expensive boat simply as a hobby.
They burn up. They burn up spectacularly. They burn up without warning.
This is not me being alarmist. This is me having had lithium batteries (LiPo to be precise) go up in flames
(and you cannot put them out)
You might want to see how your insurance adjuster feels about your experiments.
Click to expand...

These are not lipo batteries. It's a different chemistry. They are LiFePO4 and do not get hot. Not even warm. They have a good history in marine use and RV use.
 
Cutwater28GG":w5rnkclq said:
I've found that the standard UB 121100's struggle to start the D4-260 in very cold weather. so I would er on the side of more cranking amps even for the slighlty more agile D3-200.. I dare say the factory will have the best advice though.
Click to expand...

I've been looking for any information that gives the requirements for the D3-200. I found one reference suggesting to use 2 group 24 batteries. That's it.
 
According to the technical data in the D3 Operators Manual: 2 connected parallelly 12V, max. 88Ah
Starting batteries or SLI (starting, lighting, ignition) are commonly used for starting and running engines. Generally speaking, deep cycle batteries can be utilized for starting as long as an allowance is made for the lower cranking amps comapared to a similar sized starting battery. If one is going to use a deep cycle battery for starting battery, it should be oversized by a factor of about 20%. The selection of an 110Ah AGM meets this requirement as 88Ah x 1.2= 105.6Ah. It generally takes less battery power to start and crank modern engines with electronic ignitions and fuel injection, so raw cranking amps are less important than they used to be. It will not hurt a deep cycle battery to be used as a starting battery, but for the same size battery they cannot supply as many cranking amps as a regular starting battery and are usually much more expensive.
 
That reference I was finding confusing. By saying connected parallel, I was thinking they are saying using two batteries - 88 ah each, for a total of 176 ah? It that was the requirement, then a single Group 31 would be woefully short, even if it was a starter battery and not deep cycle.

But I don't think the AH measurement really means anything in this case. It's the rapidity of the power delivery that is important - that's why starter batteries have a CCA measure - that tells you how much they can deliver instantly. When I looked up UB121100's, I got ratings all over the place - some were 535, and others all the way up to 1205.

But I don't know for certain. There really is no "danger" in trying this new battery and seeing how easily it starts - or doesn't. The new battery is even bigger at 125 ah.
 
There's a correlation, but not necessarily a conversion. CCA is like horsepower, and AH is like the size of your gas tank.
 
And the correlation between CCA and AH is not very good or consistent. Some AGM's are designed more with cranking in mind, and have a much higher ratio of CCA to AH. Most if not all Optima's, for instance. Others are designed more with deep cycle in mind, and offer less CCA relative to their AH capacity - Deka g31 AGM's, for instance.
 
snydzy":3o9427q2 said:
There's a correlation, but not necessarily a conversion. CCA is like horsepower, and AH is like the size of your gas tank.
Click to expand...

That is a very good analogy.
 
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